altos: Keep 9 more bits of average pad IMU gyro data

This reduces the offset error by a bit, minimizing gyro drift.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/core/ao_sample.c b/src/core/ao_sample.c
index 47c5ea2e3660d15d0dcb4d526c1136653bb729e5..b425aee7b43578469180210b0db418a73c837a48 100644 (file)
--- a/src/core/ao_sample.c
+++ b/src/core/ao_sample.c
@@ -70,9 +70,9 @@ __pdata int32_t               ao_accel_scale;         /* sensor to m/s² conversion */
 __pdata accel_t                ao_ground_accel_along;
 __pdata accel_t                ao_ground_accel_across;
 __pdata accel_t                ao_ground_accel_through;
 __pdata accel_t                ao_ground_accel_along;
 __pdata accel_t                ao_ground_accel_across;
 __pdata accel_t                ao_ground_accel_through;

-__pdata gyro_t         ao_ground_pitch;
-__pdata gyro_t         ao_ground_yaw;
-__pdata gyro_t         ao_ground_roll;
+__pdata int32_t                ao_ground_pitch;
+__pdata int32_t                ao_ground_yaw;
+__pdata int32_t                ao_ground_roll;

 #endif
 
 static __pdata uint8_t ao_preflight;           /* in preflight mode */
 #endif
 
 static __pdata uint8_t ao_preflight;           /* in preflight mode */


@@ -125,9 +125,9 @@ ao_sample_preflight_set(void)
        ao_ground_accel_along = ao_sample_accel_along_sum >> 9;
        ao_ground_accel_across = ao_sample_accel_across_sum >> 9;
        ao_ground_accel_through = ao_sample_accel_through_sum >> 9;
        ao_ground_accel_along = ao_sample_accel_along_sum >> 9;
        ao_ground_accel_across = ao_sample_accel_across_sum >> 9;
        ao_ground_accel_through = ao_sample_accel_through_sum >> 9;

-       ao_ground_pitch = ao_sample_pitch_sum >> 9;
-       ao_ground_yaw = ao_sample_yaw_sum >> 9;
-       ao_ground_roll = ao_sample_roll_sum >> 9;
+       ao_ground_pitch = ao_sample_pitch_sum;
+       ao_ground_yaw = ao_sample_yaw_sum;
+       ao_ground_roll = ao_sample_roll_sum;

        ao_sample_accel_along_sum = 0;
        ao_sample_accel_across_sum = 0;
        ao_sample_accel_through_sum = 0;
        ao_sample_accel_along_sum = 0;
        ao_sample_accel_across_sum = 0;
        ao_sample_accel_through_sum = 0;


@@ -162,13 +162,9 @@ ao_sample_rotate(void)
 #else
        static const float dt = 1/100.0;
 #endif
 #else
        static const float dt = 1/100.0;
 #endif

-       float   x = ao_mpu6000_gyro(ao_sample_pitch - ao_ground_pitch) * dt;
-       float   y = ao_mpu6000_gyro(ao_sample_yaw - ao_ground_yaw) * dt;
-       float   z = ao_mpu6000_gyro(ao_sample_roll - ao_ground_roll) * dt;
-
-       float                   n_2, n;
-       float                   s, c;
-       
+       float   x = ao_mpu6000_gyro((float) ((ao_sample_pitch << 9) - ao_ground_pitch) / 512.0f) * dt;
+       float   y = ao_mpu6000_gyro((float) ((ao_sample_yaw << 9) - ao_ground_yaw) / 512.0f) * dt;
+       float   z = ao_mpu6000_gyro((float) ((ao_sample_roll << 9) - ao_ground_roll) / 512.0f) * dt;

        struct ao_quaternion    rot;
        struct ao_quaternion    point;
 
        struct ao_quaternion    rot;
        struct ao_quaternion    point;