Onboard GPS lag
Not sure why this is happening, but the onboard GPS for the Glowfiish whilst works and is on average a lot smoother and accurate than the Bluetooth receivers, seems to only get half the trip recorded on all occasions - almost like it is caching data and doing some processing on it based on previous results before it gives me new data. I am not sure why this is, so for now I shall be sticking with the Bluetooth GPS receivers as they are far more reliable at present and actually record the whole trip, even though the data they produce is a bit more on the noisy side.