RU2042548C1 - Vehicle antitheft device - Google Patents

Abstract

FIELD: transport; antitheft facilities. SUBSTANCE: device has current-limiting resistor 2, remote controlled selector switch 3 with two opposite-phase windings 4 and 5, light-emitting diode 6, hermetically sealed reed relay 7, intermittent signal generator 9, electromagnetic relay 10, driving generator 11, phase manipulator 12, transmitter 13 with antenna 14, three receiving antennas, search unit, heterodyne oscillators mixers, first and second intermediate frequency amplifiers, detector, spectrum width meters, frequency doubler, comparator unit, threshold unit, delay line, switches, frequency meter, recording units, frequency detector, flip-flop, multipliers, narrow-band filters and phase detectors. Device enhances reliability and enlarges operating capabilities by transmitting alarm signals by radio to receiving station and accurate and well-defined direction finding of hi-jacked vehicle. EFFECT: enhanced reliability and enlarged operating capabilities. 4 dwg

Description

 The invention relates to vehicles, in particular to devices for preventing the unauthorized use of vehicles, such as cars.

Known anti-theft device for a vehicle, containing an intermittent signal generator located on the vehicle, one of the supply terminals of which is connected via the ignition key to the positive bus of the power source, an electromagnetic relay, the winding of which is connected to the output of the intermittent signal generator, and an NC contact is included in the power circuit ignition coils in series with the ignition key, and a remote switch with a winding, one of the terminals of which is directly connected to plus the power supply bus, and the opening and closing contacts, the first of which is connected between the second supply terminal of the discontinuous signal generator and the negative bus of the power source, between which and one of the terminals of the remote switch winding, the operating mode switch [1]
However, this anti-theft device is not equipped with an alarm and allows an attacker to engage in criminal activity for a long time. At the same time, the hijacker, having made repeated attempts to start the engine, still has a real opportunity to detect the presence of an anti-theft device, to reveal the principle of its operation and to hijack a vehicle.

 In addition, to turn off the anti-theft device, when the ignition is turned on, press the inside wall of the cab in a certain place or drown the slightly protruding screw head without thread. In this case, due to deformation of the cab wall or pressing the screw, a microswitch located behind the cab wall is activated.

 However, the microswitch can also be triggered by accidentally pressing the screw or the cab wall, which leads to the shutdown of the anti-theft device and theft of the vehicle. In addition, since the device becomes self-locking when power is supplied to the relay, the bounce of its contacts when the vehicle is moving can lead to a breakdown of the lock and the transition from normal operation to security mode. Therefore, the specified anti-theft device has a relatively low reliability.

 The aim of the invention is to increase the reliability and expand the functionality of the device by transmitting alarm information over the air to the receiving point, accurate and unambiguous direction finding of the stolen vehicle.

