diff --git a/libraries/AP_NavEKF3/AP_NavEKF3.h b/libraries/AP_NavEKF3/AP_NavEKF3.h
index d4b70b3e14..ccd0a6e2f1 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3.h
+++ b/libraries/AP_NavEKF3/AP_NavEKF3.h
@@ -413,7 +413,7 @@ private:
     AP_Float _gyroBiasProcessNoise; // gyro bias state process noise : rad/s
     AP_Float _accelBiasProcessNoise;// accel bias state process noise : m/s^2
     AP_Int16 _hgtDelay_ms;          // effective average delay of Height measurements relative to inertial measurements (msec)
-    AP_Int8  _fusionModeGPS;        // 0 = use 3D velocity, 1 = use 2D velocity, 2 = use no velocity
+    AP_Int8  _fusionModeGPS;        // 0 = use 3D velocity, 1 = use 2D velocity, 2 = use no velocity, 3 = do not use GPS
     AP_Int16  _gpsVelInnovGate;     // Percentage number of standard deviations applied to GPS velocity innovation consistency check
     AP_Int16  _gpsPosInnovGate;     // Percentage number of standard deviations applied to GPS position innovation consistency check
     AP_Int16  _hgtInnovGate;        // Percentage number of standard deviations applied to height innovation consistency check
diff --git a/libraries/AP_NavEKF3/AP_NavEKF3_PosVelFusion.cpp b/libraries/AP_NavEKF3/AP_NavEKF3_PosVelFusion.cpp
index 7dc38b8578..e4ed3c232e 100644
--- a/libraries/AP_NavEKF3/AP_NavEKF3_PosVelFusion.cpp
+++ b/libraries/AP_NavEKF3/AP_NavEKF3_PosVelFusion.cpp
@@ -342,7 +342,7 @@ void NavEKF3_core::SelectVelPosFusion()
         // store the time of the reset
         lastPosReset_ms = imuSampleTime_ms;
 
-        // If we are alseo using GPS as the height reference, reset the height
+        // If we are also using GPS as the height reference, reset the height
         if (activeHgtSource == HGT_SOURCE_GPS) {
             // Store the position before the reset so that we can record the reset delta
             posResetD = stateStruct.position.z;
@@ -435,7 +435,7 @@ void NavEKF3_core::FuseVelPosNED()
         // Use different errors if operating without external aiding using an assumed position or velocity of zero
         if (PV_AidingMode == AID_NONE) {
             if (tiltAlignComplete && motorsArmed) {
-            // This is a compromise between corrections for gyro errors and reducing effect of manoeuvre accelerations on tilt estimate
+                // This is a compromise between corrections for gyro errors and reducing effect of manoeuvre accelerations on tilt estimate
                 R_OBS[0] = sq(constrain_float(frontend->_noaidHorizNoise, 0.5f, 50.0f));
             } else {
                 // Use a smaller value to give faster initial alignment