+#define AO_MAX_BARO_HEIGHT 12000
+
+/*
+ * Above this speed, baro measurements are unreliable
+ */
+#define AO_MAX_BARO_SPEED 300
+
+static void
+ao_kalman_predict(void)
+{
+#ifdef AO_FLIGHT_TEST
+ if (ao_flight_tick - ao_flight_prev_tick > 5) {
+ ao_k_height += ((int32_t) ao_speed * AO_K_STEP_10 +
+ (int32_t) ao_accel * AO_K_STEP_2_2_10) >> 4;
+ ao_k_speed += (int32_t) ao_accel * AO_K_STEP_10;
+
+ return;
+ }
+ if (ao_flight_debug) {
+ printf ("predict speed %g + (%g * %g) = %g\n",
+ ao_k_speed / (65536.0 * 16.0), ao_accel / 16.0, AO_K_STEP_100 / 65536.0,
+ (ao_k_speed + (int32_t) ao_accel * AO_K_STEP_100) / (65536.0 * 16.0));
+ }
+#endif
+ ao_k_height += ((int32_t) ao_speed * AO_K_STEP_100 +
+ (int32_t) ao_accel * AO_K_STEP_2_2_100) >> 4;
+ ao_k_speed += (int32_t) ao_accel * AO_K_STEP_100;
+}
+
+static __pdata int16_t ao_error_h;
+static __pdata int16_t ao_raw_alt;
+static __pdata int16_t ao_raw_height;
+static __pdata int16_t ao_error_h_sq_avg;
+
+static void
+ao_kalman_err_height(void)
+{
+ int16_t e;
+ int16_t height_distrust;
+#if HAS_ACCEL
+ int16_t speed_distrust;
+#endif
+
+ ao_error_h = ao_raw_height - (int16_t) (ao_k_height >> 16);
+
+ e = ao_error_h;
+ if (e < 0)
+ e = -e;
+ if (e > 127)
+ e = 127;
+ ao_error_h_sq_avg -= ao_error_h_sq_avg >> 4;
+ ao_error_h_sq_avg += (e * e) >> 4;
+
+ height_distrust = ao_raw_height - AO_MAX_BARO_HEIGHT;
+#if HAS_ACCEL
+ speed_distrust = (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) >> 4;
+ if (speed_distrust <= 0)
+ speed_distrust = 0;
+ else if (speed_distrust > height_distrust)
+ height_distrust = speed_distrust;
+#endif
+ if (height_distrust <= 0)
+ height_distrust = 0;
+
+ if (height_distrust) {
+#ifdef AO_FLIGHT_TEST
+ int old_ao_error_h = ao_error_h;
+#endif
+ if (height_distrust > 0x100)
+ height_distrust = 0x100;
+ ao_error_h = (int16_t) ((int32_t) ao_error_h * (0x100 - height_distrust)) >> 8;
+#ifdef AO_FLIGHT_TEST
+ if (ao_flight_debug) {
+ printf("over height %g over speed %g distrust: %g height: error %d -> %d\n",
+ (double) (ao_raw_height - AO_MAX_BARO_HEIGHT),
+ (ao_speed - AO_MS_TO_SPEED(AO_MAX_BARO_SPEED)) / 16.0,
+ height_distrust / 256.0,
+ old_ao_error_h, ao_error_h);
+ }
+#endif
+ }
+}
+
+static void
+ao_kalman_correct_baro(void)
+{
+ ao_kalman_err_height();
+#ifdef AO_FLIGHT_TEST
+ if (ao_flight_tick - ao_flight_prev_tick > 5) {
+ ao_k_height += (int32_t) AO_BARO_K0_10 * ao_error_h;
+ ao_k_speed += (int32_t) AO_BARO_K1_10 * ao_error_h;
+ ao_k_accel += (int32_t) AO_BARO_K2_10 * ao_error_h;
+ return;
+ }
+#endif
+ ao_k_height += (int32_t) AO_BARO_K0_100 * ao_error_h;
