Tire position determination system

A tire position determination system provided in a vehicle including a first tire and a second tire different from the first tire, the tire position determination system comprising:

• an initiator that transmits a command signal;
• a first detector attached to the first tire, the first detector transmitting a detection signal when the first detector receives the command signal;
• a second detector attached to the second tire, the second detector transmitting a detection signal when the second detector receives the command signal;
• and
• a monitoring unit configured to receive the detection signal, wherein
• a first distance between the first tire and the initiator is equal to or shorter than a second distance between the second tire and the initiator,
• each of the first detector and the second detector includes an acceleration sensor that detects an acceleration in a direction orthogonal to a revolution axis direction,
• the detection signal includes a detection value from the acceleration sensor, and
• when the monitoring unit receives the detection signal from the first detector or the second detector, the monitoring unit performs determination processing for determining whether a detector that has transmitted the detection signal is the first detector or the second detector based on positional relation between the detector that has transmitted the detection signal and the initiator estimated from the detection value from the acceleration sensor included in the received detection signal.