1. An anti-interference method for a laser seeker is characterized by comprising the following steps:

s1, receiving the synchronous signal transmitted by the irradiation end in real time;

s2, demodulating and detecting the synchronous signal, and decoding the synchronous signal into synchronous pulse;

and S3, controlling the wave gate signal according to the synchronous pulse, wherein the wave gate signal controls the switch of the laser detector.

2. The method of claim 1, wherein the synchronization signal comprises a synchronization pulse signal and a wireless synchronization signal;

the synchronizing pulse signal has a period T₀To T_nA random pulse sequence of pulse width τ;

the wireless synchronization signal has a period of T₀To T_nThe synchronization signal of (2);

the wireless synchronization signal is ahead of a random pulse sequence delta T;

extracting a random pulse sequence in the synchronous signal, and acquiring an accurate value of wireless transmission delay through calibration measurement;

and outputting a corresponding wave gate signal according to the pulse width tau in the synchronous pulse signal and the period of the wireless synchronous signal, wherein the period of the output wave gate signal is the same as that of the wireless synchronous signal, the opening time of the wave gate is advanced by delta T-delta T 'compared with the laser pulse sequence, the delta T is the advance of the wireless synchronous pulse relative to the laser emission pulse, and the delta T' is the accurate value of the wireless transmission delay.

3. The method of claim 1, wherein the laser pulses are first encoded by the illumination end when transmitting the synchronization signal.

4. The method of claim 1, wherein the irradiating end spreads the synchronization pulse signal with a pseudo-random code when transmitting the synchronization signal;

when the synchronous signal is demodulated and detected, pseudo-random code is used to carry out amplification and amplification on the synchronous pulse signal.

5. The method of claim 1, wherein when the irradiation end transmits the synchronization signal, a frequency synthesizer is used to perform frequency hopping on the synchronization pulse signal according to the frequency hopping frequency table;

when the synchronous signal is demodulated and detected, a frequency synthesizer is adopted to perform debounce on the synchronous pulse signal according to the frequency hopping frequency table.

6. An anti-interference device of a laser seeker is characterized by comprising a missile-borne antenna, a missile-borne wireless synchronous signal receiver, a wave gate controller and a laser detector;

the missile-borne antenna is used for receiving the synchronous signal transmitted by the irradiation end and sending the synchronous signal to the missile-borne wireless synchronous signal receiver;

the missile-borne wireless synchronous signal receiver is used for demodulating and detecting the synchronous signal, decoding the synchronous signal into synchronous pulses and sending the synchronous pulses to the wave gate controller;

the wave gate controller is used for controlling a wave gate signal according to the synchronous pulse, and the wave gate signal controls the switch of the laser detector;

the laser detector is used for detecting the target reflected laser.

7. The apparatus of claim 6, wherein the missile-borne antenna is configured to receive a synchronization signal from the ground illuminator and a synchronization signal from the airborne illuminator.

8. The apparatus of claim 6, wherein the missile-borne antenna is a microstrip conformal antenna or an inverted-F antenna, and the antenna frequency band is L, S, or C.

9. The apparatus of claim 6, wherein the laser detector samples the laser echo signal according to the gate signal outputted from the gate controller, and allows the laser detector to sample and resolve the laser echo signal in the gate whenever the gate signal is received, and outputs the resolved result to the pop-up control system.

10. The tamper-resistant device for a laser seeker of claim 6, wherein the laser detector is connected to a position marker, and the position marker is used for driving the laser detector to move and point to a target.

Background

The laser seeker is an important component of a laser seeking guidance weapon and is an object of continuous development and development of military strong countries in the world. The laser seeker receives laser diffusely reflected by the target to form a guidance instruction, and finally the guided missile is controlled to achieve tracking and accurate striking of the target. The semi-active homing guidance mode is that a laser beam is emitted by a laser device positioned on a carrier or the ground to irradiate a target, a semi-active laser seeker optical system receives a laser echo signal diffusely reflected by the target, an included angle of a missile sight line is calculated according to the position of a light spot on a detector, and a guidance and control instruction is generated by a missile-borne computer to guide a weapon to hit the target. Compared with the active laser seeker, the semi-active laser seeker has the advantages of simpler structure and cost, and has a great amount of application in actual combat.

