+++ /dev/null
-<?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
--->
\ No newline at end of file