AP_NavEKF2: use a struct for all yaw step class variables

libraries/AP_NavEKF2/AP_NavEKF2.cpp

@@ -1155,15 +1155,15 @@ uint32_t NavEKF2::getLastYawResetAngle(float &yawAngDelta)
     // check for an internal ekf yaw reset
     float temp_yaw_delta;
     uint32_t ekf_reset_ms = core[primary].getLastYawResetAngle(temp_yaw_delta);
-    if (ekf_reset_ms != last_ekf_reset_ms) {
+    if (ekf_reset_ms != yaw_step_data.last_ekf_reset_ms) {
         // record the time of the ekf's internal yaw reset event
-        last_ekf_reset_ms = ekf_reset_ms;
+        yaw_step_data.last_ekf_reset_ms = ekf_reset_ms;
 
         // record the the ekf's internal yaw reset value
-        yaw_reset_delta = temp_yaw_delta;
+        yaw_step_data.yaw_delta = temp_yaw_delta;
 
         // record the yaw reset event time
-        yaw_reset_time_ms = imuSampleTime_us/1000;
+        yaw_step_data.yaw_reset_time_ms = imuSampleTime_us/1000;
 
     }
 
@@ -1171,31 +1171,31 @@ uint32_t NavEKF2::getLastYawResetAngle(float &yawAngDelta)
     // to the difference in yaw angle between the current and last yaw angle
     Vector3f eulers_primary;
     core[primary].getEulerAngles(eulers_primary);
-    if (primary != prev_instance) {
+    if (primary != yaw_step_data.prev_instance) {
         // the delta is the difference between the current and previous yaw
         // This overwrites any yaw reset value recorded from an internal eff reset
-        yaw_reset_delta += wrap_PI(eulers_primary.z - prev_yaw);
+        yaw_step_data.yaw_delta += wrap_PI(eulers_primary.z - yaw_step_data.prev_yaw);
 
         // record the time of the yaw reset event
-        yaw_reset_time_ms = imuSampleTime_us/1000;
+        yaw_step_data.yaw_reset_time_ms = imuSampleTime_us/1000;
 
         // update the time recorded for the last ekf internal yaw reset forthe primary core to
         // prevent a yaw ekf reset event being published on the next frame due to the change in time
-        last_ekf_reset_ms = ekf_reset_ms;
+        yaw_step_data.last_ekf_reset_ms = ekf_reset_ms;
 
     }
 
     // record the yaw angle from the primary core
-    prev_yaw = eulers_primary.z;
+    yaw_step_data.prev_yaw = eulers_primary.z;
 
     // record the primary core
-    prev_instance = primary;
+    yaw_step_data.prev_instance = primary;
 
     // return the yaw delta from the last event
-    yawAngDelta = yaw_reset_delta;
+    yawAngDelta = yaw_step_data.yaw_delta;
 
     // return the time of the last event
-    return yaw_reset_time_ms;
+    return yaw_step_data.yaw_reset_time_ms;
 }
 
 // return the amount of NE position change due to the last position reset in metres

libraries/AP_NavEKF2/AP_NavEKF2.h

@@ -380,11 +380,13 @@ private:
     // time at start of current filter update
     uint64_t imuSampleTime_us;
 
-    // used to keep track of yaw angle changes due to change of primary instance
-    uint8_t prev_instance = 0;          // active core number from the previous time step
-    uint32_t last_ekf_reset_ms= 0;      // last time the active ekf performed a yaw reset (msec)
-    uint32_t last_lane_switch_ms = 0;   // last time there was a lane switch (msec)
-    uint32_t yaw_reset_time_ms = 0;     // last time a yaw reset event was published
-    float yaw_reset_delta = 0.0f;       // the amount of yaw change due to the last published yaw reset (rad)
-    float prev_yaw = 0.0f;              // yaw angle published by the active core from the previous time step (rad)
+    // used to keep track of yaw angle steps due to change of primary instance or internal ekf yaw resets
+    struct {
+        uint8_t prev_instance;          // active core number from the previous time step
+        uint32_t last_ekf_reset_ms;     // last time the active ekf performed a yaw reset (msec)
+        uint32_t last_lane_switch_ms;   // last time there was a lane switch (msec)
+        uint32_t yaw_reset_time_ms;     // last time a yaw reset event was published
+        float yaw_delta;                // the amount of yaw change due to the last published yaw step (rad)
+        float prev_yaw;                 // yaw angle published by the active core from the previous time step (rad)
+    } yaw_step_data;
 };