This seems to reflect some bad interaction between the autobauding code in gpsd and the operating system’s tty layer; when gpsd is compiled to use a fixed port speed, handshake times drop to a fraction of a second. How can I improve fix accuracy from my GPS? The bad revision is 2. The only exceptions we know of are some u-blox modules that pretend to be USB modems. With this configuration, ntpd will read the timestamp posted by gpsd every 16 seconds and send it to unit 0. The GPS may have an on-off switch which needs to be in the ‘on’ position.

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The latter is far more helpful to us and will get your bug fixed faster, so we’ll describe that procedure here. The logfile is opened for append, so you can log more than one portion of the packet stream and they will be stitched together correctly. Splitting these notifications allows ntpd to use its normal heuristics to weight them. That is why the device type listed before the prompt doesn’t change.

A platform independent method to identify serial-over-Bluetooth devices would also be nice. The Bluetooth stack returns 0 for a read from a missing device, rather than -1, and doesn’t set errno. For example, suppose you know that your GPS is on serial port 0 and operates at a fixed bps of Warm start on a modern GPS with a good skyview 4 or more sats visible normally takes about 30 seconds.

Repeat this procedure on each half that tickles the bug until you can’t make it any smaller. There’s another level of the problem, too. To be really helpful, check out the git head and test that. In either case, the current driver is re-selected; if the probe bit is enabled, probes will begin gpssd be issued immediately.


Suspect this if you have persistent off-by-one errors.

How can I verify operation of a new GPS?

For a list of the GPS protocols supported by your instance, see the output of gpsd -l flrce effectively hides the differences among the GPS types it supports. Send hex payload to device. Client methods, and various restrictions associated with the read-only nature of this interface, are documented at libgps 3.

Even if there are say revisions in the span you should only ggpsd 9 tests to nail down the exact change in question. It’s hard to know what to do, and even harder to know how to test the correctness of the extraction code once you think you have it.

Remote gpsd feed A URI with the prefix “gpsd: The program accepts the following options: Given a GPS device by either means, gpsd discovers the correct port speed and protocol for it. GPSD presently fully recognizes only the 2.

Additionally, near the century turnover, a range of dates as wide in seconds as the accuracy of your system clock may be referred to the wrong century. Generation of position error estimates eph, epv, epd, eps, epc from the incomplete data handed back by GPS reporting protocols involves both a lot of mathematical black art and fragile device-dependent assumptions. On Linux, gpsd includes support for interpreting the PPS pulses emitted at the start of every clock second on the carrier-detect lines of some serial GPSes; this pulse can be used to update NTP at much higher accuracy than message time provides.


On a Linux machine, the gpsd daemon normally takes between 0. There is no option to fix baud rate because gpsd is designed to a be autoconfiguring, and b handle multiple devices.

Will show an error if the device doesn’t have such modes. Forve -D option enables packet-getter debugging output and is probably only useful to developers of the GPSD code. This will happen very quickly, as the number of tests required will be the log to the base 2 of the number of revisions in your original span.

We don’t mind getting reports that say “I saw version foo had the following bug, but you’ve fixed it. Before using the -G flag, consider whether you consider your computer’s location to be sensitive data to be kept private or something that you wish to publish.

Ubuntu Manpage: gpsd – interface daemon for GPS receivers

If you don’t hear anything where you expect it, then you get to check nearby frequencies. This should at least keep GPSD from usurping data sources belonging to other service daemons.

Users have reported incorrect dates which appear to be due to this issue.