US 5,422,816 A · Portable personal navigation tracking system

Abstract

A data/voice modem embodiment of the present invention comprises an asynchronous-to-synchronous data converter for interface with a GPS receiver, a minimum space keyed modem, and a continuous tone controlled sub-audible squelch controller that modulates a radio transceiver interface with a discrete tone such that both voice and data may share a common radio channel. The data/voice modem periodically keys-up the radio transmitter through its interface and transmits a packet of information that contains user position and velocity obtained through the GPS transceiver interface and adds a user identification code and time tag. Incoming message packets from the radio transceiver that are sent from other similarly equipped mobile units are used to supply individual network member absolute positions and velocities, and this information is stored by user identification number as goal or waypoint equivalents. As such, distance-to-goal, estimated-time-of-arrival and velocity-made-good estimates are made available on a target track screen included in the respective GPS receiver.

Claims6

Dependent claims

A global positioning system (GPS) receiver system for use in a network of mobile users equipped with similar receiver systems, comprising:

a GPS receiver having an output port for communicating out a series of current position fixes and an input port for accepting as individual waypoints a plurality of position fixes determined by a plurality of remote GPS receiver systems;
voice communications means connected to said input and output ports of the GPS receiver and a microphone and speaker combination and a radio transceiver microphone input plug and a radio transceiver speaker output plug for automatically receiving and sending data messages that represent said position fixes of the GPS receiver and said remote GPS receiver systems transparent to a user such that ordinary voice communication between users of said remote GPS receiver systems are not prohibited;
and
waypoint substitution and selection means connected between the GPS receiver and the voice communication means and having a user display connected to the GPS receiver for indicating at least a relative heading to a selected one of said remote GPS receiver systems, and means for directing said current position fixes from said output port of the GPS receiver for transmission out by the voice communication means, and further including means for directing current position fixes received by the voice communication means from other of said remote GPS receiver systems to said input port of the GPS receiver.

1 more element

Dependencies are inferred from the claim text.

Portable personal navigation tracking system

Life of this patent

Portable personal navigation tracking system

Life of this patent

Abstract

Claims6