altos: Add gyro-based orientation tracking

This tracks the angle-from-vertical as an additional input to the pyro
channels.

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

16 files changed, 343 insertions, 268 deletions

diff --git a/src/core/ao_data.h b/src/core/ao_data.h
index 339afe69..5a232885 100644
--- a/src/core/ao_data.h
+++ b/src/core/ao_data.h
@@ -18,6 +18,8 @@
 #ifndef _AO_DATA_H_
 #define _AO_DATA_H_
 
+#define GRAVITY 9.80665
+
 #if HAS_ADC
 #define AO_DATA_ADC	(1 << 0)
 #else
@@ -300,8 +302,8 @@ typedef int16_t accel_t;
 
 #define HAS_GYRO	1
 
-typedef int16_t	gyro_t;
-typedef int32_t angle_t;
+typedef int16_t	gyro_t;		/* in raw sample units */
+typedef int16_t angle_t;	/* in degrees */
 
 /* Y axis is aligned with the direction of motion (along) */
 /* X axis is aligned in the other board axis (across) */
diff --git a/src/core/ao_flight.c b/src/core/ao_flight.c
index 2495a44b..240b348a 100644
--- a/src/core/ao_flight.c
+++ b/src/core/ao_flight.c
@@ -20,6 +20,10 @@
 #include <ao_log.h>
 #endif
 
+#if HAS_MPU6000
+#include <ao_quaternion.h>
+#endif
+
 #ifndef HAS_ACCEL
 #error Please define HAS_ACCEL
 #endif
diff --git a/src/core/ao_kalman.c b/src/core/ao_kalman.c
index 762b2c0a..7fd4f889 100644
--- a/src/core/ao_kalman.c
+++ b/src/core/ao_kalman.c
@@ -292,7 +292,4 @@ ao_kalman(void)
 	else 
 #endif
 		ao_avg_height = (ao_avg_height_scaled + 63) >> 7;
-#ifdef AO_FLIGHT_TEST
-	ao_sample_prev_tick = ao_sample_tick;
-#endif
 }
diff --git a/src/core/ao_pyro.c b/src/core/ao_pyro.c
index 531e1f50..24c9fe99 100644
--- a/src/core/ao_pyro.c
+++ b/src/core/ao_pyro.c
@@ -113,7 +113,7 @@ ao_pyro_ready(struct ao_pyro *pyro)
 				continue;
 			break;
 
-#if HAS_ORIENT
+#if HAS_GYRO
 		case ao_pyro_orient_less:
 			if (ao_orient <= pyro->orient_less)
 				continue;
@@ -310,7 +310,7 @@ const struct {
 	{ "h<",	ao_pyro_height_less,	offsetof(struct ao_pyro, height_less), HELP("height less (m)") },
 	{ "h>",	ao_pyro_height_greater,	offsetof(struct ao_pyro, height_greater), HELP("height greater (m)") },
 
