Abstract: The present invention relates to a system for managing assets such as vehicles and/or equipment in an area such as a repair yard or parking lot. A plurality of mobile devices periodically wake-up at different times and transmit their uncorrected GPS location data to one or more fixed local devices. Each fixed local device periodically forwards its accumulated, uncorrected GPS data for each mobile device to a reference device. A reference device is precisely located and capable of differentially correcting the data and forwarding the corrected result sets either back to the local devices and/or to third parties.

Abstract: A multi-tone vehicle motion alarm is provided as an augmentation of a single-tone alarm by imbedding in the alarm sound a plurality band-limited single-tone acoustic signals of different frequencies that are emitted in pulsed synchronism so that the warning signal is emitted in a form that allows directionality of the source to be determined by those around the alarmed equipment. This functional extension preserves many of the familiar aspects of existing alarms. Further, limiting the frequency band of the alarm reduces useless noise in the worksite. The preferred embodiment emits a pulsating tone alarm consisting of two discrete and identifiable monotones. The alarm is an extension of widely recognized pulsating reverse warning sounds. Additional tones may be employed to aid in the speed with which the sound source can be located with human hearing.

Abstract: The present invention relates to a system for managing assets such as vehicles and/or equipment in an area such as a repair yard or parking lot. A plurality of mobile devices periodically wake-up at different times and transmit their uncorrected GPS location data to one or more fixed local devices. Each fixed local device periodically forwards its accumulated, uncorrected GPS data for each mobile device to a reference device. A reference device is precisely located and capable of differentially correcting the data and forwarding the corrected result sets either back to the local devices and/or to third parties.