ekf2: Allow adjustment of min arrival time delta parameter

src/modules/ekf2/ekf2_params.c

@@ -39,6 +39,18 @@
  *
  */
 
+
+/**
+ * Minimum time of arrival delta between non-IMU observations before data is downsampled.
+ * Baro and Magnetometer data will be averaged before downsampling, other data will be point sampled resulting in loss of information.
+ *
+ * @group EKF2
+ * @min 10
+ * @max 50
+ * @unit ms
+ */
+PARAM_DEFINE_INT32(EKF2_MIN_OBS_DT, 20);
+
 /**
  * Magnetometer measurement delay relative to IMU measurements
  *