Vehicle detection system

A vehicle detection system, comprising:

• a reading device that is provided in a vehicle, transmits and receives a signal, and transmits a transmission signal including at least a signal that supplies power;
• a detection device that is provided in the vehicle and that includes
• an antenna that mutually transmits and receives a signal from and to the reading device,
• a signal output circuit that is activated using the signal that supplies power included in the transmission signal received by the antenna as driving power, and outputs a detection signal to the antenna, and
• a first connection switch provided between the antenna and the signal output circuit, and that switches a first electrical connection portion between the antenna and the signal output circuit to a contact state or to a non-contact state according to a first characteristic of a state inside the vehicle;
• a second connection switch provided between the antenna and the signal output circuit, and that switches a second electrical connection portion between the antenna and the signal output circuit to a contact state or to a non-contact state according to a second characteristic of the state inside the vehicle;
• and
• at least one processor that is connected to the reading device and is configured to determine the state inside the vehicle based on the detection signal received by the reading device, wherein
• the detection device is configured to
• connect the signal output circuit and the antenna, and transmit the detection signal from the signal output circuit via the antenna to the reading device, when the first electrical connection portion and the second electrical connection portion are simultaneously in the contact state, and
• disconnect the signal output circuit and the antenna, and refrain from transmitting the detection signal from the signal output circuit via the antenna to the reading device, when either the first electrical connection portion or the second electrical connection portion is in the non-contact state, and
• the at least one processor determines the state inside the vehicle based on the detection signal received by the reading device.