Add option to warn the pilot in case of strong magnetic interference but still allow arming.

This PR changes the COM_ARM_MAG_STR parameter to accept values. If the parameter is set to 2, the check is performed and a warning is logged but the vehicle can still arm.

src/modules/commander/Arming/PreFlightCheck/checks/ekf2Check.cpp

@@ -49,8 +49,8 @@ bool PreFlightCheck::ekf2Check(orb_advert_t *mavlink_log_pub, vehicle_status_s &
 {
 	bool success = true; // start with a pass and change to a fail if any test fails
 
-	int32_t mag_strength_check_enabled = 1;
-	param_get(param_find("COM_ARM_MAG_STR"), &mag_strength_check_enabled);
+	int32_t mag_strength_check = 1;
+	param_get(param_find("COM_ARM_MAG_STR"), &mag_strength_check);
 
 	float hgt_test_ratio_limit = 1.f;
 	param_get(param_find("COM_ARM_EKF_HGT"), &hgt_test_ratio_limit);
@@ -107,13 +107,20 @@ bool PreFlightCheck::ekf2Check(orb_advert_t *mavlink_log_pub, vehicle_status_s &
 		goto out;
 	}
 
-	if ((mag_strength_check_enabled == 1) && status.pre_flt_fail_mag_field_disturbed) {
-		if (report_fail) {
-			mavlink_log_critical(mavlink_log_pub, "Preflight Fail: strong magnetic interference detected");
-		}
+	if ((mag_strength_check >= 1) && status.pre_flt_fail_mag_field_disturbed) {
+		const char *message = "Preflight%s: Strong magnetic interference detected";
 
-		success = false;
-		goto out;
+		if (mag_strength_check == 1) {
+			if (report_fail) {
+				mavlink_log_critical(mavlink_log_pub, message, " Fail");
+			}
+
+			success = false;
+			goto out;
+
+		} else if (report_fail) {
+			mavlink_log_warning(mavlink_log_pub, message, "");
+		}
 	}
 
 	// check vertical position innovation test ratio

src/modules/commander/commander_params.c

@@ -620,10 +620,13 @@ PARAM_DEFINE_INT32(COM_ARM_MAG_ANG, 45);
 /**
  * Enable mag strength preflight check
  *
- * Deny arming if the estimator detects a strong magnetic
+ * Check if the estimator detects a strong magnetic
  * disturbance (check enabled by EKF2_MAG_CHECK)
  *
- * @boolean
+ * @value 0 Disabled
+ * @value 1 Deny arming
+ * @value 2 Warning only
+ *
  * @group Commander
  */
 PARAM_DEFINE_INT32(COM_ARM_MAG_STR, 1);