-#if HAS_ORIENT
+#if HAS_GYRO
 	{ "o<",	ao_pyro_orient_less,	offsetof(struct ao_pyro, orient_less), HELP("orient less (deg)") },
 	{ "o>",	ao_pyro_orient_greater,	offsetof(struct ao_pyro, orient_greater), HELP("orient greater (deg)")  },
 #endif
diff --git a/src/core/ao_quaternion.h b/src/core/ao_quaternion.h
new file mode 100644
index 00000000..f4b8aaa4
--- /dev/null
+++ b/src/core/ao_quaternion.h
@@ -0,0 +1,116 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#ifndef _AO_QUATERNION_H_
+#define _AO_QUATERNION_H_
+
+#include <math.h>
+
+struct ao_quaternion {
+	float	r;		/* real bit */
+	float	x, y, z;	/* imaginary bits */
+};
+
+static inline void ao_quaternion_multiply(struct ao_quaternion *r,
+					  struct ao_quaternion *a,
+					  struct ao_quaternion *b)
+{
+	struct ao_quaternion	t;
+#define T(_a,_b)	(((a)->_a) * ((b)->_b))
+	t.r = T(r,r) - T(x,x) - T(y,y) - T(z,z);
+	t.x = T(r,x) + T(x,r) + T(y,z) - T(z,y);
+	t.y = T(r,y) - T(x,z) + T(y,r) + T(z,x);
+	t.z = T(r,z) + T(x,y) - T(y,x) + T(z,r);
+#undef T
+	*r = t;
+}
+
+static inline void ao_quaternion_conjugate(struct ao_quaternion *r,
+					   struct ao_quaternion *a)
+{
+	r->r = a->r;
+	r->x = -a->x;
+	r->y = -a->y;
+	r->z = -a->z;
+}
+
+static inline float ao_quaternion_normal(struct ao_quaternion *a)
+{
+#define S(_a)	(((a)->_a) * ((a)->_a))
+	return S(r) + S(x) + S(y) + S(z);
+#undef S
+}
+
+static inline void ao_quaternion_scale(struct ao_quaternion *r,
+				       struct ao_quaternion *a,
+				       float b)
+{
+	r->r = a->r * b;
+	r->x = a->x * b;
+	r->y = a->y * b;
+	r->z = a->z * b;
+}
+
+static inline void ao_quaternion_normalize(struct ao_quaternion *r,
+					   struct ao_quaternion *a)
+{
+	float	n = ao_quaternion_normal(a);
+
+	if (n > 0)
+		ao_quaternion_scale(r, a, 1/sqrtf(n));
+	else
+		*r = *a;
+}
+
+static inline void ao_quaternion_rotate(struct ao_quaternion *r,
+					struct ao_quaternion *a,
+					struct ao_quaternion *b)
+{
+	struct ao_quaternion	c;
+	struct ao_quaternion	t;
+
+	ao_quaternion_conjugate(&c, b);
+	ao_quaternion_multiply(&t, b, a);
+	ao_quaternion_multiply(r, &t, &c);
+}
+
+static inline void ao_quaternion_init_vector(struct ao_quaternion *r,
+					     float x, float y, float z)
+{
+	r->r = 0;
+	r->x = x;
+	r->y = y;
+	r->z = z;
+}
+
+static inline void ao_quaternion_init_rotation(struct ao_quaternion *r,
+					       float x, float y, float z,
+					       float s, float c)
+{
+	r->r = c;
+	r->x = s * x;
+	r->y = s * y;
+	r->z = s * z;
+}
+
+static inline void ao_quaternion_init_zero_rotation(struct ao_quaternion *r)
+{
+	r->r = 1;
+	r->x = r->y = r->z = 0;
+}
+
+#endif /* _AO_QUATERNION_H_ */
diff --git a/src/core/ao_sample.c b/src/core/ao_sample.c
index dec44f9f..676e0ffd 100644
--- a/src/core/ao_sample.c
+++ b/src/core/ao_sample.c
@@ -20,6 +20,10 @@
 #include <ao_data.h>
 #endif
 
+#if HAS_GYRO
+#include <ao_quaternion.h>
+#endif
+
 /*
  * Current sensor values
  */
@@ -44,8 +48,7 @@ __pdata accel_t		ao_sample_accel_through;
 __pdata gyro_t		ao_sample_roll;
 __pdata gyro_t		ao_sample_pitch;
 __pdata gyro_t		ao_sample_yaw;
-__pdata angle_t		ao_sample_angle;
-__pdata angle_t		ao_sample_roll_angle;
+__pdata angle_t		ao_orient;
 #endif
 
 __data uint8_t		ao_sample_data;
@@ -86,6 +89,8 @@ __pdata int32_t	ao_sample_accel_through_sum;
 __pdata int32_t ao_sample_pitch_sum;
 __pdata int32_t ao_sample_yaw_sum;
 __pdata int32_t	ao_sample_roll_sum;
+static struct ao_quaternion ao_rotation;
+static struct ao_quaternion ao_pad_orientation;
 #endif
 
 static void
@@ -129,11 +134,91 @@ ao_sample_preflight_set(void)
 	ao_sample_pitch_sum = 0;
 	ao_sample_yaw_sum = 0;
 	ao_sample_roll_sum = 0;
-	ao_sample_angle = 0;
+	ao_orient = 0;
+
+	/* No rotation yet */
+	ao_quaternion_init_zero_rotation(&ao_rotation);
+
+	/* XXX Assume we're pointing straight up for now */
+	ao_quaternion_init_vector(&ao_pad_orientation,
+				  ao_ground_accel_across,
+				  ao_ground_accel_through,
+				  -ao_ground_accel_along);
+	ao_quaternion_normalize(&ao_pad_orientation,
+				&ao_pad_orientation);
+				  
+	printf ("pad r%8.5f x%8.5f y%8.5f z%8.5f\n",
+		ao_pad_orientation.r,
+		ao_pad_orientation.x,
+		ao_pad_orientation.y,
+		ao_pad_orientation.z);
 #endif	
 	nsamples = 0;
 }
 
