Subversion Repositories FlightCtrl

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GPS Implementation by Peter Muehlenbrock ("Salvo") for Mikrokopter/FlightCrtl

As of February, 9th 2008

Please note the files Licensce_LPGL.txt and Licensce_GPL.txt

This SW is based on Holgers V00.67g.

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Hardware-requirements:

Calibrated compass of type CMPS03, horizontally adjusted

GPS module of type ublox, The messages "NAV_STATUS", "NAV_POSUTM" and  "NAV_VELNED"

must be activated with  4 HZ update rate. All messages of type NMEA should be disabled.

The TX port of the GPS module must be connected to the RX input  of the Flight Crtl. Baudrate is 57600 (like Kopter Tool).

UserParameter 4 tells the software the orientation for the compass. The difference between the "north" direction

( = Motor "vorne" or 1 as described in Holgers Flight Crtl manual)  of the kopter

and the north direction of the compass is represented as follows: 0...360 degree offset corresponds to a value of 0...180.

(A userparameter ist only 1 byte long and therefore can not directly represent 0..360 degree). Please check the

correct value via the Koptertool. The "Kompass" debug value  has to show the correct orientation:

kopter Motor vorne  orientated to north => value approx 0 Degree)

Other requirements:

Please calibrate the ACC Sensor values (pitch full, yaw full right) in horizontal orientation of the kopter

as exactly as possible.

Parameters:

The GPS Hold regulator is of type PID: UserParameter1 =P(proportional), UserParameter2 = I(ntegral),

UserParameter3 = D(ifferential). Standardvalues for P,I and D are 60,8,100.

The I-Part may be set to 0 if a small deviation from hold position is acceptable. The D-Part is important to avoid

oscillating.

Please find out the best values yourself.

It might be useful to put the P and D Part on potis and test the behaviour in flight.

Requirements for GPS_Hold:

The gps module has do provide a 3D-fix. If succesfull, you can hear a longer beep when performing a gyro calibration.

Without a succesfull position fix at calibration the GPS functionality ist completely disabled.

The red led on the FlightCrtl flashes with a 4 Hz rate if the gps module delivers a position fix.

There are two ways to enable the GPS Hold functionality:

Either enable the GPS flag in the setting OR

disable the GPS flag in the setting AND set UserParameter5 to a value > 75 and < 170.

Enabling GPS_Hold in flight:

GPS Hold is automatically activated if the sticks for roll and nick are in neutral position for about 400ms.

Moving the stick immediately  disables the Hold mode. The GPS Hold function doesn not change height, pitch or yaw.

GPS Coming-Home function

There are tow ways to enable the GPS Coming Home functionality:

Either enable the GPS flag in the setting AND set the Height Switch ("ParameterMAxhoehe) to a value > 170 OR

disable the GPS flag in the setting AND set UserParameter5 to a value > 170.

The height regulator itself is activated with a value >= 50.

Other changes:

- automatic pitch reduction if the battery voltage falls more than 0.2V below the warning limit.

- Output PC6 can be used to switch TX data between a Bluetooth and the GPS Module (further hardware required) to the RX input of the FlightCrtl

- automatic Yaw gyro compensation if compass is available.