I haven't had good luck with style of GPS module on my models, even a <100 mW 5.8 GHz FPV transmitter tends to swamp the GPS signal to the point where getting a

I haven't had good luck with style of GPS module on my models, even a <100 mW 5.8 GHz FPV transmitter tends to swamp the GPS signal to the point where getting a lock is impossible. They're also prohibitively heavy on smaller models. A 10% increase in mass (for a 300g quadrotor) can shave an entire minute off of your run time.