I have a USB GPS (Holux SIRF Star III) that is driving me nuts. It has never worked reliably when connected to my Cerbo GX (running 3.54) yet works flawlessly when connected to my laptop.
When connected to the Cerbo, it will occasionally give me a fix that I can see on VRM. I though maybe it was because it was buried in the guts of my RV so I am trying to mount it externally. The Cerbo does see it as an NMEA 0183 on USB0 but will not show a fix now.
I have tried connecting to both usable USB ports both direct and via a powered hub. Rebooted the Cerbo many times as well.
On my laptop using a basic terminal program it runs at 4,800 baud and gives me NMEA sentences about once a second.
Running out of ideas. Suggestions welcome.
How many satellites does it show in the device?
None. Just shows the GPS connected, but no fix.
If the device is connected to the Cerbo but can’t find satellites that sounds like a GPS receiver issue.
That was my thinking so I plugged it in on my laptop and it is fine there.
Leaving the GPS receiver in the same spot?
Tried multiple locations. Currently outside with a clear view of the sky. If I use my laptop in the same location I get good sentences and $GPGSV sentence shows 7+ sats in view.
I am using a USB extension but have tried without and no difference. I did get some data through the Cerbo briefly but at that point the antenna was buried in a tangle of cables. Once I cleaned things up it quit! Go figure.
That’s odd. I don’t see how a connection to the Cerbo would disrupt the receiver. Is your RV on shore power during the test? Is the receiver plugged directly into the Cerbo or behind a hub?
I have a cheap no brand GPS, $19 from Amazon. I was a bit surprised, it gets a fix in the basement of my coach, while it’s in the barn. Right now it’s stuck vertically to a metal plate behind the aluminum engine access door, connected with an unpowered 4 way USB splitter cable, at the end of a 16 foot extender, and it sees 7 satellites.
You can check the log file to see if there is a clue in there: /data/log/gps-dbus.tty??/current. Just checked, mine has a few checksum & frame errors from a few days ago but still works fine.
Yes, we’re on shore power but everything runs thru our Multiplus II. I have tried both direct and through the hub, powered and not. It definitely seems to work better without any extensions but is still not great.
I am beginning to wonder if my Cerbo has a weak USB driver chip in it.
I’m trying to get the GPS receiver up onto my roof but that will require about a 10-12’ extension. I have 2 6’ extensions and it barely works on one and nothing at all on both. I may try a single high quality 12’ next I guess.
Checked the logs and nothing to speak of there.
I’ve found the Cerbo USB to be pretty robust so far.
You could try pulling the shore power connection. Maybe something to do with grounding is messing up the GPS signal?
I’m having a similar (ish) issue.
posted here for you to follow, maybe you can try these commands and determine if it’s related.
Interesting! I tried the cat command as you suggested (didn’t realize you could do that) and found that every few seconds the data switches from intelligible sentences to gibberish and back again.
$GPRMC,144230.000,A,5040.7256,N,12018.8686,W,0.00,270425,A69
$GPVTG,T,M,0.00,N,0.0,K,A13
$GPGGA,144231.000,5040.7256,N,12018.8686,W,1,09,1.0,349.3,M,-16.0,M,00006D
$GPRMC,144231.000,A,5040.7256,N,12018.8686,W,0.00,270425,A68
$GPVTG,T,M,0.00,N,0.0,K,A13
$GPGGA,144232.000,5040.7256,N,12018.8686,W,1,09,1.0,349.3,M,-16.0,M,00006E
$GPGSA,A,3,22,30,14,24,17,01,13,19,15,1.8,1.0,1.5*37
,xøøxxxxøxøxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxøxxxxxxxxxxøxøxxxxxxxxxxxøxxxxxxxxxxxxøxxxxxxxxxxxxxxxxxxxøxxxøxxxxøxøxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxøxxxxxxxxøxøxxxxxxxxxxxøxxxxxxxxxxxøxxxxxxxxxxxxxxxxxxøøøxxxxxøxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxøxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxøxxxxxxxxxxxxøxxøøxxxxxxxxxxxxxxxxxxxxxxøøxxxøxxxxxxxxxxxxxxxxøxxxxxxøxxxxxxxøxøøøxxxøxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxøxxxxxøxxxxxxxxøxøxxxxxxxxxxxøxxxxxxøxxxxxøxxxxxxxxxxxxxxxxxxxxøxxxøxxxxøxøxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxøxxøxxxxxxøxøxxxxxxxxxxxøxxxxxxxxxxxøxxxxxxxxxxxxxxxxxxxx~xxxxxxxfxxx~xfxxxxxx~xxxxxxxxàæààxxxxx怘xæxxxxxxfxxx~xxøàxxxxxxxæàxxxxxxàfxxxx~ààæ昆xxxàxxfxx怘x~xxxxxxfxxx~xføxxxxx~xxxxxxxààxxxxfxxææxxxxxxxxfxx~xfxøàxxxxxxx~àxxxxxxxà
fxxæ~àæàxxàxxfxx怘~`x`x`xxfxxx~xxfxøàxxxxxxx~àxxxxxxxxàæxxààxxxxfxx`怀æxxxxxxfxx~xxføxxxxxx~àxxxàfxxxxx~ààæàxxxàxxfxxx~xxxxxxxfxxx~xxfxøàxxxxxxx~àxxxxxxxxàæxxààxxxfxxx~xxxxxxxxxxxxxxxààxxxxxfxfx怘x~fxxxxxx~xxxxxxx~xxxxxxfxxx
Maybe the problem is the GPS. I’ll have to try another one I guess.
Wrong baud rate, data format or signal quality ?
Missing terminator ?
It does kinda look like it is changing data rates but no idea why it would do that. If that is what it is doing it only does it on the Cerbo. Direct connected to my laptop is solid. I’ll try another GPS and see if that helps.
Maybe it interprets a commandstring from cerbo to change data rate ?