X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=doc%2Faltusmetrum.xsl;h=aeb43acb4a0b8c7fdb6616e1feff9a9ec55ae009;hp=3a8f51d311569b3f6a7a7a61178b705a2f0c7e69;hb=e268798dc260311f5f0167909481b41c9d27fc1c;hpb=edfb553bb4fa5b0c7c6c658505b2a99d05fb13bf diff --git a/doc/altusmetrum.xsl b/doc/altusmetrum.xsl index 3a8f51d3..aeb43acb 100644 --- a/doc/altusmetrum.xsl +++ b/doc/altusmetrum.xsl @@ -536,7 +536,7 @@ NAR #88757, TRA #12200 or radio link via TeleDongle.
- Radio Frequencies + Radio Frequency Altus Metrum boards support radio frequencies in the 70cm band. By default, the configuration interface provides a @@ -548,19 +548,6 @@ NAR #88757, TRA #12200 altimeter and TeleDongle must be configured to the same frequency to successfully communicate with each other. - - To set the radio frequency, use the 'c R' command to specify the - radio transceiver configuration parameter. This parameter is computed - using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and - the standard calibration reference frequency, 'S', (normally 434.550MHz): - - R = F / S * C - - Round the result to the nearest integer value. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board flash on - your altimeter board if you want the change to stay in place across reboots. -
Apogee Delay @@ -573,20 +560,14 @@ NAR #88757, TRA #12200 primary and backup pyrotechnic charges do not fire simultaneously. - To set the apogee delay, use the 'c d' command. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. - - - Please note that the Altus Metrum apogee detection algorithm - fires exactly at apogee. If you are also flying an - altimeter like the PerfectFlite MAWD, which only supports - selecting 0 or 1 seconds of apogee delay, you may wish to - set the MAWD to 0 seconds delay and set the TeleMetrum to - fire your backup 2 or 3 seconds later to avoid any chance of - both charges firing simultaneously. We've flown several - air-frames this way quite happily, including Keith's - successful L3 cert. + The Altus Metrum apogee detection algorithm fires exactly at + apogee. If you are also flying an altimeter like the + PerfectFlite MAWD, which only supports selecting 0 or 1 + seconds of apogee delay, you may wish to set the MAWD to 0 + seconds delay and set the TeleMetrum to fire your backup 2 + or 3 seconds later to avoid any chance of both charges + firing simultaneously. We've flown several air-frames this + way quite happily, including Keith's successful L3 cert.
@@ -601,99 +582,79 @@ NAR #88757, TRA #12200 than the primary so that both pyrotechnic charges don't fire simultaneously. - - To set the main deployment altitude, use the 'c m' command. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. -
- -
- Calibration - - There are only two calibrations required for a TeleMetrum board, and - only one for TeleDongle and TeleMini. -
- Radio Frequency - - The radio frequency is synthesized from a clock based on the 48 MHz - crystal on the board. The actual frequency of this oscillator must be - measured to generate a calibration constant. While our GFSK modulation - bandwidth is wide enough to allow boards to communicate even when - their oscillators are not on exactly the same frequency, performance - is best when they are closely matched. - Radio frequency calibration requires a calibrated frequency counter. - Fortunately, once set, the variation in frequency due to aging and - temperature changes is small enough that re-calibration by customers - should generally not be required. - - - To calibrate the radio frequency, connect the UHF antenna port to a - frequency counter, set the board to 434.550MHz, and use the 'C' - command to generate a CW carrier. Wait for the transmitter temperature - to stabilize and the frequency to settle down. - Then, divide 434.550 MHz by the - measured frequency and multiply by the current radio cal value show - in the 'c s' command. For an unprogrammed board, the default value - is 1186611. Take the resulting integer and program it using the 'c f' - command. Testing with the 'C' command again should show a carrier - within a few tens of Hertz of the intended frequency. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. - + Maximum Flight Log + + TeleMetrum version 1.1 has 2MB of on-board flash storage, + enough to hold over 40 minutes of data at full data rate + (100 samples/second). TeleMetrum 1.0 has 1MB of on-board + storage. As data are stored at a reduced rate during + descent, there's plenty of space to store many flights worth + of data. + - when the radio calibration value is changed, the radio - frequency value is reset to the same value, so you'll need - to recompute and reset the radio frequency value using the - new radio calibration value. + The on-board flash is partitioned into separate flight logs, + each of a fixed maximum size. Increase the maximum size of + each log and you reduce the number of flights that can be + stored. Decrease the size and TeleMetrum can store more + flights. + + + All of the configuration data is also stored in the flash + memory, which consumes 64kB on TeleMetrum v1.1 and 256B on + TeleMetrum v1.0. This configuration space is not available + for storing flight log data. + + + To compute the amount of space needed for a single flight, + you can multiply the expected ascent time (in seconds) by + 800, multiply the expected descent time (in seconds) by 80 + and add the two together. That will slightly under-estimate + the storage (in bytes) needed for the flight. For instance, + a flight spending 20 seconds in ascent and 150 seconds in + descent will take about (20 * 800) + (150 * 80) = 28000 + bytes of storage. You could store dozens of these flights in + the on-board flash. + + + The default size, 192kB, allows for 10 flights of storage on + TeleMetrum v1.1 and 5 flights on TeleMetrum v1.0. This + ensures that you won't need to erase the memory before + flying each time while still allowing more than sufficient + storage for each flight.
