doc: Convert telemetry and companion docs to asciidoc

Signed-off-by: Keith Packard <keithp@keithp.com>

6 files changed, 866 insertions, 1583 deletions

diff --git a/doc/companion-docinfo.xml b/doc/companion-docinfo.xml
new file mode 100644
index 00000000..2e0bc567
--- /dev/null
+++ b/doc/companion-docinfo.xml
@@ -0,0 +1,27 @@
+<subtitle>Protocol Definitions</subtitle>
+<author>
+  <firstname>Keith</firstname>
+  <surname>Packard</surname>
+  <email>keithp@keithp.com</email>
+</author>
+<date>13 January 2012</date>
+<copyright>
+  <year>2012</year>
+  <holder>Keith Packard</holder>
+</copyright>
+<legalnotice>
+  <para>
+    This document is released under the terms of the
+    <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
+      Creative Commons ShareAlike 3.0
+    </ulink>
+    license.
+  </para>
+</legalnotice>
+<revhistory>
+  <revision>
+    <revnumber>0.1</revnumber>
+    <date>13 January 2012</date>
+    <revremark>Initial content</revremark>
+  </revision>
+</revhistory>
diff --git a/doc/companion.txt b/doc/companion.txt
new file mode 100644
index 00000000..75ffa228
--- /dev/null
+++ b/doc/companion.txt
@@ -0,0 +1,241 @@
+= AltOS Companion Port
+:doctype: article
+:toc:
+
+== Companion Port
+
+	Many Altus Metrum products come with an eight pin Micro MaTch
+	connector, called the Companion Port. This is often used to
+	program devices using a programming cable. However, it can
+	also be used to connect TeleMetrum to external companion
+	boards (hence the name).
+
+	The Companion Port provides two different functions:
+      
+	* Power. Both battery-level and 3.3V regulated power are
+	  available. Note that the amount of regulated power is not
+	  huge; TeleMetrum contains a 150mA regulator and uses, at
+	  peak, about 120mA or so. For applications needing more than
+	  a few dozen mA, placing a separate regulator on them and
+	  using the battery for power is probably a good idea.
+
+	
+	* SPI. The flight computer operates as a SPI master, using
+	  a protocol defined in this document. Companion boards
+	  provide a matching SPI slave implementation which supplies
+	  telemetry information for the radio downlink during flight
+  
+== Companion SPI Protocol
+
+	The flight computer implements a SPI master communications
+	channel over the companion port, and uses this to get
+	information about a connected companion board and then to get
+	telemetry data for transmission during flight.
+
+	At startup time, the flight computer sends a setup request
+	packet, and the companion board returns a board identifier,
+	the desired telemetry update period and the number of data
+	channels provided. The flight computer doesn't interpret the
+	telemetry data at all, simply packing it up and sending it
+	over the link.  Telemetry packets are 32 bytes long, and
+	companion packets use 8 bytes as a header leaving room for a
+	maximum of 12 16-bit data values.
+
+	Because of the limits of the AVR processors used in the first
+	two companion boards, the SPI data rate is set to 187.5kbaud.
+
+== SPI Message Formats
+
+	This section first defines the command message format sent from
+	the flight computer to the companion board, and then the various
+	reply message formats for each type of command message.
+
+	.Companion Command Message
+	[options="border",cols="1,3,3,9"]
+	|====
+	|Offset
+	|Data Type
+	|Name
+	|Description
+
+	|0
+	|uint8_t
+	|command
+	|Command identifier
+
+	|1
+	|uint8_t
+	|flight_state
+	|Current flight computer state
+
+	|2
+	|uint16_t
+	|tick
+	|Flight computer clock (100 ticks/second)
+
+	|4
+	|uint16_t
+	|serial
+	|Flight computer serial number
+
+	|6
+	|uint16_t
+	|flight
+	|Flight number
+
+	|8
+	|
+	|
+	|
+	
+	|====  
+
+	.Companion Command Identifiers
+	[options="border",cols="1,3,9"]
+	|====
+	|Value
+	|Name
+	|Description
+
+	|1
+	|SETUP
+	|Supply the flight computer with companion
+	information
+
+	|2
+	|FETCH
+	|Return telemetry information
+
+	|3
+	|NOTIFY
+	|Tell companion board when flight state changes
+	|====
+
+	The flight computer will send a SETUP message shortly after
+	power-up and will then send FETCH messages no more often than
+	the rate specified in the SETUP reply. NOTIFY messages will be
+	sent whenever the flight state changes.
+
+	'flight_state' records the current state of the flight,
+	whether on the pad, under power, coasting to apogee or
+	descending on the drogue or main chute.
+
+	'tick' provides the current flight computer clock, which
+	be used to synchronize data recorded on the flight computer
+	with that recorded on the companion board in post-flight analysis.
+
+	'serial' is the product serial number of the flight computer,
+	'flight' is the flight sequence number. Together, these two
+	uniquely identify the flight and can be recorded with any
+	companion board data logging to associate the companion data
+	with the proper flight.
+
+	NOTIFY commands require no reply at all, they are used solely
+	to inform the companion board when the state of the flight, as
+	computed by the flight computer, changes. Companion boards can
+	use this to change data collection parameters, disabling data
+	logging until the flight starts and terminating it when the
+	flight ends.
+
+	=== SETUP reply message
+
+		.SETUP reply contents
+		[options="border",cols="1,3,3,9"]
+		|====
+		|Offset
+		|Data Type
+		|Name
+		|Description
+
+		|0
+		|uint16_t
+		|board_id
+		|Board identifier
+
+		|2
+		|uint16_t
+		|board_id_inverse
+		|~board_id—used to tell if a board is present
+
+		|4
+		|uint8_t
+		|update_period
+		|Minimum time (in 100Hz ticks) between FETCH commands
+
+		|5
+		|uint8_t
+		|channels
+		|Number of data channels to retrieve in FETCH command
+
+		|6
+		|
+		|
+		|
+		|====
+
+		The SETUP reply contains enough information to uniquely
+		identify the companion board to the end user as well as for
+		the flight computer to know how many data values to expect in
+		reply to a FETCH command, and how often to fetch that data.
+
+		To detect the presence of a companion board, the flight
+		computer checks to make sure that board_id_inverse is the
+		bit-wise inverse of board_id. Current companion boards use
+		USB product ID as the board_id, but the flight computer does
+		not interpret this data and so it can be any value.
+
+	=== FETCH reply message
+
+		.FETCH reply contents
+		[options="border",cols="1,3,3,9"]
+		|====
+		|Offset
+		|Data Type
+		|Name
+		|Description
+
+		|0
+		|uint16_t
+		|data0
+		|0th data item
+
+		|2
+		|uint16_t
+		|data1
+		|1st data item
+
+		|...
+		|
+		|
+		|
+		|====
+
+		The FETCH reply contains arbitrary data to be reported
+		over the flight computer telemetry link. The number of
+		16-bit data items must match the 'channels' value
+		provided in the SETUP reply message.
+  
+== History and Motivation
+
+	To allow cross-programming, the original TeleMetrum and
+	TeleDongle designs needed to include some kind of
+	connector. With that in place, adding the ability to connect
+	external cards to TeleMetrum was fairly simple. We set the
+	software piece of this puzzle aside until we had a companion
+	board to use.
+
+	The first companion board was TeleScience. Designed to collect
+	temperature data from the nose and fin of the airframe, the main
+	requirement for the companion port was that it be able to report
+	telemetry data during flight as a back-up in case the
+	TeleScience on-board data was lost.
+
+	The second companion board, TelePyro, provides 8 additional
+	channels for deployment, staging or other activities. To avoid
+	re-programming the TeleMetrum to use TelePyro, we decided to
+	provide enough information over the companion link for it to
+	independently control those channels.
+
+	Providing a standard, constant interface between the flight
+	computer and companion boards allows for the base flight
+	computer firmware to include support for companion boards.
diff --git a/doc/companion.xsl b/doc/companion.xsl
deleted file mode 100644
index 14e2194e..00000000
--- a/doc/companion.xsl
+++ /dev/null
@@ -1,353 +0,0 @@
-<?xml version="1.0" encoding="utf-8" ?>
-<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
-"/usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
-
-<article>
-  <articleinfo>
-    <title>AltOS Companion Port</title>
-    <subtitle>Protocol Definitions</subtitle>
-    <author>
-      <firstname>Keith</firstname>
-      <surname>Packard</surname>
-    </author>
-    <copyright>
-      <year>2012</year>
-      <holder>Keith Packard</holder>
-    </copyright>
-    <legalnotice>
-      <para>
-	This document is released under the terms of the
-	<ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
-	  Creative Commons ShareAlike 3.0
-	</ulink>
-	license.
-      </para>
-    </legalnotice>
-    <revhistory>
-      <revision>
-	<revnumber>0.1</revnumber>
-	<date>13 January 2012</date>
-	<revremark>Initial content</revremark>
-      </revision>
-    </revhistory>
-  </articleinfo>
-  <section>
-    <title>Companion Port</title>
-    <para>
-      Many Altus Metrum products come with an eight pin Micro MaTch
-      connector, called the Companion Port. This is often used to
-      program devices using a programming cable. However, it can also
-      be used to connect TeleMetrum to external companion boards
-      (hence the name).
