Description This unique Navisys GR-8013W 1PPS GPS (upgraded version of GR-601W & GR-701W models), true plug and play USB GPS 1 Pulse Per Second (1PPS) GPS time reference for your server, desktop, firewall or single board project giving your better than 1 ms accuracy once the GPS is locked. The GPS is a ublox UBX-M8030-KT 72 channel that can track both GPS & GLOSNASS satellites simultaneously, increasing the accuracy of the fix. In addition the ublox chip can be set to stationary mode via ublox U-Center software, once again improving its accuracy for fixed location systems. Datasheet downloads GR-8013W Flyer with full specifications GR-8013W User manual ublox 8M Protocol specifications (chip level configuration) GPS Specifications (full specs see datasheet)
FAQ What is unique about this GPS? Other 1PPS GPS time reference solutions with this degree of accuracy require you to either build your own time server on a Single Board Computer or make your own special Y-shaped serial cable with a special Y-shaped TTL to RS232 converter IC for the DCD pin 1 to generate the 1PPS signal - 5 signals required in addition to a USB power source & a 12V power supply to the serial GPS. This GPS does away with all that. It has a unique design that already has the DCD line wired into the USB Prolific chipset, triggering the 1PPS signal via USB without any additional soldering, construction or cables. Is it as accurate as a serial GPS? No, it will provide <1ms accuracy, however a true serial bus GPS should be able to provide <50ns accuracy due to the USB bus latency. However, you will have to build your own solution. If you need an even more accurate time source you need a GPSDO. What Software do I need? For Linux systems you need both NTP and GPSD to enable 1PPS. NTP is available for Windows. How Do I configure NTP to use kernel discipline for <1ms accuracy? GPSD must be installed # GPS Serial data reference server 127.127.28.0 minpoll 4 maxpoll 4 # no fudge see http://www.catb.org/gpsd/gpsd-time-service-howto.html fudge 127.127.28.0 refid GPS # GPS PPS reference server 127.127.28.1 minpoll 4 maxpoll 4 prefer fudge 127.127.28.1 refid PPS Can I tweak the GPS? Yes, the ublox chipset can be tweaked with ublox u-center GNSS evaluation software. For example, GPS motion model can be set to stationary mode to enable a more accurate position fix for by assuming the GPS is stationary. Does the u-centre run under Linux? There are reports that it does: u-centre running with WINE. It also runs with Virtualbox on Linux Will 1PPS work with NTP for Windows? Short answer, maybe. NTP should recognise it as a GPS and will use this as a time reference, however, it may not enable the accuracy of 1PPS. Unfortunately this depends upon the USB UART driver recognising the DCD line signal. There are some reports of similar patched drivers working, see http://www.satsignal.eu/ntp/Sure-GPS.htm Will it work on an Apple Mac? It should recognised as a USB GPS, however it won't be added as a time reference to the Mac kernel Tags NTP 1PPS Pulse Per Second GPS Time GR-601W GR-701W ublox GLONASS |