RU2201362C1 - Vehicle user identification method - Google Patents

Abstract

FIELD: transport engineering; security systems. SUBSTANCE: transport with individual code is given to each user. Coded enquiry and answer in form of interrupted radio pulses with fixed carrier frequency representing unities and zeroes are generated in stationary part of security complex and in transponder on supergenerative stages with external superization. For said stages, starting signals are formed with smoothly building up leading edges and frequencies constant in process of transmission of each digit, F_C"1",F_T"1" or F_C"0",F_T"0". Answers are generated simultaneously with enquiry. Enquiry code digit received by transport and answer code digit received by stationary part are determined with account of transmitted code digit and frequency difference providing pulselength modulation of radio pulses. Answer frequencies (F_T"1",F_T"0") are set depending on enquiry frequencies (F_C"1",F_C"0") and chosen ratio M of frequencies of pulse-length modulation

. Coincidence and noncoincidence of transmitted and received digits are determined by presence of pulse-length modulation of radio signal envelope with frequencies (F_C"1"-F_C"0")/(M+1) and M(F_C"1"-F_C"0")/(M+1, respectively. EFFECT: improved reliability of protection against hi-jacking. 3 cl, 6 dwg

Description

 The invention relates to the field of vehicles, is intended to identify the user of the vehicle and prevent unauthorized use of vehicles. The invention can be applied in motor vehicles to combat theft and theft.

 Known methods for identifying a user of a vehicle (i.e., one of those persons for whom the owner of the vehicle allowed to use this vehicle), according to which each user is provided with their own identification transponder, and a stationary part of the security complex is installed on the vehicle. At the same time, an individual function for generating a response to any of the request codes is introduced into the stationary part and into each of the transponders. The security complex is almost always in a state of protection, in which the admission of any person to the vehicle and its use is prohibited. The security status is removed only for short periods of time (no more than a few minutes) after the security complex recognizes one of the user's transponders. Upon recognition, the stationary part of the security complex issues a pseudo-random request, which receives the transponder and then generates a response to it. The request and response are transmitted in the form of low-frequency radio signals that can only be identified within a relatively small communication area.

 The request and response are transmitted in the form of signals of the same carrier frequency, formed in the form of separate packages, following each other. Each parcel defines one of the bits in the transmitted code (request or response). Parcels are transmitted with a strictly fixed period, and the duration of the transmission of the package determines the information that it contains (for example, when transmitting a logical zero, the duration of the package is several times shorter than when transmitting a logical unit).

 The stationary part generates a response to the request submitted to the transponder and compares it with the response of the transponder. With complete coincidence, the protection is removed for a short time. Such methods of preventing unauthorized use of a vehicle and devices for their implementation are described in a large number of patents (for example, DE 4318596 A1, 60 R 25/00, 08.12.1994; RU 2155683 C1, 60 R 25/00, 10.09.2000; RU 2160675, 60 R 25/00, 12.20.2000).

 As a rule, users of a vehicle have the ability to send commands to the stationary part of the security complex using an external keyboard, as well as through a paging communication network. It is precisely the possibility of filing a wide range of different types of teams and determining the interaction between them that is the subject of most such inventions.

 However, each of the methods relies on a time division of the request and response. Various options for such methods of preventing unauthorized use of a vehicle are implemented, in particular, in mass-produced automobile security systems. Information on automotive security systems produced by the applicant enterprise is given in the catalog of the applicant enterprise (ALTONIKA, Automotive Security Systems. Catalog 2002). Separation by time of filing a request and response is one of the prerequisites for hijacking a vehicle. However, there are other prerequisites for realizing the possibility of hijacking a guarded vehicle.

 The second prerequisite for hijacking is a violation of the principle of disabling protection for only a short period of time. This principle is only proclaimed, but in real-life security complexes it is always violated. This is due to the fact that the presence of a security complex should not impede the maintenance of a vehicle in a car service. Therefore, the security complex switches to the mode necessary for repair or maintenance of the vehicle in any security complex according to a standard command. Such a team is necessary, but it creates yet another prerequisite for hijacking a vehicle, which exists in absolutely all known technical solutions.

