Abstract: A system for determining the location of a person relative to a vehicle. In one embodiment, the system includes a first device comprising a first Bluetooth transceiver in the vehicle, a portable second device comprising a second Bluetooth transceiver and a first application program. The first application program identifies a first condition in which a link based on Bluetooth RF transmission exists between the first device and the second device when the person is in a first position close to or in the vehicle. The application program determines when the link is broken based on drop in signal level and provides notification through a network to a computer system when a determination is made that the link is broken. The notification is indicative of the person having moved farther away from the vehicle to a second position.

Abstract: A non-transitory computer readable medium containing computer program instructions for monitoring whether persons in a group are each away from an associated vehicle. In one embodiment, the computer system receives an association between each of multiple persons in the group with one of multiple vehicles and automatically receives digital information, derived from measured rf signal strength, indicating whether any one of multiple persons in the group has moved from a first relatively close position with respect to an associated vehicle and farther away from the associated vehicle than the first position. A notification is sent from the computer system to at least one device associated with a person in the group based on received information that a first of said multiple persons is farther away from the associated vehicle than the first relatively close position is from the associated vehicle.

Abstract: A method providing persons in a group information about the whereabouts of others in the group, including whether persons in the group have moved away from an associated vehicle. The method includes receiving information into a computer system derived from measured rf signal strength sent in digital form from one or more portable devices. The information indicates whether any of the persons has moved from a first relatively close position with respect to an associated vehicle and farther away from the associated vehicle than the first position. A timer function may be initiated if the received information indicates that a first person has moved farther away from the associated vehicle than the first position. Updated information may be received, indicating whether the first person remains farther away from, or has moved to a position at least as close as the first relatively close position is to, the associated vehicle.