Here's a short video that shows two GPS prototypes ready to be tested on the water:
The one on the left uses a Raspberry Pi Zero W, an e-paper display (similar to what a Kindle uses), and a Stratux GPYes USB GPS module. The one on the right is inside the GoPro case. It's a ublox-8 based GPS connected to a battery and a bluetooth module; the Android phone below it grabs the data over Bluetooth and logs them. Now the wind just has to play along for on-the-water tests tomorrow!