+#if HAS_GYRO
+static void
+ao_sample_rotate(void)
+{
+#ifdef AO_FLIGHT_TEST
+	float	dt = (ao_sample_tick - ao_sample_prev_tick) / 100.0;
+#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;
+	
+	struct ao_quaternion	rot;
+	struct ao_quaternion	point;
+
+	/* The amount of rotation is just the length of the vector. Now,
+	 * here's the trick -- assume that the rotation amount is small. In this case,
+	 * sin(x) ≃ x, so we can just make this the sin.
+	 */
+
+	n_2 = x*x + y*y + z*z;
+	n = sqrtf(n_2);
+	s = n / 2;
+	if (s > 1)
+		s = 1;
+	c = sqrtf(1 - s*s);
+
+	/* Make unit vector */
+	if (n > 0) {
+		x /= n;
+		y /= n;
+		z /= n;
+	}
+
+	/* Now compute the unified rotation quaternion */
+
+	ao_quaternion_init_rotation(&rot,
+				    x, y, z,
+				    s, c);
+
+	/* Integrate with the previous rotation amount */
+	ao_quaternion_multiply(&ao_rotation, &ao_rotation, &rot);
+
+	/* And normalize to make sure it remains a unit vector */
+	ao_quaternion_normalize(&ao_rotation, &ao_rotation);
+
+	/* Compute pitch angle from vertical by taking the pad
+	 * orientation vector and rotating it by the current total
+	 * rotation value. That will be a unit vector pointing along
+	 * the airframe axis. The Z value will be the cosine of the
+	 * change in the angle from vertical since boost
+	 */
+
+	ao_quaternion_rotate(&point, &ao_pad_orientation, &ao_rotation);
+
+	ao_orient = acosf(point.z) * (float) (180.0/M_PI);
+}
+#endif
+
 static void
 ao_sample_preflight(void)
 {
@@ -232,9 +317,12 @@ ao_sample(void)
 				ao_sample_preflight_update();
 			ao_kalman();
 #if HAS_GYRO
-			/* do quaternion stuff here... */
+			ao_sample_rotate();
 #endif
 		}
+#ifdef AO_FLIGHT_TEST
+		ao_sample_prev_tick = ao_sample_tick;
+#endif
 		ao_sample_data = ao_data_ring_next(ao_sample_data);
 	}
 	return !ao_preflight;
@@ -264,7 +352,7 @@ ao_sample_init(void)
 	ao_sample_pitch = 0;
 	ao_sample_yaw = 0;
 	ao_sample_roll = 0;
-	ao_sample_angle = 0;
+	ao_orient = 0;
 #endif
 	ao_sample_data = ao_data_head;
 	ao_preflight = TRUE;
diff --git a/src/core/ao_sample.h b/src/core/ao_sample.h
index 5bd29536..1d1bcc7c 100644
--- a/src/core/ao_sample.h
+++ b/src/core/ao_sample.h
@@ -64,8 +64,6 @@
  * for all further flight computations
  */
 
-#define GRAVITY 9.80665
-
 /*
  * Above this height, the baro sensor doesn't work
  */
@@ -118,6 +116,7 @@ extern __pdata accel_t	ao_ground_accel_through;
 extern __pdata gyro_t	ao_ground_pitch;
 extern __pdata gyro_t	ao_ground_yaw;
 extern __pdata gyro_t	ao_ground_roll;
+extern __pdata angle_t	ao_orient;
 #endif
 
 void ao_sample_init(void);
diff --git a/src/core/ao_telemetry.c b/src/core/ao_telemetry.c
index 6b47a06a..a2726016 100644
--- a/src/core/ao_telemetry.c
+++ b/src/core/ao_telemetry.c
@@ -115,6 +115,7 @@ ao_send_mega_sensor(void)
 	telemetry.generic.tick = packet->tick;
 	telemetry.generic.type = AO_TELEMETRY_MEGA_SENSOR;
 
+	telemetry.mega_sensor.orient = ao_orient;
 	telemetry.mega_sensor.accel = ao_data_accel(packet);
 	telemetry.mega_sensor.pres = ao_data_pres(packet);
 	telemetry.mega_sensor.temp = ao_data_temp(packet);
diff --git a/src/core/ao_telemetry.h b/src/core/ao_telemetry.h
index fd6b76b3..237a35ab 100644
--- a/src/core/ao_telemetry.h
+++ b/src/core/ao_telemetry.h
@@ -162,7 +162,7 @@ struct ao_telemetry_mega_sensor {
 	uint16_t	tick;		/*  2 */
 	uint8_t		type;		/*  4 */
 
