Passive approach detection system and method using a unidirectional FOB

A passive approach detection system, comprising:

• a fob device configured to transmit a plurality of data signals corresponding to multiple power levels respectively based on motion detected in the fob device;
• each of the plurality of data signals includes initial bytes encoded with a power level and transmitter identification (ID);
• a receiver of a vehicle communicatively coupled to the fob device, the receiver receives receive one or more of the plurality of data signals based on a distance between the fob device and the receiver;
• a secondary processor communicatively coupled to the receiver, the secondary processor filters out signals by comparing one or more of the plurality of data signals received to a predetermined list of signals valid for reception;
• and
• a primary processor communicatively coupled to the secondary processor, the secondary processor transmits a wake-up signal to the primary processor based on the comparison, the wake-up signal enables the primary processor to transition from a sleep mode to a wake-up mode.

A passive approach detection system, comprising:

• a fob device configured to transmit a plurality of data signals corresponding to multiple power levels respectively based on motion detected in the fob device;
• each of the plurality of data signals includes initial bytes encoded with a power level and transmitter identification (ID);
• a receiver of a vehicle communicatively coupled to the fob device, the receiver receives one or more of the plurality of data signals based on a distance between the fob device and the receiver;
• a secondary processor communicatively coupled to the receiver, the secondary processor filters out signals by comparing one or more of the plurality of data signals received to a predetermined list of signals valid for reception;
• and
• a primary processor communicatively coupled to the secondary processor, the secondary processor transmits a wake-up signal to the primary processor based on the comparison, the wake-up signal enables the primary processor to transition from a sleep mode to a wake-up mode;
• wherein the plurality of data signals are transmitted periodically for a predetermined amount of time in response to the fob device being in continuous motion past a predefined motion timeout, the fob device communicates to the receiver in a unidirectional manner.