Carpc project - GPS

I recently uploaded a new video to show my custom-made carpc based on a Raspberry Pi. In the video, I had to leave a lot of information out for the sake of runtime, so, I decided to write a little series of posts to explore thoughts and ideas about this project.

This episode is about GPS.

Disclaimer (sort of):
Be aware that this post is not self-contained. If you haven't seen the video, you probably won't get much out of this reading. Also, this is not a tutorial on how to build a carpc like the one I made. For that, I'd need much more time and space. I just want to document the thought process behind a few hardware and software choices, share some techno-ramblings, and provide you with some links to get you started using the components I used.

Have you ever modified your car with custom electronics? Are you planning to hack a Raspberry Pi into a device that was not intended to be modified? Have you ever started a simple project (such as adding music to your car), and somehow turned it into a huge, titanic undertaking?

GPS

 

Nothing really special to report on GPS hardware. This part of the project was disappointingly simple and smooth.

Adafruit Ultimate GPS breakout.

I quickly stumbled upon the Adafruit Ultimate GPS module, and I decided to get it. This module is controlled via serial communication instead of I2C, but that is not a problem because the Pi supports serial too, and Adafruit has good example code to start from.

The GPS module has an integrated antenna, which is notoriously slow and (by my limited experience) imprecise. In order to improve the speed of cold starts, and to guarantee the best possible positioning, I decided to invest 13 USD into an active antenna. The antenna needs to be exposed to the sky in order to optimize its performance, therefore I will need to install it somewhere close to the windshield. This won't be a problem, for the cable it comes with is quite long. I haven't measured it, but it's loooooooooooong.

GPS active antenna.

On the software side, the GPS module just needs the gpsd module to be installed and running. At that point, the navigation software can successfully read GPS data from the serial port.

Have fun,
Kradion.