-	uint8_t		pad5;		/*  5 */
+	uint8_t		orient;		/*  5 angle from vertical */
 	int16_t		accel;		/*  6 Z axis */
 
 	int32_t		pres;		/*  8 Pa * 10 */
diff --git a/src/drivers/ao_mpu6000.c b/src/drivers/ao_mpu6000.c
index 73057820..5e75b78a 100644
--- a/src/drivers/ao_mpu6000.c
+++ b/src/drivers/ao_mpu6000.c
@@ -118,6 +118,7 @@ _ao_mpu6000_sample(struct ao_mpu6000_sample *sample)
 
 #define G	981	/* in cm/s² */
 
+#if 0
 static int16_t /* cm/s² */
 ao_mpu6000_accel(int16_t v)
 {
@@ -129,6 +130,7 @@ ao_mpu6000_gyro(int16_t v)
 {
 	return (int16_t) ((v * (int32_t) 20000) / 32767);
 }
+#endif
 
 static uint8_t
 ao_mpu6000_accel_check(int16_t normal, int16_t test, char *which)
diff --git a/src/drivers/ao_mpu6000.h b/src/drivers/ao_mpu6000.h
index a42f69c4..2241bf80 100644
--- a/src/drivers/ao_mpu6000.h
+++ b/src/drivers/ao_mpu6000.h
@@ -18,6 +18,10 @@
 #ifndef _AO_MPU6000_H_
 #define _AO_MPU6000_H_
 
+#ifndef M_PI
+#define M_PI 3.1415926535897832384626433
+#endif
+
 #define MPU6000_ADDR_WRITE	0xd0
 #define MPU6000_ADDR_READ	0xd1
 
@@ -166,9 +170,20 @@
 /* Self test gyro is approximately 50°/s */
 #define MPU6000_ST_GYRO(full_scale)	((int16_t) (((int32_t) 32767 * (int32_t) 50) / (full_scale)))
 
-#define MPU6000_GYRO_FULLSCALE	2000
+#define MPU6000_GYRO_FULLSCALE	((float) 2000 * M_PI/180.0)
+
+static inline float
+ao_mpu6000_gyro(int16_t sensor) {
+	return (float) sensor * ((float) (MPU6000_GYRO_FULLSCALE / 32767.0));
+}
+
 #define MPU6000_ACCEL_FULLSCALE	16
 
+static inline float
+ao_mpu6000_accel(int16_t sensor) {
+	return (float) sensor * ((float) (MPU6000_ACCEL_FULLSCALE * GRAVITY / 32767.0));
+}
+
 struct ao_mpu6000_sample {
 	int16_t		accel_x;
 	int16_t		accel_y;
diff --git a/src/stm/Makefile.defs b/src/stm/Makefile.defs
index ee1cb658..0710d747 100644
--- a/src/stm/Makefile.defs
+++ b/src/stm/Makefile.defs
@@ -1,4 +1,4 @@
-vpath % ../stm:../product:../drivers:../core:../util:../kalman:../aes:..
+vpath % ../stm:../product:../drivers:../core:../util:../kalman:../aes:../math:..
 vpath make-altitude ../util
 vpath make-kalman ../util
 vpath kalman.5c ../kalman
@@ -24,7 +24,7 @@ include $(TOPDIR)/Makedefs
 CC=$(ARM_CC)
 LIBS=-lpdclib-cortex-m3 -lgcc
 
-AO_CFLAGS=-I. -I../stm -I../core -I../drivers -I..
+AO_CFLAGS=-I. -I../stm -I../core -I../drivers -I../math -I..
 STM_CFLAGS=-std=gnu99 -mlittle-endian -mcpu=cortex-m3 -mthumb -ffreestanding -nostdlib $(AO_CFLAGS)
 
 LDFLAGS=-L../stm -Wl,-Taltos.ld
diff --git a/src/telemega-v0.3/Makefile b/src/telemega-v0.3/Makefile
index 6e5da721..2f460105 100644
--- a/src/telemega-v0.3/Makefile
+++ b/src/telemega-v0.3/Makefile
@@ -27,6 +27,7 @@ INC = \
 	ao_sample_profile.h \
 	ao_mpu.h \
 	stm32l.h \
+	math.h \
 	Makefile
 