- TeleMetrum Accelerometer - - The TeleMetrum accelerometer we use has its own 5 volt power supply and - the output must be passed through a resistive voltage divider to match - the input of our 3.3 volt ADC. This means that unlike the barometric - sensor, the output of the acceleration sensor is not ratio-metric to - the ADC converter, and calibration is required. We also support the - use of any of several accelerometers from a Freescale family that - includes at least +/- 40g, 50g, 100g, and 200g parts. Using gravity, - a simple 2-point calibration yields acceptable results capturing both - the different sensitivities and ranges of the different accelerometer - parts and any variation in power supply voltages or resistor values - in the divider network. - - - To calibrate the acceleration sensor, use the 'c a 0' command. You - will be prompted to orient the board vertically with the UHF antenna - up and press a key, then to orient the board vertically with the - UHF antenna down and press a key. - As with all 'c' sub-commands, follow this with a 'c w' to write the - change to the parameter block in the on-board DataFlash chip. - - - The +1g and -1g calibration points are included in each telemetry - frame and are part of the header extracted by ao-dumplog after flight. - Note that we always store and return raw ADC samples for each - sensor... nothing is permanently "lost" or "damaged" if the - calibration is poor. - - - In the unlikely event an accel cal that goes badly, it is possible - that TeleMetrum may always come up in 'pad mode' and as such not be - listening to either the USB or radio link. If that happens, - there is a special hook in the firmware to force the board back - in to 'idle mode' so you can re-do the cal. To use this hook, you - just need to ground the SPI clock pin at power-on. This pin is - available as pin 2 on the 8-pin companion connector, and pin 1 is - ground. So either carefully install a fine-gauge wire jumper - between the two pins closest to the index hole end of the 8-pin - connector, or plug in the programming cable to the 8-pin connector - and use a small screwdriver or similar to short the two pins closest - to the index post on the 4-pin end of the programming cable, and - power up the board. It should come up in 'idle mode' (two beeps). - + Ignite Mode + + Instead of firing one charge at apogee and another charge at + a fixed height above the ground, you can configure the + altimeter to fire both at apogee or both during + descent. This was added to support an airframe that has two + TeleMetrum computers, one in the fin can and one in the + nose. + + + Providing the ability to use both igniters for apogee or + main allows some level of redundancy without needing two + flight computers. In Redundant Apogee or Redundant Main + mode, the two charges will be fired two seconds apart. + +
+
+ Pad Orientation + + TeleMetrum measures acceleration along the axis of the + board. Which way the board is oriented affects the sign of + the acceleration value. Instead of trying to guess which way + the board is mounted in the air frame, TeleMetrum must be + explicitly configured for either Antenna Up or Antenna + Down. The default, Antenna Up, expects the end of the + TeleMetrum board connected to the 70cm antenna to be nearest + the nose of the rocket, with the end containing the screw + terminals nearest the tail. +
@@ -1325,10 +1286,10 @@ NAR #88757, TRA #12200
Callsign - This value is used in command packet mode and is transmitted - in each packet sent from TeleDongle and received from - TeleMetrum. It is not used in telemetry mode as that transmits - packets only from TeleMetrum to TeleDongle. Configure this + This value is transmitted in each command packet sent from + TeleDongle and received from an altimeter. It is not used in + telemetry mode, as the callsign configured in the altimeter board + is included in all telemetry packets. Configure this with the AltosUI operators call sign as needed to comply with your local radio regulations. @@ -2287,6 +2248,43 @@ NAR #88757, TRA #12200 Verify you can connect and disconnect from the units while in your terminal program by sending the escape-disconnect mentioned above. + + To set the radio frequency, use the 'c R' command to specify the + radio transceiver configuration parameter. This parameter is computed + using the desired frequency, 'F', the radio calibration parameter, 'C' (showed by the 'c s' command) and + the standard calibration reference frequency, 'S', (normally 434.550MHz): + + R = F / S * C + + Round the result to the nearest integer value. + As with all 'c' sub-commands, follow this with a 'c w' to write the + change to the parameter block in the on-board flash on + your altimeter board if you want the change to stay in place across reboots. + + + To set the apogee delay, use the 'c d' command. + As with all 'c' sub-commands, follow this with a 'c w' to write the + change to the parameter block in the on-board DataFlash chip. + + + To set the main deployment altitude, use the 'c m' command. + As with all 'c' sub-commands, follow this with a 'c w' to write the + change to the parameter block in the on-board DataFlash chip. + + + To calibrate the radio frequency, connect the UHF antenna port to a + frequency counter, set the board to 434.550MHz, and use the 'C' + command to generate a CW carrier. Wait for the transmitter temperature + to stabilize and the frequency to settle down. + Then, divide 434.550 MHz by the + measured frequency and multiply by the current radio cal value show + in the 'c s' command. For an unprogrammed board, the default value + is 1186611. Take the resulting integer and program it using the 'c f' + command. Testing with the 'C' command