 To do this, in an apparatus containing an intermittent signal generator located on the vehicle, one of the supply terminals of which is connected via the ignition key to the plus bus of the power source, an electromagnetic relay, the winding of which is connected to the output of the intermittent signal generator, and the NC contact is connected in series to the ignition coil circuit with an ignition key, and a remote switch with a winding, one of the terminals of which is directly connected to the plus bus of the power source, and disconnecting and closing ayuschim contacts, first of which is connected between the second supply terminal intermittent signal generator and the negative power supply rail, between which and one of the terminals of the winding remote switch mode switch is turned on; additionally introduced a current limiting resistor, an LED, a reed switch, a master oscillator, a phase manipulator and a transmitter associated with a transmitting antenna, and a measuring channel located at the receiving station, consisting of a series-connected search unit, a first local oscillator, a first mixer, the second input of which is introduced connected to the output of the receiving antenna, an amplifier of the first intermediate frequency, a frequency doubler, a first spectral width meter, a comparison unit, the second input of which is black the second spectral width meter is connected to the output of the amplifier of the first intermediate frequency, a threshold unit, the second input of which is connected to the output of the delay line, the first key, the second input of which is connected to the output of the amplifier of the first intermediate frequency, the second mixer, the second input of which is connected to the output of the second local oscillator , an amplifier of the second intermediate frequency, a frequency detector, a trigger, and a first registration unit, and from a second key in series connected to the output of the first local oscillator, the second input of which connected to the output of the threshold unit, the frequency meter and the second registration unit, and the output of the threshold unit is additionally connected to the inputs of the delay line and the search unit, and two direction finding channels, each of which consists of a series-connected receiving antenna, a mixer, the second input of which is connected to the output the first oscillator of the measuring channel, the amplifier of the first intermediate frequency, a multiplier, the second input of which is connected to the output of the amplifier of the second intermediate frequency of the measuring channel, narrowly filter, phase detector, the second input of which is connected to the output of the second local oscillator of the measuring channel, and the registration unit, while on the vehicle the remote switch is made with additional winding and opening and closing contacts, and the operating mode switch is in the form of a reed switch with a source pole bus one of the terminals of the current-limiting resistor and the second winding of the remote switch is connected directly, and through the ignition key, one of the terminals of the master generator, phase manipulator and transmitter, the closing and opening contacts of the second winding of the remote switch are connected between one of the terminals of the reed switch and the second conclusions of the first and second windings of the remote switch, the closing contact of the first winding of which is connected between the other terminal of the current-limiting resistor and the anode of the LED, the cathode of which the other output of the reed switch directly, and the other supplying conclusions of the master oscillator of the phase manipulator and the transmitter through the closing to ntakt first winding remote switch connected to the negative supply rail.

 Figure 1 and 2 presents a structural diagram of the proposed device; in FIG. 3 illustrates the principle of direction finding of a specified vehicle by the phase method; figure 4 shows a timing diagram explaining the operation of the device.

 The anti-theft device for a vehicle includes: a power source 1, a current limiting resistor 2, a remote switch 3 with two antiphase windings 4 and 5, an LED 6, a reed switch 7, an ignition key 8, an intermittent signal generator 9, an electromagnetic relay 10, a driving generator 11, a phase manipulator 12, a transmitter 13, and a transmitting antenna 14; at the receiving center: first 15, second 16 and third 17 receiving antennas, first 20, third 21 and fourth 22 mixers, search unit 18, first local oscillator 19, first 23, second 24 and third 25 amplifiers of the first intermediate frequency, detector 26, first 29 and second 27 spectrum width meters, frequency doubler 28, comparison unit 30, threshold block 31, delay line 32, first 33 and second 34 keys, frequency meter 35, second recording unit 36, second local oscillator 37, second mixer 38, amplifier 39 second intermediate frequency, frequency detector 40, trigger 41, first block to 42 registration, the first 43 and second 44 multipliers, the first 45 and second 46 narrow-band filters, the third 49 and fourth 50 registration blocks. Moreover, the current limiting resistor 2, pins 5.1 and LED 6 are connected in series to the positive bus of the power supply, remote switch 3, pins 4.1 and 4.2 and reed switch 7. are connected in series to the positive bus of the power source 7. Ignition coil through the ignition key 8, pins 10.1 and relay 10 connected to the positive bus of power supply 1. To the output of the ignition key 8, an intermittent signal generator 9 and contacts 5.2 of the winding 5 are connected in series. To the output of the master oscillator 11, a phase manipulator 12 and a transmitter 13 connected to the transmitting antenna 14 are connected in series. The supply voltage to the master oscillator 11, the phase manipulator 12 and the transmitter 13 fed through the ignition key 8 and contacts 5.2 of the winding 5. A mixer 20 is connected in series to the output of the receiving antenna 15, the second input of which through the local oscillator 9 is connected to the output of the search unit 18, the amplifier 23 of the first frequency frequency doubler 28, a spectral width meter 29, a comparison unit 30, the second input of which is connected to the output of the amplifier 23 of the first intermediate frequency through a spectral width meter 27, a threshold unit 31, the second input of which is connected to the output of the delay line 32, key 33, the second input of which is connected to the output of the amplifier 23 of the first intermediate frequency, the mixer 38, the second input of which is connected to the output of the local oscillator 37, the amplifier 39 of the second intermediate frequency, the frequency detector 40, the trigger 41 and the registration unit 42. A key 34 is sequentially connected to the output of the local oscillator 19, the second input of which is connected to the output of the threshold unit 31, a frequency meter 35, and a recording unit 36. To the output of the receiving antenna 16 (17), a mixer 21 (22) is connected in series, the second input of which is connected to the output of the local oscillator 19, the amplifier 24 (25) of the first intermediate frequency, the multiplier 43 (44), the second input of which is connected to the output of the amplifier 39 of the second intermediate frequency, a narrow-band filter 45 (46), a phase detector 47 (48), the second input of which is connected to the output of the local oscillator 37, and the registration unit 49 (50).