 The third prerequisite for theft is the presence of a relatively large communication zone (transponders can be removed up to 2.5 m from the stationary part of the security complex). However, a large communication zone is convenient in that it allows the user not to remove the transponder from the pocket for identification.

 Consider the technique by which a vehicle can be stolen with a known anti-theft system installed (having all three of the theft preconditions discussed above). Such a hijacking technique (called "using a repeater") is designed to select a point in time when the user temporarily leaves the vehicle, heading from it to some public institution (catering, shop, etc.). The user’s distance from the vehicle is about 100 m. An empty vehicle is guarded, the temporary removal of which is possible only when one of the user's transponders is brought into the communication zone.

 Attackers, of course, do not have the opportunity to get a transponder, but one of them can be located near the vehicle, and the other can establish surveillance of the user. For definiteness, we call an attacker who is near a vehicle a "hijacker", and who has set up surveillance of a user - an "accomplice". The hijacker and accomplice must have specially designed portable transceivers with them. The hijacker places its transceiver in the communication zone of the stationary part of the security complex. The hijacker transceiver receives the request signal of the stationary part and forwards the request signal to the accomplice transceiver in the form of high-frequency radio signals. The accomplice transceiver forms a communication zone around its antenna into which the user transponder should fall. In this case, the transceiver of the accomplice, upon receiving a request message from the hijacker, generates a request signal that repeats the signal that was issued by the stationary part of the security complex. The user's transponder responds to the received request. The response of the user transponder is received by the accomplice transceiver and in the form of high-frequency radio signals, transmits a response signal to the hijacker transceiver. In turn, the hijacker transceiver generates a response signal by the response message received by it, repeating the signal that was issued by the user transponder. As a result, the stationary part of the security complex receives the correct answer to the request. Since the request and response are separated in time, the security complex perceives the hijacker's transceiver signal as the response of the user transponder. At the same time, the security complex temporarily removes protection. The hijacker immediately enters the vehicle and instructs the security complex to enter the mode corresponding to vehicle maintenance. After that, the hijacker must prohibit the arrival of commands to the security complex via the paging network. For this, a mechanical disconnection of the paging receiver from the other parts of the security complex is sufficient. After that, the vehicle is under the complete control of the hijacker, and the hijacking can be carried out successfully.

 As part of the stationary part of the security complex, a super-generator with external superization can be used. Such hardware implementation of the stationary part allows security agencies, in particular, to detect a stolen vehicle in the stream of cars and transmit special commands to it. Based on this principle, the work of security complexes is based on the patents RU 2086437, 60 R 25/04, 08/10/97, and RU 2093387, 60 R 25/04, 10.20.97.

 However, for the transmission of request and response codes, superregenerators with external superization are not used in these security complexes, which makes it possible to carry out hijackings in these security complexes using a repeater.

 This general disadvantage of methods for preventing unauthorized use of a vehicle is fully manifested in the method that is closest to the subject of the present invention. This method is implemented in a system of protection against unauthorized access for vehicles according to patent RU 2123441, 60 R 25/00, 12.20.1998. This is a method of identifying a vehicle user, according to which each user is provided with a transponder with an individual binary code of the user’s sign, in the stationary part of the security complex and the transponder, code signals of request and response are generated in the form of intermittently transmitted radio pulses with a fixed carrier frequency, reflecting logical units and zeros .

 The disadvantage of this method (as well as the above technical solutions) is the possibility of hijacking a vehicle when using a repeater in the form of two transceivers, which allow transmitting a request signal (for a transponder) and a response signal (at least up to 100 m) for the stationary part of the security complex).

 The objective of the invention is a modification of the method, completely eliminating the aforementioned possibility of theft by combining in time the transmission of the security complex request and the response of the transponder. Excluding all other prerequisites is irrational, as this reduces the usability of the anti-theft system for each user.

