Thomson Consumer Electronics S.a.

Patrice Fremanteau

David Naccache

Wolfgang Hartnack

Masahiro Fujimoto

David Harrison

Christopher Howson

Normally, speed control is carried out by police using radar and camera. The speed of a car can also be recorded in a tachograph. According to the invention car speed is controlled and/or limited using driver-specific smart-cards and millimeter wave communications. When a car (13) enters the sector of a new transmitter (11), its card reader receives a signal telling the reader to consider the time information (t.sub.1) received from the transmitter as a starting time. When the car exits this first sector and penetrates the perimeter of a second transmitter (12), the reader receives over the air a second time information (t.sub.2) and other information (v.sub.1, d.sub.1) from which the speed is calculated and recorded within the card reader. The police can check the recorded information by inserting a special card into the reader.

Method and apparatus for controlling and/or limiting speed excess by

An antenna system for receiving radiowaves includes a Lundeburg-type lens which reflects radiowaves to a focal point of the lens. A helical primary feed is located in the proximity of the focal point. Electronic circuitry for processing the radiowaves in a desired manner and the primary feed are supported in a hollow support structure in the proximity of the focal point.

Radiowave antenna system

Memory cards are cheap and contain memory means, but can be forged and duplicated easily. Smart-cards contain also a microprocessor and can be used for cryptographic purposes, but are much more expensive. The plastic support of the card contains randomly distributed ferrite particles (eg. small steel marbles, introduced into the plastic paste during the melting process). This random distribution of the particles is assumed to be impossible to control or influence during the process of fabrication. For personalizing a card, the issuing authority scans the plastic support of the card with a magnetic inductance detector, thereby reading the emplacement of the ferrite particles as a number p. Then the authority computes s=SIG(ID,p), where 'SIG' denotes any secure public-key digital signature algorithm and ID the identification details of the card's owner. Finally, s and ID are recorded in the memory means of the card. When such a card is inserted into a reader, the reader scans the plastic part of the card and reads the distribution characteristics as a number p. Then ID and s are retrieved from the card's memory means and the reader checks that s is the valid signature of {ID,p} .

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Strasbourg, France

Patrice Fremanteau