GSG-5 Series GNSS simulator teardown and exploration - Page 1
Forum section: electronics / testgear

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: April 23, 2024, 06:45:21 pm
content: Recently needed to acquire capabilities to simulate GNSS for a variety of reasons, so I snagged a discount GSG-54 8ch sim.These were higher on my list due to actual software support and availability of control stuff vs the Spirent units which are best described as "good luck, have fun, not happening"Of course I slid off the covers to inspect ASAP.Looks to be based around a LPC3250 SOM from embedded artists. No immediately visible serial port either.Will have to break out logic analyzer to inspect the high pin count 2.54 headers for serial.Weird note is I cannot seem to enumerate the ethernet port, set to auto IP but never raises the link to a switch.Firmware is VERY out of date and I have sent a request to Safran(parent company who bought the others) for firmware upgrade chain.More exploration to come

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: April 27, 2024, 07:55:02 pm
content: Bad news, Looks like the unit I obtained is broken in odd ways. Ethernet is non-responsive and does not initiate a link, USB fails IVI with a timeout and I cannot update the firmware.Did however obtain the firmware chain from Safran, I will repost it when I am back in the office for future ref.If anyone has a 2014ish vintage of GSG Studioview it would be appreciated, would like to take one more attempt at cracking it onto a newer firmware rev before giving up.

author: Kean
author_rank: Unknown
timestamp: April 27, 2024, 08:17:37 pm
content: Thanks for the update.Great to hear Safran responded, but sad to hear you aren't having any luck with comms.I own one of the (mostly useless) Spirent units (GSS4100).

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: April 30, 2024, 02:39:01 pm
content: Here's the archived link of all the firmware chain in case anyone needs ithttps://web.archive.org/web/20240426151311/https://safran-navigation-timing.com/portal/client-downloads/download-8328317399/Have Safran talking and working on figuring out what is going on

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: April 30, 2024, 09:36:37 pm
content: Tore down instrument proper to have a look see at what is going on with the Ethernet not working while I wait to hear back from Safran about USB alternative IVI methods.Based around an OEM SOM, fairly simple internals where the magic sauce is definitely in the software.

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: April 30, 2024, 09:38:12 pm
content: Further probing of both sides of the magnetics seems to show why it would be failing to communicate.Input end looks great, nice symmetrical differential about bias voltage, but the Jack side is abysmal.Timebase is the same and vbias centered on graticule center.

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: May 01, 2024, 10:32:57 pm
content: Post-replacement of magnetics, I have now obtained a link and it negotiates an address.However, there is no webserver spun up and it only instantiates a FTP server with unknown login details.Time to ask Safran for more details.

author: ArsenioDev
author_rank: Frequent Contributor
timestamp: May 16, 2024, 03:43:56 am
content: Well, Safran is very confused as well.I've requested a full flash memory dump to re-load manually but I doubt they will send it.In any case, I still have the return option.