make_json_input

Before you estimate reflector heights, you need a set of instructions. These are made using make_json_input. The required inputs are:

• station name

• latitude (degrees)

• longitude (degrees)

• ellipsoidal height (meters).

The station location does not have to be cm-level for the reflections code. Within a few hundred meters is sufficient. For example:

make_json_input p101 41.692 -111.236 2016.1

If you happen to have the Cartesian coordinates (in meters), you can set -xyz True and input those instead of lat, long, and height.

If you are using a site that is in the UNR station database, the a priori values can be set to zeros:

make_json_input p101 0 0 0

A full listing of the possible inputs and examples for make_json_input can be found here.

The json file of instructions will be put in $REFL_CODE/input/p101.json.

The default azimuth inputs are four regions, each of 90 degrees. You set your preferred azimuth regions using -azlist. Azimuth regions should not be larger than ~100 degrees. If for example you want to use the region from 0 to 270 degrees, you should not set a region from 0 - 270, but instead a region from 0-90, 90-180, and the last from 180-270.

Example:

make_json_input p101 0 0 0 -azlist 0 90 90 180 180 270

We try to enforce homogenous track lengths by using a quality control factor called ediff. Its default value is 2 degrees, which means your arc should be within 2 degrees of the requested elevation angle inputs. So if you ask for 5 and 25 degrees, your arcs should at least be from 7 to 23 degrees. To tell gnssir you want to allow more arcs, just set ediff to a much larger value.