-    </para>
-    <para>
-      The Companion Port provides two different functions:
-      <itemizedlist>
-	<listitem>
-	  <para>
-	  Power. Both battery-level and 3.3V regulated power are
-	  available. Note that the amount of regulated power is not
-	  huge; TeleMetrum contains a 150mA regulator and uses, at
-	  peak, about 120mA or so. For applications needing more than
-	  a few dozen mA, placing a separate regulator on them and
-	  using the battery for power is probably a good idea.
-	  </para>
-	</listitem>
-	<listitem>
-	  <para>
-	  SPI. The flight computer operates as a SPI master, using
-	  a protocol defined in this document. Companion boards
-	  provide a matching SPI slave implementation which supplies
-	  telemetry information for the radio downlink during flight
-	  </para>
-	</listitem>
-      </itemizedlist>
-    </para>
-  </section>
-  <section>
-    <title>Companion SPI Protocol</title>
-    <para>
-      The flight computer implements a SPI master communications
-      channel over the companion port, and uses this to get
-      information about a connected companion board and then to get
-      telemetry data for transmission during flight.
-    </para>
-    <para>
-      At startup time, the flight computer sends a setup request
-      packet, and the companion board returns a board identifier, the
-      desired telemetry update period and the number of data channels
-      provided. The flight computer doesn't interpret the telemetry
-      data at all, simply packing it up and sending it over the link.
-      Telemetry packets are 32 bytes long, and companion packets use 8
-      bytes as a header leaving room for a maximum of 12 16-bit data
-      values.
-    </para>
-    <para>
-      Because of the limits of the AVR processors used in the first
-      two companion boards, the SPI data rate is set to 187.5kbaud.
-    </para>
-  </section>
-  <section>
-    <title>SPI Message Formats</title>
-    <para>
-    This section first defines the command message format sent from
-    the flight computer to the companion board, and then the various
-    reply message formats for each type of command message.
-    </para>
-    <section>
-      <title>Command Message</title>
-      <table frame='all'>
-	<title>Companion Command Message</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0</entry>
-	      <entry>uint8_t</entry>
-	      <entry>command</entry>
-	      <entry>Command identifier</entry>
-	    </row>
-	    <row>
-	      <entry>1</entry>
-	      <entry>uint8_t</entry>
-	      <entry>flight_state</entry>
-	      <entry>Current flight computer state</entry>
-	    </row>
-	    <row>
-	      <entry>2</entry>
-	      <entry>uint16_t</entry>
-	      <entry>tick</entry>
-	      <entry>Flight computer clock (100 ticks/second)</entry>
-	    </row>
-	    <row>
-	      <entry>4</entry>
-	      <entry>uint16_t</entry>
-	      <entry>serial</entry>
-	      <entry>Flight computer serial number</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry>
-	      <entry>uint16_t</entry>
-	      <entry>flight</entry>
-	      <entry>Flight number</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <table frame='all'>
-	<title>Companion Command Identifiers</title>
-	<tgroup cols='3' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Value'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Value</entry>
-	      <entry>Name</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>1</entry>
-	      <entry>SETUP</entry>
-	      <entry>Supply the flight computer with companion
-	      information</entry>
-	    </row>
-	    <row>
-	      <entry>2</entry>
-	      <entry>FETCH</entry>
-	      <entry>Return telemetry information</entry>
-	    </row>
-	    <row>
-	      <entry>3</entry>
-	      <entry>NOTIFY</entry>
-	      <entry>Tell companion board when flight state
-	      changes</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <para>
-	The flight computer will send a SETUP message shortly after
-	power-up and will then send FETCH messages no more often than
-	the rate specified in the SETUP reply. NOTIFY messages will be
-	sent whenever the flight state changes.
-      </para>
-      <para>
-	'flight_state' records the current state of the flight,
-	whether on the pad, under power, coasting to apogee or
-	descending on the drogue or main chute.
-      </para>
-      <para>
-	'tick' provides the current flight computer clock, which 
-	be used to synchronize data recorded on the flight computer
-	with that recorded on the companion board in post-flight analysis.
-      </para>
-      <para>
-	'serial' is the product serial number of the flight computer,
-	'flight' is the flight sequence number. Together, these two
-	uniquely identify the flight and can be recorded with any
-	companion board data logging to associate the companion data
-	with the proper flight.
-      </para>
-      <para>
-	NOTIFY commands require no reply at all, they are used solely
-	to inform the companion board when the state of the flight, as
-	computed by the flight computer, changes. Companion boards can
-	use this to change data collection parameters, disabling data
-	logging until the flight starts and terminating it when the
-	flight ends.
-      </para>
-    </section>
-    <section>
-      <title>SETUP reply message</title>
-      <table frame='all'>
-	<title>SETUP reply contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0</entry>
-	      <entry>uint16_t</entry>
-	      <entry>board_id</entry>
-	      <entry>Board identifier</entry>
-	    </row>
-	    <row>
-	      <entry>2</entry>
-	      <entry>uint16_t</entry>
-	      <entry>board_id_inverse</entry>
-	      <entry>~board_id—used to tell if a board is present</entry>
-	    </row>
-	    <row>
-	      <entry>4</entry>
-	      <entry>uint8_t</entry>
-	      <entry>update_period</entry>
-	      <entry>Minimum time (in 100Hz ticks) between FETCH commands</entry>
-	    </row>
-	    <row>
-	      <entry>5</entry>
-	      <entry>uint8_t</entry>
-	      <entry>channels</entry>
-	      <entry>Number of data channels to retrieve in FETCH command</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <para>
-	The SETUP reply contains enough information to uniquely
-	identify the companion board to the end user as well as for
-	the flight computer to know how many data values to expect in
-	reply to a FETCH command, and how often to fetch that data.
-      </para>
-      <para>
-	To detect the presence of a companion board, the flight
-	computer checks to make sure that board_id_inverse is the
-	bit-wise inverse of board_id. Current companion boards use
-	USB product ID as the board_id, but the flight computer does
-	not interpret this data and so it can be any value.
-      </para>
-    </section>
-    <section>
-      <title>FETCH reply message</title>
-      <table frame='all'>
-	<title>FETCH reply contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0</entry>
-	      <entry>uint16_t</entry>
-	      <entry>data0</entry>
-	      <entry>0th data item</entry>
-	    </row>
-	    <row>
-	      <entry>2</entry>
-	      <entry>uint16_t</entry>
-	      <entry>data1</entry>
-	      <entry>1st data item</entry>
-	    </row>
-	    <row>
-	      <entry>...</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <para>
-	The FETCH reply contains arbitrary data to be reported over
-	the flight computer telemetry link. The number of 16-bit data items
-	must match the 'channels' value provided in the SETUP reply
-	message.
-      </para>
-    </section>
-  </section>
-  <section>
-    <title>History and Motivation</title>
-    <para>
-      To allow cross-programming, the original TeleMetrum and
-      TeleDongle designs needed to include some kind of
-      connector. With that in place, adding the ability to connect
-      external cards to TeleMetrum was fairly simple. We set the
-      software piece of this puzzle aside until we had a companion
-      board to use.
-    </para>
-    <para>
-      The first companion board was TeleScience. Designed to collect
-      temperature data from the nose and fin of the airframe, the main
-      requirement for the companion port was that it be able to report
-      telemetry data during flight as a back-up in case the
-      TeleScience on-board data was lost.
-    </para>
-    <para>
-      The second companion board, TelePyro, provides 8 additional
-      channels for deployment, staging or other activities. To avoid
-      re-programming the TeleMetrum to use TelePyro, we decided to
-      provide enough information over the companion link for it to
-      independently control those channels.
-    </para>
-    <para>
-      Providing a standard, constant interface between the flight
-      computer and companion boards allows for the base flight
-      computer firmware to include support for companion boards.
-    </para>
-  </section>
-</article>
diff --git a/doc/telemetry-docinfo.xml b/doc/telemetry-docinfo.xml
new file mode 100644
index 00000000..c7b1f060
--- /dev/null
+++ b/doc/telemetry-docinfo.xml
@@ -0,0 +1,27 @@
+<subtitle>Packet Definitions</subtitle>
+<author>
+  <firstname>Keith</firstname>
+  <surname>Packard</surname>
+  <email>keithp@keithp.com</email>
+</author>
+<date>1 July 2011</date>
+<copyright>
+  <year>2011</year>
+  <holder>Keith Packard</holder>
+</copyright>
+<legalnotice>
+  <para>
+    This document is released under the terms of the
+    <ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
+      Creative Commons ShareAlike 3.0
+    </ulink>
+    license.
