A soil measurement system is provided, comprising a soil surveying device, a radio receiver, a plurality of subterranean antennas, and a processor. The soil surveying device comprises a wireless radio transmitter configured to emit a wireless signal at a predetermined bandwidth in a predetermined spectrum. The plurality of subterranean antennas are in an array electronically connected to the radio receiver and configured to be mounted in a subterranean environment at different depths in the subterranean environment. Each of the plurality of subterranean antennas is configured to receive the wireless signal at a respective point in time. The processor is configured to determine a relative time of flight of the received wireless signal between the plurality of antennas at the respective point in time, and estimate a soil permittivity based on the determined relative time of flight. The measurement system may be applied to materials other than soil, in some examples.