AP_NavEKF2: Fix bugs preventing use of optical flow navigation

libraries/AP_NavEKF2/AP_NavEKF2_Outputs.cpp

@@ -180,7 +180,7 @@ bool NavEKF2_core::getPosNED(Vector3f &pos) const
     // There are three modes of operation, absolute position (GPS fusion), relative position (optical flow fusion) and constant position (no position estimate available)
     nav_filter_status status;
     getFilterStatus(status);
-    if (status.flags.horiz_pos_abs || status.flags.horiz_pos_rel) {
+    if (PV_AidingMode != AID_NONE) {
         // This is the normal mode of operation where we can use the EKF position states
         pos.x = outputDataNew.position.x;
         pos.y = outputDataNew.position.y;
@@ -398,7 +398,6 @@ void  NavEKF2_core::getFilterStatus(nav_filter_status &status) const
     bool doingFlowNav = (PV_AidingMode == AID_RELATIVE) && flowDataValid;
     bool doingWindRelNav = !tasTimeout && assume_zero_sideslip();
     bool doingNormalGpsNav = !posTimeout && (PV_AidingMode == AID_ABSOLUTE);
-    bool notDeadReckoning = (PV_AidingMode == AID_ABSOLUTE);
     bool someVertRefData = (!velTimeout && useGpsVertVel) || !hgtTimeout;
     bool someHorizRefData = !(velTimeout && posTimeout && tasTimeout) || doingFlowNav;
     bool optFlowNavPossible = flowDataValid && (frontend._fusionModeGPS == 3);
@@ -407,10 +406,10 @@ void  NavEKF2_core::getFilterStatus(nav_filter_status &status) const
 
     // set individual flags
     status.flags.attitude = !stateStruct.quat.is_nan() && filterHealthy;   // attitude valid (we need a better check)
-    status.flags.horiz_vel = someHorizRefData && notDeadReckoning && filterHealthy;      // horizontal velocity estimate valid
+    status.flags.horiz_vel = someHorizRefData && filterHealthy;      // horizontal velocity estimate valid
     status.flags.vert_vel = someVertRefData && filterHealthy;        // vertical velocity estimate valid
-    status.flags.horiz_pos_rel = ((doingFlowNav && gndOffsetValid) || doingWindRelNav || doingNormalGpsNav) && notDeadReckoning && filterHealthy;   // relative horizontal position estimate valid
-    status.flags.horiz_pos_abs = doingNormalGpsNav && notDeadReckoning && filterHealthy; // absolute horizontal position estimate valid
+    status.flags.horiz_pos_rel = ((doingFlowNav && gndOffsetValid) || doingWindRelNav || doingNormalGpsNav) && filterHealthy;   // relative horizontal position estimate valid
+    status.flags.horiz_pos_abs = doingNormalGpsNav && filterHealthy; // absolute horizontal position estimate valid
     status.flags.vert_pos = !hgtTimeout && filterHealthy;            // vertical position estimate valid
     status.flags.terrain_alt = gndOffsetValid && filterHealthy;		// terrain height estimate valid
     status.flags.const_pos_mode = (PV_AidingMode == AID_NONE) && filterHealthy;     // constant position mode