 The device operates as follows.

 The vehicle can be in two modes: in normal operation, when the anti-theft device is turned off, and in security mode, when the anti-theft device is turned on.

 In the first mode, the vehicle is transferred by bringing the permanent magnet, made, for example, in the form of a keychain, to the reed switch 7, installed behind the skin of the vehicle in a place known only to the owner. In this case, the winding 4 of the remote switch 3 through closed contacts 4.1 and reed switch 7 is connected to a power source 1. Remote switch 3 is transferred to its first stable state, in which contacts 4.2 are closed and contacts 4.1 are opened. Contacts 5.1 and 5.2 are in open state. When the ignition is turned on, the voltage to the ignition coil and the engine are operating in normal mode, there is no malfunction in the ignition circuit.

 To put the vehicle in security mode, i.e. to turn on the anti-theft device, the owner again brings the permanent magnet to the reed switch 7. In this case, the coil 5 is activated and the remote switch 3 is transferred to the second stable state, in which contacts 4.1, 5.1 and 5.2 are closed and contacts 4.2 are opened. In this case, the supply voltage through the current-limiting resistor 2 and closed contacts 5.1 is supplied to the LED 6, which is activated and signals to the owner that the anti-theft device is turned on. When the ignition is switched on through the closed contacts 5.2, the vehicle body is connected to the second inputs of the intermittent signal generator 9, the master oscillator 11, the phase manipulator 12 and the transmitter 13. The generator 9 begins to produce rectangular pulses (Fig. 4, b) periodically opening and closing the electromagnetic contacts 10.1 relay 10, and the master oscillator 11 begins to generate harmonic voltage (Fig.4, a). In this case, the engine is started during the closed state of contacts 10.1, but theft is impossible, because after some time the generator 9 gives a pulse, contacts 10.1 open, the ignition system and the engine are turned off.

 A person trying to hijack begins to consistently look for the cause of engine failure. At the same time, it is assumed that most of the faults occur in the ignition system. Usually they start checking the ignition system, since it is most simple to verify its serviceability (by the presence of a spark on high-voltage wires suitable for candles). Suppose a person trying to hijack has brought a high-voltage wire to the ground and cranks the engine. If there is a spark (the period when the 9-pulse generator does not deliver), then the hijacker switches to search for a malfunction in the power system and starts to check the power supply sections, i.e. moves away from the correct search path.

 If during the test there is no spark (the period the generator generates 9 pulses), the hijacker examines the electrical circuit and looks for the damaged area before the interruption in the pulse supply and the failure disappears. This serves as a pointer to replace the allegedly faulty section of the circuit, i.e. misleading again. Troubleshooting is getting complicated.

 Consequently, the absence of an audible alarm does not cause concern and allows an attacker to engage in their criminal activities for a long time. At the same time, the hijacker, having made repeated attempts to start the engine, still has a real opportunity to detect the presence of an anti-theft device, to reveal the principle of its operation and to hijack a vehicle. To prevent theft of the vehicle, a radio channel is used, through which alarm information is transmitted to the reception center, where measures are taken to detain the hijacker.