+  </para>
+</legalnotice>
+<revhistory>
+  <revision>
+    <revnumber>0.1</revnumber>
+    <date>1 July 2011</date>
+    <revremark>Initial content</revremark>
+  </revision>
+</revhistory>
diff --git a/doc/telemetry.txt b/doc/telemetry.txt
new file mode 100644
index 00000000..36d2edba
--- /dev/null
+++ b/doc/telemetry.txt
@@ -0,0 +1,571 @@
+= AltOS Telemetry
+:doctype: article
+:toc:
+:numbered:
+
+== Packet Format Design
+
+	AltOS telemetry data is split into multiple different packets,
+	all the same size, but each includs an identifier so that the
+	ground station can distinguish among different types. A single
+	flight board will transmit multiple packet types, each type on
+	a different schedule. The ground software need look for only a
+	single packet size, and then decode the information within the
+	packet and merge data from multiple packets to construct the
+	full flight computer state.
+
+	Each AltOS packet is 32 bytes long. This size was chosen based
+	on the known telemetry data requirements. The power of two
+	size allows them to be stored easily in flash memory without
+	having them split across blocks or leaving gaps at the end.
+
+	All packet types start with a five byte header which encodes
+	the device serial number, device clock value and the packet
+	type. The remaining 27 bytes encode type-specific data.
+
+== Packet Formats
+
+      This section first defines the packet header common to all packets
+      and then the per-packet data layout.
+
+	=== Packet Header
+
+		.Telemetry Packet Header
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name	|Description
+		|0	|uint16_t	|serial	|Device serial Number
+		|2	|uint16_t	|tick	|Device time in 100ths of a second
+		|4	|uint8_t	|type	|Packet type
+		|5
+		|====
+
+		Each packet starts with these five bytes which serve to identify
+		which device has transmitted the packet, when it was transmitted
+		and what the rest of the packet contains.
+
+	=== TeleMetrum v1.x, TeleMini and TeleNano Sensor Data
+
+		.Sensor Packet Type
+		[options="border",cols="1,3"]
+		|====
+		|Type	|Description
+		|0x01	|TeleMetrum v1.x Sensor Data
+		|0x02	|TeleMini Sensor Data
+		|0x03	|TeleNano Sensor Data
+		|====
+
+		TeleMetrum v1.x, TeleMini and TeleNano share this same
+		packet format for sensor data. Each uses a distinct
+		packet type so that the receiver knows which data
+		values are valid and which are undefined.
+
+		Sensor Data packets are transmitted once per second on
+		the ground, 10 times per second during ascent and once
+		per second during descent and landing
+
+		.Sensor Packet Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|state		|Flight state
+		|6	|int16_t	|accel		|accelerometer (TM only)
+		|8	|int16_t	|pres		|pressure sensor
+		|10	|int16_t	|temp		|temperature sensor
+		|12	|int16_t	|v_batt		|battery voltage
+		|14	|int16_t	|sense_d	|drogue continuity sense (TM/Tm)
+		|16	|int16_t	|sense_m	|main continuity sense (TM/Tm)
+		|18	|int16_t	|acceleration	|m/s² * 16
+		|20	|int16_t	|speed		|m/s * 16
+		|22	|int16_t	|height		|m
+		|24	|int16_t	|ground_pres	|Average barometer reading on ground
+		|26	|int16_t	|ground_accel	|TM
+		|28	|int16_t	|accel_plus_g	|TM
+		|30	|int16_t	|accel_minus_g	|TM
+		|32
+		|====
+
+	=== TeleMega Sensor Data
+
+		.TeleMega Packet Type
+		[options="border",cols="1,3"]
+		|====
+		|Type	|Description
+		|0x08	|TeleMega IMU Sensor Data
+		|0x09	|TeleMega Kalman and Voltage Data
+		|====
+
+		TeleMega has a lot of sensors, and so it splits the sensor
+		data into two packets. The raw IMU data are sent more often;
+		the voltage values don't change very fast, and the Kalman
+		values can be reconstructed from the IMU data.
+
+		IMU Sensor Data packets are transmitted once per second on the
+		ground, 10 times per second during ascent and once per second
+		during descent and landing
+
+		Kalman and Voltage Data packets are transmitted once per second on the
+		ground, 5 times per second during ascent and once per second
+		during descent and landing
+
+		The high-g accelerometer is reported separately from the data
+		for the 9-axis IMU (accel/gyro/mag). The 9-axis IMU is mounted
+		so that the X axis is "across" the board (along the short
+		axis0, the Y axis is "along" the board (along the long axis,
+		with the high-g accelerometer) and the Z axis is "through" the
+		board (perpendicular to the board). Rotation measurements are
+		around the respective axis, so Y rotation measures the spin
+		rate of the rocket while X and Z rotation measure the tilt
+		rate.
+
+		The overall tilt angle of the rocket is computed by first
+		measuring the orientation of the rocket on the pad using the 3
+		axis accelerometer, and then integrating the overall tilt rate
+		from the 3 axis gyroscope to compute the total orientation
+		change of the airframe since liftoff.
+
+		.TeleMega IMU Sensor Packet Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|orient		|Angle from vertical in degrees
+		|6	|int16_t	|accel		|High G accelerometer
+		|8	|int32_t	|pres		|pressure (Pa * 10)
+		|12	|int16_t	|temp		|temperature (°C * 100)
+		|14	|int16_t	|accel_x	|X axis acceleration (across)
+		|16	|int16_t	|accel_y	|Y axis acceleration (along)
+		|18	|int16_t	|accel_z	|Z axis acceleration (through)
+		|20	|int16_t	|gyro_x		|X axis rotation (across)
+		|22	|int16_t	|gyro_y		|Y axis rotation (along)
+		|24	|int16_t	|gyro_z		|Z axis rotation (through)
+		|26	|int16_t	|mag_x		|X field strength (across)
+		|28	|int16_t	|mag_y		|Y field strength (along)
+		|30	|int16_t	|mag_z		|Z field strength (through)
+		|32
+		|====
+
+		.TeleMega Kalman and Voltage Data Packet Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|state		|Flight state
+		|6	|int16_t	|v_batt		|battery voltage
+		|8	|int16_t	|v_pyro		|pyro battery voltage
+		|10	|int8_t[6]	|sense		|pyro continuity sense
+		|16	|int32_t	|ground_pres	|Average barometer reading on ground
+		|20	|int16_t	|ground_accel	|Average accelerometer reading on ground
+		|22	|int16_t	|accel_plus_g	|Accel calibration at +1g
+		|24	|int16_t	|accel_minus_g	|Accel calibration at -1g
+		|26	|int16_t	|acceleration	|m/s² * 16
+		|28	|int16_t	|speed		|m/s * 16
+		|30	|int16_t	|height		|m
+		|32
+		|====
+
+	=== TeleMetrum v2 Sensor Data
+
+		.TeleMetrum v2 Packet Type
+		[options="border",cols="1,3"]
+		|====
+		|Type	|Description
+		|0x0A	|TeleMetrum v2 Sensor Data
+		|0x0B	|TeleMetrum v2 Calibration Data
+		|====
+
+		TeleMetrum v2 has higher resolution barometric data than
+		TeleMetrum v1, and so the constant calibration data is
+		split out into a separate packet.
+
+		TeleMetrum v2 Sensor Data packets are transmitted once per second on the
+		ground, 10 times per second during ascent and once per second
+		during descent and landing
+
+		TeleMetrum v2 Calibration Data packets are always transmitted once per second.
+
+		.TeleMetrum v2 Sensor Packet Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|state		|Flight state
+		|6	|int16_t	|accel		|accelerometer
+		|8	|int32_t	|pres		|pressure sensor (Pa * 10)
+		|12	|int16_t	|temp		|temperature sensor (°C * 100)
+		|14	|int16_t	|acceleration	|m/s² * 16
+		|16	|int16_t	|speed		|m/s * 16
+		|18	|int16_t	|height		|m
+		|20	|int16_t	|v_batt		|battery voltage
+		|22	|int16_t	|sense_d	|drogue continuity sense
+		|24	|int16_t	|sense_m	|main continuity sense
+		|26	|pad[6]		|pad bytes	|
+		|32
+		|====
+
+		.TeleMetrum v2 Calibration Data Packet Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|pad[3]		|pad bytes	|
+		|8	|int32_t	|ground_pres	|Average barometer reading on ground
+		|12	|int16_t	|ground_accel	|Average accelerometer reading on ground
+		|14	|int16_t	|accel_plus_g	|Accel calibration at +1g
+		|16	|int16_t	|accel_minus_g	|Accel calibration at -1g
+		|18	|pad[14]	|pad bytes	|
+		|32
+		|====
+
+	=== Configuration Data
+
+		.Configuration Packet Type
+		[options="border",cols="1,3"]
+		|====
+		|Type	|Description
+		|0x04	|Configuration Data
+		|====
+
+		This provides a description of the software installed on the
+		flight computer as well as any user-specified configuration data.
