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AP_Compass: add explaination for sample acceptance based on angular distance

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Siddharth Bharat Purohit 2015-07-29 16:26:10 -07:00 committed by Andrew Tridgell
parent f108383c11
commit f085e274c7
1 changed files with 11 additions and 7 deletions
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18
libraries/AP_Compass/CompassCalibrator.cpp
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@ -58,8 +58,12 @@
* http://en.wikipedia.org/wiki/Levenberg%E2%80%93Marquardt_algorithm
*
* The sample acceptance distance is determined as follows:
* < EXPLANATION OF SAMPLE ACCEPTANCE TO BE FILLED IN BY SID >
*
* for any regular polyhedron with Triangular faces
* angle subtended by two closest point = arccos(cos(A)/(1-cos(A)))
* : where A = (4pi/F + pi)/3
* : and F is the number of faces
* for polyhedron in consideration F = 2V-4 (where V is vertices or points in our case)
* above equation was proved after solving for spherical triangular excess and related equations
*/
#include "CompassCalibrator.h"
@ -448,7 +452,7 @@ void CompassCalibrator::run_sphere_fit()
memset(&JTJ,0,sizeof(JTJ));
memset(&JTJ2,0,sizeof(JTJ2));
memset(&JTFI,0,sizeof(JTFI));
// Gauss Newton Part common for all kind of extensions including LM
for(uint16_t k = 0; k<_samples_collected; k++) {
Vector3f sample = _sample_buffer[k].get();
@ -468,7 +472,7 @@ void CompassCalibrator::run_sphere_fit()
}
//------------------------Levenberg-part-starts-here---------------------------------//
//------------------------Levenberg-Marquardt-part-starts-here---------------------------------//
//refer: http://en.wikipedia.org/wiki/Levenberg%E2%80%93Marquardt_algorithm#Choice_of_damping_parameter
for(uint8_t i = 0; i < COMPASS_CAL_NUM_SPHERE_PARAMS; i++) {
JTJ[i*COMPASS_CAL_NUM_SPHERE_PARAMS+i] += _sphere_lambda;
@ -502,7 +506,7 @@ void CompassCalibrator::run_sphere_fit()
} else if(fit1 < _fitness){
fitness = fit1;
}
//--------------------Levenberg-part-ends-here--------------------------------//
//--------------------Levenberg-Marquardt-part-ends-here--------------------------------//
if(!isnan(fitness) && fitness < _fitness) {
_fitness = fitness;
@ -563,7 +567,7 @@ void CompassCalibrator::run_ellipsoid_fit()
memset(&JTJ,0,sizeof(JTJ));
memset(&JTJ2,0,sizeof(JTJ2));
memset(&JTFI,0,sizeof(JTFI));
// Gauss Newton Part common for all kind of extensions including LM
for(uint16_t k = 0; k<_samples_collected; k++) {
Vector3f sample = _sample_buffer[k].get();
@ -584,7 +588,7 @@ void CompassCalibrator::run_ellipsoid_fit()
//------------------------Levenberg-part-starts-here---------------------------------//
//------------------------Levenberg-Marquardt-part-starts-here---------------------------------//
//refer: http://en.wikipedia.org/wiki/Levenberg%E2%80%93Marquardt_algorithm#Choice_of_damping_parameter
for(uint8_t i = 0; i < COMPASS_CAL_NUM_ELLIPSOID_PARAMS; i++) {
JTJ[i*COMPASS_CAL_NUM_ELLIPSOID_PARAMS+i] += _ellipsoid_lambda;