When the contacts 5.2 are closed, the supply voltage is supplied to the intermittent signal generator 9, the master oscillator 11, the phase manipulator 12 and the transmitter 13 through the closed ignition key 8. Harmonic voltage (Fig. 4, a)
U _o (t) = U _o ˙cos (2 π f _o t + φ _o ),
where V _o , f _o , φ _o amplitude, carrier frequency and the initial phase of the voltage;
from the output of the master oscillator 11 is fed to the first input of the phase manipulator 12, the second input of which is supplied by rectangular pulses (modulating code M (t)) (Fig. 4, b). At the output of the phase manipulator, a phase-shift (PSK) signal is generated, which, after amplification in the transmitter 13, is emitted by the antenna 14 (Fig. 4, c).

At the receiving point, viewing the specified frequency range and searching for PSK signals is performed using the search unit 18, which periodically with a period T _p, according to the sawtooth law, adjusts the frequency of the local oscillator 19. The keys 33 and 34 are closed in the initial state.

Received QPSK signals U ₁ (t) = U _c ˙cos [2 π f _o t + φ _к (t) + φ ₁ ] U ₂ (t) = U _c ˙cos [2 π f _o t + φ _к (t) + φ ₂ ] U ₃ (t) = U _c ˙cos [2 π f _o t + φ _к (t) + φ ₃ ] 0≅ t ≅ T _c,
where U _c , T are the amplitude and duration of the signals;
φ _к (t) = 0, π is the manipulated phase component that displays the phase manipulation law in accordance with the modulating code M (t) (Fig. 4, b), and φ _к (t) = const for K τ _and <t <( K + 1) τ _and u can change abruptly at t = Кτ _, i.e. at the borders between elementary premises (K = 1,2, N-1).

скорость изменения частоты гетеродина 19 (скорость перестройки гетеродина 19).τ _and , N are the duration and number of chips that make up a signal of duration T _s (T _s = N ˙ τ _and ,);
from the outputs of the antennas 15-17 are fed to the first inputs of the mixers 20-22, respectively, the second inputs of which are supplied with a voltage of a ramp frequency from the local oscillator output 19 U _g1 (t) U _g1 ˙ cos (2 π f _g1 t + π γ t ² + φ _g1 ), 0≅ t ≅T _p ,
where U _g1 , f _g1 , φ _g1 , T _p amplitude, initial frequency, initial phase and the repetition period of the local oscillator voltage 19;
γ

the rate of change of the frequency of the local oscillator 19 (the tuning rate of the local oscillator 19).

=

K₁·U_c·U

К₁ коэффициент передачи смесителей;
f_пр1 f_o f_г1 первая промежуточная частота,
φ_пр1 φ₁ φ_г1,
φ_пр2 φ₂ φ_г1,
φ_пр3 φ₃ φ_г1.At the outputs of the mixers 20-22, voltages of combination frequencies are generated. Amplifiers 23-25 distinguish the voltage of the first intermediate frequency
U _pr1 (t) U _pr1 ˙ cos (2 π f _pr t + φ _к (t) π γ t ² + φ _pr1 ),
U _pr2 (t) U _pr1 ˙ cos (2 π f _pr t + φ _к (t) π γ t ² + φ _pr2 ),
U _pr3 (t) U _pr1 ˙ cos (2 π f _pr t + φ _к (t) π γ t ² + φ _pr3 ), 0≅ t ≅T _p ,
where u

=

K ₁ · U _c · U

To ₁ gear ratio of mixers;
f _pr1 f _o f _g1 first intermediate frequency,
φ _pr1 φ ₁ φ _g1 ,
φ _pr2 φ ₂ φ _g1 ,
φ _pr3 φ ₃ φ _g1 .

