diff --git a/src/main/navigation/navigation_pos_estimator.c b/src/main/navigation/navigation_pos_estimator.c
index d5a342173d..d20087f9e3 100755
--- a/src/main/navigation/navigation_pos_estimator.c
+++ b/src/main/navigation/navigation_pos_estimator.c
@@ -617,7 +617,7 @@ static bool estimationCalculateCorrection_Z(estimationContext_t * ctx)
             ctx->estPosCorr.z += gpsAltResudual * positionEstimationConfig()->w_z_gps_p * ctx->dt;
             ctx->estVelCorr.z += gpsAltResudual * sq(positionEstimationConfig()->w_z_gps_p) * ctx->dt;
             ctx->estVelCorr.z += gpsVelZResudual * positionEstimationConfig()->w_z_gps_v * ctx->dt;
-            ctx->newEPV = updateEPE(posEstimator.est.epv, ctx->dt, MAX(posEstimator.gps.epv, gpsAltResudual), positionEstimationConfig()->w_z_gps_p);
+            ctx->newEPV = updateEPE(posEstimator.est.epv, ctx->dt, MAX(posEstimator.gps.epv, fabsf(gpsAltResudual)), positionEstimationConfig()->w_z_gps_p);
 
             // Accelerometer bias
             ctx->accBiasCorr.z -= gpsAltResudual * sq(positionEstimationConfig()->w_z_gps_p);