Base Station Compatibility

Are older base stations compatible with newer receivers or vice versa? I am aware that there are different output standards for basestations (RTCM, CMR, etc) but was wondering more on the signal frequency. The older rtk bases and receivers didn’t have the multiple gps signals that are available to today’s receivers and bases.

Older base stations are usually fine with latest rovers but the rover performance is obviously somewhat lower when corrections are limited to GPS or GPS + Glonass satellites only.

Older rovers often do not support MSM-messages that are needed for multiple constellation corrections (GPS + Glonass + Galileo + Beidou).

Are you talking about the GNSS frequencies or radios for correction signals?

Only looking at the GNSS frequencies. Radios are a completely different matter for compatibility.

Satellites still broadcast signals on the same frequencies for older and more recent receivers. Some very old receivers may only support L1 signals. I doubt there are any L1 only commercial products in use today, some low cost DIY devices may exist.

GPS has been modernized with the L2C code that low cost receivers like Ardusimple simpleRTK2B use. I’d say older receivers are better in this aspect because they can use every GPS satellite on L2 while L2C is still not available from all currently active GPS satellites. SimpleRTK2B will then see a few less GPS satellites compared to old or new commercial products. L5 support is another topic but it is not a question about old base stations or rovers versus new. More like a cost of product topic.

This is true if you can only receive GPS signal. But when activating other constellations you get enough satellites in wiew, so it it does not really matter that you can’t use every GPS satellite.

Some info here.

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A good clarification. My intention was not to say how much F9P suffers from L2C only, just make a note about the issue.

The topic however was about base station compatibility and if F9P was used with an “old” dual constellation base, the performance degradation starts to be visible although not really “significant”.

Then again, F9P is so cheap that one can easily afford another F9P for the base instead of using an old base.