A method and system for measuring the time-of-flight (TOF) of a radio
signal is described herein. According to various implementations, the
system uses multiple antennas, each of which receives direct path radio
signals and reflected radio signals. In various implementations, the
system sends a sequence of bursts that are detected using a cross
correlation detector. The receiver steers antenna nulls to a different
angles for each burst and measures the TOF at each angle. The system then
calculates the minimum correlation peak from all measurements, and treats
that correlation peak as the true, direct path TOF measurement.