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Problem Statement

I need a GPS transmitter that uses new technology (NOT AX.25). I want a tiny, low power, top of the line GPS module. I want to interface it with a wireless protocol which is common to all of my designs and is inexpensive. Something that I can hike with, or put in my car, or use to track a high altitude balloon. I want something that is 'smart' meaning I can tweak the settings without reprogramming the thing.

Ublox Overview

This circuit was created for use with Ginger for tracking high altitude balloons. I also used it to find my way around town as the unit is small enough to be placed anywhere in a car. The circuit uses a modified EZ430-RF2500 board from TI and a Ublox-5H GPS module with a helical antenna. The frequency is 2.4Ghz, the output power is 1mW and the range is only about 50 feet. The data rate is 250kbps but there is no reason why it couldn't be reduced for further range. The GPS module has no problem getting a lock inside of my house. The module works well with GPSTrack as well as for tracking high altitude balloons.

Sirf Overview

A Sirf III version was also made, also based on the ez430-RF2500. The sirf module is much smaller and easier to fit onto the back of the EZ430 module, eliminating the need for a daughterboard. Altitude is limited to 60k feet, so this design is not suitable for ballooning.

MSP430 Source Code

Ublox based chip code be found here (For reference only, all rights reserved)

Sirf III based chip code be found here (For reference only, all rights reserved)

Ublox Node Photos

Sirf III Node Photos

2009 Jasper Nance KE7PHI