 #
@@ -44,6 +45,20 @@ INC = \
 #STACK_GUARD=ao_mpu_stm.c
 #STACK_GUARD_DEF=-DHAS_STACK_GUARD=1
 
+MATH_SRC=\
+	ef_acos.c \
+	ef_sqrt.c
+
+#	ef_rem_pio2.c \
+#	kf_cos.c \
+#	kf_sin.c \
+#	kf_rem_pio2.c \
+#	sf_copysign.c \
+#	sf_cos.c \
+#	sf_fabs.c \
+#	sf_floor.c \
+#	sf_scalbn.c
+
 ALTOS_SRC = \
 	ao_boot_chain.c \
 	ao_interrupt.c \
@@ -93,6 +108,7 @@ ALTOS_SRC = \
 	ao_companion.c \
 	ao_pyro.c \
 	ao_aprs.c \
+	$(MATH_SRC) \
 	$(PROFILE) \
 	$(SAMPLE_PROFILE) \
 	$(STACK_GUARD)
diff --git a/src/test/Makefile b/src/test/Makefile
index 5eee6bbb..f64a9531 100644
--- a/src/test/Makefile
+++ b/src/test/Makefile
@@ -1,15 +1,15 @@
-vpath % ..:../core:../drivers:../util:../micropeak:../aes
+vpath % ..:../core:../drivers:../util:../micropeak:../aes:../product
 
 PROGS=ao_flight_test ao_flight_test_baro ao_flight_test_accel ao_flight_test_noisy_accel ao_flight_test_mm \
 	ao_gps_test ao_gps_test_skytraq ao_gps_test_ublox ao_convert_test ao_convert_pa_test ao_fec_test \
 	ao_aprs_test ao_micropeak_test ao_fat_test ao_aes_test ao_int64_test \
-	ao_ms5607_convert_test
+	ao_ms5607_convert_test ao_quaternion_test
 
 INCS=ao_kalman.h ao_ms5607.h ao_log.h ao_data.h altitude-pa.h altitude.h
 
 KALMAN=make-kalman 
 
-CFLAGS=-I.. -I. -I../core -I../drivers -I../micropeak -O0 -g -Wall
+CFLAGS=-I.. -I. -I../core -I../drivers -I../micropeak -I../product -O0 -g -Wall
 
 all: $(PROGS) ao_aprs_data.wav
 
@@ -80,3 +80,6 @@ ao_int64_test: ao_int64_test.c ao_int64.c ao_int64.h
 
 ao_ms5607_convert_test: ao_ms5607_convert_test.c ao_ms5607_convert_8051.c ao_int64.c ao_int64.h
 	cc $(CFLAGS) -o $@ ao_ms5607_convert_test.c
+
+ao_quaternion_test: ao_quaternion_test.c ao_quaternion.h
+	cc $(CFLAGS) -o $@ ao_quaternion_test.c -lm
\ No newline at end of file
diff --git a/src/test/ao_flight_test.c b/src/test/ao_flight_test.c
index faf31aa7..e2f63e34 100644
--- a/src/test/ao_flight_test.c
+++ b/src/test/ao_flight_test.c
@@ -25,6 +25,8 @@
 #include <getopt.h>
 #include <math.h>
 
+#define GRAVITY 9.80665
+
 #define AO_HERTZ	100
 
 #define HAS_ADC 1
@@ -36,6 +38,11 @@
 #define AO_MS_TO_SPEED(ms)	((int16_t) ((ms) * 16))
 #define AO_MSS_TO_ACCEL(mss)	((int16_t) ((mss) * 16))
 
+#define AO_GPS_NEW_DATA		1
+#define AO_GPS_NEW_TRACKING	2
+
+int ao_gps_new;
+
 #if TELEMEGA
 #define AO_ADC_NUM_SENSE	6
 #define HAS_MS5607		1
@@ -240,7 +247,6 @@ struct ao_config ao_config;
 #define DATA_TO_XDATA(x) (x)
 
 
-#define GRAVITY 9.80665
 extern int16_t ao_ground_accel, ao_flight_accel;
 extern int16_t ao_accel_2g;
 
