Abstract: A wind measuring system utilizing a very low frequency (VLF) radio navigation system including an observation station, at least three transmitting stations for sending out the VLF signal, and a sounding device positioned in the atmosphere for receiving the VLF signals from the transmitting stations and retransmitting them by way of a telemetric link to the observation station where processing equipment measures the phases of the signal transmission and determines therefrom the position or velocity directions of the sounding device. The processing equipment includes a receiving circuit for receiving the VLF signal from the sounding device, and limiting circuitry for amplitude limiting the VLF signal. A local signal generator included in the observation station generates a reference signal which has the same frequency as the VLF signal. Polar cross correlation circuitry is also included for forming cross correlation functions of the amplitude limited VLF signals and the reference signal.