However, as laser guided munitions continue to evolve, the means by which the laser is interfered with continues to increase. Technologies such as smoke screen interference, deceptive interference, and strong laser suppression interference are constantly being developed. In the field of existing laser countermeasure, in order to improve the anti-interference capability of a laser seeker, a more complex and encrypted coding mode is often adopted, and the damage of a laser alarm interference system to codes is avoided by combining the opening time of a wave gate; the target search algorithm may be optimized to avoid missing targets or being spoofed by decoys.

The disadvantages of these methods are: 1. a more complex and encrypted coding and wave gate opening time mode is adopted, complex algorithm support is needed, and once a password is leaked or identified by an enemy, the anti-interference effect is lost; 2. the target search algorithm needs complex algorithm support, and the target is searched and identified by means of big data deep learning and the like, a large amount of original data is needed for training, and the research and development cost is very high.

Disclosure of Invention

The invention aims to overcome the defects and provides an anti-interference method and device for a laser seeker, which do not need to increase a complex target detection search circuit and algorithm and have small increase of the total cost of a missile.

In order to achieve the purpose, the anti-interference method of the laser seeker comprises the following steps:

s1, receiving the synchronous signal transmitted by the irradiation end in real time;

s2, demodulating and detecting the synchronous signal, decoding the wireless synchronous signal into synchronous pulse;

and S3, controlling the wave gate signal according to the synchronous pulse, wherein the wave gate signal controls the switch of the laser detector.

The synchronous signal comprises a synchronous pulse signal and a wireless synchronous signal;

the synchronizing pulse signal has a period T₀To T_nA random pulse sequence of pulse width τ;

the wireless synchronization signal has a period of T₀To T_nThe synchronization signal of (2);

the wireless synchronization signal precedes the random pulse sequence at.

And extracting a random pulse sequence in the wireless synchronization signal, and acquiring an accurate value of wireless transmission delay through calibration measurement.

And outputting a corresponding wave gate signal according to the pulse width tau in the synchronous pulse signal and the period of the wireless synchronous signal, wherein the period of the output wave gate signal is the same as that of the wireless synchronous signal, the opening time of the wave gate is advanced by delta T-delta T 'compared with the laser pulse sequence, the delta T is the advance of the wireless synchronous pulse relative to the laser emission pulse, and the delta T' is the accurate value of the wireless transmission delay.

When the irradiation end transmits the synchronization signal, the laser pulse is encoded first.

When the irradiation end transmits a synchronous signal, spread spectrum is carried out on the synchronous pulse signal by adopting a pseudo-random code;

when the synchronous signal is demodulated and detected, pseudo-random code is used to carry out amplification and amplification on the synchronous pulse signal.

When the irradiation end transmits the synchronous signal, a frequency synthesizer is adopted to carry out frequency hopping on the synchronous pulse signal according to the frequency hopping frequency table;

when the synchronous signal is demodulated and detected, a frequency synthesizer is adopted to perform debounce on the synchronous pulse signal according to the frequency hopping frequency table.

An anti-interference device of a laser seeker comprises a missile-borne antenna, a missile-borne wireless synchronous signal receiver, a wave gate controller and a laser detector;

the missile-borne antenna is used for receiving the synchronous signal transmitted by the irradiation end and sending the synchronous signal to the missile-borne wireless synchronous signal receiver;

the missile-borne wireless synchronous signal receiver is used for demodulating and detecting the synchronous signal, decoding the synchronous signal into synchronous pulses and sending the synchronous pulses to the wave gate controller;

the wave gate controller is used for controlling a wave gate signal according to the synchronous pulse, and the wave gate signal controls the switch of the laser detector;

the laser detector is used for detecting the target reflected laser.

The missile-borne antenna is used for receiving the synchronous signals transmitted by the ground irradiators and the synchronous signals transmitted by the airborne irradiators.