The voltage U _pr1 (t) from the output of the amplifier 23 of the first intermediate frequency is supplied to the inputs of the detector 26, consisting of measuring instruments 27 and 29 of the spectral width, frequency doubler 28, comparison unit 30, threshold block 31 and delay line 32.

The output of the frequency doubler 28 produces a harmonic voltage
U ₁ (t) U _pr1 ˙ cos (4 π f _pr1 t 2 π γ t ² + 2 φ _pr1 ), 0≅ t ≅T _c,
in which phase manipulation is already absent. The width of the spectrum of the second harmonic Δf ₂ is determined by the duration T of _the signal (Δ f ₂ = 1 / T _c ). Whereas the width of the spectrum of the QPSK signal of the first intermediate frequency is determined by the duration τ _and its elementary premises (Δf _c = 1 / τ _и ). Therefore, when the first intermediate frequency is multiplied by two, the spectrum of the PSK signal is “folded” N times (Δ f _c / Δf ₂ = N). This circumstance makes it possible to detect and select the PSK signal even when its power at the input of the receiving device is less than the power of noise and interference.

The spectral width Δf _{c of the} QPSK signal is measured using a spectral width meter 27, and the spectrum width of the second harmonic U ₁ (t) of the signal is measured using a spectral width meter 29. The voltages U ₁ and U ₂ proportional to Δ f _c and Δf _2, respectively, from the outputs of the meters 27 and 29 of the width of the spectrum are supplied to the two inputs of the comparison unit 30. Since U ₁ >> U ₂ , a constant voltage is generated at the output of the comparison unit 30, which is compared with the threshold level U _then in the threshold block 31. The threshold level U _then is selected so that this level does not exceed random interference. The threshold level U _{pore is} exceeded only when a complex PSK signal is detected. If the threshold level U _pores is exceeded, a constant voltage is generated in the threshold unit 31, which is supplied to the control inputs of the keys 33 and 34, opening them to the input of the delay line 32 and to the control input of the search unit 18, putting it in the stop mode. From this point in time, viewing the specified frequency range D _f and searching for the PSK signals stops for the time of analysis and registration of the detected PSK signal, which is determined by the delay time τ _{s of} the delay line 32.

The frequency of the local oscillator 19 is measured by a frequency meter 35 and is fixed by the recording unit 36. Knowing the frequency of the tunable local oscillator 19 at the time of detection of the PSK signal, it is possible to determine the carrier frequency f _{o the} detected PSK signal. Vehicles of certain territories and areas may have their own carrier frequencies, which is an additional sign of recognition of a stolen vehicle.

When the tuning of the local oscillator 19 stops, the following voltages are allocated by amplifiers 23-25 of the first intermediate frequency:
U _CR4 (t) U _CR1 ˙ cos (2 π f _CR1 t + φ _k (t) + φ _CR1 ),
U _CR5 (t) U _CR1 ˙ cos (2 π f _CR1 t + φ _k (t) + φ _CR2 ),
U _CR6 (t) U _CR1 ˙ cos (2 π f _CR1 t + φ _k (t) + φ _CR3 ), 0≅ t ≅T _c ,
Voltages U _CR5 (t) and U _CR6 (t) from the outputs of amplifiers 24 and 25 of the first intermediate frequency are supplied to the first inputs of the multipliers 43 and 44, respectively. The voltage U _CR4 (t) (Fig. 4, c) from the output of the amplifier 23 of the first intermediate frequency through the public key 33 is supplied to the first input of the mixer 38, the second input of which supplies the voltage of the local oscillator 37, the frequency of which is stabilized by quartz
U _g2 (t) U _g2 ˙ cos (2 π f _g2 t + φ _g2 ),
where U _g2 , f _g2 , φ _g2 amplitude, frequency and initial phase of the local oscillator voltage 37.

 The output of the mixer 38 is formed voltage Raman frequencies. The amplifier 39 is allocated the voltage of the second intermediate frequency (figure 4, g).