The problem is solved in that in the method of identifying the user of the vehicle, according to which each user is provided with a transponder with an individual binary code of the user’s sign, in the stationary part of the security complex and the transponder, code signals of request and response are generated in the form of intermittently transmitted radio pulses with a fixed carrier frequency , reflecting logical units and zeros, - in the stationary part of the security complex and the transponder, the mentioned radio pulses s obtained at superregenerative cascades with external superizatsiey, which is formed having a smoothly growing front edges of trigger signals with frequencies F _"1" F _{T "1"} or F _{C "0",} F _{T "0"} is constant during time intervals transmission of each bit, in this case, the response code is generated simultaneously with the request code, at each moment of time the discharge of the request code and the stationary part of the security complex received by the transponder - the discharge of the response code is determined taking into account the code discharge transmitted by them and the absolute value of the frequency difference F _{C "1"} and F _{T "1"} , or F _{C "0"} and F _{T "0"} , or F _{C "1"} and F _{T "0"} , or F _{C "0"} and F _{T "1"} , causing pulse width modulation of radio pulses.

 Partial essential features of the invention contribute to the solution of the problem.

In the transponder and the stationary part of the security complex, the coincidence of the transmitted and received discharges is determined by the presence of pulse-width modulation of the envelope of the radio signals with a frequency (F _{C "1"} -F _{C "0"} ) / (M + 1), and the mismatch - by the presence of the latitudinal pulse modulation of the envelope of radio signals with a frequency of M (F _{C "1"} -F _{C "0"} ) / (M + 1), where M is the selected ratio of the absolute values of the differences F _{C "1"} -F _{C "0"} and F _{C " 1 "} -F _{T" 1 "} .

The frequency of the response signals in the transponder is set depending on the frequency of the request signals in the stationary part of the security complex and on the selected ratio M of pulse-width modulation frequencies
F _{T "1"} = F _{C "1"} - (F _{C "1"} -F _{C "0"} ) / (M + 1),
F _{T "0"} = F _{C "0"} + (F _{C "1"} -F _{C "0"} ) / (M + 1).

 In FIG. Figure 1 shows the electrical circuit diagram of one of the possible options for a super regenerative cascade with external superization, and also shows the blocks to which it is necessary to connect the super regenerative cascade when used in a transponder and in the stationary part of the security complex. Figure 2 presents the timing diagrams of the super-regenerative cascade, made according to the circuit shown in figure 1. Figure 3 shows the timing diagrams of the joint operation of the transponder and the stationary part of the security complex when forming a logical zero in the transponder, and a logical unit in the stationary part of the security complex. Figure 4 shows the timing diagrams of the joint operation of the transponder and the stationary part of the security complex when forming a logical unit both in the transponder and in the stationary part of the security complex. Figure 5 presents the timing diagrams of the joint operation of the transponder and the stationary part of the security complex when forming a logical zero both in the transponder and in the stationary part of the security complex. Figure 6 shows the timing diagrams of the joint operation of the transponder and the stationary part of the security complex when a logical zero is formed in the stationary part of the security complex and a logical unit in the transponder.

 In FIG. 1 the following notation is introduced: 1 - shaper; 2 - superregenerative cascade; 3 - low pass filter.

 Shaper 1 in the simplest case can be performed according to the scheme of an integrating chain.

 One of the possible schemes of the super regenerative cascade 2 is shown in FIG. 1. This cascade is made on the transistor V1 according to the scheme with external superization. The oscillation circuit L1, C2 is tuned to the selected carrier frequency (for example, 1.0 MHz). Capacitor C3 acts as a feedback element. Inductor L2 is used to prevent short circuit at high frequency. The carrier frequency signals enter the antenna, and the envelope signals to the low-pass filter 3. Features of the construction of super-regenerative cascades are considered in the monograph "Super-Regenerators", ed. M.K. Belkina, Moscow: Radio and Communications, 1983.

