Abstract: A method and system for detecting unauthorized account access. The system may operate in conjunction with known methods of remote access authentication. The system provides a unique account for each authorized person (i.e., each user) and a system sequence number and a user sequence number for each account. For each access to the account, the system updates the system sequence number corresponding to that account to the next number in a preselected sequence, and the user updates the user sequence number in like manner. The preselected sequence comprises a sequence of pseudorandom numbers and the update comprises selecting the next pseudorandom number using a pseudorandom number generator, but the sequence number may be updated using other techniques, so long as the system and the user are both capable of performing the same updates. The system and the user perform a handshake process, to assure that the system updates the system sequence number, and the user updates the user sequence number, in synchrony.

Abstract: Methods and apparatus for the determination of the location of a mobile vehicle relative to a radio transceiver. The apparatus incorporates a mobile transceiver that calculates its location relative to at least a first stationary transceiver, and communicates this location back to the stationary transceiver. As a mobile vehicle enters the radio field radiated from at least a first stationary transceiver unit, the mobile vehicle transceiver begins measuring the energy of one or more radiated signals as an analog value, converts the analog value to digital form, from which a microprocessor and software algorithm calculates the specific distance from the stationary transceiver, and then returns a data string that informs the stationary transceiver of its location. This system thus allows both the mobile transceiver and the stationary transceiver unit to gain specific information with regard to the relative distance between mobile and base station units.

Abstract: An apparatus for automatic payment of parking fees in a parking zone includes a stationary RF transmitter unit transmitting a signal encoding the parking fee rate per unit time and, in some embodiments, the maximum parking period and time and date to cooperate with a transponder carried in the vehicles to be parked. A portable transponder in each vehicle includes a receiver for receiving the broadcast signal from the stationary transmitter, a memory which can be preloaded with monetary amounts to generate a prepaid credit, a data processor for controlling the activity of the responder and decoding incoming signals, and a display for indicating to the vehicle operator or to a traffic monitoring person external to the vehicle, the status of the memory in the transponder as to the whether the vehicle is validly parked at any given time.

Abstract: A hazardous waste shipment system provides monitoring and control to verify the location and condition of each shipment. Two-way base stations receive status and identification signals from vehicle-mounted transponders as the shipments pass by, and the base stations relay the information to a central data bank. The vehicle mounted transponders may receive data from sensors that monitor the load, and may actuate alarms or a message display for operator intervention. The three-tier system also provides notifications, and safety instructions in the event of a mishap, with the base stations relaying instructions or route changes to the vehicle mounted transponders.

Abstract: Methods and apparatus for the automatic and management of traffic, utilizing a microprocessor-based, read-write vehicle borne transponder device. The system includes plurality of transceivers spaced along and positioned adjacent to a roadway, a plurality of vehicle borne transponders, and an independent network management computer. As vehicles traverse the roadway the transponders communicate with the transceivers and one or both of those units collect information such as, vehicle entrance point, vehicle exit point, vehicle speed, number of passengers in each vehicle, and vehicle class. Some of the collected information is processed by the transceivers and transponders, while other information is transmitted to the network management computer for processing.

Abstract: A system for automatic collection of tolls includes a toll facility, an in-vehicle toll processor having memory for storing a toll-money-available quantity purchased by the user, and a toll-facility-identification site that transmits a toll-facility-identifier signal indicating the identity of the upcoming toll facility and the toll to be collected. As the vehicle approaches the identification site, the in-vehicle processor receives the identifier signal and calculates the toll to be debited. When the vehicle passes through the toll facility, the facility transmits a toll-collect signal instructing the in-vehicle toll processor to debit the calculated toll from memory. The in-vehicle processor debits the calculated amount and transmits an acknowledgement signal to the toll facility.This application is related to the subject matter of application Ser. No. 525,103 filed May 17, 1990 now U.S. Pat. No. 5,144,553, issued Sep. 1, 1992, and application Ser. No. 524,654 filed May 17, 1990 now U.S. Pat. No.