What do you mean by "transmission broadcast"? The GNSS receiver cannot transmit anything.

Neither is the NMEA0183 data output by the GNSS receiver, representative of the data or signal received from the constellation. The data output is the locally calculated solution derived from the signal timing differences between three or more satellites of known location.

You can get GNSS recorders that record the raw signal and timing, and you can get GNSS simulators that can generate arbitrary signals to simulate any position and time. They are used for testing and development purposes for navigation electronics and are expensive. , Rebroadcasting that signal would be disruptive to nearby GNSS receivers. Such "spoofing" of GNSS can get you into trouble (with law enforcement kind of trouble), and could be a safety issue in some cases. Don't do that.

LabSat and Spectracom on are two manufacturers so such test equipment.

If on the other hand you simply want to feed the NMEA data directly to your application bypassing the GNSS for test purposes, then you only need to generate valid sentences. That is easy to do, but software such as NemaStudio will do that for you.

Thanks (and apologies for the late reply).

I believe this is the corresponding Wolfram Language function to implement your algorithm:

convert[{lat_, ns_, long_, we_}] := Module[{},
  {
   If[ns === "N", 1, -1] (IntegerPart[lat/100] + (5/3) FractionalPart[lat/100]),
   If[we === "W", -1, 1] (IntegerPart[long/100] + (5/3) FractionalPart[long/100])
   }
  ]

For example:

convert[{4005.832`, "N", 8814.7365`, "W"}]

gives:

{40.0972, -88.2456}

which seems to be correct:

GeoGraphics[GeoMarker[{40.0972`, -88.24560833333335`}], GeoRange -> Quantity[1, "km"]]