+ ao_k_speed += (int32_t) AO_BARO_K1_100 * ao_error_h;
+ ao_k_accel += (int32_t) AO_BARO_K2_100 * ao_error_h;
+}
+
+#if HAS_ACCEL
+static __pdata int16_t ao_error_a;
+static __pdata int32_t ao_accel_scale;
+
+static void
+ao_kalman_err_accel(void)
+{
+ int32_t accel;
+
+ accel = (ao_ground_accel - ao_raw_accel) * ao_accel_scale;
+
+ /* Can't use ao_accel here as it is the pre-prediction value still */
+ ao_error_a = (accel - ao_k_accel) >> 16;
+}
+
+static void
+ao_kalman_correct_both(void)
+{
+ ao_kalman_err_height();
+ ao_kalman_err_accel();
+
+#ifdef AO_FLIGHT_TEST
+ if (ao_flight_tick - ao_flight_prev_tick > 5) {
+ if (ao_flight_debug) {
+ printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
+ ao_k_speed / (65536.0 * 16.0),
+ (double) ao_error_h, AO_BOTH_K10_10 / 65536.0,
+ (double) ao_error_a, AO_BOTH_K11_10 / 65536.0,
+ (ao_k_speed +
+ (int32_t) AO_BOTH_K10_10 * ao_error_h +
+ (int32_t) AO_BOTH_K11_10 * ao_error_a) / (65536.0 * 16.0));
+ }
+ ao_k_height +=
+ (int32_t) AO_BOTH_K00_10 * ao_error_h +
+ (int32_t) (AO_BOTH_K01_10 >> 4) * ao_error_a;
+ ao_k_speed +=
+ ((int32_t) AO_BOTH_K10_10 << 4) * ao_error_h +
+ (int32_t) AO_BOTH_K11_10 * ao_error_a;
+ ao_k_accel +=
+ ((int32_t) AO_BOTH_K20_10 << 4) * ao_error_h +
+ (int32_t) AO_BOTH_K21_10 * ao_error_a;
+ return;
+ }
+ if (ao_flight_debug) {
+ printf ("correct speed %g + (%g * %g) + (%g * %g) = %g\n",
+ ao_k_speed / (65536.0 * 16.0),
+ (double) ao_error_h, AO_BOTH_K10_100 / 65536.0,
+ (double) ao_error_a, AO_BOTH_K11_100 / 65536.0,
+ (ao_k_speed +
+ (int32_t) AO_BOTH_K10_100 * ao_error_h +
+ (int32_t) AO_BOTH_K11_100 * ao_error_a) / (65536.0 * 16.0));
+ }
+#endif
+ ao_k_height +=
+ (int32_t) AO_BOTH_K00_100 * ao_error_h +
+ (int32_t) AO_BOTH_K01_100 * ao_error_a;
+ ao_k_speed +=
+ (int32_t) AO_BOTH_K10_100 * ao_error_h +
+ (int32_t) AO_BOTH_K11_100 * ao_error_a;
+ ao_k_accel +=
+ (int32_t) AO_BOTH_K20_100 * ao_error_h +
+ (int32_t) AO_BOTH_K21_100 * ao_error_a;
+}
+
+#ifdef FORCE_ACCEL
+static void
+ao_kalman_correct_accel(void)
+{
+ ao_kalman_err_accel();
+
+ if (ao_flight_tick - ao_flight_prev_tick > 5) {
+ ao_k_height +=(int32_t) AO_ACCEL_K0_10 * ao_error_a;
+ ao_k_speed += (int32_t) AO_ACCEL_K1_10 * ao_error_a;
+ ao_k_accel += (int32_t) AO_ACCEL_K2_10 * ao_error_a;
+ return;
+ }
+ ao_k_height += (int32_t) AO_ACCEL_K0_100 * ao_error_a;
+ ao_k_speed += (int32_t) AO_ACCEL_K1_100 * ao_error_a;
+ ao_k_accel += (int32_t) AO_ACCEL_K2_100 * ao_error_a;
+}
+#endif
+#endif /* HAS_ACCEL */
+
+__xdata int32_t ao_raw_pres_sum;
+
+#ifdef HAS_ACCEL
+__xdata int32_t ao_raw_accel_sum;
+#endif