AP_NavEKF2: use parent class for intermediate static variables

this makes the code faster as well as using less memory when both EK2
and EK3 are enabled

libraries/AP_NavEKF2/AP_NavEKF2.cpp

@@ -660,6 +660,8 @@ bool NavEKF2::InitialiseFilter(void)
             gcs().send_text(MAV_SEVERITY_CRITICAL, "NavEKF2: allocation failed");
             return false;
         }
+
+        //Call Constructors on all cores
         for (uint8_t i = 0; i < num_cores; i++) {
             //Call Constructors
             new (&core[i]) NavEKF2_core();

libraries/AP_NavEKF2/AP_NavEKF2_MagFusion.cpp

@@ -780,6 +780,7 @@ void NavEKF2_core::fuseEulerYaw()
     float measured_yaw;
     float H_YAW[3];
     Matrix3f Tbn_zeroYaw;
+
     if (fabsf(prevTnb[0][2]) < fabsf(prevTnb[1][2])) {
         // calculate observation jacobian when we are observing the first rotation in a 321 sequence
         float t2 = q0*q0;
@@ -1037,6 +1038,7 @@ void NavEKF2_core::FuseDeclination(float declErr)
     float t12 = 1.0f/t11;
 
     float H_MAG[24];
+
     H_MAG[16] = -magE*t5;
     H_MAG[17] = magN*t5;
 

libraries/AP_NavEKF2/AP_NavEKF2_core.cpp

@@ -42,7 +42,8 @@ NavEKF2_core::NavEKF2_core(void) :
     _perf_FuseAirspeed(hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "EK2_FuseAirspeed")),
     _perf_FuseSideslip(hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "EK2_FuseSideslip")),
     _perf_TerrainOffset(hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "EK2_TerrainOffset")),
-    _perf_FuseOptFlow(hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "EK2_FuseOptFlow"))
+    _perf_FuseOptFlow(hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "EK2_FuseOptFlow")),
+    frontend(_frontend)
 {
     _perf_test[0] = hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "EK2_Test0");
     _perf_test[1] = hal.util->perf_alloc(AP_HAL::Util::PC_ELAPSED, "EK2_Test1");
@@ -170,8 +171,9 @@ void NavEKF2_core::InitialiseVariables()
     lastKnownPositionNE.zero();
     prevTnb.zero();
     memset(&P[0][0], 0, sizeof(P));
+    memset(&KH[0][0], 0, sizeof(KH));
+    memset(&KHP[0][0], 0, sizeof(KHP));
     memset(&nextP[0][0], 0, sizeof(nextP));
-    memset(&processNoise[0], 0, sizeof(processNoise));
     flowDataValid = false;
     rangeDataToFuse  = false;
     Popt = 0.0f;
@@ -545,6 +547,8 @@ void NavEKF2_core::UpdateFilter(bool predict)
 #endif
     hal.util->perf_begin(_perf_UpdateFilter);
 
+    fill_scratch_variables();
+
     // TODO - in-flight restart method
 
     //get starting time for update step

libraries/AP_NavEKF2/AP_NavEKF2_core.h

@@ -30,6 +30,7 @@
 #include "AP_NavEKF2.h"
 #include <stdio.h>
 #include <AP_Math/vectorN.h>
+#include <AP_NavEKF/AP_NavEKF_core_common.h>
 #include <AP_NavEKF2/AP_NavEKF2_Buffer.h>
 #include <AP_InertialSensor/AP_InertialSensor.h>
 
@@ -58,7 +59,7 @@
 
 class AP_AHRS;
 
-class NavEKF2_core
+class NavEKF2_core : public NavEKF_core_common
 {
 public:
     // Constructor
@@ -336,7 +337,6 @@ private:
     uint8_t core_index;
     uint8_t imu_buffer_length;
 
-    typedef float ftype;
 #if MATH_CHECK_INDEXES
     typedef VectorN<ftype,2> Vector2;
     typedef VectorN<ftype,3> Vector3;
@@ -356,7 +356,6 @@ private:
     typedef VectorN<ftype,24> Vector24;
     typedef VectorN<ftype,25> Vector25;
     typedef VectorN<ftype,31> Vector31;
-    typedef VectorN<ftype,28> Vector28;
     typedef VectorN<VectorN<ftype,3>,3> Matrix3;
     typedef VectorN<VectorN<ftype,24>,24> Matrix24;
     typedef VectorN<VectorN<ftype,34>,50> Matrix34_50;
@@ -379,7 +378,6 @@ private:
     typedef ftype Vector23[23];
     typedef ftype Vector24[24];
     typedef ftype Vector25[25];
-    typedef ftype Vector28[28];
     typedef ftype Matrix3[3][3];
     typedef ftype Matrix24[24][24];
     typedef ftype Matrix34_50[34][50];
@@ -799,9 +797,6 @@ private:
     bool badIMUdata;                // boolean true if the bad IMU data is detected
 
     float gpsNoiseScaler;           // Used to scale the  GPS measurement noise and consistency gates to compensate for operation with small satellite counts
-    Vector28 Kfusion;               // Kalman gain vector
-    Matrix24 KH;                    // intermediate result used for covariance updates
-    Matrix24 KHP;                   // intermediate result used for covariance updates
     Matrix24 P;                     // covariance matrix
     imu_ring_buffer_t<imu_elements> storedIMU;      // IMU data buffer
     obs_ring_buffer_t<gps_elements> storedGPS;      // GPS data buffer
@@ -856,12 +851,6 @@ private:
     bool allMagSensorsFailed;       // true if all magnetometer sensors have timed out on this flight and we are no longer using magnetometer data
     uint32_t lastYawTime_ms;        // time stamp when yaw observation was last fused (msec)
     uint32_t ekfStartTime_ms;       // time the EKF was started (msec)
-    Matrix24 nextP;                 // Predicted covariance matrix before addition of process noise to diagonals
-    Vector24 processNoise;          // process noise added to diagonals of predicted covariance matrix
-    Vector25 SF;                    // intermediate variables used to calculate predicted covariance matrix
-    Vector5 SG;                     // intermediate variables used to calculate predicted covariance matrix
-    Vector8 SQ;                     // intermediate variables used to calculate predicted covariance matrix
-    Vector23 SPP;                   // intermediate variables used to calculate predicted covariance matrix
     Vector2f lastKnownPositionNE;   // last known position
     uint32_t lastDecayTime_ms;      // time of last decay of GPS position offset
     float velTestRatio;             // sum of squares of GPS velocity innovation divided by fail threshold