Passive entry and/or passive go system and associated operating method

An electronic key comprising:

• an antenna circuit operable to receive using an antenna a carrier signal associated with a base station;
• and
• one or more non-transitory computer-readable storage media that embody logic that is operable when executed to:
• calibrate an output value output from the antenna circuit by measuring characteristic parameters of the antenna circuit using a reference input value generated by the electronic key as an input to the antenna circuit;
• calculate an actual field strength of the carrier signal using the calibrated output value;
• determine a distance between the base station and the electronic key based on the actual field strength;
• and
• transmit, based on a determination that the distance between the base station and the electronic key is within a pre-specified range, a signal to the base station, receipt of the signal at the base station causing the base station to initiate a function performed by an apparatus.

One or more non-transitory computer-readable storage media that embody logic that is operable when executed to:

• calibrate an output value output from an antenna circuit of an electronic key by measuring characteristic parameters of the antenna circuit using a reference input value generated by the electronic key as an input to the antenna circuit, the antenna circuit having received using an antenna a carrier signal associated with a base station;
• calculate an actual field strength of the carrier signal using the calibrated output value;
• determine a distance between the base station and the electronic key based on the actual field strength;
• and
• transmit, based on a determination that the distance between the base station and the electronic key is within a pre-specified range, a signal to the base station, receipt of the signal at the base station causing the base station to initiate a function performed by an apparatus.