It's according to what you are using it for. Regarding canopy and terrain, I can show you strings of noisy data that have multipath issues, but then again I use similar single frequencey units at about 5 times the cost with sub-cm capability which the average person hasn't any use for. Single frequency units are heavily affect by canopy and terrain. There's not another frequency for a check. When the data leaves the bird it has a time stamp. And when you catch it with your device, which is just a data logger, you know the time. Using both known time stamps and the speed of light, the distance from the birds to you can be calculated and a position also calcualted thru least squares adjustment with knowns and unknows equations. So a deflected/retarded signal from one bird, say on a 10 second data capture epoch, will put you at a seemingly longer distance and your position cannot be resolved.
By the way a second was added to the time to better model the Earth yesterday, which made it the longest day, which you wouldn't notice on a handheld 10m error of ellipse unit. If you haven't any accurate position to compare your position or check your device, you'll never know the difference.
Kind Regards,
Raimey
rse
Last edited by ellenbr; 01/01/09 09:13 AM.
