#include "ao.h"
#endif
+#ifndef HAS_ACCEL
+#error Please define HAS_ACCEL
+#endif
+
+#ifndef HAS_GPS
+#error Please define HAS_GPS
+#endif
+
+#ifndef HAS_USB
+#error Please define HAS_USB
+#endif
+
+#ifndef USE_KALMAN
+#error Please define USE_KALMAN
+#endif
+
/* Main flight thread. */
__pdata enum ao_flight_state ao_flight_state; /* current flight state */
__pdata uint16_t ao_flight_tick; /* time of last data */
__pdata uint16_t ao_flight_prev_tick; /* time of previous data */
-__pdata int16_t ao_flight_accel; /* filtered acceleration */
__pdata int16_t ao_flight_pres; /* filtered pressure */
__pdata int16_t ao_ground_pres; /* startup pressure */
-__pdata int16_t ao_ground_accel; /* startup acceleration */
__pdata int16_t ao_min_pres; /* minimum recorded pressure */
__pdata uint16_t ao_launch_tick; /* time of launch detect */
__pdata int16_t ao_main_pres; /* pressure to eject main */
+#if HAS_ACCEL
+__pdata int16_t ao_flight_accel; /* filtered acceleration */
+__pdata int16_t ao_ground_accel; /* startup acceleration */
+#endif
/*
* track min/max data over a long interval to detect
* resting
*/
__pdata uint16_t ao_interval_end;
-__pdata int16_t ao_interval_cur_min_accel;
-__pdata int16_t ao_interval_cur_max_accel;
__pdata int16_t ao_interval_cur_min_pres;
__pdata int16_t ao_interval_cur_max_pres;
-__pdata int16_t ao_interval_min_accel;
-__pdata int16_t ao_interval_max_accel;
__pdata int16_t ao_interval_min_pres;
__pdata int16_t ao_interval_max_pres;
+#if HAS_ACCEL
+__pdata int16_t ao_interval_cur_min_accel;
+__pdata int16_t ao_interval_cur_max_accel;
+__pdata int16_t ao_interval_min_accel;
+__pdata int16_t ao_interval_max_accel;
+#endif
__data uint8_t ao_flight_adc;
-__pdata int16_t ao_raw_accel, ao_raw_accel_prev, ao_raw_pres;
-__pdata int16_t ao_accel_2g;
-
+__pdata int16_t ao_raw_pres;
__xdata uint8_t ao_flight_force_idle;
+#if HAS_ACCEL
+__pdata int16_t ao_raw_accel, ao_raw_accel_prev;
+__pdata int16_t ao_accel_2g;
+
/* Accelerometer calibration
*
* We're sampling the accelerometer through a resistor divider which
#define ACCEL_VEL_MACH VEL_MPS_TO_COUNT(200)
#define ACCEL_VEL_BOOST VEL_MPS_TO_COUNT(5)
-int32_t accel_vel_mach;
-int32_t accel_vel_boost;
+#endif
/*
* Barometer calibration
#define BOOST_TICKS_MAX AO_SEC_TO_TICKS(15)
+#if HAS_ACCEL
/* This value is scaled in a weird way. It's a running total of accelerometer
* readings minus the ground accelerometer reading. That means it measures
* velocity, and quite accurately too. As it gets updated 100 times a second,
__pdata int32_t ao_min_vel;
__pdata int32_t ao_old_vel;
__pdata int16_t ao_old_vel_tick;
-__xdata int32_t ao_raw_accel_sum, ao_raw_pres_sum;
+__xdata int32_t ao_raw_accel_sum;
+#endif
+
+#if USE_KALMAN
+__pdata int16_t ao_ground_height;
+__pdata int32_t ao_k_max_height;
+__pdata int32_t ao_k_height;
+__pdata int32_t ao_k_speed;
+__pdata int32_t ao_k_accel;
+
+#define to_fix16(x) ((int16_t) ((x) * 65536.0 + 0.5))
+#define to_fix32(x) ((int32_t) ((x) * 65536.0 + 0.5))
+
+#define from_fix(x) ((x) >> 16)
+
+#define AO_K0_100 to_fix16(0.05680323)
+#define AO_K1_100 to_fix16(0.16608182)
+#define AO_K2_100 to_fix16(0.24279580)
+
+#define AO_K_STEP_100 to_fix16(0.01)
+#define AO_K_STEP_2_2_100 to_fix16(0.00005)
+
+#define AO_K0_10 to_fix16(0.23772023)
