diff --git a/libraries/AP_GPS/AP_GPS_NMEA.cpp b/libraries/AP_GPS/AP_GPS_NMEA.cpp
index e5ebe04327..cc28e88b81 100644
--- a/libraries/AP_GPS/AP_GPS_NMEA.cpp
+++ b/libraries/AP_GPS/AP_GPS_NMEA.cpp
@@ -827,4 +827,22 @@ bool AP_GPS_NMEA::is_healthy(void) const
     return true;
 }
 
+// get the velocity lag
+bool AP_GPS_NMEA::get_lag(float &lag_sec) const
+{
+    switch (get_type()) {
+#if AP_GPS_NMEA_UNICORE_ENABLED
+    case AP_GPS::GPS_TYPE_UNICORE_MOVINGBASE_NMEA:
+    case AP_GPS::GPS_TYPE_UNICORE_NMEA:
+        lag_sec = 0.14;
+        break;
+#endif // AP_GPS_NMEA_UNICORE_ENABLED
+
+    default:
+        lag_sec = 0.2;
+        break;
+    }
+    return true;
+}
+
 #endif // AP_GPS_NMEA_ENABLED
diff --git a/libraries/AP_GPS/AP_GPS_NMEA.h b/libraries/AP_GPS/AP_GPS_NMEA.h
index 81198edbd3..f7f9bfbd0d 100644
--- a/libraries/AP_GPS/AP_GPS_NMEA.h
+++ b/libraries/AP_GPS/AP_GPS_NMEA.h
@@ -68,7 +68,10 @@ public:
 
     // driver specific health, returns true if the driver is healthy
     bool is_healthy(void) const override;
-    
+
+    // get lag in seconds
+    bool get_lag(float &lag_sec) const override;
+
 private:
     /// Coding for the GPS sentences that the parser handles
     enum _sentence_types : uint16_t {      //there are some more than 10 fields in some sentences , thus we have to increase these value.