Patent attributes
A distance measurement apparatus, which calculates distances between a first device and a second device based on carrier phase detection, includes a distance measurement operation unit that calculates the distances based on respective phases of a plurality of carrier signals included in each of a first distance measurement signal and a second distance measurement signal respectively transmitted from the first device and the second device, a received signal strength indicator measurement unit that measures respective received signal strength indicators of at least some of the plurality of carrier signals, and a carrier signal relay presence or absence judgment unit that judges presence or absence of relay of the carrier signals based on distance information about the plurality of distances calculated in the distance measurement operation unit and received signal strength indicator information about the plurality of received signal strength indicators measured in the received signal strength indicator measurement unit.