+#define AO_K1_10 to_fix16(0.32214149)
+#define AO_K2_10 to_fix16(0.21827159)
+
+#define AO_K_STEP_10 to_fix16(0.1)
+#define AO_K_STEP_2_2_10 to_fix16(0.005)
+
+static void
+ao_kalman_baro(void)
+{
+ int16_t err = ((ao_pres_to_altitude(ao_raw_pres) - ao_ground_height))
+ - (int16_t) (ao_k_height >> 16);
+
+#ifdef AO_FLIGHT_TEST
+ if (ao_flight_tick - ao_flight_prev_tick > 5) {
+ ao_k_height += ((ao_k_speed >> 16) * AO_K_STEP_10 +
+ (ao_k_accel >> 16) * AO_K_STEP_2_2_10);
+ ao_k_speed += (ao_k_accel >> 16) * AO_K_STEP_10;
+
+ /* correct */
+ ao_k_height += (int32_t) AO_K0_10 * err;
+ ao_k_speed += (int32_t) AO_K1_10 * err;
+ ao_k_accel += (int32_t) AO_K2_10 * err;
+ return;
+ }
+#endif
+ ao_k_height += ((ao_k_speed >> 16) * AO_K_STEP_100 +
+ (ao_k_accel >> 16) * AO_K_STEP_2_2_100);
+ ao_k_speed += (ao_k_accel >> 16) * AO_K_STEP_100;
+
+ /* correct */
+ ao_k_height += (int32_t) AO_K0_100 * err;
+ ao_k_speed += (int32_t) AO_K1_100 * err;
+ ao_k_accel += (int32_t) AO_K2_100 * err;
+}
+#endif
+
+__xdata int32_t ao_raw_pres_sum;
/* Landing is detected by getting constant readings from both pressure and accelerometer
* for a fairly long time (AO_INTERVAL_TICKS)
__pdata static uint16_t nsamples = 0;
ao_flight_adc = ao_adc_head;
+ ao_raw_pres = 0;
+#if HAS_ACCEL
ao_raw_accel_prev = 0;
ao_raw_accel = 0;
- ao_raw_pres = 0;
+#endif
ao_flight_tick = 0;
for (;;) {
- ao_sleep(&ao_adc_ring);
+ ao_wakeup(DATA_TO_XDATA(&ao_flight_adc));
+ ao_sleep(DATA_TO_XDATA(&ao_adc_head));
while (ao_flight_adc != ao_adc_head) {
+#if HAS_ACCEL
__pdata uint8_t ticks;
__pdata int16_t ao_vel_change;
+#endif
+ __xdata struct ao_adc *ao_adc;
ao_flight_prev_tick = ao_flight_tick;
/* Capture a sample */
- ao_raw_accel = ao_adc_ring[ao_flight_adc].accel;
- ao_raw_pres = ao_adc_ring[ao_flight_adc].pres;
- ao_flight_tick = ao_adc_ring[ao_flight_adc].tick;
+ ao_adc = &ao_adc_ring[ao_flight_adc];
+ ao_flight_tick = ao_adc->tick;
+ ao_raw_pres = ao_adc->pres;
+ ao_flight_pres -= ao_flight_pres >> 4;
+ ao_flight_pres += ao_raw_pres >> 4;
+
+#if HAS_ACCEL
+ ao_raw_accel = ao_adc->accel;
+#if HAS_ACCEL_REF
+ /*
+ * Ok, the math here is a bit tricky.
+ *
+ * ao_raw_accel: ADC output for acceleration
+ * ao_accel_ref: ADC output for the 5V reference.
+ * ao_cook_accel: Corrected acceleration value
+ * Vcc: 3.3V supply to the CC1111
+ * Vac: 5V supply to the accelerometer
+ * accel: input voltage to accelerometer ADC pin
+ * ref: input voltage to 5V reference ADC pin
+ *
+ *
+ * Measured acceleration is ratiometric to Vcc:
+ *
+ * ao_raw_accel accel
+ * ------------ = -----
+ * 32767 Vcc
+ *
+ * Measured 5v reference is also ratiometric to Vcc:
+ *
+ * ao_accel_ref ref
+ * ------------ = -----
+ * 32767 Vcc
+ *
+ *
+ * ao_accel_ref = 32767 * (ref / Vcc)
+ *
+ * Acceleration is measured ratiometric to the 5V supply,
+ * so what we want is:
+ *
+ * ao_cook_accel accel
+ * ------------- = -----
+ * 32767 ref
+ *
+ *
+ * accel Vcc
+ * = ----- * ---
+ * Vcc ref
+ *
+ * ao_raw_accel 32767
+ * = ------------ * ------------
+ * 32737 ao_accel_ref
+ *
+ * Multiply through by 32767:
+ *
+ * ao_raw_accel * 32767
+ * ao_cook_accel = --------------------
+ * ao_accel_ref
+ *
+ * Now, the tricky part. Getting this to compile efficiently
+ * and keeping all of the values in-range.
