RINEX to UBX-MGA converter

[jheaff1]

Hi,

Awesome library!

Given the recent announcement that the u-blox AssistNow service will be terminated in May 2028 (for M8 devices), it would be great to have a tool which can converter ephemeris and almanac RINEX to UBX-MGA messages, as a replacement for the AssistNow service.

[gwbres]

Hello @jheaff1,

interesting. I think in the long term, the combination of the ublox parser and this framework should enable pretty much everything. Including assistance / correction upload, and it's going to be super interesting.

I just initiated a branch to play with this topic, it's named ublox, it creates a new crate option to obtain a RNX2UBX streamer.
As similarly done for BINEX. I will keep this branch alive until we reach some kind of conclusion

Before going any further, please note that:

• the ublox parser is currently limited in its MGA support, there's still a bit of work if I recall correctly
• MGA is deprecated and was developped for GPS Only. SFRBX is the new approach and it covers Multi-GNSS.
• SFRBX is also work in progress, it correctly supports GPS as of right now

Currently I am not able to achieve anything that you want, because apparently the ublox library does not offer MGA / SFRBX forging, only parsing. It seems that forging is done using the XXXBuilder structure, and it is not provided for those frames. I'm not sure what needs to be done to unlock this.

Another problem I see is that the ublox library does not allow all-features to be enabled, protocols version are exclusive.
So to truly be perfect, you would need to introduce one library option per UBX protocol so everyone can use the proto version they desire, and inhibit all-features for the rinex library - which I will not allow. So eventually, we should have partial or good support, but It will remain limited to a specific UBX protocol version, which is not perfect.

Join us on this channel or ublox discord channel

PS : in case you're interested, we also have UBX2RINEX, the mirror operation, as a command line application

[jheaff1]

Hi @gwbres ,

Thank you for the prompt response. Great to hear you've already started to play around with implementing a Rinex to UBX streamer.

It seems to me that MGA messages do support constellations other than GPS, ie see UBX-MGA-GLO, UBX-MGA-GAL and UBX-MGA-BS - https://cdn.sparkfun.com/assets/learn_tutorials/8/6/9/u-blox8-M8_ReceiverDescrProtSpec__UBX-13003221__Public.pdf#page269.

At any rate, looking forward to seeing how this progresses

[gwbres]

Ok so first off, the synthesis of UBX-MGA/SFRBX was provided by my last contribution and this has not been released yet. So we should reindex the branch to the following, this should enable frame forging. I don't have time to try this as of right now. I don't know if a ublox release will happen in the next few days/weeks, I will try to push for it

ublox = { git = "https://github.com/ublox-rs/ublox",  rev = "2fa6761b2ccd4344326ad55f0dadc5965e06e957" }

or

ublox = { git = "https://github.com/ublox-rs/ublox",  branch = "master" }

It seems to me that MGA messages do support constellations other than GPS, ie see UBX-MGA-GLO, UBX-MGA-GAL and UBX-MGA-BS

Yeah I know, I provided those frames to the library years ago, but it's only recently that I have some little time to look into this, and also got to a stage where we can think of using them. So, to be more accurate, I should have said the support exist but principle remeains to be demonstrated.

Let's reindex the branch, see if we can take advantage of the frame forger. The interface we provide should provide both MGA (GPS/GLO deprecated and limited frames) and SFRBX (modern) frames. We can start with MGA to make it simple

[gwbres]

Will get back to this next week hopefully, keep you updated

[jheaff1]

Thanks for keeping me updated, it’s very much appreciated! Looking forward to seeing what you implement