 The low-pass filter 3 is designed to extract pulse-width modulation from the envelope of the frequency. It is a standard electronic unit.

 Let us analyze in detail the operation of the security complex for vehicles, which implements the proposed method for identifying a user of a vehicle.

 A super-regenerative cascade 2 with external superization has been introduced into the transponder (for which an individual binary code of the user attribute has been set) and into the stationary part of the security complex. In this case, the oscillatory circuit (L1, C2) both in the transponder and in the stationary part of the security complex is tuned to the same selected carrier frequency. For definiteness, let this frequency be equal to 1.0 MHz (with such a carrier, without large energy costs, radio signals can be received at a distance of 2-2.5 m between the antennas of the transponder and the stationary part of the security complex).

The input of the superregenerative cascade 2 is connected to the output of the driver 1. To the input of the driver 1 (located in the stationary part of the security complex), depending on which of the symbols (logical zero or logical unit) is to be transmitted, pulses are sent either with frequency F _{C "0"} , or with a frequency of F _{C "1"} . If the former 1 is located in the transponder, then pulses are sent to it either with a frequency F _{T "0"} (logical zero is to be transmitted) or with a frequency F _{T "1"} (logical unit is subject to transmission). On the timing diagrams of operation (Fig. 2), the input signals of the driver 1 are indicated by the symbol "A".

Shaper 1 converts the pulse arriving at it into a signal with a smoothly rising leading edge (diagram "B" in figure 2). When the output signal of the shaper 1 reaches a certain level U _{0, the} superregenerative cascade 2 goes into a mode in which the generation of radio pulses with a carrier frequency (in this case, 1.0 MHz) is induced in the antenna. However, a feature of super-regenerative cascades is that when its antenna receives radio signals of the same carrier that is induced in the antenna, the transition to the radio signal generation mode is carried out at the output signal level of driver 1 (U ₁ ), significantly lower than U ₀ (diagrams С ₀ and C ₁ in Fig. 2). This feature of superregenerative cascades is widely known and used, for example, in patents RU 2086437, 60 R 25/04, 08/10/97 and RU 2093387, 60 R 25/04, 10.20.97.

 Thus, the duration of the generation of radio signals for each of the output pulses of the driver 1 depends on whether there is a source emitting signals from the same carrier near the antenna of the super regenerative cascade 2. For the stationary part of the security complex, such a source is the transponder, and for the transponder it is the stationary part of the security complex.

 At the output of the superregenerative cascade 2 (indicated by the letter "D" in the drawing of figure 1), the envelope of the radio pulse is allocated. Thus, pulses of different durations are received on the low-pass filter 3, the trailing edge of which coincides with the trailing edge of the input pulses of the driver 1 (diagram "A" in figure 2), and the leading edge can be shifted by time ΔT (diagram "D" figure 2) depending on the presence or absence of an external signal with the same carrier frequency as the carrier frequency of the radio pulse.

Figure 3 shows an example when, in the stationary part of the security complex, signals with a frequency corresponding to the frequency of the signals of a logical unit in the stationary part of the security complex continuously arrive at the input of the shaper 1 (diagram A _{C "1"} in figure 3). At the same time, in the transponder, signals with a frequency corresponding to the frequency of logical zero signals in the transponder are continuously fed to the input of the shaper 1 (diagram A _{T "0"} in Fig. 3). The duration of the generation of each radio pulse (diagrams C _{C "1"} and C _{T "0"} in Fig. 3) depends on whether there is generation from an external source at the time of the start of generation of each radio pulse. That is, ultimately, from the phase difference of the signals A _{C "1"} and A _{T "0"} . However, any particular phase difference must be repeated with a frequency equal to the absolute value of the frequency difference of the signals A _{C "1"} and A _{T "0"} . This means that the low-pass filter 3 in the stationary part of the security complex and in the transponder receives signals that are repeated with a frequency equal to the absolute value of the frequency difference of the signals A _{C "1"} and A _{T "0"} . This difference frequency is allocated at the output of each of the low-pass filters 3 (diagrams E _{C “1”} and ET _{T “0”} in FIG. 3).