=

K₁·U

U

f_пр2 f_пр1 f_г2 вторая промежуточная частота;
φ_пр4 φ_пр1 φ_г2,
которое поступает на вход частотного детектора 40. На выходе последнего образуются короткие разнополярные импульсы (фиг.4, д), соответствующие моментам скачкообразного изменения фазы принимаемого ФМн-сигнала второй промежуточной частоты U_пр7 (t) (фиг.4, г). Указанные импульсы поступают на вход триггера 41. Каждым положительным коротким импульсом триггер 41 переводится в одно устойчивое состояние, а каждым отрицательным коротким импульсом в другое устойчивое состояние. На выходе триггера 41 формируются прямоугольные импульсы (фиг.4, е), соответствующие модулирующему коду М(t) (фиг.4, б). Эти импульсы фиксируются блоком 42 регистрации. При этом каждое транспортное сpедство имеет свой модулирующий код, который состоит из адресной и информационной частей. Адресная часть состоит из n элементарных посылок и используется для передачи сведений, например о номере стоянки, гаража, района и т. д. Информационная часть состоит из m элементарных посылок (m=N-n) и используется для передачи сведений о номерном знаке транспортного средства и его владельце. Причем модулирующий код М(t) выделяется из принимаемого ФМн-сигнала без традиционного опорного напряжения. Для этого используются структурные свойства ФМн-сигнала, частотный детектор 40 и триггер 41.U _pr7 (t) U _pr2 ˙ cos (2 π f _pr2 t + φ _к (t) + φ _пр4 ), 0≅ t ≅T _c ,
where u

=

K ₁ · U

U

_np2 f f f _{r2 pr1} second intermediate frequency;
_WP4 φ φ φ _{r2 pr1,}
which is fed to the input of the frequency detector 40. At the output of the latter, short bipolar pulses are generated (Fig. 4, e), corresponding to the moments of the abrupt phase change of the received PSK signal of the second intermediate frequency U _pr7 (t) (Fig. These pulses are fed to the input of trigger 41. With each positive short pulse, trigger 41 is transferred to one stable state, and with each negative short pulse, to another stable state. At the output of the trigger 41, rectangular pulses are formed (Fig. 4, e) corresponding to the modulating code M (t) (Fig. 4, b). These pulses are recorded by the block 42 registration. Moreover, each vehicle has its own modulating code, which consists of address and information parts. The address part consists of n elementary parcels and is used to transmit information, for example, about the number of a parking lot, garage, district, etc. The information part consists of m elementary parcels (m = Nn) and is used to transmit information about the vehicle’s license plate number and its to the owner. Moreover, the modulating code M (t) is extracted from the received QPSK signal without a traditional reference voltage. For this, the structural properties of the QPSK signal, a frequency detector 40, and a trigger 41 are used.

sinβ
где d измерительная база;
λ длина волны;
β угол прихода радиоволны; фазовая система тем чувствительнее к изменению угла β чем больше относительный размер базы d/λ Однако с ростом d/λ уменьшается значение угловой координаты, при котором разность фаз превосходит значение 2 π т.е. наступает неоднозначность отсчета.Direction finding of a vehicle that is stolen or stolen is carried out by the phase method, which is characterized by a contradiction between the requirements of measurement accuracy and the uniqueness of the angle reading. Indeed, according to the formula
Δφ 2π

sinβ
where d is the measuring base;
λ wavelength;
β angle of arrival of the radio wave; the phase system is the more sensitive to the change in the angle β the larger the relative size of the base d / λ. However, with increasing d / λ, the value of the angular coordinate decreases at which the phase difference exceeds 2 π i.e. ambiguity of counting occurs.