+
+		Configuration data packets are transmitted once per second
+		during all phases of the flight
+
+		.Configuration Packet Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|type		|Device type
+		|6	|uint16_t	|flight		|Flight number
+		|8	|uint8_t	|config_major	|Config major version
+		|9	|uint8_t	|config_minor	|Config minor version
+		|10	|uint16_t	|apogee_delay	|Apogee deploy delay in seconds
+		|12	|uint16_t	|main_deploy	|Main deploy alt in meters
+		|14	|uint16_t	|flight_log_max	|Maximum flight log size (kB)
+		|16	|char		|callsign[8]	|Radio operator identifier
+		|24	|char		|version[8]	|Software version identifier
+		|32
+		|====
+
+	=== GPS Location
+
+		.GPS Packet Type
+		[options="border",cols="1,3"]
+		|====
+		|Type	|Description
+		|0x05	|GPS Location
+		|====
+
+		This packet provides all of the information available from the
+		GPS receiver—position, time, speed and precision
+		estimates.
+
+		GPS Location packets are transmitted once per second during
+		all phases of the flight
+
+		.GPS Location Packet Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|flags		|See GPS Flags table below
+		|6	|int16_t	|altitude	|m
+		|8	|int32_t	|latitude	|degrees * 107
+		|12	|int32_t	|longitude	|degrees * 107
+		|16	|uint8_t	|year		|
+		|17	|uint8_t	|month		|
+		|18	|uint8_t	|day		|
+		|19	|uint8_t	|hour		|
+		|20	|uint8_t	|minute		|
+		|21	|uint8_t	|second		|
+		|22	|uint8_t	|pdop		|* 5
+		|23	|uint8_t	|hdop		|* 5
+		|24	|uint8_t	|vdop		|* 5
+		|25	|uint8_t	|mode		|See GPS Mode table below
+		|26	|uint16_t	|ground_speed	|cm/s
+		|28	|int16_t	|climb_rate	|cm/s
+		|30	|uint8_t	|course		|/ 2
+		|31	|uint8_t	|unused[1]	|
+		|32
+		|====
+
+		Packed into a one byte field are status flags and the
+		count of satellites used to compute the position
+		fix. Note that this number may be lower than the
+		number of satellites being tracked; the receiver will
+		not use information from satellites with weak signals
+		or which are close enough to the horizon to have
+		significantly degraded position accuracy.
+
+		.GPS Flags
+		[options="border",cols="1,2,7"]
+		|====
+		|Bits	|Name		|Description
+		|0-3	|nsats		|Number of satellites in solution
+		|4	|valid		|GPS solution is valid
+		|5	|running	|GPS receiver is operational
+		|6	|date_valid	|Reported date is valid
+		|7	|course_valid	|ground speed, course and climb rates are valid
+		|====
+
+		Here are all of the valid GPS operational modes. Altus
+		Metrum products will only ever report 'N' (not valid),
+		'A' (Autonomous) modes or 'E' (Estimated). The
+		remaining modes are either testing modes or require
+		additional data.
+
+		.GPS Mode
+		[options="border",cols="1,3,7"]
+		|====
+		|Mode		|Name			|Description
+		|N		|Not Valid		|All data are invalid
+		|A		|Autonomous mode	|
+		  Data are derived from satellite data
+
+		|D		|Differential Mode	|
+		  Data are augmented with differential data from a
+		  known ground station. The SkyTraq unit in TeleMetrum
+		  does not support this mode
+
+		|E		|Estimated		|
+		  Data are estimated using dead reckoning from the
+		  last known data
+
+		|M		|Manual			|
+		  Data were entered manually
+
+		|S		|Simulated		|
+		  GPS receiver testing mode
+
+		|====
+
+	=== GPS Satellite Data
+
+		.GPS Satellite Data Packet Type
+		[options="border",cols="1,3"]
+		|====
+		|Type		|Description
+		|0x06		|GPS Satellite Data
+		|====
+
+		This packet provides space vehicle identifiers and
+		signal quality information in the form of a C/N1
+		number for up to 12 satellites. The order of the svids
+		is not specified.
+
+		GPS Satellite data are transmitted once per second
+		during all phases of the flight.
+
+		.GPS Satellite Data Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|channels	|Number of reported satellite information
+		|6	|sat_info_t	|sats[12]	|See Per-Satellite data table below
+		|30	|uint8_t	|unused[2]	|
+		|32
+		|====
+
+		.GPS Per-Satellite data (sat_info_t)
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|0	|uint8_t	|svid		|Space Vehicle Identifier
+		|1	|uint8_t	|c_n_1		|C/N1 signal quality indicator
+		|2
+		|====
+
+	=== Companion Data
+
+		.Companion Data Packet Type
+		[options="border",cols="1,3"]
+		|====
+		|Type	|Description
+		|0x07	|Companion Data
+		|====
+
+		When a companion board is attached to TeleMega or
+		TeleMetrum, it can provide telemetry data to be
+		included in the downlink. The companion board can
+		provide up to 12 16-bit data values.
+
+		The companion board itself specifies the transmission
+		rate. On the ground and during descent, that rate is
+		limited to one packet per second. During ascent, that
+		rate is limited to 10 packets per second.
+
+		.Companion Data Contents
+		[options="border",cols="2,3,3,9"]
+		|====
+		|Offset	|Data Type	|Name		|Description
+		|5	|uint8_t	|board_id	|Type of companion board attached
+		|6	|uint8_t	|update_period	|How often telemetry is sent, in 1/100ths of a second
+		|7	|uint8_t	|channels	|Number of data channels supplied
+		|8	|uint16_t[12]	|companion_data	|Up to 12 channels of 16-bit companion data
+		|32
+		|====
+
+== Data Transmission
+
+	Altus Metrum devices use Texas Instruments sub-GHz digital
+	radio products. Ground stations use parts with HW FEC while
+	some flight computers perform FEC in software. TeleGPS is
+	transmit-only.
+
+	.Altus Metrum Radio Parts
+	[options="border",cols="1,4,4"]
+	|====
+	|Part Number	|Description	|Used in
+
+	|CC1111
+	|10mW transceiver with integrated SoC
+	|TeleDongle v0.2, TeleBT v1.0, TeleMetrum v1.x, TeleMini
+
+	|CC1120
+	|35mW transceiver with SW FEC
+	|TeleMetrum v2, TeleMega
+
+	|CC1200
+	|35mW transceiver with HW FEC
+	|TeleDongle v3.0, TeleBT v3.0
+
+	|CC115L
+	|14mW transmitter with SW FEC
+	|TeleGPS
+
+	|====
+
+	=== Modulation Scheme
+
+		Texas Instruments provides a tool for computing
+		modulation parameters given a desired modulation
+		format and basic bit rate.
+
+		While we might like to use something with better
+		low-signal performance like BPSK, the radios we use
+		don't support that, but do support Gaussian frequency
+		shift keying (GFSK). Regular frequency shift keying
+		(FSK) encodes the signal by switching the carrier
+		between two frequencies. The Gaussian version is
+		essentially the same, but the shift between
+		frequencies gently follows a gaussian curve, rather
+		than switching immediately. This tames the bandwidth
+		of the signal without affecting the ability to
+		transmit data.
+
+		For AltOS, there are three available bit rates,
+		38.4kBaud, 9.6kBaud and 2.4kBaud resulting in the
+		following signal parmeters:
+
+		.Modulation Scheme
+		[options="border",cols="1,1,1"]
+		|====
+		|Rate		|Deviation	|Receiver Bandwidth
+		|38.4kBaud	|20.5kHz	|100kHz
+		|9.6kBaud	|5.125kHz	|25kHz
+		|2.4kBaud	|1.5kHz		|5kHz
+		|====
+
+	=== Error Correction
+
+		The cc1111 and cc1200 provide forward error correction
+		in hardware; on the cc1120 and cc115l that's done in
+		software. AltOS uses this to improve reception of weak
+		signals. As it's a rate 1/2 encoding, each bit of data
+		takes two bits when transmitted, so the effective data
+		rate is half of the raw transmitted bit rate.
+
+		.Error Correction
+		[options="border",cols="1,1,1"]
+		|====
+		|Parameter	|Value	|Description
+
+		|Error Correction
+		|Convolutional coding
+		|1/2 rate, constraint length m=4
+
+		|Interleaving
+		|4 x 4
+		|Reduce effect of noise burst
+
+		|Data Whitening
+		|XOR with 9-bit PNR
+		|Rotate right with bit 8 = bit 0 xor bit 5, initial value 111111111
+
+		|====
+
+== TeleDongle serial packet format
+
+	TeleDongle does not do any interpretation of the packet data,
+	instead it is configured to receive packets of a specified
+	length (32 bytes in this case). For each received packet,
+	TeleDongle produces a single line of text. This line starts with
+	the string "TELEM " and is followed by a list of hexadecimal
+	encoded bytes.
+
+	....
+	TELEM 224f01080b05765e00701f1a1bbeb8d7b60b070605140c000600000000000000003fa988
+	....
+
+	The hexadecimal encoded string of bytes contains a length byte,
+	the packet data, two bytes added by the cc1111 radio receiver
+	hardware and finally a checksum so that the host software can
+	validate that the line was transmitted without any errors.
