Geocast (Location Based Selective Distribution of Generally Broadcast Information), US5636245, 06/03/1997

A system for determining whether information broadcast by a general transmitter is relevant to a particular user based on the location, velocity and/or time of an object of interest. Includes a remote terminal, a general broadcasting unit, a transmitter at the general broadcasting unit for broadcasting messages including a segment comprising a region, a velocity and/or a time corresponding to an event, as well as an event specific tag, and storage for storing selection criteria including current position, time and/or velocity information of the user and/or manually entered data of interest. The selection criteria may also include event specific tags. The receiver at the remote terminal receives the messages from the transmitter at the general broadcasting unit. A navigational receiver may also be used to acquire navigational information from an appropriate external source. A matching processor at the remote terminal evaluates the segment in the messages, determines if the segment sufficiently matches the stored selection criteria and outputs a match signal. A processor in the remote unit receives the match signal, and processes and disseminates the messages in accordance with the match signal.

Radar Processing Method and Apparatus, US5614912, 03/25/1997

Radar processing method and apparatus in which the receiver need not accept the transmitted signal directly in order to determine the timing information required to locate targets. Processing apparatus according to the invention employs signals transponded or reflected from at least two targets to computer target and/or transmitter locations, or to simulate the transmitted signal for input to a conventional bistatic processor.