@@ -339,20 +345,6 @@ ao_test_exit(void)
 	exit(0);
 }
 
-#if HAS_MPU6000
-static double
-ao_mpu6000_accel(int16_t sensor)
-{
-	return sensor / 32767.0 * MPU6000_ACCEL_FULLSCALE * GRAVITY;
-}
-
-static double
-ao_mpu6000_gyro(int32_t sensor)
-{
-	return sensor / 32767.0 * MPU6000_GYRO_FULLSCALE;
-}
-#endif
-
 void
 ao_insert(void)
 {
@@ -408,23 +400,23 @@ ao_insert(void)
 		if (!ao_summary) {
 			printf("%7.2f height %8.2f accel %8.3f "
 #if TELEMEGA
-			       "roll %8.3f angle %8.3f qangle %8.3f "
-			       "accel_x %8.3f accel_y %8.3f accel_z %8.3f gyro_x %8.3f gyro_y %8.3f gyro_z %8.3f "
+			       "angle %5d "
+/*			       "accel_x %8.3f accel_y %8.3f accel_z %8.3f gyro_x %8.3f gyro_y %8.3f gyro_z %8.3f " */
 #endif
 			       "state %-8.8s k_height %8.2f k_speed %8.3f k_accel %8.3f avg_height %5d drogue %4d main %4d error %5d\n",
 			       time,
 			       height,
 			       accel,
 #if TELEMEGA
-			       ao_mpu6000_gyro(ao_sample_roll_angle) / 100.0,
-			       ao_mpu6000_gyro(ao_sample_angle) / 100.0,
-			       ao_sample_qangle,
+			       ao_orient,
+/*
 			       ao_mpu6000_accel(ao_data_static.mpu6000.accel_x),
 			       ao_mpu6000_accel(ao_data_static.mpu6000.accel_y),
 			       ao_mpu6000_accel(ao_data_static.mpu6000.accel_z),
 			       ao_mpu6000_gyro(ao_data_static.mpu6000.gyro_x - ao_ground_mpu6000.gyro_x),
 			       ao_mpu6000_gyro(ao_data_static.mpu6000.gyro_y - ao_ground_mpu6000.gyro_y),
 			       ao_mpu6000_gyro(ao_data_static.mpu6000.gyro_z - ao_ground_mpu6000.gyro_z),
+*/
 #endif
 			       ao_state_names[ao_flight_state],
 			       ao_k_height / 65536.0,
@@ -589,207 +581,6 @@ int32(uint8_t *bytes, int off)
 
 static int log_format;
 