+
+	.TeleDongle serial Packet Format
+
+	[options="border",cols="2,1,1,5"]
+	|====
+	|Offset	|Name	|Example	|Description
+
+	|0
+	|length
+	|22
+	|Total length of data bytes in the line. Note that
+	 this includes the added RSSI and status bytes
+
+	|1 ·· length-3
+	|packet
+	|4f ·· 00
+	|Bytes of actual packet data
+
+	|length-2
+	|rssi
+	|3f
+	|Received signal strength. dBm = rssi / 2 - 74
+
+	|length-1
+	|lqi
+	|a9
+	|Link Quality Indicator and CRC status. Bit 7
+	 is set when the CRC is correct
+
+	|length
+	|checksum
+	|88
+	|(0x5a + sum(bytes 1 ·· length-1)) % 256
+
+	|====
+
+== History and Motivation
+
+      The original AltoOS telemetry mechanism encoded everything
+      available piece of information on the TeleMetrum hardware into a
+      single unified packet. Initially, the packets contained very
+      little data—some raw sensor readings along with the current GPS
+      coordinates when a GPS receiver was connected. Over time, the
+      amount of data grew to include sensor calibration data, GPS
+      satellite information and a host of internal state information
+      designed to help diagnose flight failures in case of a loss of
+      the on-board flight data.
+
+      Because every packet contained all of the data, packets were
+      huge—95 bytes long. Much of the information was also specific to
+      the TeleMetrum hardware. With the introduction of the TeleMini
+      flight computer, most of the data contained in the telemetry
+      packets was unavailable. Initially, a shorter, but still
+      comprehensive packet was implemented. This required that the
+      ground station be pre-configured as to which kind of packet to
+      expect.
+
+      The development of several companion boards also made the
+      shortcomings evident—each companion board would want to include
+      telemetry data in the radio link; with the original design, the
+      packet would have to hold the new data as well, requiring
+      additional TeleMetrum and ground station changes.
diff --git a/doc/telemetry.xsl b/doc/telemetry.xsl
deleted file mode 100644
index 2e0b3ea1..00000000
--- a/doc/telemetry.xsl
+++ /dev/null
@@ -1,1230 +0,0 @@
-<?xml version="1.0" encoding="utf-8" ?>
-<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
-"/usr/share/xml/docbook/schema/dtd/4.5/docbookx.dtd">
-
-<article>
-  <articleinfo>
-    <title>AltOS Telemetry</title>
-    <subtitle>Packet Definitions</subtitle>
-    <author>
-      <firstname>Keith</firstname>
-      <surname>Packard</surname>
-    </author>
-    <copyright>
-      <year>2011</year>
-      <holder>Keith Packard</holder>
-    </copyright>
-    <legalnotice>
-      <para>
-	This document is released under the terms of the
-	<ulink url="http://creativecommons.org/licenses/by-sa/3.0/">
-	  Creative Commons ShareAlike 3.0
-	</ulink>
-	license.
-      </para>
-    </legalnotice>
-    <revhistory>
-      <revision>
-	<revnumber>0.1</revnumber>
-	<date>01 July 2011</date>
-	<revremark>Initial content</revremark>
-      </revision>
-    </revhistory>
-  </articleinfo>
-  <section>
-    <title>Packet Format Design</title>
-    <para>
-      AltOS telemetry data is split into multiple different packets,
-      all the same size, but each includs an identifier so that the
-      ground station can distinguish among different types. A single
-      flight board will transmit multiple packet types, each type on a
-      different schedule. The ground software need look for only a
-      single packet size, and then decode the information within the
-      packet and merge data from multiple packets to construct the
-      full flight computer state.
-    </para>
-    <para>
-      Each AltOS packet is 32 bytes long. This size was chosen based
-      on the known telemetry data requirements. The power of two size
-      allows them to be stored easily in flash memory without having
-      them split across blocks or leaving gaps at the end.
-    </para>
-    <para>
-      All packet types start with a five byte header which encodes the
-      device serial number, device clock value and the packet
-      type. The remaining 27 bytes encode type-specific data.
-    </para>
-  </section>
-  <section>
-    <title>Packet Formats</title>
-    <para>
-      This section first defines the packet header common to all packets
-      and then the per-packet data layout.
-    </para>
-    <section>
-      <title>Packet Header</title>
-      <table frame='all'>
-	<title>Telemetry Packet Header</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0</entry>
-	      <entry>uint16_t</entry>
-	      <entry>serial</entry>
-	      <entry>Device serial Number</entry>
-	    </row>
-	    <row>
-	      <entry>2</entry>
-	      <entry>uint16_t</entry>
-	      <entry>tick</entry>
-	      <entry>Device time in 100ths of a second</entry>
-	    </row>
-	    <row>
-	      <entry>4</entry>
-	      <entry>uint8_t</entry>
-	      <entry>type</entry>
-	      <entry>Packet type</entry>
-	    </row>
-	    <row>
-	      <entry>5</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <para>
-      Each packet starts with these five bytes which serve to identify
-      which device has transmitted the packet, when it was transmitted
-      and what the rest of the packet contains.
-      </para>
-    </section>
-    <section>
-      <title>TeleMetrum v1.x, TeleMini and TeleNano Sensor Data</title>
-      <informaltable frame='none' label='' tocentry='0'>
-	<tgroup cols='2' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='left' colwidth='3*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Type</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0x01</entry>
-	      <entry>TeleMetrum v1.x Sensor Data</entry>
-	    </row>
-	    <row>
-	      <entry>0x02</entry>
-	      <entry>TeleMini Sensor Data</entry>
-	    </row>
-	    <row>
-	      <entry>0x03</entry>
-	      <entry>TeleNano Sensor Data</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </informaltable>
-      <para>
-	TeleMetrum v1.x, TeleMini and TeleNano share this same packet
-	format for sensor data. Each uses a distinct packet type so
-	that the receiver knows which data values are valid and which
-	are undefined.
-      </para>
-      <para>
-	Sensor Data packets are transmitted once per second on the
-	ground, 10 times per second during ascent and once per second
-	during descent and landing
-      </para>
-      <table frame='all'>
-	<title>Sensor Packet Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>state</entry><entry>Flight state</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>int16_t</entry><entry>accel</entry><entry>accelerometer (TM only)</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>int16_t</entry><entry>pres</entry><entry>pressure sensor</entry>
-	    </row>
-	    <row>
-	      <entry>10</entry><entry>int16_t</entry><entry>temp</entry><entry>temperature sensor</entry>
-	    </row>
-	    <row>
-	      <entry>12</entry><entry>int16_t</entry><entry>v_batt</entry><entry>battery voltage</entry>
-	    </row>
-	    <row>
-	      <entry>14</entry><entry>int16_t</entry><entry>sense_d</entry><entry>drogue continuity sense (TM/Tm)</entry>
-	    </row>
-	    <row>
-	      <entry>16</entry><entry>int16_t</entry><entry>sense_m</entry><entry>main continuity sense (TM/Tm)</entry>
-	    </row>
-	    <row>
-	      <entry>18</entry><entry>int16_t</entry><entry>acceleration</entry><entry>m/s² * 16</entry>
-	    </row>
-	    <row>
-	      <entry>20</entry><entry>int16_t</entry><entry>speed</entry><entry>m/s * 16</entry>
-	    </row>
-	    <row>
-	      <entry>22</entry><entry>int16_t</entry><entry>height</entry><entry>m</entry>
-	    </row>
-	    <row>
-	      <entry>24</entry><entry>int16_t</entry><entry>ground_pres</entry><entry>Average barometer reading on ground</entry>
-	    </row>
-	    <row>
-	      <entry>26</entry><entry>int16_t</entry><entry>ground_accel</entry><entry>TM</entry>
-	    </row>
-	    <row>
-	      <entry>28</entry><entry>int16_t</entry><entry>accel_plus_g</entry><entry>TM</entry>
-	    </row>
-	    <row>
-	      <entry>30</entry><entry>int16_t</entry><entry>accel_minus_g</entry><entry>TM</entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-    <section>
-      <title>TeleMega Sensor  Data</title>
-      <informaltable frame='none' label='' tocentry='0'>
-	<tgroup cols='2' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='left' colwidth='3*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Type</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0x08</entry>
-	      <entry>TeleMega IMU Sensor Data</entry>
-	    </row>
-	    <row>
-	      <entry>0x09</entry>
-	      <entry>TeleMega Kalman and Voltage Data</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </informaltable>
-      <para>
-	TeleMega has a lot of sensors, and so it splits the sensor
-	data into two packets. The raw IMU data are sent more often;
-	the voltage values don't change very fast, and the Kalman
-	values can be reconstructed from the IMU data.
-      </para>
-      <para>
-	IMU Sensor Data packets are transmitted once per second on the
-	ground, 10 times per second during ascent and once per second
-	during descent and landing
-      </para>
-      <para>
-	Kalman and Voltage Data packets are transmitted once per second on the
-	ground, 5 times per second during ascent and once per second
-	during descent and landing
-      </para>
-      <para>
-	The high-g accelerometer is reported separately from the data
-	for the 9-axis IMU (accel/gyro/mag). The 9-axis IMU is mounted
-	so that the X axis is "across" the board (along the short
-	axis0, the Y axis is "along" the board (along the long axis,
-	with the high-g accelerometer) and the Z axis is "through" the
-	board (perpendicular to the board). Rotation measurements are
-	around the respective axis, so Y rotation measures the spin
-	rate of the rocket while X and Z rotation measure the tilt
-	rate.
