diff --git a/src/modules/position_estimator_inav/position_estimator_inav_main.c b/src/modules/position_estimator_inav/position_estimator_inav_main.c
index bc6e0b0209..ef13ade886 100644
--- a/src/modules/position_estimator_inav/position_estimator_inav_main.c
+++ b/src/modules/position_estimator_inav/position_estimator_inav_main.c
@@ -75,8 +75,11 @@ static bool thread_should_exit = false; /**< Deamon exit flag */
 static bool thread_running = false; /**< Deamon status flag */
 static int position_estimator_inav_task; /**< Handle of deamon task / thread */
 static bool verbose_mode = false;
-static hrt_abstime gps_timeout = 1000000;	// GPS timeout = 1s
-static hrt_abstime flow_timeout = 1000000;	// optical flow timeout = 1s
+
+static const hrt_abstime gps_timeout = 1000000;	// GPS timeout = 1s
+static const hrt_abstime flow_timeout = 1000000;	// optical flow timeout = 1s
+static const uint32_t updates_counter_len = 1000000;
+static const uint32_t pub_interval = 4000;	// limit publish rate to 250 Hz
 
 __EXPORT int position_estimator_inav_main(int argc, char *argv[]);
 
@@ -172,6 +175,7 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 	float alt_avg = 0.0f;
 	bool landed = true;
 	hrt_abstime landed_time = 0;
+	bool flag_armed = false;
 
 	uint32_t accel_counter = 0;
 	uint32_t baro_counter = 0;
@@ -275,10 +279,7 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 	uint16_t flow_updates = 0;
 
 	hrt_abstime updates_counter_start = hrt_absolute_time();
-	uint32_t updates_counter_len = 1000000;
-
 	hrt_abstime pub_last = hrt_absolute_time();
-	uint32_t pub_interval = 4000;	// limit publish rate to 250 Hz
 
 	/* acceleration in NED frame */
 	float accel_NED[3] = { 0.0f, 0.0f, -CONSTANTS_ONE_G };
@@ -407,7 +408,6 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 							} else {
 								// new ground level
 								baro_alt0 += sonar_corr;
-								warnx("new home: alt = %.3f", baro_alt0);
 								mavlink_log_info(mavlink_fd, "[inav] new home: alt = %.3f", baro_alt0);
 								local_pos.ref_alt = baro_alt0;
 								local_pos.ref_timestamp = hrt_absolute_time();
@@ -486,6 +486,15 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 		float dt = t_prev > 0 ? (t - t_prev) / 1000000.0f : 0.0f;
 		t_prev = t;
 
+		/* reset ground level on arm */
+		if (armed.armed && !flag_armed) {
+			baro_alt0 -= z_est[0];
+			z_est[0] = 0.0f;
+			local_pos.ref_alt = baro_alt0;
+			local_pos.ref_timestamp = hrt_absolute_time();
+			mavlink_log_info(mavlink_fd, "[inav] new home on arm: alt = %.3f", baro_alt0);
+		}
+
 		/* accel bias correction, now only for Z
 		 * not strictly correct, but stable and works */
 		accel_bias[2] += (accel_NED[2] + CONSTANTS_ONE_G) * params.w_acc_bias * dt;
@@ -629,6 +638,7 @@ int position_estimator_inav_thread_main(int argc, char *argv[])
 
 			orb_publish(ORB_ID(vehicle_global_position), vehicle_global_position_pub, &global_pos);
 		}
+		flag_armed = armed.armed;
 	}
 
 	warnx("exiting.");