Homemade GPS receiver

A slightly abbreviated post today – we’ve just driven 380 miles to Phoenix from LA for Intel ISEF, where Eben’s talking tomorrow, and we’re ready to drop. But I was mailed this amazing piece of work this morning, and it really deserves your attention.

Andrew Holme is a member of the Systems Group at Broadcom Cambridge. He’s friends with several of Raspberry Pi’s engineers, and he’s been working on a homemade GPS receiver in the evenings for the last few years. Recently, he’s added a Pi to create a truly portable, battery-powered receiver.

It’s a remarkable piece of work. It shouldn’t be possible to build a GPS receiver like this out off-the-shelf parts. There is no custom silicon in this build; it’s all very, very clever use of an FPGA (field-programmable gate array) to implement the digital logic sections of the pipeline. My electronics isn’t good enough to really understand much of what’s going on here: all I can really tell you is that there’s an analogue front end and 1-bit ADC (analogue to digital converter) followed by all kinds of mad-clever digital stuff. So I’m not going to summarise what Andrew has done, but fortunately for us all he’s written the project up in incredible detail, so you can have a poke around yourself. Please do visit the link; this is one of the most impressive projects we’ve ever seen attempted with the Pi.

A bit of housekeeping: please be aware that posts this week will be a bit (or, as today, a lot) later in the day that you’re used to, because I’m several thousand miles further to the left than normal. There also won’t be quite as much Twitter activity from us as usual while we’re travelling, but the official Facebook and G+ pages will be forging ahead as normal. (Thanks Lorna!)