-      </para>
-      <para>
-	The overall tilt angle of the rocket is computed by first
-	measuring the orientation of the rocket on the pad using the 3
-	axis accelerometer, and then integrating the overall tilt rate
-	from the 3 axis gyroscope to compute the total orientation
-	change of the airframe since liftoff.
-      </para>
-      <table frame='all'>
-	<title>TeleMega IMU Sensor Packet Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>orient</entry><entry>Angle from vertical in degrees</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>int16_t</entry><entry>accel</entry><entry>High G accelerometer</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>int32_t</entry><entry>pres</entry><entry>pressure (Pa * 10)</entry>
-	    </row>
-	    <row>
-	      <entry>12</entry><entry>int16_t</entry><entry>temp</entry><entry>temperature (°C * 100)</entry>
-	    </row>
-	    <row>
-	      <entry>14</entry><entry>int16_t</entry><entry>accel_x</entry><entry>X axis acceleration (across)</entry>
-	    </row>
-	    <row>
-	      <entry>16</entry><entry>int16_t</entry><entry>accel_y</entry><entry>Y axis acceleration (along)</entry>
-	    </row>
-	    <row>
-	      <entry>18</entry><entry>int16_t</entry><entry>accel_z</entry><entry>Z axis acceleration (through)</entry>
-	    </row>
-	    <row>
-	      <entry>20</entry><entry>int16_t</entry><entry>gyro_x</entry><entry>X axis rotation (across)</entry>
-	    </row>
-	    <row>
-	      <entry>22</entry><entry>int16_t</entry><entry>gyro_y</entry><entry>Y axis rotation (along)</entry>
-	    </row>
-	    <row>
-	      <entry>24</entry><entry>int16_t</entry><entry>gyro_z</entry><entry>Z axis rotation (through)</entry>
-	    </row>
-	    <row>
-	      <entry>26</entry><entry>int16_t</entry><entry>mag_x</entry><entry>X field strength (across)</entry>
-	    </row>
-	    <row>
-	      <entry>28</entry><entry>int16_t</entry><entry>mag_y</entry><entry>Y field strength (along)</entry>
-	    </row>
-	    <row>
-	      <entry>30</entry><entry>int16_t</entry><entry>mag_z</entry><entry>Z field strength (through)</entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <table frame='all'>
-	<title>TeleMega Kalman and Voltage Data Packet Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>state</entry><entry>Flight state</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>int16_t</entry><entry>v_batt</entry><entry>battery voltage</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>int16_t</entry><entry>v_pyro</entry><entry>pyro battery voltage</entry>
-	    </row>
-	    <row>
-	      <entry>10</entry><entry>int8_t[6]</entry><entry>sense</entry><entry>pyro continuity sense</entry>
-	    </row>
-	    <row>
-	      <entry>16</entry><entry>int32_t</entry><entry>ground_pres</entry><entry>Average barometer reading on ground</entry>
-	    </row>
-	    <row>
-	      <entry>20</entry><entry>int16_t</entry><entry>ground_accel</entry><entry>Average accelerometer reading on ground</entry>
-	    </row>
-	    <row>
-	      <entry>22</entry><entry>int16_t</entry><entry>accel_plus_g</entry><entry>Accel calibration at +1g</entry>
-	    </row>
-	    <row>
-	      <entry>24</entry><entry>int16_t</entry><entry>accel_minus_g</entry><entry>Accel calibration at -1g</entry>
-	    </row>
-	    <row>
-	      <entry>26</entry><entry>int16_t</entry><entry>acceleration</entry><entry>m/s² * 16</entry>
-	    </row>
-	    <row>
-	      <entry>28</entry><entry>int16_t</entry><entry>speed</entry><entry>m/s * 16</entry>
-	    </row>
-	    <row>
-	      <entry>30</entry><entry>int16_t</entry><entry>height</entry><entry>m</entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-    <section>
-      <title>TeleMetrum v2 Sensor  Data</title>
-      <informaltable frame='none' label='' tocentry='0'>
-	<tgroup cols='2' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='left' colwidth='3*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Type</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0x0A</entry>
-	      <entry>TeleMetrum v2 Sensor Data</entry>
-	    </row>
-	    <row>
-	      <entry>0x0B</entry>
-	      <entry>TeleMetrum v2 Calibration Data</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </informaltable>
-      <para>
-	TeleMetrum v2 has higher resolution barometric data than
-	TeleMetrum v1, and so the constant calibration data is
-	split out into a separate packet.
-      </para>
-      <para>
-	TeleMetrum v2 Sensor Data packets are transmitted once per second on the
-	ground, 10 times per second during ascent and once per second
-	during descent and landing
-      </para>
-      <para>
-	TeleMetrum v2 Calibration Data packets are always transmitted once per second.
-      </para>
-      <table frame='all'>
-	<title>TeleMetrum v2 Sensor Packet Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>state</entry><entry>Flight state</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>int16_t</entry><entry>accel</entry><entry>accelerometer</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>int32_t</entry><entry>pres</entry><entry>pressure sensor (Pa * 10)</entry>
-	    </row>
-	    <row>
-	      <entry>12</entry><entry>int16_t</entry><entry>temp</entry><entry>temperature sensor (°C * 100)</entry>
-	    </row>
-
-	    <row>
-	      <entry>14</entry><entry>int16_t</entry><entry>acceleration</entry><entry>m/s² * 16</entry>
-	    </row>
-	    <row>
-	      <entry>16</entry><entry>int16_t</entry><entry>speed</entry><entry>m/s * 16</entry>
-	    </row>
-	    <row>
-	      <entry>18</entry><entry>int16_t</entry><entry>height</entry><entry>m</entry>
-	    </row>
-
-	    <row>
-	      <entry>20</entry><entry>int16_t</entry><entry>v_batt</entry><entry>battery voltage</entry>
-	    </row>
-	    <row>
-	      <entry>22</entry><entry>int16_t</entry><entry>sense_d</entry><entry>drogue continuity sense</entry>
-	    </row>
-	    <row>
-	      <entry>24</entry><entry>int16_t</entry><entry>sense_m</entry><entry>main continuity sense</entry>
-	    </row>
-	    <row>
-	      <entry>26</entry><entry>pad[6]</entry><entry>pad bytes</entry><entry></entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <table frame='all'>
-	<title>TeleMetrum v2 Calibration Data Packet Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>pad[3]</entry><entry>pad bytes</entry><entry></entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>int32_t</entry><entry>ground_pres</entry><entry>Average barometer reading on ground</entry>
-	    </row>
-	    <row>
-	      <entry>12</entry><entry>int16_t</entry><entry>ground_accel</entry><entry>Average accelerometer reading on ground</entry>
-	    </row>
-	    <row>
-	      <entry>14</entry><entry>int16_t</entry><entry>accel_plus_g</entry><entry>Accel calibration at +1g</entry>
-	    </row>
-	    <row>
-	      <entry>16</entry><entry>int16_t</entry><entry>accel_minus_g</entry><entry>Accel calibration at -1g</entry>
-	    </row>
-	    <row>
-	      <entry>18</entry><entry>pad[14]</entry><entry>pad bytes</entry><entry></entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-    <section>
-      <title>Configuration Data</title>
-      <informaltable frame='none' label='' tocentry='0'>
-	<tgroup cols='2' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='left' colwidth='3*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Type</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0x04</entry>
-	      <entry>Configuration Data</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </informaltable>
-      <para>
-	This provides a description of the software installed on the
-	flight computer as well as any user-specified configuration data.
-      </para>
-      <para>
-	Configuration data packets are transmitted once per second
-	during all phases of the flight
-      </para>
-      <table frame='all'>
-	<title>Sensor Packet Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>type</entry><entry>Device type</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>uint16_t</entry><entry>flight</entry><entry>Flight number</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>uint8_t</entry><entry>config_major</entry><entry>Config major version</entry>
-	    </row>
-	    <row>
-	      <entry>9</entry><entry>uint8_t</entry><entry>config_minor</entry><entry>Config minor version</entry>
-	    </row>
-	    <row>
-	      <entry>10</entry><entry>uint16_t</entry><entry>apogee_delay</entry>
-	      <entry>Apogee deploy delay in seconds</entry>
-	    </row>
-	    <row>
-	      <entry>12</entry><entry>uint16_t</entry><entry>main_deploy</entry><entry>Main deploy alt in meters</entry>
-	    </row>
-	    <row>
-	      <entry>14</entry><entry>uint16_t</entry><entry>flight_log_max</entry>
-	      <entry>Maximum flight log size (kB)</entry>
-	    </row>
-	    <row>
-	      <entry>16</entry><entry>char</entry><entry>callsign[8]</entry><entry>Radio operator identifier</entry>
-	    </row>
-	    <row>
-	      <entry>24</entry><entry>char</entry><entry>version[8]</entry><entry>Software version identifier</entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-    <section>
-      <title>GPS Location</title>
-      <informaltable frame='none' label='' tocentry='0'>
-	<tgroup cols='2' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='left' colwidth='3*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Type</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0x05</entry>
-	      <entry>GPS Location</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </informaltable>
-      <para>
-	This packet provides all of the information available from the
-	GPS receiver—position, time, speed and precision
-	estimates. 