-#if TELEMEGA
-
-static double
-ao_vec_norm(double x, double y, double z)
-{
-	return x*x + y*y + z*z;
-}
-
-static void
-ao_vec_normalize(double *x, double *y, double *z)
-{
-	double	scale = 1/sqrt(ao_vec_norm(*x, *y, *z));
-
-	*x *= scale;
-	*y *= scale;
-	*z *= scale;
-}
-
-struct ao_quat {
-	double	q0, q1, q2, q3;
-};
-
-static void
-ao_quat_mul(struct ao_quat *r, struct ao_quat *a, struct ao_quat *b)
-{
-	r->q0 = a->q0 * b->q0 - a->q1 * b->q1 - a->q2 * b->q2 - a->q3 * b->q3;
-	r->q1 = a->q0 * b->q1 + a->q1 * b->q0 + a->q2 * b->q3 - a->q3 * b->q2;
-	r->q2 = a->q0 * b->q2 - a->q1 * b->q3 + a->q2 * b->q0 + a->q3 * b->q1;
-	r->q3 = a->q0 * b->q3 + a->q1 * b->q2 - a->q2 * b->q1 + a->q3 * b->q0;
-}
-
-#if 0
-static void
-ao_quat_scale(struct ao_quat *r, struct ao_quat *a, double s)
-{
-	r->q0 = a->q0 * s;
-	r->q1 = a->q1 * s;
-	r->q2 = a->q2 * s;
-	r->q3 = a->q3 * s;
-}
-#endif
-
-static void
-ao_quat_conj(struct ao_quat *r, struct ao_quat *a)
-{
-	r->q0 =  a->q0;
-	r->q1 = -a->q1;
-	r->q2 = -a->q2;
-	r->q3 = -a->q3;
-}
-
-static void
-ao_quat_rot(struct ao_quat *r, struct ao_quat *a, struct ao_quat *q)
-{
-	struct ao_quat	t;
-	struct ao_quat	c;
-	ao_quat_mul(&t, q, a);
-	ao_quat_conj(&c, q);
-	ao_quat_mul(r, &t, &c);
-}
-
-static void
-ao_quat_from_angle(struct ao_quat *r,
-		   double x_rad,
-		   double y_rad,
-		   double z_rad)
-{
-	double angle = sqrt (x_rad * x_rad + y_rad * y_rad + z_rad * z_rad);
-	double s = sin(angle/2);
-	double c = cos(angle/2);
-
-	r->q0 = c;
-	r->q1 = x_rad * s / angle;
-	r->q2 = y_rad * s / angle;
-	r->q3 = z_rad * s / angle;
-}
-
-static void
-ao_quat_from_vector(struct ao_quat *r, double x, double y, double z)
-{
-	ao_vec_normalize(&x, &y, &z);
-	double	x_rad = atan2(z, y);
-	double	y_rad = atan2(x, z);
-	double	z_rad = atan2(y, x);
-
-	ao_quat_from_angle(r, x_rad, y_rad, z_rad);
-}
-
-static double
-ao_quat_norm(struct ao_quat *a)
-{
-	return (a->q0 * a->q0 +
-		a->q1 * a->q1 +
-		a->q2 * a->q2 +
-		a->q3 * a->q3);
-}
-
-static void
-ao_quat_normalize(struct ao_quat *a)
-{
-	double	norm = ao_quat_norm(a);
-
-	if (norm) {
-		double m = 1/sqrt(norm);
-
-		a->q0 *= m;
-		a->q1 *= m;
-		a->q2 *= m;
-		a->q3 *= m;
-	}
-}
-
-static struct ao_quat	ao_up, ao_current;
-static struct ao_quat	ao_orient;
-static int		ao_orient_tick;
-
-void
-set_orientation(double x, double y, double z, int tick)
-{
-	struct ao_quat	t;
-
-	printf ("set_orientation %g %g %g\n", x, y, z);
-	ao_quat_from_vector(&ao_orient, x, y, z);
-	ao_up.q1 = ao_up.q2 = 0;
-	ao_up.q0 = ao_up.q3 = sqrt(2)/2;
-	ao_orient_tick = tick;
-
-	ao_orient.q0 = 1;
-	ao_orient.q1 = 0;
-	ao_orient.q2 = 0;
-	ao_orient.q3 = 0;
-
-	printf ("orient (%g) %g %g %g up (%g) %g %g %g\n",
-		ao_orient.q0,
-		ao_orient.q1,
-		ao_orient.q2,
-		ao_orient.q3,
-		ao_up.q0,
-		ao_up.q1,
-		ao_up.q2,
-		ao_up.q3);
-
-	ao_quat_rot(&t, &ao_up, &ao_orient);
-	printf ("pad orient (%g) %g %g %g\n",
-		t.q0,
-		t.q1,
-		t.q2,
-		t.q3);
-
-}
-
-void
-update_orientation (double rate_x, double rate_y, double rate_z, int tick)
-{
-	struct ao_quat	q_dot;
-	double		lambda;
-	double		dt = (tick - ao_orient_tick) / 100.0;
-
-	ao_orient_tick = tick;
- 
-//	lambda = 1 - ao_quat_norm(&ao_orient);
-	lambda = 0;
-
-	q_dot.q0 = -0.5 * (ao_orient.q1 * rate_x + ao_orient.q2 * rate_y + ao_orient.q3 * rate_z) + lambda * ao_orient.q0;
-	q_dot.q1 =  0.5 * (ao_orient.q0 * rate_x + ao_orient.q2 * rate_z - ao_orient.q3 * rate_y) + lambda * ao_orient.q1;
-	q_dot.q2 =  0.5 * (ao_orient.q0 * rate_y + ao_orient.q3 * rate_x - ao_orient.q1 * rate_z) + lambda * ao_orient.q2;
