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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> |