-      </para>
-      <para>
-	GPS Location packets are transmitted once per second during
-	all phases of the flight
-      </para>
-      <table frame='all'>
-	<title>GPS Location Packet Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>flags</entry>
-	      <entry>See GPS Flags table below</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>int16_t</entry><entry>altitude</entry><entry>m</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>int32_t</entry><entry>latitude</entry><entry>degrees * 10<superscript>7</superscript></entry>
-	    </row>
-	    <row>
-	      <entry>12</entry><entry>int32_t</entry><entry>longitude</entry><entry>degrees * 10<superscript>7</superscript></entry>
-	    </row>
-	    <row>
-	      <entry>16</entry><entry>uint8_t</entry><entry>year</entry>
-	    </row>
-	    <row>
-	      <entry>17</entry><entry>uint8_t</entry><entry>month</entry>
-	    </row>
-	    <row>
-	      <entry>18</entry><entry>uint8_t</entry><entry>day</entry>
-	    </row>
-	    <row>
-	      <entry>19</entry><entry>uint8_t</entry><entry>hour</entry>
-	    </row>
-	    <row>
-	      <entry>20</entry><entry>uint8_t</entry><entry>minute</entry>
-	    </row>
-	    <row>
-	      <entry>21</entry><entry>uint8_t</entry><entry>second</entry>
-	    </row>
-	    <row>
-	      <entry>22</entry><entry>uint8_t</entry><entry>pdop</entry><entry>* 5</entry>
-	    </row>
-	    <row>
-	      <entry>23</entry><entry>uint8_t</entry><entry>hdop</entry><entry>* 5</entry>
-	    </row>
-	    <row>
-	      <entry>24</entry><entry>uint8_t</entry><entry>vdop</entry><entry>* 5</entry>
-	    </row>
-	    <row>
-	      <entry>25</entry><entry>uint8_t</entry><entry>mode</entry>
-	      <entry>See GPS Mode table below</entry>
-	    </row>
-	    <row>
-	      <entry>26</entry><entry>uint16_t</entry><entry>ground_speed</entry><entry>cm/s</entry>
-	    </row>
-	    <row>
-	      <entry>28</entry><entry>int16_t</entry><entry>climb_rate</entry><entry>cm/s</entry>
-	    </row>
-	    <row>
-	      <entry>30</entry><entry>uint8_t</entry><entry>course</entry><entry>/ 2</entry>
-	    </row>
-	    <row>
-	      <entry>31</entry><entry>uint8_t</entry><entry>unused[1]</entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <para>
-	Packed into a one byte field are status flags and the count of
-	satellites used to compute the position fix. Note that this
-	number may be lower than the number of satellites being
-	tracked; the receiver will not use information from satellites
-	with weak signals or which are close enough to the horizon to
-	have significantly degraded position accuracy.
-      </para>
-      <table frame='all'>
-	<title>GPS Flags</title>
-	<tgroup cols='3' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='bits'/>
-	  <colspec align='left' colwidth='2*' colname='name'/>
-	  <colspec align='left' colwidth='7*' colname='description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Bits</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0-3</entry>
-	      <entry>nsats</entry>
-	      <entry>Number of satellites in solution</entry>
-	    </row>
-	    <row>
-	      <entry>4</entry>
-	      <entry>valid</entry>
-	      <entry>GPS solution is valid</entry>
-	    </row>
-	    <row>
-	      <entry>5</entry>
-	      <entry>running</entry>
-	      <entry>GPS receiver is operational</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry>
-	      <entry>date_valid</entry>
-	      <entry>Reported date is valid</entry>
-	    </row>
-	    <row>
-	      <entry>7</entry>
-	      <entry>course_valid</entry>
-	      <entry>ground speed, course and climb rates are valid</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <para>
-	Here are all of the valid GPS operational modes. Altus Metrum
-	products will only ever report 'N' (not valid), 'A'
-	(Autonomous) modes or 'E' (Estimated). The remaining modes
-	are either testing modes or require additional data.
-      </para>
-      <table frame='all'>
-	<title>GPS Mode</title>
-	<tgroup cols='3' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='value'/>
-	  <colspec align='center' colwidth='3*' colname='name'/>
-	  <colspec align='left' colwidth='7*' colname='description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Mode</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Decsription</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>N</entry>
-	      <entry>Not Valid</entry>
-	      <entry>All data are invalid</entry>
-	    </row>
-	    <row>
-	      <entry>A</entry>
-	      <entry>Autonomous mode</entry>
-	      <entry>Data are derived from satellite data</entry>
-	    </row>
-	    <row>
-	      <entry>D</entry>
-	      <entry>Differential Mode</entry>
-	      <entry>
-		  Data are augmented with differential data from a
-		  known ground station. The SkyTraq unit in TeleMetrum
-		  does not support this mode
-		</entry>
-	    </row>
-	    <row>
-	      <entry>E</entry>
-	      <entry>Estimated</entry>
-	      <entry>
-		  Data are estimated using dead reckoning from the
-		  last known data
-		</entry>
-	    </row>
-	    <row>
-	      <entry>M</entry>
-	      <entry>Manual</entry>
-	      <entry>Data were entered manually</entry>
-	    </row>
-	    <row>
-	      <entry>S</entry>
-	      <entry>Simulated</entry>
-	      <entry>GPS receiver testing mode</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-    <section>
-      <title>GPS Satellite Data</title>
-      <informaltable frame='none' label='' tocentry='0'>
-	<tgroup cols='2' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='left' colwidth='3*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Type</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0x06</entry>
-	      <entry>GPS Satellite Data</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </informaltable>
-      <para>
-	This packet provides space vehicle identifiers and signal
-	quality information in the form of a C/N1 number for up to 12
-	satellites. The order of the svids is not specified.
-      </para>
-      <para>
-	GPS Satellite data are transmitted once per second during all
-	phases of the flight.
-      </para>
-      <table frame='all'>
-	<title>GPS Satellite Data Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='right' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>channels</entry>
-	      <entry>Number of reported satellite information</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>sat_info_t</entry><entry>sats[12]</entry>
-	      <entry>See Per-Satellite data table below</entry>
-	    </row>
-	    <row>
-	      <entry>30</entry><entry>uint8_t</entry><entry>unused[2]</entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-      <table frame='all'>
-	<title>GPS Per-Satellite data (sat_info_t)</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='right' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0</entry><entry>uint8_t</entry><entry>svid</entry>
-	      <entry>Space Vehicle Identifier</entry>
-	    </row>
-	    <row>
-	      <entry>1</entry><entry>uint8_t</entry><entry>c_n_1</entry>
-	      <entry>C/N1 signal quality indicator</entry>
-	    </row>
-	    <row>
-	      <entry>2</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-    <section>
-      <title>Companion Data Data</title>
-      <informaltable frame='none' label='' tocentry='0'>
-	<tgroup cols='2' align='center' colsep='1' rowsep='1'>
-	  <colspec align='center' colwidth='*' colname='Offset'/>
-	  <colspec align='left' colwidth='3*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry>Type</entry>
-	      <entry>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>0x07</entry>
-	      <entry>Companion Data Data</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </informaltable>
-      <para>
-	When a companion board is attached to TeleMega or TeleMetrum,
-	it can provide telemetry data to be included in the
-	downlink. The companion board can provide up to 12 16-bit data
-	values.
-      </para>
-      <para>
-	The companion board itself specifies the transmission rate. On
-	the ground and during descent, that rate is limited to one
-	packet per second. During ascent, that rate is limited to 10
-	packets per second.
-      </para>
-      <table frame='all'>
-	<title>Companion Data Contents</title>
-	<tgroup cols='4' align='center' colsep='1' rowsep='1'>
-	  <colspec align='right' colwidth='*' colname='Offset'/>
-	  <colspec align='center' colwidth='3*' colname='Data Type'/>
-	  <colspec align='left' colwidth='3*' colname='Name'/>
-	  <colspec align='left' colwidth='9*' colname='Description'/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Offset</entry>
-	      <entry align='center'>Data Type</entry>
-	      <entry align='center'>Name</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>5</entry><entry>uint8_t</entry><entry>board_id</entry>
-	      <entry>Type of companion board attached</entry>
-	    </row>
-	    <row>
-	      <entry>6</entry><entry>uint8_t</entry><entry>update_period</entry>
-	      <entry>How often telemetry is sent, in 1/100ths of a second</entry>
-	    </row>
-	    <row>
-	      <entry>7</entry><entry>uint8_t</entry><entry>channels</entry>
-	      <entry>Number of data channels supplied</entry>
-	    </row>
-	    <row>
-	      <entry>8</entry><entry>uint16_t[12]</entry><entry>companion_data</entry>
-	      <entry>Up to 12 channels of 16-bit companion data</entry>
-	    </row>
-	    <row>
-	      <entry>32</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-  </section>
-  <section>
-    <title>Data Transmission</title>
-    <para>
-      Altus Metrum devices use Texas Instruments sub-GHz digital radio
-      products. Ground stations use parts with HW FEC while some
-      flight computers perform FEC in software. TeleGPS is
-      transmit-only.
