wiki:osmo-lea6t-gps

osmo-lea6t-gps

The swiss makes of GPS receiver chips and modules u-blox has (among others), a line of so-called timing GPS modules.

The main difference of such modules compared to the standard modules is their ability to output arbitrary GPS-derived clock signals anywhere between 0.25 Hz and 10 MHz.

This allows such modules to be used in a varity of high-precision timing applications where a simpler/traditional approach using regular 1PPS outputs is not sufficient.

The Osmocom project has developed an evaluation / development board for the u-blox LEA-6T timing module. Like all other Osmocom projects, it is fully open source, i.e. schematics and layout files are freely available.

photograph of the assembled osmo-lea6t-gps board

Electrical Design

Schematics and Layout

The most up-to-date versions of the schematics and layout files can be found in the projects git repository which can be browsed at http://cgit.osmocom.org/cgit/osmo-lea6t-gps/ or cloned like this:

$ git clone git://git.osmocom.org/osmo-lea6t-gps

For your convenience, PDF files are also attached to the bottom of this wiki page.

Major components

How to use

You can connect to it using one of the Osmocom-style serial cables (3.3V UART on 2.5mm audio jack) or using USB. You will get a serial port that can speak either NMEA or the proprietary UBX protocol.

The full protocol is specified in the u-blox 6 protocol specifiation.

Where to buy

You can have the PCB etched anywhere you'd like, using the layout data we have provided. Most of the components are available via distributors like Digikey. Only the LEA-6T module has to be obtained through an u-blox distributor.

Alternatively, sysmocom is selling fully assembled boards in their webshop.

Who

osmo-lea6t-gps was designed by Sylvain Munaut. Prototype manufacturing and testing was performed by Harald Welte of sysmocom.

Last modified 10 months ago Last modified on Dec 16, 2013, 11:13:33 AM

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