Beidou codes higher than 30

+2 votes
I see from RXM-SVSI that generation 8th of GNSS positioning modules is capable of Beidou codes up to 37, but as far as I can measure the receiver is not tracking anything above 30. Is there a special message to enable code search up to C37?



asked Sep 29, 2015 by michelegnss
reopened Feb 5, 2016 by michelegnss
But now with FW3.01 the command below does not work anymore??

2 Answers

+1 vote
Best answer
Sending this UBX message to the receiver will enable the other BeiDou SVs:

B5 62 06 4A 18 00 00 00 00 00 00 00 00 00 1F 00 00 00 FF FF FF FF 00 00 00 00 00 00 00 00 83 AC
answered Oct 22, 2015 by rmcn Senior Principal Expert
selected Nov 13, 2015 by √Črei
works, thank you very much
I found the UBX message center/Custom Messages, do I just paste and send? My M8T isn't seeing any BeiDou even with BeiDou the only satellite enabled.
–1 vote
u-bloxM8 receivers can track any operational Beidou satellite (B1 band). Checking the "List of Beidou Satellites" Wikipedia page, it appears there are just no operational BeiDou satellites with PRN above 30 yet.
answered Sep 29, 2015 by rmcn Senior Principal Expert
reshown Aug 21, 2017 by mazgch
I don't think this is an answer :/

Modernised Beidou satellites use codes C33 and C34.
Although not operational (yet) they are indeed broadcasting.
Understood that C33 and C34 have been launched but are not yet operational.

There is no filtering out of Beidou signals based upon PRN, so the receiver must be discarding the signals because they are not yet considered to be valid. Please check again once C33 and C34 are fully operational.
Typical stubborn reply from uBlox support >:|

As I am quite stubborn myself, I went off and programmed the Spectracom GSG-6 simulator we have in our lab.
I modified the simulator ephemeris to use C34 instead of a perfectly valid C12.
Result, the receiver does track C12 with that ephemeris but does not track C34.
In addition, the acquisition threshold for Beidou seems to be very high around 35 dB/Hz, a good 5 dB worse than GPS. At the same C/N0, the acquisition is also quite a bit slower on Beidou than it is for GPS (maybe 4 times as per literature?).

I was looking for a command to enable acquisition of Beidou PRNs above 30 (for which the protocol is ready). If there is no such command, a good answer would have been "sorry, no".
Hi michellegnss. I'm sorry you did not find my comments useful. All the documentation I found on this receiver indicates that it should process these signals no differently than other Beidou signals, so this is the conclusion I reached. You might consider contacting u-blox support, I bet they will be able to provide more information that forum community members.
Hi rmcn, apologies if you don't work for uBlox support yourself.
And many thanks for the effort you put in answering my question anyway.
Cheers, Michele