Doppler effect for aircraft navigation?

Hi! I know that aircraft navigation is based on DME equipments which provide a measure of distance and VOR equipments which provide a measure of angle. DME measure is done by measuring the time distance between pulses generated by aircraft and echoed by DME.
I've heard that the measure of the angle is achieved by Doppler effect of RF signal generated by VOR equipments.
Can anyone plz explain how Doppler effect can reveal the angle information?

Thanx.

Hi a_fischetti,

I think it is not possible to reveal angle information based on Doppler effect. VOR is using something similar to Direction Finding. (a kind of rotating antenna beams)

Regards,
eblue

There is one other system on the plane that uses Doppler effect for determining the speed of aircraft acording to the ground.

eblue