+ *
+ * First off, we need to use a shift of 16 instead of * 32767 as SDCC
+ * does the obvious optimizations for byte-granularity shifts:
+ *
+ * ao_cook_accel = (ao_raw_accel << 16) / ao_accel_ref
+ *
+ * Next, lets check our input ranges:
+ *
+ * 0 <= ao_raw_accel <= 0x7fff (singled ended ADC conversion)
+ * 0x7000 <= ao_accel_ref <= 0x7fff (the 5V ref value is close to 0x7fff)
+ *
+ * Plugging in our input ranges, we get an output range of 0 - 0x12490,
+ * which is 17 bits. That won't work. If we take the accel ref and shift
+ * by a bit, we'll change its range:
+ *
+ * 0xe000 <= ao_accel_ref<<1 <= 0xfffe
+ *
+ * ao_cook_accel = (ao_raw_accel << 16) / (ao_accel_ref << 1)
+ *
+ * Now the output range is 0 - 0x9248, which nicely fits in 16 bits. It
+ * is, however, one bit too large for our signed computations. So, we
+ * take the result and shift that by a bit:
+ *
+ * ao_cook_accel = ((ao_raw_accel << 16) / (ao_accel_ref << 1)) >> 1
+ *
+ * This finally creates an output range of 0 - 0x4924. As the ADC only
+ * provides 11 bits of data, we haven't actually lost any precision,
+ * just dropped a bit of noise off the low end.
+ */
+ ao_raw_accel = (uint16_t) ((((uint32_t) ao_raw_accel << 16) / (ao_accel_ref[ao_flight_adc] << 1))) >> 1;
+ ao_adc->accel = ao_raw_accel;
+#endif
ao_flight_accel -= ao_flight_accel >> 4;
ao_flight_accel += ao_raw_accel >> 4;
- ao_flight_pres -= ao_flight_pres >> 4;
- ao_flight_pres += ao_raw_pres >> 4;
/* Update velocity
*
* The accelerometer is mounted so that
ao_flight_vel += (int32_t) ao_vel_change;
else
ao_flight_vel += (int32_t) ao_vel_change * (int32_t) ticks;
+#endif
+#if USE_KALMAN
+ if (ao_flight_state > ao_flight_idle)
+ ao_kalman_baro();
+#endif
ao_flight_adc = ao_adc_ring_next(ao_flight_adc);
}
if (ao_flight_pres < ao_min_pres)
ao_min_pres = ao_flight_pres;
+#if HAS_ACCEL
if (ao_flight_vel >= 0) {
if (ao_flight_vel < ao_min_vel)
ao_min_vel = ao_flight_vel;
if (-ao_flight_vel < ao_min_vel)
ao_min_vel = -ao_flight_vel;
}
+#endif
switch (ao_flight_state) {
case ao_flight_startup:
/* startup state:
*
- * Collect 1000 samples of acceleration and pressure
+ * Collect 512 samples of acceleration and pressure
* data and average them to find the resting values
*/
- if (nsamples < 1000) {
+ if (nsamples < 512) {
+#if HAS_ACCEL
ao_raw_accel_sum += ao_raw_accel;
+#endif
ao_raw_pres_sum += ao_raw_pres;
++nsamples;
continue;
}
- ao_ground_accel = (ao_raw_accel_sum / nsamples);
- ao_ground_pres = (ao_raw_pres_sum / nsamples);
+#if HAS_ACCEL
+ ao_ground_accel = ao_raw_accel_sum >> 9;
+#endif
+ ao_ground_pres = ao_raw_pres_sum >> 9;
ao_min_pres = ao_ground_pres;
ao_config_get();
+#if USE_KALMAN
+ ao_ground_height = ao_pres_to_altitude(ao_ground_pres);
+#endif
ao_main_pres = ao_altitude_to_pres(ao_pres_to_altitude(ao_ground_pres) + ao_config.main_deploy);
+#if HAS_ACCEL
ao_accel_2g = ao_config.accel_minus_g - ao_config.accel_plus_g;
- accel_vel_mach = ACCEL_VEL_MACH;
- accel_vel_boost = ACCEL_VEL_BOOST;
ao_flight_vel = 0;
ao_min_vel = 0;
ao_old_vel = ao_flight_vel;
ao_old_vel_tick = ao_flight_tick;
+#endif
- /* Go to pad state if the nose is pointing up */
+ /* Check to see what mode we should go to.
