mirror of https://github.com/ArduPilot/ardupilot
20 lines
938 B
Mathematica
20 lines
938 B
Mathematica
|
function quat = AlignTilt( ...
|
||
|
|
quat, ... % quaternion state vector
|
||
|
|
initAccel) % initial accelerometer vector
|
||
|
|
% check length
|
||
|
|
lengthAccel = sqrt(dot([initAccel(1);initAccel(2);initAccel(3)],[initAccel(1);initAccel(2);initAccel(3)]));
|
||
|
|
% if length is > 0.7g and < 1.4g initialise tilt using gravity vector
|
||
|
|
if (lengthAccel > 5 && lengthAccel < 14)
|
||
|
|
% calculate length of the tilt vector
|
||
|
|
tiltMagnitude = atan2(sqrt(dot([initAccel(1);initAccel(2)],[initAccel(1);initAccel(2)])),-initAccel(3));
|
||
|
|
% take the unit cross product of the accel vector and the -Z vector to
|
||
|
|
% give the tilt unit vector
|
||
|
|
if (tiltMagnitude > 1e-3)
|
||
|
|
tiltUnitVec = cross([initAccel(1);initAccel(2);initAccel(3)],[0;0;-1]);
|
||
|
|
tiltUnitVec = tiltUnitVec/sqrt(dot(tiltUnitVec,tiltUnitVec));
|
||
|
|
tiltVec = tiltMagnitude*tiltUnitVec;
|
||
|
|
quat = [cos(0.5*tiltMagnitude); tiltVec/tiltMagnitude*sin(0.5*tiltMagnitude)];
|
||
|
|
end
|
||
|
|
end
|
||
|
|
|
||
|
|
end
|