Abstract: A method is provided for self-aligning a transmitting RF frequency between a portable transceiving device and a base station transceiving device. The base station transceiving device is mounted in a vehicle for controlling a vehicle accessory function in response to RF messages broadcast between the transceiving devices. The RF signal is transmitted from one of the portable or base station transceiving devices to the other of the portable or base station transceiving devices. The frequency of the RF signal is varied during the transmission. A RSSI value of a received RF signal is measured at selected frequencies. A respective frequency having a maximum RSSI value is determined. At least a portion of a subsequent RF message is transmitted from one of the portable transceiving device or base station transceiving device using the respective frequency.

Abstract: A vehicle locating system for directing a user to a remotely-located vehicle comprises a vehicle-mounted location unit and a personal fob. The vehicle-mounted location unit includes a first global positioning receiver for receiving satellite location signals which operates at a duty cycle sufficient to maintain predetermined aiding data. The vehicle-mounted location unit processes vehicle location data and further includes a first local data transceiver for transmitting the predetermined aiding data. The portable fob includes a second global positioning receiver for receiving the satellite location signals, wherein the second global positioning receiver operates substantially only when the user initiates a request for directions to the vehicle. The portable fob further includes a second local data transceiver for receiving the predetermined aiding data from the first local data transceiver. The portable fob processes fob location data in response to the predetermined aiding data.

Abstract: A method is provided for self-aligning a transmitting RF frequency between a portable transceiving device and a base station transceiving device. The base station transceiving device is mounted in a vehicle for controlling a vehicle accessory function in response to RF messages broadcast between the transceiving devices. The RF signal is transmitted from one of the portable or base station transceiving devices to the other of the portable or base station transceiving devices. The frequency of the RF signal is varied during the transmission. A RSSI value of a received RF signal is measured at selected frequencies. A respective frequency having a maximum RSSI value is determined. At least a portion of a subsequent RF message is transmitted from one of the portable transceiving device or base station transceiving device using the respective frequency.

Abstract: A vehicle locating system for directing a user to a remotely-located vehicle comprises a vehicle-mounted location unit and a personal fob. The vehicle-mounted location unit includes a first global positioning receiver for receiving satellite location signals which operates at a duty cycle sufficient to maintain predetermined aiding data. The vehicle-mounted location unit processes vehicle location data and further includes a first local data transceiver for transmitting the predetermined aiding data. The portable fob includes a second global positioning receiver for receiving the satellite location signals, wherein the second global positioning receiver operates substantially only when the user initiates a request for directions to the vehicle. The portable fob further includes a second local data transceiver for receiving the predetermined aiding data from the first local data transceiver. The portable fob processes fob location data in response to the predetermined aiding data.