K₂·U

U

К₂ коэффициент передачи перемножителей,

фазовые сдвиги, определяющие направление на источник излучения.The voltage U _pr7 (t) from the output of the amplifier 39 of the second intermediate frequency is simultaneously supplied to the second inputs of the multiplier 43 and 44, at the outputs of which harmonic voltages are generated
U ₄ (t) U ₃ ˙ cos (2 π f _g2 t + φ _g2 + Δ φ ₁ )
U ₅ (t) U ₃ ˙ cos (2 π f _g2 t + φ _g2 + Δ φ ₂ ), 0≅ t ≅T _c ,
where U ₃ =

K ₂ · U

U

K ₂ transmission coefficient of multipliers,

phase shifts that determine the direction to the radiation source.

K₃U₃·U

К₃ коэффициент передачи фазовых детекторов;
Δφ₁= 2π

sinβ,
Δφ₂= 2π

sinβ,
которые фиксируются блоками 49 и 50 регистрации.The indicated voltages are extracted by narrow-band filters 45 and 46 and fed to the first inputs of the phase detectors 47 and 48, the second inputs of which are supplied with voltage U _g2 (t) from the output of the local oscillator 37. Constant voltages are generated at the outputs of the phase detectors 47 and 48
U _n1 U _n ˙ sin Δ φ ₁ ,
U _n2 U _n ˙ sin Δ φ ₂ ,
where U _n =

K ₃ U ₃ · U

K ₃ transfer coefficient of phase detectors;
Δφ ₁ = 2π

sinβ
Δφ ₂ = 2π

sinβ
which are fixed by blocks 49 and 50 of the registration.

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<

При этом меньшая база d₁ образует грубую, но однозначную шкалу отсчета, а большая база d₂ точную, но неоднозначную шкалу отсчета. Время задержки τ_з линии 32 задержки выбирается таким, чтобы можно было зарегистрировать и проанализировать основные параметры обнаруженного ФМн-сигнала. По истечении этого времени напряжение с выхода линии 32 задержки поступает на вход сброса порогового блока 31 и сбрасывает его содержимое на нулевое значение. При этом блок 18 поиска переводится в режим поиска, а ключи 33 и 34 закрываются, т. е. возвращаются в свои исходные состояния. При обнаружении следующего ФМн-сигнала работа устройства происходит аналогичным образом.The following relationship is established between the relative dimensions of the measuring bases

<

<

In this case, a smaller base d ₁ forms a rough but unambiguous reference scale, and a large base d ₂ an accurate but ambiguous reference scale. The delay time τ _{s of} the delay line 32 is selected so that it is possible to register and analyze the main parameters of the detected PSK signal. After this time, the voltage from the output of the delay line 32 is supplied to the reset input of the threshold unit 31 and resets its contents to zero. In this case, the search unit 18 is transferred to the search mode, and the keys 33 and 34 are closed, that is, returned to their original states. When the next QPSK signal is detected, the device operates in a similar way.

 Having received at the reception point information about the frequency, modulating code and bearing of the vehicle being stolen, the traffic police take appropriate measures to detain the hijacker.

<

<

При этом меньшая база d₁ образует грубую, но однозначную шкалу отсчета, а большая база d₂ точную, но неоднозначную шкалу отсчета. Причем антенна 15 измерительного канала является общей для антенн 16 и 17 пеленгационных каналов. Предлагаемый пеленгатор позволяет также повысить чувствительность за счет свертки спектра принимаемых ФМн-сигналов, пеленгация источника излучения которых осуществляется на фиксированной частоте f_г2 кварцевого гетеродина 37, что исключает влияние нестабильности несущей частоты принимаемых ФМн-сигналов на результаты пеленгации. Следует также отметить, что предлагаемый пеленгатор инвариантен к виду модуляции принимаемых сложных сигналов. Кроме того, исключаются случайные выключения противоугонного устройства. Тем самым надежность противоугонного устройства повышается и расширяются его функциональные возможности.Thus, the proposed device in comparison with the prototype and other similar devices provides the transmission of alarm information over the air to the receiving point. Moreover, to transmit this information, a phase-shift key signal is used, which has increased resistance to interference, structural and energy stealth. Due to the convolution of the spectrum, the detection and structural selection of the FMN signal is carried out. Accurate and unambiguous direction finding of the vehicle is achieved through the use of three antennas and two measuring bases, between the relative sizes of which the following relationship is established

