Abstract: A stolen vehicle recovery system (20) in which a vehicle transceiver (30) is disposed on each vehicle (28) for cyclically transmitting a pulsed signal which is modulated by a data stream comprising a verification code, a unique identity code associated with the vehicle (28), and a code which corresponds to whether the detected vehicle (28) is moving or stationary. The vehicle transceiver (30) is automatically activated if a proper authorization signal is not provided to the transceiver (30) by a verification unit. A scanning receiver (42) decodes the pulsed signal and provides the information to a control processor (40) which, in turn, sets remote direction finding receivers (44, 46, 48), set up in a triangulation antenna array, to the appropriate channel. The D.F.

Abstract: A method and system for updating a digitized map. An operator-controlled vehicle provided with an onboard computer and a navigational transmitter unit is dispatched to a location provided on the map near to an unknown location. The vehicle would then traverse the segment between the known intersection and an unknown intersection while it is being tracked by the navigational tracking unit. When the unit reaches the unknown intersection, the address range as well as the street names of the intersection are verbally inputted into the system. The information collected by the computer is then inputted to the central computer which edits this information and updates its central file to produce a new updated version of the digital map.

Abstract: A method for accurately displaying positional information of a map. A street or terrain map is produced and then digitized. The actual location of various antenna monuments is determined and a coordinate grid map is produced. A table of positional data is created using information derived from calculating the position of each of the antenna monuments utilizing a navigational tracking system, such as the LORAN-C system. Positional information received from various vehicles and the antenna monuments is used to calculate correctional factors used to distort and skew the grid lines constructed from said table of positional data in such a manner that the exact position of a vehicle can be displayed on the street or terrain map.

Abstract: A method and apparatus for positively indicating the position of a land-based vehicle, a marine vessel or an aircraft, utilizing a security system provided in the secured mode of transportation monitored by a central station. Navigational information transmitted by LORAN-C transmitters or satellite transmitters are received and then retransmitted to the central station which determines the exact latitude/longitude coordinates of the secured mode of transportation. The secured mode of transportation also includes a security panel for monitoring the condition of various parameters. An interface is connected to the security panel and the navigational receiver for coordinating the transmission of information relating to the conditions monitored by the security panel as well as the information received by the navigational receiver before they are sent to a radio for transmission to the central station.