Merge branch 'master' into navigator_rewrite

Conflicts:
	src/drivers/gps/gps.cpp
	src/drivers/gps/mtk.cpp
	src/modules/commander/commander.cpp
	src/modules/ekf_att_pos_estimator/ekf_att_pos_estimator_main.cpp
	src/modules/navigator/mission.cpp
	src/modules/navigator/mission.h
	src/modules/navigator/navigator_main.cpp
	src/modules/navigator/navigator_state.h
	src/modules/position_estimator_inav/position_estimator_inav_main.c

src/modules/position_estimator_inav/module.mk

@@ -39,3 +39,5 @@ MODULE_COMMAND	 	= position_estimator_inav
 SRCS		 	= position_estimator_inav_main.c \
 			position_estimator_inav_params.c \
 			inertial_filter.c
+
+MODULE_STACKSIZE = 1200

src/modules/position_estimator_inav/position_estimator_inav_main.c

@@ -135,7 +135,7 @@ int position_estimator_inav_main(int argc, char *argv[])
 
 		thread_should_exit = false;
 		position_estimator_inav_task = task_spawn_cmd("position_estimator_inav",
-					       SCHED_RR, SCHED_PRIORITY_MAX - 5, 4096,
+					       SCHED_DEFAULT, SCHED_PRIORITY_MAX - 5, 4000,
 					       position_estimator_inav_thread_main,
 					       (argv) ? (const char **) &argv[2] : (const char **) NULL);
 		exit(0);
@@ -199,6 +199,9 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 	float y_est[3] = { 0.0f, 0.0f, 0.0f };
 	float z_est[3] = { 0.0f, 0.0f, 0.0f };
 
+	float eph = 1.0;
+	float epv = 1.0;
+
 	float x_est_prev[3], y_est_prev[3], z_est_prev[3];
 	memset(x_est_prev, 0, sizeof(x_est_prev));
 	memset(y_est_prev, 0, sizeof(y_est_prev));
@@ -535,6 +538,8 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 
 					flow_valid = true;
 
+					eph = fminf(eph, 0.1 / att.R[2][2] / flow_q * fmaxf(1.0f, flow_dist));	// under ideal conditions, on 1m distance assume EPH = 10cm
+
 				} else {
 					w_flow = 0.0f;
 					flow_valid = false;
@@ -673,6 +678,9 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 							corr_gps[2][1] = 0.0f;
 						}
 
+						eph = fminf(eph, gps.eph);
+						epv = fminf(epv, gps.epv);
+
 						w_gps_xy = min_eph_epv / fmaxf(min_eph_epv, gps.eph);
 						w_gps_z = min_eph_epv / fmaxf(min_eph_epv, gps.epv);
 					}
@@ -712,6 +720,10 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 		dt = fmaxf(fminf(0.02, dt), 0.002);		// constrain dt from 2 to 20 ms
 		t_prev = t;
 
+		/* increase EPH/EPV on each step */
+		eph *= 1.0 + dt;
+		epv += 0.005 * dt;	// add 1m to EPV each 200s (baro drift)
+
 		/* use GPS if it's valid and reference position initialized */
 		bool use_gps_xy = ref_inited && gps_valid && params.w_xy_gps_p > MIN_VALID_W;
 		bool use_gps_z = ref_inited && gps_valid && params.w_z_gps_p > MIN_VALID_W;
@@ -723,7 +735,7 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 			xy_src_time = t;
 		}
 
-		bool can_estimate_xy = (t < xy_src_time + xy_src_timeout);
+		bool can_estimate_xy = eph < max_eph_epv * 1.5;
 
 		bool dist_bottom_valid = (t < sonar_valid_time + sonar_valid_timeout);
 
@@ -922,6 +934,8 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 			local_pos.landed = landed;
 			local_pos.yaw = att.yaw;
 			local_pos.dist_bottom_valid = dist_bottom_valid;
+			local_pos.eph = eph;
+			local_pos.epv = epv;
 
 			if (local_pos.dist_bottom_valid) {
 				local_pos.dist_bottom = -z_est[0] - surface_offset;
@@ -950,9 +964,8 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 
 				global_pos.yaw = local_pos.yaw;
 
-				// TODO implement dead-reckoning
-				global_pos.eph = gps.eph;
-				global_pos.epv = gps.epv;
+				global_pos.eph = eph;
+				global_pos.epv = epv;
 
 				if (vehicle_global_position_pub < 0) {
 					vehicle_global_position_pub = orb_advertise(ORB_ID(vehicle_global_position), &global_pos);