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GNSS radio + number of satellite issue
I use both Geomax Zenith40’s in my solo practice and Leica GS18’s for a firm I do quite a bit of contract work for. Both run GPS/GLO/GAL/BEI.
Typically I use an elevation mask of 10° at RTK base (in case logging static at same time) and 15° at rover. Both are satel 1w radio’s using 8-FSK with Geomax on rtcm3.2 msm protocol and Leica on their Lecia 4g protocol.
In last few months started to have problems with Zenith40’s dropping a constellation and then reacquiring it quickly enough that I don’t lose RTK fix but CQs jump up slightly and is disconcerting. Dealer suggested turning off GPS L2C which didn’t help but more recently they also suggested dropping BEI which when I disabled at the base seemed to fix issue straight away (but didn’t do a full day after testing). I had wondered if I was getting interference on my radio channel but when dropping BEI out seemed to fix it, I figured must be a data transfer problem.
Restarted the base/rover using 15° mask at both base/rover and working ok with ~35 satellites max. being used in solution. Again restarted base/rover with 10° masks and 16-FSK on radio and working ok with ~40 satellites max. in solution. So appears either need to use 15° mask and keep 8-FSK for slightly better range or if base is to use 10° mask then use 16-FSK and accept radio not punching as far. Cell latency around here more problematic than radio too so that’s not my solution.
Seems RTCM3.2 MSM with 8-FSK can’t transfer much more the 35 satellites worth to rover, not a problem all day but at peak times it is. Probably the best option would be to drop out all the geostationary BEI satellites only not the whole constellation but Zenith 40’s not that fine grained.
Questions:
1) Haven’t had same issue with GS18’s (yet) so Lecia 4G must be more compact than rtcm3.2 msm?
2) How many satellites are being used in your RTK base/rover solution and can your internal base radio/radio protocol get the message though in time?
3) My problems started back in April so I’m thinking that must have coincided with more satellites coming onstream; where would I confirm this?
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