altos: Continuously update ground state while on pad (trac #42)

Average data for 5 seconds, wait 5 seconds and if still in pad mode,
replace the existing data with the new data. This should avoid
averaging in boost data while still keeping things reasonably current.

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

diff --git a/src/core/ao_sample.c b/src/core/ao_sample.c
index ac11eef000783fb4d42a226914e310c25a9b17d0..6461def06abbb764a6ce5dc4e7ac6ed91dbd50d2 100644 (file)
--- a/src/core/ao_sample.c
+++ b/src/core/ao_sample.c
@@ -61,6 +61,29 @@ __pdata int32_t ao_sample_pres_sum;
 __pdata int32_t ao_sample_accel_sum;
 #endif
 
+static void
+ao_sample_preflight_add(void)
+{
+#if HAS_ACCEL
+       ao_sample_accel_sum += ao_sample_accel;
+#endif
+       ao_sample_pres_sum += ao_sample_pres;
+       ++nsamples;
+}
+
+static void
+ao_sample_preflight_set(void)
+{
+#if HAS_ACCEL
+       ao_ground_accel = ao_sample_accel_sum >> 9;
+       ao_sample_accel_sum = 0;
+#endif
+       ao_ground_pres = ao_sample_pres_sum >> 9;
+       ao_ground_height = pres_to_altitude(ao_ground_pres);
+       nsamples = 0;
+       ao_sample_pres_sum = 0;
+}
+
 static void
 ao_sample_preflight(void)
 {
@@ -70,29 +93,38 @@ ao_sample_preflight(void)
         * data and average them to find the resting values
         */
        if (nsamples < 512) {
-#if HAS_ACCEL
-               ao_sample_accel_sum += ao_sample_accel;
-#endif
-               ao_sample_pres_sum += ao_sample_pres;
-               ++nsamples;
+               ao_sample_preflight_add();
        } else {
-               ao_config_get();
 #if HAS_ACCEL
-               ao_ground_accel = ao_sample_accel_sum >> 9;
                ao_accel_2g = ao_config.accel_minus_g - ao_config.accel_plus_g;
                ao_accel_scale = to_fix32(GRAVITY * 2 * 16) / ao_accel_2g;
 #endif
-               ao_ground_pres = ao_sample_pres_sum >> 9;
-               ao_ground_height = pres_to_altitude(ao_ground_pres);
+               ao_sample_preflight_set();
                ao_preflight = FALSE;
        }
 }
 
+/*
+ * While in pad mode, constantly update the ground state by
+ * re-averaging the data.  This tracks changes in orientation, which
+ * might be caused by adjustments to the rocket on the pad and
+ * pressure, which might be caused by changes in the weather.
+ */
+
+static void
+ao_sample_preflight_update(void)
+{
+       if (nsamples < 512)
+               ao_sample_preflight_add();
+       else if (nsamples < 1024)
+               ++nsamples;
+       else
+               ao_sample_preflight_set();
+}
 
 uint8_t
 ao_sample(void)
 {
-       ao_config_get();
        ao_wakeup(DATA_TO_XDATA(&ao_sample_data));
        ao_sleep((void *) DATA_TO_XDATA(&ao_data_head));
        while (ao_sample_data != ao_data_head) {
@@ -116,8 +148,11 @@ ao_sample(void)
 
                if (ao_preflight)
                        ao_sample_preflight();
-               else
+               else {
+                       if (ao_flight_state < ao_flight_boost)
+                               ao_sample_preflight_update();
                        ao_kalman();
+               }
                ao_sample_data = ao_data_ring_next(ao_sample_data);
        }
        return !ao_preflight;
@@ -126,6 +161,7 @@ ao_sample(void)
 void
 ao_sample_init(void)
 {
+       ao_config_get();
        nsamples = 0;
        ao_sample_pres_sum = 0;
        ao_sample_pres = 0;