I've used two GPS loggers: the i-Blue 747 Bluetooth device from Transytems, and the Trackstick II. The first I can recommend highly; the second I can't recommend at all. Here are the facts so you can make up your own mind.
[Note: the software communicates with the device via a virtual Com port, handled by a driver. It can be a little tricky to figure out which Com port, however, so I suggest you go to your Windows device manager and see which port was assigned to the device and set the software to use that. On one of my machines it was port 5; on the other it was port 10; it depends on how many other drivers you've already loaded.)
It also saves GPS positions once per second, which is important when you're trying to match it with pictures you're taking at least that fast. In our testing, it aquired a satellite lock in less than minute and was rock-solid in keeping it, even when we just tossed the device randomly into an aircraft's instrument bay, buried under other electronics and bathed with other radio emissions. Basically, we've used this devices on dozens of flights, UAV and otherwise, and its performance has been top-notch.
In testing, three serious problems cropped up with the Trackstick (aside from it being expensive, big, and badly underfeatured):
- It only records a GPS record every 15 seconds in low-power mode and every 5 seconds in high-power mode. Even at the highest, battery-draining settings, that's way too slow for aerial mapping.
- It takes forever to get a satellite lock. The first time, it took more than half an hour and subsequently it took more than three minutes.
- Keeping that satellite lock is a struggle, too. By having a terrible GPS chip that only sees 12 satellites, the Trackstick II suffers from frequent drop-outs and glitchy datapoints. We found it essentially unusable.
