diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_Logging.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_Logging.cpp
index 684d22ca4c..76bc29cbfa 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_Logging.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_Logging.cpp
@@ -169,7 +169,7 @@ void NavEKF2_core::Log_Write_NKF5(uint64_t time_us) const
         normInnov : (uint8_t)(MIN(100*MAX(flowTestRatio[0],flowTestRatio[1]),255)),  // normalised innovation variance ratio for optical flow observations fused by the main nav filter
         FIX : (int16_t)(1000*innovOptFlow[0]),  // optical flow LOS rate vector innovations from the main nav filter
         FIY : (int16_t)(1000*innovOptFlow[1]),  // optical flow LOS rate vector innovations from the main nav filter
-        AFI : (int16_t)(1000*norm(auxFlowObsInnov.x,auxFlowObsInnov.y)),  // optical flow LOS rate innovation from terrain offset estimator
+        AFI : (int16_t)(1000 * auxFlowObsInnov.length()),  // optical flow LOS rate innovation from terrain offset estimator
         HAGL : (int16_t)(100*(terrainState - stateStruct.position.z)),  // height above ground level
         offset : (int16_t)(100*terrainState),  // // estimated vertical position of the terrain relative to the nav filter zero datum
         RI : (int16_t)(100*innovRng),  // range finder innovations
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_MagFusion.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_MagFusion.cpp
index 2552a20230..9db5aaa2c8 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_MagFusion.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_MagFusion.cpp
@@ -1124,7 +1124,7 @@ void NavEKF2_core::alignMagStateDeclination()
 
     // rotate the NE values so that the declination matches the published value
     Vector3F initMagNED = stateStruct.earth_magfield;
-    ftype magLengthNE = norm(initMagNED.x,initMagNED.y);
+    ftype magLengthNE = initMagNED.xy().length();
     stateStruct.earth_magfield.x = magLengthNE * cosF(magDecAng);
     stateStruct.earth_magfield.y = magLengthNE * sinF(magDecAng);
 
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_Measurements.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_Measurements.cpp
index 24d51709a0..0dd728669e 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_Measurements.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_Measurements.cpp
@@ -735,7 +735,7 @@ void NavEKF2_core::correctEkfOriginHeight()
     } else if (activeHgtSource == HGT_SOURCE_RNG) {
         // use the worse case expected terrain gradient and vehicle horizontal speed
         const ftype maxTerrGrad = 0.25f;
-        ekfOriginHgtVar += sq(maxTerrGrad * norm(stateStruct.velocity.x , stateStruct.velocity.y) * deltaTime);
+        ekfOriginHgtVar += sq(maxTerrGrad * stateStruct.velocity.xy().length() * deltaTime);
     } else {
         // by definition our height source is absolute so cannot run this filter
         return;
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_PosVelFusion.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_PosVelFusion.cpp
index 9190c65574..5e44dfa4a5 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_PosVelFusion.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_PosVelFusion.cpp
@@ -983,7 +983,7 @@ void NavEKF2_core::selectHeightForFusion()
         // If the terrain height is consistent and we are moving slowly, then it can be
         // used as a height reference in combination with a range finder
         // apply a hysteresis to the speed check to prevent rapid switching
-        ftype horizSpeed = norm(stateStruct.velocity.x, stateStruct.velocity.y);
+        ftype horizSpeed = stateStruct.velocity.xy().length();
         bool dontTrustTerrain = ((horizSpeed > frontend->_useRngSwSpd) && filterStatus.flags.horiz_vel) || !terrainHgtStable;
         ftype trust_spd_trigger = MAX((frontend->_useRngSwSpd - 1.0f),(frontend->_useRngSwSpd * 0.5f));
         bool trustTerrain = (horizSpeed < trust_spd_trigger) && terrainHgtStable;
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp
index 23121106d5..d8162503fc 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_VehicleStatus.cpp
@@ -105,7 +105,7 @@ void NavEKF2_core::calcGpsGoodToAlign(void)
     // This check can only be used if the vehicle is stationary
     bool gpsHorizVelFail;
     if (onGround) {
-        gpsHorizVelFilt = 0.1f * norm(gpsDataDelayed.vel.x,gpsDataDelayed.vel.y) + 0.9f * gpsHorizVelFilt;
+        gpsHorizVelFilt = 0.1f * gpsDataDelayed.vel.xy().length() + 0.9f * gpsHorizVelFilt;
         gpsHorizVelFilt = constrain_ftype(gpsHorizVelFilt,-10.0f,10.0f);
         gpsHorizVelFail = (fabsF(gpsHorizVelFilt) > 0.3f*checkScaler) && (frontend->_gpsCheck & MASK_GPS_HORIZ_SPD);
     } else {
diff --git a/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp b/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp
index d04b0f5313..94765ea2dd 100644
--- a/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp
+++ b/libraries/AP_NavEKF2/AP_NavEKF2_core.cpp
@@ -676,7 +676,7 @@ void NavEKF2_core::UpdateStrapdownEquationsNED()
     // calculate a magnitude of the filtered nav acceleration (required for GPS
     // variance estimation)
     accNavMag = velDotNEDfilt.length();
-    accNavMagHoriz = norm(velDotNEDfilt.x , velDotNEDfilt.y);
+    accNavMagHoriz = velDotNEDfilt.xy().length();
 
     // if we are not aiding, then limit the horizontal magnitude of acceleration
     // to prevent large manoeuvre transients disturbing the attitude