Removing GLONASS Message Content

This article shows how to set the the PFAT controls to remove classical GLONASS RTCM 3.x messages (message types 1009~1012) from a stream, leaving only the GPS types.

This action is often desired to create a new (smaller) stream without GLONASS message payloads for end users who do not need it.

The resulting setting as shown by the PFAT summary dialog display is shown below.

In this example we enable the following PFAT steps:

  1. Parse the RTCM3.x message content to detect the message types
  2. Filter the GLONASS observational messages (in this case MT1012)
  3. Translate the message flags in the remaining GPS observational messages (in this case MT1004) to indicate that they are the last in the measurement epoch.

The resulting final stream contains MT1004 ( the raw GPS observations) and MT1005 (the ECEF location of the Base Station).

If any GLONASS orbital data is present (MT 1019), that could be filtered as well.

If an offset to a new datum is required, an additional translation step could be added.

The tool-tip for this stream also summarizes the PFAT operations that have been performed on it.

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