Comment by brakar on December 3, 2010 at 4:02pm

"It is a good start for anyone looking at a non-GPS method of finding altitude while landing."

Prabably not a big thing, but I think borometric altimeters have been the prefered measure for measuring altitude before landings for quite some time. They are usually more accurate then gps'.

Moderator Comment by Jack Crossfire on December 3, 2010 at 4:07pm

Maybe it could be the start of cheap collision avoidance.

Comment by Otto Leiben on December 3, 2010 at 6:04pm

Excellent project, it requires two antenna one for the TX and one for RX with a seperation distance. because it TX and RX are on at the same time, see CWFM RADAR. It needs isolation between the antennas, so the TX signal doesn't not overpower the weak RX returns from the ground. There could be an circuit improvements by using a DDS IC for the chirp generator circuit, and a more stable LO source. Other than that, it's very nice approach and it in the legal band for altimeters.

Comment by Lew Payne on December 3, 2010 at 11:18pm

@brakar - Yea but barometric altimeters won't work in zero gravity. We're shooting for FPV to the moon !

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