Port-arm archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: GPS reciever for cubetruck


thanks very much for your pentiful answers. Indeed, that PPS thing opend a new can of worms, as I've always thought of getting one of those OXCO Disciplined Oscillators, but eventually never really could part with the money. I still would like to be able to provide the nmea data via network to other clients, so gpsd support would still be on the wishlist.

However, searching for gps mouses that explicitly advertise PPS and linux support was harder that I've assumed. Assuming, if there is linux support, they will run most likely with NetBSD as well.

As for the Venus8 chips, I have found a german article, that uses exactly one of those chips for ntp using pps. However, in the comments section of amazon for that gps mouse someone claimed, that pps is not available. Makes one wonder.

The ready to use u-blox 8 available here are rather expensive, and mostly from navilock.

Something like this:


which leads to the next question, however slightly off topic:

Like the Microstack recommended earlier this thread by Mr. Bouyer, I have seen a couple of recievers, usually for arduino, that have a 5 pin connection. Next to powersupply and your transmit/recieve, there also exists a dedicated pps pin. However, I have not been able to find out, what pin on a RS232 connector this should go to. And if in genereal those are suitable for direct RS232 connection anyway or wether buffers are needed.

I am by no means at all an electronics expert, but am able to hold a soldering iron, so this could be the cheapest choice - as the Microstack does not seem to be available any more.

The navilock mentioned above claims to require a rs232 interface, they use pin6 for pps, but also mess up pins 2/3 and 4/5 in their documentation, so not sure, wether this is to trust or maybe even propietary to navilock.

Oh, and millisecond accuracy would well be sufficient.

Am 21.06.20 um 18:57 schrieb Greg Troxel:
Brad Spencer <brad%anduin.eldar.org@localhost> writes:

Depends what you want to do with it, but gpsd may have trouble for you.
The last I looked NetBSD does not support the IOCTLs required to get the
PPS signal into it ...  Linux has an unusual ability in this matter.  If
you are looking to just get NEMA serial data then gpsd should be ok.

Linux implements TIOCMWAIT that is not part of the RFC.  gpsd is
defective in that it depends on this beyond-RFC behavior, in the typical
Linuxy style of coding to the development system rather than the
standard.  It's probably not super hard to fix.

The PPS support in ntpd works fine.

However, most USB-attached GPS receivers do not have PPS anyway.  A few
do, and there is actually kernel PPS support for this, although USB PPS
is limited to about 1 ms.

Home | Main Index | Thread Index | Old Index