Figure 4 shows an example when, in the stationary part of the security complex, signals with a frequency corresponding to the frequency of the signals of a logical unit in the stationary part of the security complex continuously arrive at the input of the shaper 1 (diagram A _{C "1"} in figure 4). At the same time, in the transponder, signals with a frequency corresponding to the frequency of the signals of a logical unit in the transponder are continuously fed to the input of the former 1 (diagram _{AT T “1”} in FIG. 4). For this case, at the output of each of the low-pass filters 3, signals are generated with a frequency equal to the absolute value of the frequency difference of the signals A _{C "1"} and A _{T "1"} (diagrams E _{C "1"} and E _{T "1"} in figure 4 )

Figure 5 shows an example when, in the stationary part of the security complex, signals with a frequency corresponding to the frequency of logical zero signals in the stationary part of the security complex continuously arrive at the input of the shaper 1 (diagram A _{C "0"} in figure 5). At the same time, in the transponder, signals with a frequency corresponding to the frequency of logical zero signals in the transponder are continuously fed to the input of the former 1 (diagram А _{T "0"} in Fig. 5). For this case, at the output of each of the low-pass filters 3, signals are generated with a frequency equal to the absolute value of the frequency difference of the signals A _{C "0"} and A _{T "0"} (diagrams E _{C "0"} and Е _{T "0"} in Fig. 5 )

Figure 6 shows an example when, in the stationary part of the security complex, signals with a frequency corresponding to the frequency of the logic zero signals in the stationary part of the security complex continuously arrive at the input of the shaper 1 (diagram A _{C "0"} in Fig.6). At the same time, in the transponder, signals with a frequency corresponding to the frequency of the logical unit signals in the transponder are continuously fed to the input of the former 1 (diagram А _{T "1"} in Fig. 6). For this case, at the output of each of the low-pass filters 3, signals are generated with a frequency equal to the absolute value of the frequency difference of the signals A _{C "0"} and A _{T "1"} (diagrams E _{C "0"} and E _{T "1"} in Fig.6 )

A reasonable choice of signal frequencies encoding logical units and logical zeros in the stationary part of the security complex and in the transponder can significantly simplify the identification of generated codes. The method proposes to allocate no more than two difference frequencies. In this case, you can set the ratio of the allocated difference frequencies (coefficient M). Suppose that the difference between the frequencies of the signals of a logical unit and a logical zero in the stationary part of the security complex exceeds a similar difference in the transponder. Then, using the selected frequencies of the signals encoding logical units and logical zeros in the stationary part of the security complex (F _{C "1"} , F _{C "0"} ) and the coefficient M, we can unambiguously calculate the signal frequencies (F _{T "1"} , F _{T "0 "} ) encoding logical units and logical zeros in the transponder
F _{T "1"} = F _{C "1"} - (F _{C "1"} -F _{C "0"} ) / (M + 1),
F _{T "0"} = F _{C "0"} + (F _{C "1"} -F _{C "0"} ) / (M + 1).

In the example shown in the drawings of FIGS. 3-6, M = 2 was selected; F _{C "1"} = 10.0 kHz, F _{C "0"} = 8.5 kHz. These values correspond to F _{T "1"} = 9.5 kHz; F _{T "0"} = 9.0 kHz. At the same time, if signals encoding matching values (two logical zeros or two logical units) are generated in the transponder and in the stationary part of the security complex, then the signals at the outputs of the 3 low-pass filters in the stationary part of the security complex and in the transponder will have a frequency of 0, 5 kHz. If the information encoded in the transponder and in the stationary part of the security complex does not match, then the signals at the outputs of the 3 low-pass filters in the stationary part of the security complex and in the transponder will have a frequency of 1.0 kHz (frequency ratio 1.0 kHz and 0 5 kHz is exactly M = 2).