-	q_dot.q3 =  0.5 * (ao_orient.q0 * rate_z + ao_orient.q1 * rate_y - ao_orient.q2 * rate_x) + lambda * ao_orient.q3;
-
-#if 0
-	printf ("update_orientation %g %g %g (%g s)\n", rate_x, rate_y, rate_z, dt);
-	printf ("q_dot (%g) %g %g %g\n",
-		q_dot.q0,
-		q_dot.q1,
-		q_dot.q2,
-		q_dot.q3);
-#endif
-
-	ao_orient.q0 += q_dot.q0 * dt;
-	ao_orient.q1 += q_dot.q1 * dt;
-	ao_orient.q2 += q_dot.q2 * dt;
-	ao_orient.q3 += q_dot.q3 * dt;
-
-	ao_quat_normalize(&ao_orient);
-
-	ao_quat_rot(&ao_current, &ao_up, &ao_orient);
-
-	ao_sample_qangle = 180 / M_PI * acos(ao_current.q3 * sqrt(2));
-#if 0
-	printf ("orient (%g) %g %g %g current (%g) %g %g %g\n",
-		ao_orient.q0,
-		ao_orient.q1,
-		ao_orient.q2,
-		ao_orient.q3,
-		ao_current.q0,
-		ao_current.q1,
-		ao_current.q2,
-		ao_current.q3);
-#endif
-}
-#endif
-
 void
 ao_sleep(void *wchan)
 {
@@ -872,32 +663,6 @@ ao_sleep(void *wchan)
 #if HAS_MMA655X
 					ao_data_static.mma655x = int16(bytes, 26);
 #endif
-					if (ao_records_read == 0)
-						ao_ground_mpu6000 = ao_data_static.mpu6000;
-					else if (ao_records_read < 10) {
-#define f(f) ao_ground_mpu6000.f = ao_ground_mpu6000.f + ((ao_data_static.mpu6000.f - ao_ground_mpu6000.f) >> 2)
-						f(accel_x);
-						f(accel_y);
-						f(accel_z);
-						f(gyro_x);
-						f(gyro_y);
-						f(gyro_z);
-
-						double		accel_x = ao_mpu6000_accel(ao_ground_mpu6000.accel_x);
-						double		accel_y = ao_mpu6000_accel(ao_ground_mpu6000.accel_y);
-						double		accel_z = ao_mpu6000_accel(ao_ground_mpu6000.accel_z);
-
-						/* X and Y are in the ground plane, arbitraryily picked as MPU X and Z axes
-						 * Z is normal to the ground, the MPU y axis
-						 */
-						set_orientation(accel_x, accel_z, accel_y, tick);
-					} else {
-						double		rate_x = ao_mpu6000_gyro(ao_data_static.mpu6000.gyro_x - ao_ground_mpu6000.gyro_x);
-						double		rate_y = ao_mpu6000_gyro(ao_data_static.mpu6000.gyro_y - ao_ground_mpu6000.gyro_y);
-						double		rate_z = ao_mpu6000_gyro(ao_data_static.mpu6000.gyro_z - ao_ground_mpu6000.gyro_z);
-
-						update_orientation(rate_x * M_PI / 180, rate_z * M_PI / 180, rate_y * M_PI / 180, tick);
-					}
 					ao_records_read++;
 					ao_insert();
 					return;
diff --git a/src/test/ao_quaternion_test.c b/src/test/ao_quaternion_test.c
new file mode 100644
index 00000000..0e4b5b07
--- /dev/null
+++ b/src/test/ao_quaternion_test.c
@@ -0,0 +1,67 @@
+/*
+ * Copyright © 2013 Keith Packard <keithp@keithp.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#define _GNU_SOURCE
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <string.h>
+#include <getopt.h>
+#include <math.h>
+
+#include "ao_quaternion.h"
+
+static void
+print_q(char *name, struct ao_quaternion *q)
+{
+	printf ("%8.8s: r%8.5f x%8.5f y%8.5f z%8.5f ", name,
+		q->r, q->x, q->y, q->z);
+}
+
+int main(int argc, char **argv)
+{
+	struct ao_quaternion	position;
+	struct ao_quaternion	rotation;
+	struct ao_quaternion	little_rotation;
+	int			i;
+
+	/* unit x vector */
+	ao_quaternion_init_vector(&position, 1, 0, 0);
+
+	/* zero rotation */
+	ao_quaternion_init_zero_rotation(&rotation);
+
+	/* π/16 rotation around Z axis */
+	ao_quaternion_init_rotation(&little_rotation, 0, 0, 1,
+				    sin((M_PI/16)/2),
+				    cos((M_PI/16)/2));
+	for (i = 0; i <= 16; i++) {
+		struct ao_quaternion	rotated;
+
+		ao_quaternion_rotate(&rotated, &position, &rotation);
+		print_q("position", &position);
+		print_q("rotated", &rotated);
+		print_q("rotation", &rotation);
+		printf ("\n");
+		ao_quaternion_multiply(&rotation, &rotation, &little_rotation);
+		ao_quaternion_normalize(&rotation, &rotation);
+	}
+	return 0;
+}
+