AP_Compass: added COMPASS_OPTIONS

this allows user to set that calibration requires GPS lock

libraries/AP_Compass/AP_Compass.cpp

@@ -533,7 +533,14 @@ const AP_Param::GroupInfo Compass::var_info[] = {
     // @Range: 0 1.3
     AP_GROUPINFO("SCALE3", 42, Compass, _state[2].scale_factor, 0),
 #endif
-    
+
+    // @Param: OPTIONS
+    // @DisplayName: Compass options
+    // @Description: This sets options to change the behaviour of the compass
+    // @Bitmask: 0:CalRequireGPS
+    // @User: Advanced
+    AP_GROUPINFO("OPTIONS", 43, Compass, _options, 0),
+
     AP_GROUPEND
 };
 

libraries/AP_Compass/AP_Compass.h

@@ -472,6 +472,12 @@ private:
 
     AP_Int16 _offset_max;
 
+    // bitmask of options
+    enum class Option : uint16_t {
+        CAL_REQUIRE_GPS = (1U<<0),
+    };
+    AP_Int16 _options;
+
 #if COMPASS_CAL_ENABLED
     CompassCalibrator _calibrator[COMPASS_MAX_INSTANCES];
 #endif

libraries/AP_Compass/AP_Compass_Calibration.cpp

@@ -1,5 +1,6 @@
 #include <AP_HAL/AP_HAL.h>
 #include <AP_Notify/AP_Notify.h>
+#include <AP_GPS/AP_GPS.h>
 #include <GCS_MAVLink/GCS.h>
 
 #include "AP_Compass.h"
@@ -54,6 +55,12 @@ bool Compass::_start_calibration(uint8_t i, bool retry, float delay)
     if (!use_for_yaw(i)) {
         return false;
     }
+    if (_options.get() & uint16_t(Option::CAL_REQUIRE_GPS)) {
+        if (AP::gps().status() < AP_GPS::GPS_OK_FIX_2D) {
+            gcs().send_text(MAV_SEVERITY_ERROR, "Compass cal requires GPS lock");
+            return false;
+        }
+    }
     if (!is_calibrating()) {
         AP_Notify::events.initiated_compass_cal = 1;
     }