From: Keith Packard <keithp@keithp.com>
Date: Mon, 7 May 2018 15:51:36 +0000 (-0700)
Subject: altos: Eliminate height requirement for coast detect
X-Git-Tag: 1.8.6~1^2~63
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=cc83d57454ed07e4828b4413e5af6ae2ecfe2e5a;hp=49aafcbb6c0f3ecda4b668776be74a04a5654377

altos: Eliminate height requirement for coast detect

We had required a minimum altitude of 100m to transition from boost to
coast. With small motors in a heavy multi-staged rocket, this can fail
to detect coast in time to light the second motor.

Also, this would fail to deploy recovery systems if the flight failed
before reaching 100m.

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

diff --git a/src/kernel/ao_flight.c b/src/kernel/ao_flight.c
index cb02c454..7b3cb9fa 100644
--- a/src/kernel/ao_flight.c
+++ b/src/kernel/ao_flight.c
@@ -233,7 +233,7 @@ ao_flight(void)
 			 * deceleration, or by waiting until the maximum burn duration
 			 * (15 seconds) has past.
 			 */
-			if ((ao_accel < AO_MSS_TO_ACCEL(-2.5) && ao_height > AO_M_TO_HEIGHT(100)) ||
+			if ((ao_accel < AO_MSS_TO_ACCEL(-2.5)) ||
 			    (int16_t) (ao_sample_tick - ao_boost_tick) > BOOST_TICKS_MAX)
 			{
 #if HAS_ACCEL
@@ -310,7 +310,7 @@ ao_flight(void)
 #if HAS_ACCEL
 			else {
 			check_re_boost:
-				ao_coast_avg_accel = ao_coast_avg_accel - (ao_coast_avg_accel >> 6) + (ao_accel >> 6);
+				ao_coast_avg_accel = ao_coast_avg_accel + ((ao_accel - ao_coast_avg_accel) >> 5);
 				if (ao_coast_avg_accel > AO_MSS_TO_ACCEL(20)) {
 					ao_boost_tick = ao_sample_tick;
 					ao_flight_state = ao_flight_boost;