L1 Carrier Phase Data

This chart shows the error induced into the raw measurements by compression of the data from the Hagerstown broadcast data. First, we are not seeing any missed epochs. We don’t expect to see any at the range we are currently working (46 kilometers [km]).

This shows how true the carrier phase data sent from Hagerstown reaches the users. When we compare this with the raw data out of the receiver port, to what was received over the data link, the above chart results. In the process of compressing the data, we loose some insignificant precision. This is intentional to save bandwidth. The net result is that the compression technique adds a white noise error component with minor loss in resolution. The lines are the result of using RINEX as an intermediate step in that RINEX provides data to 1 millimeter (mm) precision. We could have temporarily introduced more resolution in the RINEX, but then the chart would have been a blur, hence hard to follow. This shows that the data is arriving at the user with 0.8 mm RMS and an average of zero.

We arbitrarily picked satellite number 9, all other satellites will look the same. In fact, the plots would be indistinguishable.