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ahrs_aligner.c
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1 /*
2  * Copyright (C) 2008-2009 Antoine Drouin <poinix@gmail.com>
3  *
4  * This file is part of paparazzi.
5  *
6  * paparazzi is free software; you can redistribute it and/or modify
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14  * GNU General Public License for more details.
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21 
29 #include "ahrs_aligner.h"
30 
31 #include <stdlib.h> /* for abs() */
32 #include "subsystems/imu.h"
33 #include "led.h"
34 
36 
37 #define SAMPLES_NB PERIODIC_FREQUENCY
38 
39 static struct Int32Rates gyro_sum;
40 static struct Int32Vect3 accel_sum;
41 static struct Int32Vect3 mag_sum;
44 
45 void ahrs_aligner_init(void) {
46 
51  samples_idx = 0;
52  ahrs_aligner.noise = 0;
54 }
55 
56 #ifndef LOW_NOISE_THRESHOLD
57 #define LOW_NOISE_THRESHOLD 90000
58 #endif
59 #ifndef LOW_NOISE_TIME
60 #define LOW_NOISE_TIME 5
61 #endif
62 
63 void ahrs_aligner_run(void) {
64 
68 
70  samples_idx++;
71 
72 #ifdef AHRS_ALIGNER_LED
73  RunOnceEvery(50, {LED_TOGGLE(AHRS_ALIGNER_LED);});
74 #endif
75 
76  if (samples_idx >= SAMPLES_NB) {
77  int32_t avg_ref_sensor = accel_sum.z;
78  if ( avg_ref_sensor >= 0)
79  avg_ref_sensor += SAMPLES_NB / 2;
80  else
81  avg_ref_sensor -= SAMPLES_NB / 2;
82  avg_ref_sensor /= SAMPLES_NB;
83 
84  ahrs_aligner.noise = 0;
85  int i;
86  for (i=0; i<SAMPLES_NB; i++) {
87  int32_t diff = ref_sensor_samples[i] - avg_ref_sensor;
88  ahrs_aligner.noise += abs(diff);
89  }
90 
93  VECT3_SDIV(ahrs_aligner.lp_mag, mag_sum, SAMPLES_NB);
94 
98  samples_idx = 0;
99 
102  else
103  if ( ahrs_aligner.low_noise_cnt > 0)
105 
108 #ifdef AHRS_ALIGNER_LED
109  LED_ON(AHRS_ALIGNER_LED);
110 #endif
111  }
112  }
113 
114 }
#define SAMPLES_NB
Definition: ahrs_aligner.c:37
Interface to align the AHRS via low-passed measurements at startup.
#define LOW_NOISE_THRESHOLD
Definition: ahrs_aligner.c:57
static struct Int32Vect3 mag_sum
Definition: ahrs_aligner.c:41
int32_t low_noise_cnt
Definition: ahrs_aligner.h:44
struct Int32Vect3 lp_accel
Definition: ahrs_aligner.h:41
struct Int32Vect3 accel
accelerometer measurements
Definition: imu.h:41
#define LED_ON(i)
Definition: led_hw.h:28
#define INT_RATES_ZERO(_e)
uint8_t status
Definition: ahrs_aligner.h:45
int32_t noise
Definition: ahrs_aligner.h:43
struct Int32Vect3 lp_mag
Definition: ahrs_aligner.h:42
#define AHRS_ALIGNER_RUNNING
Definition: ahrs_aligner.h:36
#define RATES_SDIV(_ro, _ri, _s)
Definition: pprz_algebra.h:350
static struct Int32Rates gyro_sum
Definition: ahrs_aligner.c:39
struct AhrsAligner ahrs_aligner
Definition: ahrs_aligner.c:35
struct Imu imu
global IMU state
Definition: imu_aspirin2.c:50
unsigned long uint32_t
Definition: types.h:18
#define AHRS_ALIGNER_LOCKED
Definition: ahrs_aligner.h:37
#define RATES_ADD(_a, _b)
Definition: pprz_algebra.h:308
#define INT_VECT3_ZERO(_v)
Inertial Measurement Unit interface.
angular rates
#define LED_TOGGLE(i)
Definition: led_hw.h:30
#define LOW_NOISE_TIME
Definition: ahrs_aligner.c:60
signed long int32_t
Definition: types.h:19
struct Int32Vect3 mag
magnetometer measurements
Definition: imu.h:42
#define VECT3_ADD(_a, _b)
Definition: pprz_algebra.h:118
struct Int32Rates gyro
gyroscope measurements
Definition: imu.h:40
arch independent LED (Light Emitting Diodes) API
static int32_t ref_sensor_samples[SAMPLES_NB]
Definition: ahrs_aligner.c:42
#define VECT3_SDIV(_vo, _vi, _s)
Definition: pprz_algebra.h:167
void ahrs_aligner_init(void)
Definition: ahrs_aligner.c:45
void ahrs_aligner_run(void)
Definition: ahrs_aligner.c:63
static uint32_t samples_idx
Definition: ahrs_aligner.c:43
struct Int32Rates lp_gyro
Definition: ahrs_aligner.h:40
static struct Int32Vect3 accel_sum
Definition: ahrs_aligner.c:40