again should show a carrier + within a few tens of Hertz of the intended frequency. + As with all 'c' sub-commands, follow this with a 'c w' to write the + change to the parameter block in the on-board DataFlash chip. + Note that the 'reboot' command, which is very useful on the altimeters, will likely just cause problems with the dongle. The *correct* way @@ -2353,7 +2351,7 @@ NAR #88757, TRA #12200 strength providing an indication of the direction from receiver to rocket. - TeleMetrum also provides GPS trekking data, which can further simplify + TeleMetrum also provides GPS tracking data, which can further simplify locating the rocket once it has landed. (The last good GPS data received before touch-down will be on the data screen of 'ao-view'.) @@ -2377,6 +2375,111 @@ NAR #88757, TRA #12200 once you enable the voice output! + + Calibration + + There are only two calibrations required for a TeleMetrum board, and + only one for TeleDongle and TeleMini. All boards are shipped from + the factory pre-calibrated, but the procedures are documented here + in case they are ever needed. Re-calibration is not supported by + AltosUI, you must connect to the board with a serial terminal program + and interact directly with the on-board command interpreter to effect + calibration. + +
+ Radio Frequency + + The radio frequency is synthesized from a clock based on the 48 MHz + crystal on the board. The actual frequency of this oscillator + must be measured to generate a calibration constant. While our + GFSK modulation + bandwidth is wide enough to allow boards to communicate even when + their oscillators are not on exactly the same frequency, performance + is best when they are closely matched. + Radio frequency calibration requires a calibrated frequency counter. + Fortunately, once set, the variation in frequency due to aging and + temperature changes is small enough that re-calibration by customers + should generally not be required. + + + To calibrate the radio frequency, connect the UHF antenna port to a + frequency counter, set the board to 434.550MHz, and use the 'C' + command in the on-board command interpreter to generate a CW + carrier. For TeleMetrum, this is best done over USB. For TeleMini, + note that the only way to escape the 'C' command is via power cycle + since the board will no longer be listening for commands once it + starts generating a CW carrier. + + + Wait for the transmitter temperature to stabilize and the frequency + to settle down. Then, divide 434.550 MHz by the + measured frequency and multiply by the current radio cal value show + in the 'c s' command. For an unprogrammed board, the default value + is 1186611. Take the resulting integer and program it using the 'c f' + command. Testing with the 'C' command again should show a carrier + within a few tens of Hertz of the intended frequency. + As with all 'c' sub-commands, follow this with a 'c w' to write the + change to the parameter block in the on-board DataFlash chip. + + + Note that any time you re-do the radio frequency calibration, the + radio frequency is reset to the default 434.550 Mhz. If you want + to use another frequency, you will have to set that again after + calibration is completed. + +
+
+ TeleMetrum Accelerometer + + The TeleMetrum accelerometer we use has its own 5 volt power + supply and + the output must be passed through a resistive voltage divider to match + the input of our 3.3 volt ADC. This means that unlike the barometric + sensor, the output of the acceleration sensor is not ratio-metric to + the ADC converter, and calibration is required. Explicitly + calibrating the accelerometers also allows us to load any device + from a Freescale family that includes at least +/- 40g, 50g, 100g, + and 200g parts. Using gravity, + a simple 2-point calibration yields acceptable results capturing both + the different sensitivities and ranges of the different accelerometer + parts and any variation in power supply voltages or resistor values + in the divider network. + + + To calibrate the acceleration sensor, use the 'c a 0' command. You + will be prompted to orient the board vertically with the UHF antenna + up and press a key, then to orient the board vertically with the + UHF antenna down and press a key. Note that the accuracy of this + calibration depends primarily on how perfectly vertical and still + the board is held during the cal process. As with all 'c' + sub-commands, follow this with a 'c w' to write the + change to the parameter block in the on-board DataFlash chip. + + + The +1g and -1g calibration points are included in each telemetry + frame and are part of the header stored in onboard flash to be + downloaded after flight. We always store and return raw ADC + samples for each sensor... so nothing is permanently "lost" or + "damaged" if the calibration is poor. + + + In the unlikely event an accel cal goes badly, it is possible + that TeleMetrum may always come up in 'pad mode' and as such not be + listening to either the USB or radio link. If that happens, + there is a special hook in the firmware to force the board back + in to 'idle mode' so you can re-do the cal. To use this hook, you + just need to ground the SPI clock pin at power-on. This pin is + available as pin 2 on the 8-pin companion connector, and pin 1 is + ground. So either carefully install a fine-gauge wire jumper + between the two pins closest to the index hole end of the 8-pin + connector, or plug in the programming cable to the 8-pin connector + and use a small screwdriver or similar to short the two pins closest + to the index post on the 4-pin end of the programming cable, and + power up the board. It should come up in 'idle mode' (two beeps), + allowing a re-cal. + +
+ Release Notes