Copter: use compass_checks from AP_Arming

User-visible changes:
 - checks will fail if calibration is in progress
 - PX4FMU_V1 will now have COMPASS_OFFSETS_MAX of 600, not 500
 - if the primary compass is not set to be used then compass checks will always pass

ArduCopter/arming_checks.cpp

@@ -129,62 +129,20 @@ bool AP_Arming_Copter::barometer_checks(bool display_failure)
 
 bool AP_Arming_Copter::compass_checks(bool display_failure)
 {
-    // check Compass
-    Compass &compass = _compass; // avoid code churn
+    bool ret = AP_Arming::compass_checks(display_failure);
+
     if ((checks_to_perform == ARMING_CHECK_ALL) || (checks_to_perform & ARMING_CHECK_COMPASS)) {
-        //check if compass has calibrated and requires reboot
-        if (compass.compass_cal_requires_reboot()) {
-            if (display_failure) {
-                gcs_send_text(MAV_SEVERITY_CRITICAL, "PreArm: Compass calibrated requires reboot");
-            }
-            return false;
-        }
-
-        // check the primary compass is healthy
-        if (!compass.healthy()) {
-            if (display_failure) {
-                gcs_send_text(MAV_SEVERITY_CRITICAL,"PreArm: Compass not healthy");
-            }
-            return false;
-        }
-
-        // check compass learning is on or offsets have been set
-        if (!compass.configured()) {
+        // check compass offsets have been set.  AP_Arming only checks
+        // this if learning is off; Copter *always* checks.
+        if (!_compass.configured()) {
             if (display_failure) {
                 gcs_send_text(MAV_SEVERITY_CRITICAL,"PreArm: Compass not calibrated");
             }
-            return false;
+            ret = false;
         }
-
-        // check for unreasonable compass offsets
-        Vector3f offsets = compass.get_offsets();
-        if (offsets.length() > COMPASS_OFFSETS_MAX) {
-            if (display_failure) {
-                gcs_send_text(MAV_SEVERITY_CRITICAL,"PreArm: Compass offsets too high");
-            }
-            return false;
-        }
-
-        // check for unreasonable mag field length
-        float mag_field = compass.get_field().length();
-        if (mag_field > COMPASS_MAGFIELD_EXPECTED*1.65f || mag_field < COMPASS_MAGFIELD_EXPECTED*0.35f) {
-            if (display_failure) {
-                gcs_send_text(MAV_SEVERITY_CRITICAL,"PreArm: Check mag field");
-            }
-            return false;
-        }
-
-        // check all compasses point in roughly same direction
-        if (!compass.consistent()) {
-            if (display_failure) {
-                gcs_send_text(MAV_SEVERITY_CRITICAL,"PreArm: inconsistent compasses");
-            }
-            return false;
-        }
-
     }
 
-    return true;
+    return ret;
 }
 
 bool AP_Arming_Copter::gps_checks(bool display_failure)

ArduCopter/arming_checks.h

@@ -30,11 +30,11 @@ protected:
 
     // NOTE! the following check functions *DO* call into AP_Arming:
     bool ins_checks(bool display_failure) override;
+    bool compass_checks(bool display_failure) override;
 
     // NOTE! the following check functions *DO NOT* call into AP_Arming!
     bool gps_checks(bool display_failure);
     bool fence_checks(bool display_failure);
-    bool compass_checks(bool display_failure);
     bool board_voltage_checks(bool display_failure);
     bool parameter_checks(bool display_failure);
     bool pilot_throttle_checks(bool display_failure);

ArduCopter/compassmot.cpp

@@ -210,12 +210,12 @@ MAV_RESULT Copter::mavlink_compassmot(mavlink_channel_t chan)
             if (comp_type == AP_COMPASS_MOT_COMP_THROTTLE) {
                 for (uint8_t i=0; i<compass.get_count(); i++) {
                     // interference is impact@fullthrottle / mag field * 100
-                    interference_pct[i] = motor_compensation[i].length() / (float)COMPASS_MAGFIELD_EXPECTED * 100.0f;
+                    interference_pct[i] = motor_compensation[i].length() / (float)arming.compass_magfield_expected() * 100.0f;
                 }
             }else{
                 for (uint8_t i=0; i<compass.get_count(); i++) {
                     // interference is impact/amp * (max current seen / max throttle seen) / mag field * 100
-                    interference_pct[i] = motor_compensation[i].length() * (current_amps_max/throttle_pct_max) / (float)COMPASS_MAGFIELD_EXPECTED * 100.0f;
+                    interference_pct[i] = motor_compensation[i].length() * (current_amps_max/throttle_pct_max) / (float)arming.compass_magfield_expected() * 100.0f;
                 }
             }
 

ArduCopter/config.h

@@ -207,22 +207,6 @@
  # define MAGNETOMETER                   ENABLED
 #endif
 
-// expected magnetic field strength.  pre-arm checks will fail if 50% higher or lower than this value
-#ifndef COMPASS_MAGFIELD_EXPECTED
- #define COMPASS_MAGFIELD_EXPECTED      530        // pre arm will fail if mag field > 874 or < 185
-#endif
-
-// max compass offset length (i.e. sqrt(offs_x^2+offs_y^2+offs_Z^2))
-#ifndef CONFIG_ARCH_BOARD_PX4FMU_V1
- #ifndef COMPASS_OFFSETS_MAX
-  # define COMPASS_OFFSETS_MAX          600         // PX4 onboard compass has high offsets
- #endif
-#else   // SITL, etc
- #ifndef COMPASS_OFFSETS_MAX
-  # define COMPASS_OFFSETS_MAX          500
- #endif
-#endif
-
 #ifndef COMPASS_CAL_STICK_GESTURE_TIME
  #define COMPASS_CAL_STICK_GESTURE_TIME 2.0f // 2 seconds
 #endif