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In this case, a smaller base d ₁ forms a rough but unambiguous reference scale, and a large base d ₂ an accurate but ambiguous reference scale. Moreover, the antenna 15 of the measuring channel is common to the antennas 16 and 17 direction finding channels. The proposed direction finder can also increase sensitivity by convolving the spectrum of the received FMN signals, the direction finding of the radiation source is carried out at a fixed frequency f _{g2 of the} quartz heterodyne 37, which eliminates the influence of instability of the carrier frequency of the received FMN signals on the results of direction finding. It should also be noted that the proposed direction finder is invariant to the form of modulation of the received complex signals. In addition, accidental shutdowns of the anti-theft device are excluded. Thus, the reliability of the anti-theft device is increased and its functionality is expanded.

Claims (1)

 ANTI-THEFT DEVICE FOR A VEHICLE, which contains an intermittent signal generator located on the vehicle, one of the supply terminals of which is connected via the ignition key to the plus bus of the power source, an electromagnetic relay whose winding is connected to the output of the intermittent signal generator, and an NC contact is included in the ignition coil circuit in series with the ignition key, and a remote switch with a winding, one of the terminals of which is directly connected to the positive source bus power supply, and opening and closing contacts, the first of which is connected between the second supply terminal of the discontinuous signal generator and the negative bus of the power source, between which and one of the terminals of the remote switch winding, an operating mode switch is switched on, characterized in that vehicle current limiting resistor, LED, reed switch, master oscillator, phase manipulator and transmitter associated with the transmitting antenna, and located on the receiving unit This measuring channel consists of a series-connected search unit, a first local oscillator, a first mixer, the second input of which is connected to the output of the receiving antenna, an amplifier of the first intermediate frequency, a frequency doubler, a first spectral width meter, a comparison unit, whose second input is through a second spectrum width meter connected to the output of the amplifier of the first intermediate frequency, a threshold unit, the second input of which is connected to the output of the delay line, the first key, the second input of which is connected to the output of the amplifier a first intermediate frequency, a second mixer, the second input of which is connected to the output of the second local oscillator, an amplifier of the second intermediate frequency, a frequency detector, a trigger and the first registration unit, and of the second key, connected in series to the output of the first local oscillator, the second input of which is connected to the output of the threshold block , a frequency meter and a second registration unit, and the output of the threshold unit is additionally connected to the inputs of the delay line and the search unit, and two direction finding channels, each of which consists of a series-connected receiving antenna, a mixer, the second input of which is connected to the output of the first local oscillator of the measuring channel, an amplifier of the first intermediate frequency, a multiplier, the second input of which is connected to the output of the amplifier of the second intermediate frequency of the measuring channel, a narrow-band filter, a phase detector, the second input of which is connected with the output of the second local oscillator of the measuring channel, and the registration unit, while on the vehicle the remote switch is made with an additional wound winding and opening and closing contacts, and the operating mode switch in the form of a reed switch, with a positive bus of the power supply, directly connects one of the terminals of the current-limiting resistor and the second winding of the remote switch, and through the ignition key one of the supply terminals of the master oscillator, phase manipulator and transmitter, the closing and opening contacts of the second winding of the remote switch are connected between one of the terminals of the reed switch and the second conclusions of the first and second windings, respectively a test switch, the closing contact of the first winding of which is connected between the other terminal of the current-limiting resistor and the anode of the LED, the cathode of which and the other terminal of the reed switch are directly connected, and the other supply terminals of the master oscillator, phase manipulator and transmitter are connected to the negative bus of the power source via the opening contact of the first winding of the remote switch .

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