-    </para>
-    <table>
-      <title>Altus Metrum Radio Parts</title>
-      <tgroup cols='3'>
-	<colspec align="center" colwidth="*" colname="Part Number"/>
-	<colspec align="center" colwidth="*" colname="Description"/>
-	<colspec align="left" colwidth="*" colname="Used in"/>
-	<thead>
-	  <row>
-	    <entry align="center">Part Number</entry>
-	    <entry align="center">Description</entry>
-	    <entry align="center">Used in</entry>
-	  </row>
-	</thead>
-	<tbody>
-	  <row>
-	    <entry>CC1111</entry><entry>10mW transceiver with integrated SoC</entry>
-	    <entry>TeleDongle v0.2, TeleBT v1.0, TeleMetrum v1.x, TeleMini</entry>
-	  </row>
-	  <row>
-	    <entry>CC1120</entry><entry>35mW transceiver with SW FEC</entry>
-	    <entry>TeleMetrum v2, TeleMega</entry>
-	  </row>
-	  <row>
-	    <entry>CC1200</entry><entry>35mW transceiver with HW FEC</entry>
-	    <entry>TeleDongle v3.0, TeleBT v3.0</entry>
-	  </row>
-	  <row>
-	    <entry>CC115L</entry><entry>14mW transmitter with SW FEC</entry>
-	    <entry>TeleGPS</entry>
-	  </row>
-	</tbody>
-      </tgroup>
-    </table>
-    <section>
-      <title>Modulation Scheme</title>
-      <para>
-	Texas Instruments provides a tool for computing modulation
-	parameters given a desired modulation format and basic bit
-	rate.
-
-	While we might like to use something with better low-signal
-	performance like BPSK, the radios we use don't support that,
-	but do support Gaussian frequency shift keying (GFSK). Regular
-	frequency shift keying (FSK) encodes the signal by switching
-	the carrier between two frequencies. The Gaussian version is
-	essentially the same, but the shift between frequencies gently
-	follows a gaussian curve, rather than switching
-	immediately. This tames the bandwidth of the signal without
-	affecting the ability to transmit data.
-
-	For AltOS, there are three available bit rates, 38.4kBaud,
-	9.6kBaud and 2.4kBaud resulting in the following signal
-	parmeters:
-
-      </para>
-      <table>
-	<title>Modulation Scheme</title>
-	<tgroup cols='3'>
-	  <colspec align="center" colwidth="*" colname="rate"/>
-	  <colspec align="center" colwidth="*" colname="deviation"/>
-	  <colspec align="center" colwidth="*" colname="bandwidth"/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Rate</entry>
-	      <entry align='center'>Deviation</entry>
-	      <entry align='center'>Receiver Bandwidth</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>38.4kBaud</entry>
-	      <entry>20.5kHz</entry>
-	      <entry>100kHz</entry>
-	    </row>
-	    <row>
-	      <entry>9.6kBaud</entry>
-	      <entry>5.125kHz</entry>
-	      <entry>25kHz</entry>
-	    </row>
-	    <row>
-	      <entry>2.4kBaud</entry>
-	      <entry>1.5kHz</entry>
-	      <entry>5kHz</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-    <section>
-      <title>Error Correction</title>
-      <para>
-	The cc1111 and cc1200 provide forward error correction in
-	hardware; on the cc1120 and cc115l that's done in
-	software. AltOS uses this to improve reception of weak
-	signals. As it's a rate 1/2 encoding, each bit of data takes
-	two bits when transmitted, so the effective data rate is half
-	of the raw transmitted bit rate.
-      </para>
-      <table>
-	<title>Error Correction</title>
-	<tgroup cols='3'>
-	  <colspec align="center" colwidth="*" colname="parameter"/>
-	  <colspec align="center" colwidth="*" colname="value"/>
-	  <colspec align="center" colwidth="*" colname="description"/>
-	  <thead>
-	    <row>
-	      <entry align='center'>Parameter</entry>
-	      <entry align='center'>Value</entry>
-	      <entry align='center'>Description</entry>
-	    </row>
-	  </thead>
-	  <tbody>
-	    <row>
-	      <entry>Error Correction</entry>
-	      <entry>Convolutional coding</entry>
-	      <entry>1/2 rate, constraint length m=4</entry>
-	    </row>
-	    <row>
-	      <entry>Interleaving</entry>
-	      <entry>4 x 4</entry>
-	      <entry>Reduce effect of noise burst</entry>
-	    </row>
-	    <row>
-	      <entry>Data Whitening</entry>
-	      <entry>XOR with 9-bit PNR</entry>
-	      <entry>Rotate right with bit 8 = bit 0 xor bit 5, initial
-	      value 111111111</entry>
-	    </row>
-	  </tbody>
-	</tgroup>
-      </table>
-    </section>
-  </section>
-  <section>
-    <title>TeleDongle packet format</title>
-    <para>
-      TeleDongle does not do any interpretation of the packet data,
-      instead it is configured to receive packets of a specified
-      length (32 bytes in this case). For each received packet,
-      TeleDongle produces a single line of text. This line starts with
-      the string "TELEM " and is followed by a list of hexadecimal
-      encoded bytes.
-    </para>
-    <programlisting>TELEM 224f01080b05765e00701f1a1bbeb8d7b60b070605140c000600000000000000003fa988</programlisting>
-    <para>
-      The hexadecimal encoded string of bytes contains a length byte,
-      the packet data, two bytes added by the cc1111 radio receiver
-      hardware and finally a checksum so that the host software can
-      validate that the line was transmitted without any errors.
-    </para>
-    <table>
-      <title>Packet Format</title>
-      <tgroup cols='4'>
-	<colspec align="center" colwidth="2*" colname="offset"/>
-	<colspec align="center" colwidth="*" colname="name"/>
-	<colspec align="center" colwidth="*" colname="value"/>
-	<colspec align="center" colwidth="5*" colname="description"/>
-	<thead>
-	  <row>
-	    <entry align='center'>Offset</entry>
-	    <entry align='center'>Name</entry>
-	    <entry align='center'>Example</entry>
-	    <entry align='center'>Description</entry>
-	  </row>
-	</thead>
-	<tbody>
-	  <row>
-	    <entry>0</entry>
-	    <entry>length</entry>
-	    <entry>22</entry>
-	    <entry>Total length of data bytes in the line. Note that
-	    this includes the added RSSI and status bytes</entry>
-	  </row>
-	  <row>
-	    <entry>1 ·· length-3</entry>
-	    <entry>packet</entry>
-	    <entry>4f ·· 00</entry>
-	    <entry>Bytes of actual packet data</entry>
-	  </row>
-	  <row>
-	    <entry>length-2</entry>
-	    <entry>rssi</entry>
-	    <entry>3f</entry>
-	    <entry>Received signal strength. dBm = rssi / 2 - 74</entry>
-	  </row>
-	  <row>
-	    <entry>length-1</entry>
-	    <entry>lqi</entry>
-	    <entry>a9</entry>
-	    <entry>Link Quality Indicator and CRC status. Bit 7
-	    is set when the CRC is correct</entry>
-	  </row>
-	  <row>
-	    <entry>length</entry>
-	    <entry>checksum</entry>
-	    <entry>88</entry>
-	    <entry>(0x5a + sum(bytes 1 ·· length-1)) % 256</entry>
-	  </row>
-	</tbody>
-      </tgroup>
-    </table>
-  </section>
-  <section>
-    <title>History and Motivation</title>
-    <para>
-      The original AltoOS telemetry mechanism encoded everything
-      available piece of information on the TeleMetrum hardware into a
-      single unified packet. Initially, the packets contained very
-      little data—some raw sensor readings along with the current GPS
-      coordinates when a GPS receiver was connected. Over time, the
-      amount of data grew to include sensor calibration data, GPS
-      satellite information and a host of internal state information
-      designed to help diagnose flight failures in case of a loss of
-      the on-board flight data.
-    </para>
-    <para>
-      Because every packet contained all of the data, packets were
-      huge—95 bytes long. Much of the information was also specific to
-      the TeleMetrum hardware. With the introduction of the TeleMini
-      flight computer, most of the data contained in the telemetry
-      packets was unavailable. Initially, a shorter, but still
-      comprehensive packet was implemented. This required that the
-      ground station be pre-configured as to which kind of packet to
-      expect.
-    </para>
-    <para>
-      The development of several companion boards also made the
-      shortcomings evident—each companion board would want to include
-      telemetry data in the radio link; with the original design, the
-      packet would have to hold the new data as well, requiring
-      additional TeleMetrum and ground station changes.
-    </para>
-  </section>
-</article>