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rtklibexplorer / RTKLIB

A version of RTKLIB optimized for low cost GNSS receivers, especially u-blox receivers. It is based on RTKLIB 2.4.3 and is kept reasonably closely synced to that branch. This software is provided “AS IS” without any warranties of any kind so please be careful, especially if using it in any kind of real-time application.
http://rtkexplorer.com/
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The b34i version cannot be fixed when using the bds system for moving base calculation #267

Open joseph-chunhui opened 4 months ago

joseph-chunhui commented 4 months ago

The following is the solution related configuration and solution result. It is obvious that the solution result has failed. 微信截图_20240511102926 微信截图_20240511102934 微信截图_20240511102851 In the data, the base station signal undergoes occlusion once every period of time and then recovers to a good signal. bds.zip

rtklibexplorer commented 4 months ago

I am able to duplicate your issue. The solution fixes OK with integer ambiguity for Beidou disabled ( "Integer Ambiguity Res (BDS)"=OFF in Setting2 tab) but not with this enabled. I need to take a closer look to see if this is an issue with your Beidou receiver data or an issue with the RTKLIB code but in the meantime you should be fine with this option disabled. Beidou integer ambiguity resolution does work fine in RTKLIB in general with other receivers.

By the way, you have L1/L2/L5 observations for both rover and base so you can set the Frequencies option to L1/L2/L5 for better results.

joseph-chunhui commented 4 months ago

ok！The bds system also fails to fix ambiguity when using full-system solutions in rtklib. What algorithm is used to solve L1/L2/L5 RTK in RTKLIB? Is it EWL+WL mode?

rtklibexplorer commented 4 months ago

I just realized from your screenshot that you are trying to solve for BDS only. Because RTKLIB was originally written for GPS only, in normal circumstances you should always have GPS selected for a RTK or PPK solution. Also, for PPK solutions, you will generally get a better solution with "Filter Type" set to combined rather than forward.

RTKLIB does not not use wide-lane or extra wide-lane combinations for ambiguity resolution, only uncombined signals.

joseph-chunhui commented 4 months ago

Yes, I would like to confirm whether rtklib can be solved using only BDS system for RTK? Logically, as long as the signal supports, the RTK solution using only the BDS system and the RTK solution using only the GPS system should have the same result.Is the reason why rtklib cannot be solved because the BDS system signal is not defined when RTK settlement is performed?

rtklibexplorer commented 4 months ago

Yes, in theory, you should be able to get an RTK solution with just BDS satellites, but RTKLIB has some dependencies on the GPS satellites due to its GPS-only origins, so you do need to include them.

On Wed, May 15, 2024 at 6:49 PM joseph-chunhui @.***> wrote:

Yes, I would like to confirm whether rtklib can be solved using only BDS system for RTK? Logically, as long as the signal supports, the RTK solution using only the BDS system and the RTK solution using only the GPS system should have the same result.

— Reply to this email directly, view it on GitHub https://github.com/rtklibexplorer/RTKLIB/issues/267#issuecomment-2113709313, or unsubscribe https://github.com/notifications/unsubscribe-auth/AC3YLOWFYXCBYEWKJ2UWNHLZCP7DNAVCNFSM6AAAAABHRQ6EJ6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDCMJTG4YDSMZRGM . You are receiving this because you commented.Message ID: @.***>

joseph-chunhui commented 4 months ago

But in fact, I use GPS+BDS at the same time, the BDS satellite can not fix the integer ambiguity, only GPS satellite can fix the integer ambiguity, what is the reason?