The missile-borne antenna adopts a microstrip conformal antenna or an inverted F antenna, and the frequency band of the antenna adopts an L frequency band, an S frequency band or a C frequency band.

And the laser detector samples the laser echo signal according to the wave gate signal output by the wave gate controller, and allows the laser detector to sample and calculate the laser signal in the wave gate every time the wave gate signal is received, and outputs a calculation result to the missile-borne control system.

The laser detector is connected with the position marker, and the position marker is used for driving the laser detector to move and point to a target.

Compared with the prior art, the method of the invention receives the wireless synchronization signal transmitted by the irradiation end in real time; demodulating and detecting the wireless synchronous signal, and decoding the wireless synchronous signal into synchronous pulses; compared with an encoding anti-interference method, the method does not need to improve the complexity of encryption encoding and does not need to keep an encoding key secret; the invention can randomly generate synchronous signals in real time, so that the interference end is difficult to decode the coding rule; compared with a target search algorithm, the method does not need complex algorithm support and does not need data training.

Furthermore, when the synchronization information is transmitted, the anti-interference performance is further improved by adopting a frequency hopping method, and or the concealment is improved by burying the signal power under the noise in modes of spread spectrum and the like.

The device only needs to additionally install or multiplex the existing wireless synchronous signal receiver on the missile-borne equipment, receives the wireless synchronous signal sent by the laser irradiation end, controls the opening and closing of the laser detection wave gate through the wireless synchronous signal, and enables the wave gate to be completely controlled by the laser irradiation end, so that the random state of 'one-time-pad' is achieved without appointing the laser coding rule and the wave gate opening time in advance, and an enemy cannot crack the laser coding; meanwhile, the invention does not need to add complex target detection search circuit and algorithm, the total cost increase of the bomb is very small, and the device is simple, and the cost of the synchronous equipment is low, thereby further reducing the cost.

Drawings

FIG. 1 is a system diagram of the present invention;

fig. 2 is a schematic view of a laser irradiation system composed of the airborne irradiator and the missile-borne strapdown seeker in embodiment 1;

FIG. 3 is a timing chart of a pulse sequence and a synchronization signal according to embodiment 1;

FIG. 4 is a timing diagram of a transmitting end synchronization signal and a receiving end synchronization signal in embodiment 1;

FIG. 5 is a timing chart of an output gate signal of the gate controller according to embodiment 1;

FIG. 6 is a schematic diagram showing the structure of a laser seeker device of example 2;

FIG. 7 is a control block diagram of embodiment 3;

FIG. 8 is a control block diagram of embodiment 4;

fig. 9 is a control block diagram of embodiment 5.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Referring to fig. 1, an anti-jamming device of a laser seeker comprises a missile-borne antenna, a missile-borne wireless synchronous signal receiver, a wave gate controller and a laser detector;

the missile-borne antenna is used for receiving the synchronous signal transmitted by the irradiation end and sending the synchronous signal to the missile-borne wireless synchronous signal receiver;

the missile-borne wireless synchronous signal receiver is used for demodulating and detecting the synchronous signal, decoding the synchronous signal into synchronous pulses and sending the synchronous pulses to the wave gate controller;

the wave gate controller is used for controlling a wave gate signal according to the synchronous pulse, and the wave gate signal controls the switch of the laser detector;

the laser detector is used for detecting the target reflected laser.

An anti-interference method of a laser seeker comprises the following steps:

s1, receiving the wireless synchronization signal transmitted by the irradiation end in real time;

s2, demodulating and detecting the synchronous signal, and decoding the synchronous signal into synchronous pulse;

and S3, controlling the wave gate signal according to the synchronous pulse, wherein the wave gate signal controls the switch of the laser detector.

Example 1:

referring to fig. 2, the laser guidance system of the present embodiment is composed of an airborne irradiator and a missile-borne strapdown guidance head. A missile-borne strapdown seeker device (hereinafter referred to as a seeker) consists of a missile-borne antenna, a wireless synchronous signal receiver, a wave gate controller and a laser detector.

