A positioning sensor includes m receiving antennas connected to a feeder circuit and n variable loads, and a receiver that receives a first signal via the m receiving antennas. The positioning sensor further includes a memory that stores a first signal strength value of a first signal that the receiver receives when a variable load varies in value, and a processor that calculates a second signal strength value from a complex propagation channel, searches for a complex propagation channel candidate that has a minimum difference between a first signal strength and a second signal strength, determines the complex propagation channel candidate to be a complex propagation channel when the receiver receives the first signal, and estimates an incoming direction of the first signal from the determined complex propagation channel.