diff options
| -rw-r--r-- | doc/telemetry.xsl | 499 |
1 files changed, 459 insertions, 40 deletions
diff --git a/doc/telemetry.xsl b/doc/telemetry.xsl index e4101507..2e0b3ea1 100644 --- a/doc/telemetry.xsl +++ b/doc/telemetry.xsl @@ -110,7 +110,7 @@ </para> </section> <section> - <title>Sensor Data</title> + <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'/> @@ -124,7 +124,7 @@ <tbody> <row> <entry>0x01</entry> - <entry>TeleMetrum Sensor Data</entry> + <entry>TeleMetrum v1.x Sensor Data</entry> </row> <row> <entry>0x02</entry> @@ -138,7 +138,7 @@ </tgroup> </informaltable> <para> - TeleMetrum, TeleMini and TeleNano share this same packet + 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. @@ -214,6 +214,316 @@ </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'> @@ -315,7 +625,7 @@ </informaltable> <para> This packet provides all of the information available from the - Venus SkyTraq GPS receiver—position, time, speed and precision + GPS receiver—position, time, speed and precision estimates. </para> <para> @@ -604,62 +914,169 @@ </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 the Texas Instruments CC1111 - microcontroller which includes an integrated sub-GHz digital - transceiver. This transceiver is used to both transmit and - receive the telemetry packets. This section discusses what - modulation scheme is used and how this device is configured. + 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. For AltOS, the basic bit rate was specified as 38 kBaud, - resulting in the following signal parmeters: + 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="parameter"/> - <colspec align="center" colwidth="*" colname="value"/> - <colspec align="center" colwidth="*" colname="description"/> + <colspec align="center" colwidth="*" colname="rate"/> + <colspec align="center" colwidth="*" colname="deviation"/> + <colspec align="center" colwidth="*" colname="bandwidth"/> <thead> <row> - <entry align='center'>Parameter</entry> - <entry align='center'>Value</entry> - <entry align='center'>Description</entry> + <entry align='center'>Rate</entry> + <entry align='center'>Deviation</entry> + <entry align='center'>Receiver Bandwidth</entry> </row> </thead> <tbody> <row> - <entry>Modulation</entry> - <entry>GFSK</entry> - <entry>Gaussian Frequency Shift Keying</entry> - </row> - <row> - <entry>Deviation</entry> - <entry>20.507812 kHz</entry> - <entry>Frequency modulation</entry> - </row> - <row> - <entry>Data rate</entry> - <entry>38.360596 kBaud</entry> - <entry>Raw bit rate</entry> + <entry>38.4kBaud</entry> + <entry>20.5kHz</entry> + <entry>100kHz</entry> </row> <row> - <entry>RX Filter Bandwidth</entry> - <entry>93.75 kHz</entry> - <entry>Receiver Band pass filter bandwidth</entry> + <entry>9.6kBaud</entry> + <entry>5.125kHz</entry> + <entry>25kHz</entry> </row> <row> - <entry>IF Frequency</entry> - <entry>140.62 kHz</entry> - <entry>Receiver intermediate frequency</entry> + <entry>2.4kBaud</entry> + <entry>1.5kHz</entry> + <entry>5kHz</entry> </row> </tbody> </tgroup> @@ -668,10 +1085,12 @@ <section> <title>Error Correction</title> <para> - The cc1111 provides forward error correction in hardware, - which AltOS uses to improve reception of weak signals. The - overall effect of this is to halve the available bandwidth for - data from 38 kBaud to 19 kBaud. + 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> |