 So, in the drawings of FIG. 3 and FIG. 6 (information does not match), the frequency of the signals from the outputs of the low-pass filters 3 is twice the frequency of the signals while transmitting two logical units (FIG. 4) or two logical zeros (FIG. 5) .

This means that while transmitting signals simultaneously with the stationary part of the security complex and the transponder, you can easily determine what information is generated by the other part of the security complex:
- when transmitting signals encoding a logical unit to any part of the security complex, and when the frequency of the signals at the output of the low-pass filter 3 is 0.5 kHz, the signals of the logical unit also go to the output of the second part of the security complex;
- when transmitting signals encoding a logical unit to any part of the security complex and at a frequency of signals at the output of the low-pass filter 3 equal to 1.0 kHz, logical zero signals go at the output of the second part of the security complex;
- when transmitting signals encoding a logical zero to any part of the security complex, and when the frequency of the signals at the output of the low-pass filter 3 is 1.0 kHz, the signals of the logical unit go to the output of the second part of the security complex;
- when transmitting signals encoding a logical zero to any part of the security complex, and when the frequency of the signals at the output of the low-pass filter 3 is 0.5 kHz, logical zero signals also go at the output of the second part of the security complex.

 At the same time, it is impossible for hijackers to use a relay, since signal relaying is impossible - on the air simultaneously and on one carrier frequency there are request and response signals, which cannot be further relayed.

 It should be noted that this application for the invention considers only the method of identifying the user of a vehicle in the most general form, but not the type of codes transmitted during identification (they can be very different). Mutual synchronization of transponder messages and the stationary part of the security complex does not apply to the subject considered in this application. All these are issues of specific hardware implementation of this method.

 In private form, they were solved at the applicant enterprise, and devices implementing the inventive method were brought up to the level of prototype models, tests of which confirmed the high efficiency of this method.

Claims (3)

1. A method of identifying a vehicle user, according to which each user is provided with a transponder with an individual binary code of the user’s sign, in the stationary part of the security complex and the transponder, code request and response signals are generated in the form of intermittently transmitted radio pulses with a fixed carrier frequency, reflecting logical units and zeros, characterized in that in the stationary part of the security complex and the transponder, said radio pulses are received at a check hregenerative cascades with external superization, for which start-up signals with frequencies F _{C "1"} , F _{T "1"} or F _{C "0"} , F _{T "0" are formed} that are constant over the transmission time intervals of each discharge in this case, the response code is generated simultaneously with the request code, at each moment of time the discharge of the request code and the stationary part of the security complex received by the transponder — the discharge of the response code is determined taking into account the discharge of the code and the absolute value of the frequency difference F _{C "1"} and F _{T " 1 'or} F _{C "0"} F _{T "0",} or F _{C "1"} and F _{T "0",} or F _{C "0"} and _T F _"1" causes the pulse width modulated RF pulse. 2. The method according to p. 1, characterized in that in the transponder and the stationary part of the security complex, the coincidence of the transmitted and received discharges is determined by the presence of pulse-width modulation of the envelope of the radio signals with a frequency of (F _{C "1"} -F _{C "0"} ) / ( M + 1), and the mismatch is due to the presence of pulse-width modulation of the envelope of radio signals with a frequency of M (F _{C "1"} -F _{C "0"} ) / (M + 1), where M is the selected ratio of the absolute values of the differences F _{C " 1 "} -F _{T" 0 "} and F _{C" 1 "} -F _{T" 1 "} . 3. The method according to p. 2, characterized in that the frequency of the response signals in the transponder is set depending on the frequency of the request signals in the stationary part of the security complex and on the selected ratio M of the frequency of the pulse-width modulation:
F _{T "1"} = F _{C "1"} - (F _{C "1"} -F _{C "0"} ) / (M + 1)
F _{T "0"} = F _{C "0"} + (F _{C "1"} -F _{C "0"} ) / (M + 1).

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