RU2596262C1 - System for protection from extension of signal of standard vehicle key - Google Patents

Abstract

FIELD: safety.

SUBSTANCE: invention relates to equipment for preventing unauthorised access to vehicles and can be used in motor transport to prevent theft or break-in. System for protection from extension of signal of standard key includes interaction of standard key and a protected object - vehicle. Standard key has a receiver for receiving a low-frequency (LF) authorisation request signal from a transmitting module of automobile part of comfortable access system, and also has a transmitter for response transmission of a high-frequency (HF) signal with authorisation data to receiving module of automobile part of comfortable access system. Protection system additionally comprises a broadband high-frequency receiver which does not interact with standard key, a decision device, input of which is connected to output of high-frequency broadband receiver, and a transmitter of interference signal, input of which is connected to output of decision device.

EFFECT: reliable protection against signal extension of standard key.

1 cl, 1 dwg

Description

The invention relates to equipment for preventing unauthorized access to vehicles and can be used in road transport to prevent theft or hacking.

Recently, cases of hijacking and / or hacking of cars equipped with a comfortable access system with the help of extension cords of a standard key signal or remote relay of radio signals from a standard key have become more frequent. The standard key signal extender consists of two transceivers connected by a high-frequency radio channel. One of the transceivers is located next to the car’s standard key and interacts with it by analogy with the car’s part of the comfort access system, and the second is next to the car (from the hijacker) and interacts with the car’s part of the comfort access system by analogy with the car’s key. Therefore, when the extension key signal of the regular key is turned on, requests from the car are relayed to the key and vice versa, which allows the hijacker to open the car and start the engine without having a regular key. Thus, there was a need to create a vehicle protection system from the extension signal of the standard key.

A known security system consisting of a key with a transmitter and a guarded object with a base station including a receiver, where the receiver interacts with a key transmitter to exchange authorization data, while the base station controls the level of the high-frequency signal received by the receiver, detects interference in the level of the high-frequency signal and detects repeater (application for US patent US 2006255909 (A1), 2006). This device is taken as the closest analogue.

The disadvantage of this device is the relatively low level of reliability of protection against the extension signal of the standard key.

The technical result, to which the claimed invention is directed, is to increase the reliability of protection against the extension signal of the standard key.

The indicated technical result is achieved in that the protection system from the extension key of the standard key signal, including the regular key interacting with each other and the guarded object - the car, additionally contains a broadband high-frequency receiver that does not interact with the standard key, a resolving device, as well as an interference signal transmitter operating on the frequency of signal reception of the standard key, and the input of the deciding device is connected to the output of the broadband high-frequency receiver, and the output of the deciding device connected to the input of the transmitter of the interfering signal.

The invention is illustrated in the drawing, which shows a block diagram of a protection system against a signal extension cord of a standard key.

According to FIG. 1, the protection system from the extension key of the standard key signal includes a standard key 1 interacting with each other and a guarded object - a car 2. The standard key 1 has a receiver 3 for receiving a low-frequency (LF) authorization request signal, for example, at a frequency of 125 kHz from the transmitting module 4 of the automobile part of the comfort access system, and also has a transmitter 5 for reciprocal transmission of a high-frequency (HF) signal with authorization data to the receiving module 6 of the automobile part of the comfort access system. The high-frequency signal ranges can be, for example, 315 MHz, 433 MHz, 868 MHz, 915 MHz. The protection system further comprises a broadband high-frequency receiver 7 that does not interact with the standard key 1. Broadband high-frequency receiver 7 has several separate receive channels with separate antennas, operating, for example, in the ranges 200-400 MHz, 400-600 MHz, 600-1000 MHz. For each measurement cycle, the broadband high-frequency receiver 7 determines the signal power level for each of its channels. The protection system also includes a resolver 8, the input of which is connected to the output of the broadband high-frequency receiver 7. The solver 8 is a computing device, for example, an ATMEL ATMEGA164PA microcontroller, which, when the car engine is turned off, calibrates the sensitivity based on the data received from the broadband high-frequency receiver 7 about the measured signal power levels for each channel and calculates the thresholds for exceeding the signal power, i.e. response thresholds of the resolver 8. In addition, the resolver 8 performs calculations when digitally filtering false alarms if the signal levels established during calibration are exceeded due to interference. After calibration, the solver 8 compares the data received from the broadband high-frequency receiver 7 with the set thresholds and is triggered if these thresholds are exceeded on any channel. The protection system also contains a transmitter 9 of the interfering signal, the input of which is connected to the output of the resolving device 8. When the resolving device 8 is activated, it issues a command to turn on the transmitter 9 of the interfering signal, which generates a powerful noise signal in the operating range of the receiving module 6 (for example, 315 MHz, 433 MHz, 868 MHz, 915 MHz).

The protection system from the extension signal of the standard key works as follows.

In the initial state, the engine of the car 2 is started, and the protection system from the extension cord of the standard key signal is turned off. If the key 1 is located in the passenger compartment of the car 2, the radio exchange between the key 1 and the automobile part of the comfort access system is carried out normally. When the ignition is turned off, the system starts, the sensitivity of the decisive device 8 is calibrated - the response threshold is set. 3 seconds after the engine is turned off, the radio monitoring procedure starts. The individual receiving channels of the broadband high-frequency receiver 7 determine the signal power levels for each of the ranges and periodically transmit them to the decider 8 for comparison with the set threshold of operation. When the owner of car 2 leaves it, the distance between the key 1 and the car part of the comfort access system does not allow for regular radio communication, the comfort access system blocks attempts to open the car door or start the engine. In such a situation, attackers can use the standard key signal extension to provide the ability to open the car door and start the engine without the key in the car. The inclusion of the extension signal of the standard key near the car leads to the appearance of a relay signal in the high frequency range, received by the broadband high-frequency receiver 7. If the radiation threshold is exceeded in the high-frequency range, the resolver 8 gives the command to turn on the transmitter 9 of the interfering signal, which emits an interference signal at a frequency of which operates a comfortable access system. Thereby, the operation of the receiving module 6 of the automobile part of the comfort access system is blocked until the extension of the extension signal of the standard key.

Through the use of a broadband high-frequency receiver that does not interact with the standard key, you can identify all the possible inclusion of the extension signal of the regular key near the car.

Thanks to the decisive device, the response threshold is set in accordance with the measured level of the high-frequency signal around the car and the possibility of false operation is minimized.

The presence of a jamming signal transmitter operating at the frequency of receiving the standard key signal does not allow opening the car and starting the engine using the standard key signal extension cord.

Thus, the claimed invention allows to increase the reliability of protection against the extension signal of the standard key.

Claims (1)

The protection system from the extension key of the standard key signal, including a regular key interacting with each other and a guarded object - a car, characterized in that it additionally contains a broadband high-frequency receiver that does not interact with the standard key, a solver, as well as an interference signal transmitter operating at the frequency of signal reception standard key, and the input of the deciding device is connected to the output of the broadband high-frequency receiver, and the output of the deciding device is connected to the input of the transmitter omehovogo signal.

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