Again a noob question. What is the purpose of Air vs Ground start in practical terms? The difference seems obvious, start GPS in the Air or on the Ground. The bind plug isn't used with the IMU from what I've read so wouldn't the GPS be set to Ground start by default?
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The purpose of air start is in case you have a power glitch or for some other reason the autopilot is restarted in the air. In this case we want as quick a startup process as possible so that the plane does not crash during the time without control. During air start we pull values back out of eeprom and get going quickly.
The purpose of ground start is to collect appropriate values for the home location, zero airspeed pressure, radio center stick values and IR max levels. On the IMU side we collect values for the gyro and accelerometer offsets. This takes a bit of time. We store these values in eeprom in case we need them for an air start.
The procedure for air versus ground start has changed recently with ArduPilot 2.5 and 2.6. The bind plug is no longer used, unless you are not using throttle channel input to Ardupilot. A ground start is initialized whenever ArduPilot is powered up with the mode set to MANUAL and the throttle stick in a low position.
If you are using ArduIMU with ArduPilot it is easy to recognize a ground start because you will see a flashing sequence of the red, yellow and blue led's. Please not that the ground start is still processing after the flashing stops. You should leave the plane still until you get a solid blue on the IMU.
If you are using ArduPilot with thermopiles the easiest way to recognize if a ground start is occuring is to monitor the telemetry.
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The purpose of air start is in case you have a power glitch or for some other reason the autopilot is restarted in the air. In this case we want as quick a startup process as possible so that the plane does not crash during the time without control. During air start we pull values back out of eeprom and get going quickly.
The purpose of ground start is to collect appropriate values for the home location, zero airspeed pressure, radio center stick values and IR max levels. On the IMU side we collect values for the gyro and accelerometer offsets. This takes a bit of time. We store these values in eeprom in case we need them for an air start.
The procedure for air versus ground start has changed recently with ArduPilot 2.5 and 2.6. The bind plug is no longer used, unless you are not using throttle channel input to Ardupilot. A ground start is initialized whenever ArduPilot is powered up with the mode set to MANUAL and the throttle stick in a low position.
If you are using ArduIMU with ArduPilot it is easy to recognize a ground start because you will see a flashing sequence of the red, yellow and blue led's. Please not that the ground start is still processing after the flashing stops. You should leave the plane still until you get a solid blue on the IMU.
If you are using ArduPilot with thermopiles the easiest way to recognize if a ground start is occuring is to monitor the telemetry.