ekf2: Enable adjustment of nav validity timeout

src/modules/ekf2/ekf2_params.c

@@ -606,6 +606,17 @@ PARAM_DEFINE_INT32(EKF2_AID_MASK, 1);
  */
 PARAM_DEFINE_INT32(EKF2_HGT_MODE, 0);
 
+/**
+ * Maximum lapsed time from last fusion of measurements that constrain velocity drift before the EKF will report the horizontal nav solution as invalid.
+ *
+ * @group EKF2
+ * @group EKF2
+ * @min 500000
+ * @max 10000000
+ * @unit uSec
+ */
+PARAM_DEFINE_INT32(EKF2_NOAID_TOUT, 5000000);
+
 /**
  * Measurement noise for range finder fusion
  *