+ * - Invalid mode if accel cal appears to be out
+ * - pad mode if we're upright,
+ * - idle mode otherwise
+ */
ao_config_get();
- if (ao_config.accel_plus_g != 0 &&
- ao_config.accel_minus_g != 0 &&
- ao_flight_accel < ao_config.accel_plus_g + ACCEL_NOSE_UP &&
- !ao_flight_force_idle)
+#if HAS_ACCEL
+ if (ao_config.accel_plus_g == 0 ||
+ ao_config.accel_minus_g == 0 ||
+ ao_flight_accel < ao_config.accel_plus_g - ACCEL_NOSE_UP ||
+ ao_flight_accel > ao_config.accel_minus_g + ACCEL_NOSE_UP)
{
+ /* Detected an accel value outside -1.5g to 1.5g
+ * (or uncalibrated values), so we go into invalid mode
+ */
+ ao_flight_state = ao_flight_invalid;
+
+ } else
+#endif
+ if (!ao_flight_force_idle
+#if HAS_ACCEL
+ && ao_flight_accel < ao_config.accel_plus_g + ACCEL_NOSE_UP
+#endif
+ )
+ {
+ /* Set pad mode - we can fly! */
+ ao_flight_state = ao_flight_pad;
+#if HAS_USB
/* Disable the USB controller in flight mode
* to save power
*/
ao_usb_disable();
+#endif
- /* Turn on telemetry system
- */
+ /* Disable packet mode in pad state */
+ ao_packet_slave_stop();
+
+ /* Turn on telemetry system */
ao_rdf_set(1);
ao_telemetry_set_interval(AO_TELEMETRY_INTERVAL_PAD);
- ao_flight_state = ao_flight_pad;
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
+ /* signal successful initialization by turning off the LED */
+ ao_led_off(AO_LED_RED);
} else {
- ao_flight_state = ao_flight_idle;
-
- /* Turn on packet system in idle mode
- */
- ao_packet_slave_start();
- ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
+ /* Set idle mode */
+ ao_flight_state = ao_flight_idle;
+
+ /* signal successful initialization by turning off the LED */
+ ao_led_off(AO_LED_RED);
}
- /* signal successful initialization by turning off the LED */
- ao_led_off(AO_LED_RED);
+ /* wakeup threads due to state change */
+ ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
+
break;
case ao_flight_pad:
+#if HAS_ACCEL
/* Trim velocity
*
* Once a second, remove any velocity from
ao_flight_vel -= ao_old_vel;
ao_old_vel = ao_flight_vel;
}
+#endif
/* pad to boost:
*
* accelerometer: > 2g AND velocity > 5m/s
* the barometer, but we use both to make sure this
* transition is detected
*/
- if ((ao_flight_accel < ao_ground_accel - ACCEL_BOOST &&
- ao_flight_vel > ACCEL_VEL_BOOST) ||
+#if USE_KALMAN
+#if HAS_ACCEL
+ /*
+ * With an accelerometer, either to detect launch
+ */
+ if ((ao_k_accel > to_fix32(20) &&
+ ao_k_speed > to_fix32(5)) ||
+ ao_k_height > to_fix32(20))
+#else
+ /*
+ * Without an accelerometer, the barometer is far too
+ * noisy to rely on speed or acceleration data
+ */
+ if (ao_k_height > to_fix32(20))
+#endif
+#else
+ if (
+#if HAS_ACCEL
+ (ao_flight_accel < ao_ground_accel - ACCEL_BOOST &&
+ ao_flight_vel > ACCEL_VEL_BOOST) ||
+#endif
ao_flight_pres < ao_ground_pres - BARO_LAUNCH)
+#endif
{
+#if HAS_ACCEL || USE_KALMAN
ao_flight_state = ao_flight_boost;
+#else
+ ao_flight_state = ao_flight_coast;
+#endif
ao_launch_tick = ao_flight_tick;
/* start logging data */
/* disable RDF beacon */
ao_rdf_set(0);
+#if HAS_GPS
+ /* Record current GPS position by waking up GPS log tasks */
+ ao_wakeup(&ao_gps_data);
+ ao_wakeup(&ao_gps_tracking_data);
+#endif
+
ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
break;
}
break;
+#if HAS_ACCEL || USE_KALMAN
case ao_flight_boost:
/* boost to fast:
* deceleration, or by waiting until the maximum burn duration
* (15 seconds) has past.
