Copter: surface tracking format fixes

ArduCopter/Copter.h

@@ -293,18 +293,16 @@ private:
 
     class SurfaceTracking {
     public:
+        // get desired climb rate (in cm/s) to achieve surface tracking
         float adjust_climb_rate(float target_rate);
+
+        // get/set target altitude (in cm) above ground
         bool get_target_alt_cm(float &target_alt_cm) const;
         void set_target_alt_cm(float target_alt_cm);
-        float logging_target_alt() const {
-            if (!valid_for_logging) {
-                return AP::logger().quiet_nan();
-            }
-            return target_alt_cm * 0.01f; // cm->m
-        }
-        void invalidate_for_logging() {
-            valid_for_logging = false;
-        }
+
+        // get target altitude (in cm) for logging purposes
+        float logging_target_alt() const;
+        void invalidate_for_logging() { valid_for_logging = false; }
 
     private:
         float target_alt_cm;        // desired altitude in cm above the ground

ArduCopter/surface_tracking.cpp

@@ -13,14 +13,9 @@ float Copter::SurfaceTracking::adjust_climb_rate(float target_rate)
 
     const float current_alt = copter.inertial_nav.get_altitude();
     const float current_alt_target = copter.pos_control->get_alt_target();
-    float distance_error;
-    float velocity_correction;
-
-    uint32_t now = millis();
-
-    valid_for_logging = true;
 
     // reset target altitude if this controller has just been engaged
+    const uint32_t now = millis();
     if (now - last_update_ms > SURFACE_TRACKING_TIMEOUT_MS) {
         target_alt_cm = copter.rangefinder_state.alt_cm + current_alt_target - current_alt;
     }
@@ -30,6 +25,7 @@ float Copter::SurfaceTracking::adjust_climb_rate(float target_rate)
     if ((target_rate<0 && !copter.motors->limit.throttle_lower) || (target_rate>0 && !copter.motors->limit.throttle_upper)) {
         target_alt_cm += target_rate * copter.G_Dt;
     }
+    valid_for_logging = true;
 
     /*
       handle rangefinder glitches. When we get a rangefinder reading
@@ -39,7 +35,7 @@ float Copter::SurfaceTracking::adjust_climb_rate(float target_rate)
       row. When that happens we reset the target altitude to the new
       reading
      */
-    int32_t glitch_cm = copter.rangefinder_state.alt_cm - target_alt_cm;
+    const int32_t glitch_cm = copter.rangefinder_state.alt_cm - target_alt_cm;
     if (glitch_cm >= RANGEFINDER_GLITCH_ALT_CM) {
         copter.rangefinder_state.glitch_count = MAX(copter.rangefinder_state.glitch_count+1,1);
     } else if (glitch_cm <= -RANGEFINDER_GLITCH_ALT_CM) {
@@ -58,8 +54,8 @@ float Copter::SurfaceTracking::adjust_climb_rate(float target_rate)
     }
 
     // calc desired velocity correction from target rangefinder alt vs actual rangefinder alt (remove the error already passed to Altitude controller to avoid oscillations)
-    distance_error = (target_alt_cm - copter.rangefinder_state.alt_cm) - (current_alt_target - current_alt);
-    velocity_correction = distance_error * copter.g.rangefinder_gain;
+    const float distance_error = (target_alt_cm - copter.rangefinder_state.alt_cm) - (current_alt_target - current_alt);
+    float velocity_correction = distance_error * copter.g.rangefinder_gain;
     velocity_correction = constrain_float(velocity_correction, -SURFACE_TRACKING_VELZ_MAX, SURFACE_TRACKING_VELZ_MAX);
 
     // return combined pilot climb rate + rate to correct rangefinder alt error
@@ -69,7 +65,7 @@ float Copter::SurfaceTracking::adjust_climb_rate(float target_rate)
 #endif
 }
 
-// get surfacing tracking alt
+// get target altitude (in cm) above ground
 // returns true if there is a valid target
 bool Copter::SurfaceTracking::get_target_alt_cm(float &_target_alt_cm) const
 {
@@ -81,10 +77,17 @@ bool Copter::SurfaceTracking::get_target_alt_cm(float &_target_alt_cm) const
     return true;
 }
 
-// set surface tracking target altitude
+// set target altitude (in cm) above ground
 void Copter::SurfaceTracking::set_target_alt_cm(float _target_alt_cm)
 {
     target_alt_cm = _target_alt_cm;
     last_update_ms = AP_HAL::millis();
 }
 
+float Copter::SurfaceTracking::logging_target_alt() const
+{
+    if (!valid_for_logging) {
+        return AP::logger().quiet_nan();
+    }
+    return target_alt_cm * 0.01f; // cm->m
+}