Add more GPS checks for LPE (#4750)

* Added more GPS checks for LPE.

* Add logic to force GPS alt init.

src/modules/local_position_estimator/params.c

@@ -129,7 +129,7 @@ PARAM_DEFINE_FLOAT(LPE_ACC_Z, 0.0454f);
 PARAM_DEFINE_FLOAT(LPE_BAR_Z, 1.0f);
 
 /**
- * GPS
+ * Enables GPS data, also forces alt init with GPS
  *
  * @group Local Position Estimator
  * @boolean
@@ -203,6 +203,17 @@ PARAM_DEFINE_FLOAT(LPE_GPS_VZ, 0.25f);
  */
 PARAM_DEFINE_FLOAT(LPE_EPH_MAX, 3.0f);
 
+/**
+ * GPS max epv
+ *
+ * @group Local Position Estimator
+ * @unit m
+ * @min 1.0
+ * @max 5.0
+ * @decimal 3
+ */
+PARAM_DEFINE_FLOAT(LPE_EPV_MAX, 5.0f);
+
 /**
  * Vision xy standard deviation.
  *