*/
+#if USE_KALMAN
+ if ((ao_k_accel < to_fix32(-10) && ao_k_height > to_fix32(100)) ||
+ (int16_t) (ao_flight_tick - ao_launch_tick) > BOOST_TICKS_MAX)
+#else
if (ao_flight_accel > ao_ground_accel + ACCEL_COAST ||
(int16_t) (ao_flight_tick - ao_launch_tick) > BOOST_TICKS_MAX)
+#endif
{
ao_flight_state = ao_flight_fast;
ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
* how big a pressure change the mach transition
* generates would be useful here.
*/
+#if USE_KALMAN
+ if (ao_k_speed < to_fix32(200) ||
+ ao_k_height < ao_k_max_height - to_fix32(500))
+#else
if (ao_flight_vel < ACCEL_VEL_MACH ||
ao_flight_pres > ao_min_pres + BARO_COAST)
+#endif
{
+#if HAS_ACCEL
/* set min velocity to current velocity for
* apogee detect
*/
ao_min_vel = abs(ao_flight_vel);
+#endif
ao_flight_state = ao_flight_coast;
ao_wakeup(DATA_TO_XDATA(&ao_flight_state));
}
break;
+#endif /* HAS_ACCEL */
case ao_flight_coast:
+#if USE_KALMAN
+ /* apogee detect: coast to drogue deploy:
+ *
+ * speed: < 0
+ */
+ if (ao_k_speed < 0)
+#else
/* apogee detect: coast to drogue deploy:
*
* barometer: fall at least 10m
* we'll trust to a single sensor for this test
*/
if (ao_flight_pres > ao_min_pres + BARO_APOGEE)
+#endif
{
/* ignite the drogue charge */
ao_ignite(ao_igniter_drogue);
/* Set the 'last' limits to max range to prevent
* early resting detection
*/
+#if HAS_ACCEL
ao_interval_min_accel = 0;
ao_interval_max_accel = 0x7fff;
+#endif
ao_interval_min_pres = 0;
ao_interval_max_pres = 0x7fff;
ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
ao_interval_cur_min_pres = ao_interval_cur_max_pres = ao_flight_pres;
+#if HAS_ACCEL
ao_interval_cur_min_accel = ao_interval_cur_max_accel = ao_flight_accel;
+#endif
/* and enter drogue state */
ao_flight_state = ao_flight_drogue;
* at that point. Perhaps also use the drogue sense lines
* to notice continutity?
*/
+#if USE_KALMAN
+ if (from_fix(ao_k_height) < ao_config.main_deploy)
+#else
if (ao_flight_pres >= ao_main_pres)
+#endif
{
ao_ignite(ao_igniter_main);
ao_flight_state = ao_flight_main;
ao_interval_cur_min_pres = ao_flight_pres;
if (ao_flight_pres > ao_interval_cur_max_pres)
ao_interval_cur_max_pres = ao_flight_pres;
+#if HAS_ACCEL
if (ao_flight_accel < ao_interval_cur_min_accel)
ao_interval_cur_min_accel = ao_flight_accel;
if (ao_flight_accel > ao_interval_cur_max_accel)
ao_interval_cur_max_accel = ao_flight_accel;
+#endif
if ((int16_t) (ao_flight_tick - ao_interval_end) >= 0) {
ao_interval_max_pres = ao_interval_cur_max_pres;
ao_interval_min_pres = ao_interval_cur_min_pres;
+ ao_interval_cur_min_pres = ao_interval_cur_max_pres = ao_flight_pres;
+#if HAS_ACCEL
ao_interval_max_accel = ao_interval_cur_max_accel;
ao_interval_min_accel = ao_interval_cur_min_accel;
- ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
- ao_interval_cur_min_pres = ao_interval_cur_max_pres = ao_flight_pres;
ao_interval_cur_min_accel = ao_interval_cur_max_accel = ao_flight_accel;
+#endif
+ ao_interval_end = ao_flight_tick + AO_INTERVAL_TICKS;
- if ((uint16_t) (ao_interval_max_accel - ao_interval_min_accel) < (uint16_t) ACCEL_INT_LAND &&
+ if (
+#if HAS_ACCEL
+ (uint16_t) (ao_interval_max_accel - ao_interval_min_accel) < (uint16_t) ACCEL_INT_LAND &&
+#endif
ao_flight_pres > ao_ground_pres - BARO_LAND &&
(uint16_t) (ao_interval_max_pres - ao_interval_min_pres) < (uint16_t) BARO_INT_LAND)
{
ao_flight_init(void)
{
ao_flight_state = ao_flight_startup;
- ao_interval_min_accel = 0;
- ao_interval_max_accel = 0x7fff;
- ao_interval_min_pres = 0;
- ao_interval_max_pres = 0x7fff;
- ao_interval_end = AO_INTERVAL_TICKS;
-
ao_add_task(&flight_task, ao_flight, "flight");
}