I have connected a HOLUX GPS unit SiRF star III Model GR-213 (bought in 2008 to use for the eclipse in China) and installed the driver: GR-213 GPS Driver Program-MAC 10.5 from the website.
But Solar Eclipse Maestro 1.8.6v2 Intel Y for my Macbook pro version 10.10.5 Yosemite can't read the coordinates.
But I have no idea if the GPS unit works. But it flashes.