doc: Add telemetry format description

Document the telemetry packet contents.

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

1 files changed, 572 insertions, 0 deletions

diff --git a/doc/telemetry.xsl b/doc/telemetry.xsl
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+<?xml version="1.0" encoding="utf-8" ?>
+<!DOCTYPE book 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>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>
+  <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>
+    This section first defines the packet header common to all packets
+    and then the per-packet data layout.
+    <section>
+      <title>Packet Header</title>
+      <table frame='all'>
+	<title>Telemetry Packet Header</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>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>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 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, 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>
+      <table frame='all'>
+	<title>Sensor Packet 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>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>accel</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_accel</entry><entry>TM</entry>
+	    </row>
+	    <row>
+	      <entry>26</entry><entry>int16_t</entry><entry>ground_pres</entry><entry>Average barometer reading on ground</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>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>
+      <table frame='all'>
+	<title>Sensor Packet 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>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>main_deploy</entry><entry>Main deploy alt in meters</entry>
+	    </row>
+	    <row>
+	      <entry>12</entry><entry>uint32_t</entry><entry>flight_log_max</entry><entry>Maximum flight log size (B)</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>
+      <table frame='all'>
+	<title>GPS Location Packet 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>flags</entry><entry>GPS Flags (see 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>N, A, D, E, M, S</entry>
+	    </row>
+	    <row>
+	      <entry>26</entry><entry>uint16_t</entry><entry>ground_speed</entry><entry>cm/s</entry>
+	    </row>
+	    <row>
+	      <entry>28</entry><entry>uint8_t</entry><entry>course</entry><entry>/ 2</entry>
+	    </row>
+	    <row>
+	      <entry>29</entry><entry>uint8_t</entry><entry>unused[2]</entry>
+	    </row>
+	    <row>
+	      <entry>32</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>
+      <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>
+	    </row>
+	    <row>
+	      <entry>6</entry><entry>uint8_t</entry><entry>sat_0_id</entry>
+	    </row>
+	    <row>
+	      <entry>7</entry><entry>uint8_t</entry><entry>sat_0_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>8</entry><entry>uint8_t</entry><entry>sat_1_id</entry>
+	    </row>
+	    <row>
+	      <entry>9</entry><entry>uint8_t</entry><entry>sat_1_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>10</entry><entry>uint8_t</entry><entry>sat_2_id</entry>
+	    </row>
+	    <row>
+	      <entry>11</entry><entry>uint8_t</entry><entry>sat_2_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>12</entry><entry>uint8_t</entry><entry>sat_3_id</entry>
+	    </row>
+	    <row>
+	      <entry>13</entry><entry>uint8_t</entry><entry>sat_3_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>14</entry><entry>uint8_t</entry><entry>sat_4_id</entry>
+	    </row>
+	    <row>
+	      <entry>15</entry><entry>uint8_t</entry><entry>sat_4_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>16</entry><entry>uint8_t</entry><entry>sat_5_id</entry>
+	    </row>
+	    <row>
+	      <entry>17</entry><entry>uint8_t</entry><entry>sat_5_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>18</entry><entry>uint8_t</entry><entry>sat_6_id</entry>
+	    </row>
+	    <row>
+	      <entry>19</entry><entry>uint8_t</entry><entry>sat_6_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>20</entry><entry>uint8_t</entry><entry>sat_7_id</entry>
+	    </row>
+	    <row>
+	      <entry>21</entry><entry>uint8_t</entry><entry>sat_7_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>22</entry><entry>uint8_t</entry><entry>sat_8_id</entry>
+	    </row>
+	    <row>
+	      <entry>23</entry><entry>uint8_t</entry><entry>sat_8_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>24</entry><entry>uint8_t</entry><entry>sat_9_id</entry>
+	    </row>
+	    <row>
+	      <entry>25</entry><entry>uint8_t</entry><entry>sat_9_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>26</entry><entry>uint8_t</entry><entry>sat_10_id</entry>
+	    </row>
+	    <row>
+	      <entry>27</entry><entry>uint8_t</entry><entry>sat_10_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>28</entry><entry>uint8_t</entry><entry>sat_11_id</entry>
+	    </row>
+	    <row>
+	      <entry>29</entry><entry>uint8_t</entry><entry>sat_11_c_n_1</entry>
+	    </row>
+	    <row>
+	      <entry>30</entry><entry>uin8_t</entry><entry>unused30</entry>
+	    </row>
+	    <row>
+	      <entry>31</entry><entry>uin8_t</entry><entry>unused31</entry>
+	    </row>
+	    <row>
+	      <entry>32</entry>
+	    </row>
+	  </tbody>
+	</tgroup>
+      </table>
+    </section>
+  </section>
+</article>
+      
+<!--
+
+      
+      
+  
+ Rethinking this (over IRC), and thinking about telemetry from a
+ companion board, it looks like 32 bytes per packet would be better (12
+ channels of A/D from telescience would require 24 bytes).
+
+ Packet type 0x06: GPS satellites
+ 1 packet per second.
+
+
+ TeleScience
+
+<entry>5</entry><entry>uint8_t</entry><entry>channels</entry>
+<entry>6</entry><entry>uint16_t</entry><entry>data[12]</entry>
+<entry>30</entry><entry>uint8_t</entry><entry>unused[2]</entry>
+<entry>32</entry>
+
+ [ 2-line signature. Click/Enter to show. ]
+ - - 
+ keith.packard@intel.com
+ [ application/pgp-signature ]
+  Keith Packard <keithp@keithp.com> (Mon. 18:59) (me sent)
+  Subject: Re: New telemetry ideas
+  To: bdale@gag.com
+  Date: Mon, 27 Jun 2011 18:59:08 -0700
+
+  [ multipart/signed ]
+  [ text/plain ]
+  On Mon, 27 Jun 2011 14:25:00 -0700, Keith Packard <keithp@keithp.com> wrote:
+  Non-text part: multipart/signed
+
+  > Packet type 0x05: GPS location
+  > 1 packet per second
+  > 
+  > 5       uint8_t         flags
+
+  Let's add another field here:
+
+<entry>6</entry><entry>int16_t</entry><entry>gps_tick</entry><entry>tick when GPS data was received</entry>
+
+  That leaves a single byte unused
+-->
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