According to the synchronous pulse signal transmitter, on the one hand, a period of T is generated₀To T_nAnd the random pulse sequence with the pulse width tau is sent to an external synchronous input port of the airborne irradiator, the airborne irradiator generates laser pulses according to the sequence and irradiates a target, the pulse width tau can be set according to a system, and the system tau is 15 +/-5 ns.

On the other hand, the synchronous signal transmitter has a generation period of T₀To T_nThe synchronous signal is radiated to the space wirelessly, and the missile-borne strapdown seeker opens the wave gate in advance. The synchronization signal has a specific timing relationship with the random pulse sequence, namely: the synchronization signal is ahead of the pulse sequence Δ T, which can be set according to the system, which is set to 1 ms. The timing relationship between the random pulse sequence at the transmitting end and the synchronization signal is shown in fig. 3.

The seeker missile-borne antenna is used for receiving the wireless signals transmitted by the wireless synchronous signal transmitter at the airborne irradiator end in real time and transmitting the received wireless signals to the wireless synchronous signal receiver through the radio frequency feeder line. Under the condition that the aerodynamic characteristics of the single body are not influenced, the missile-borne antenna can adopt the forms of a microstrip conformal antenna or an inverted F antenna and the like, and the frequency band of the antenna can adopt the frequency band of L, S, C and the like.

As shown in fig. 4, the wireless synchronization signal receiver is configured to perform filtering, low-noise amplification and down-conversion on a radio frequency signal received by the missile-borne antenna to a baseband, demodulate and restore a synchronization signal generated by the transmitting end, and send the synchronization signal to the gate controller in a TTL or RS-422 level format. The wireless synchronous signal receiver consists of a synchronous signal receiving board, and an onboard radio frequency agility transceiver chip AD9361 and an FPGA. AD9361 completes the down conversion of the radio frequency signal, and the FPGA extracts the pulse sequence in the baseband signal. The receiving end synchronous signal lags behind the transmitting end synchronous signal by delta T ', the delta T ' is wireless transmission delay, an accurate value can be obtained through calibration measurement, and the delta T ' needs to be smaller than the delta T.

As shown in fig. 5, the wave gate controller performs windowing indication on the laser detection according to the received synchronization signal, outputs a corresponding wave gate signal, and the period of the output wave gate signal is completely consistent with that of the synchronization signal at the transmitting end, i.e. T₀To T_n. The opening time of the wave gate is advanced by delta T-delta T' compared with the laser pulse sequence, the wave gate signal width lambda is set according to a system, and the lambda of the system is set to be 1-100 us. A gate timing diagram for the output of the gate controller.

The laser detector samples the laser echo signal according to the wave gate signal output by the wave gate controller, and when the wave gate signal is received, the detector is allowed to sample and solve the laser signal in the wave gate, and the calculation result is output to the missile-borne control system. The laser detector does not need to store and bind the decoding key, and only needs to open the wave gate according to the wireless connection synchronous signal for sampling, so that the pulse period can be completely and randomly adapted, the enemy laser reconnaissance alarm system cannot decode the code pattern, and the anti-interference purpose is achieved.

Example 2:

referring to fig. 6, the missile-borne frame laser seeker device is composed of a missile-borne antenna, a missile-borne wireless synchronous signal receiver, a wave gate controller, a position marker and a laser detector.

The wireless synchronization signal comes from the laser irradiation end, and can be emitted by a ground irradiator or an airborne irradiator. The wireless synchronization signal has the function of providing a synchronization signal for the missile-borne wireless synchronization signal receiver.

The missile-borne antenna is used for receiving the wireless synchronization signal and outputting the wireless synchronization signal to the missile-borne wireless synchronization signal receiver. The form of the missile-borne antenna can be selected according to the structure and performance indexes of the missile body, and the missile-borne antenna can be a conformal antenna, a patch antenna, an inverted-F antenna, a microstrip antenna and the like.

The missile-borne wireless synchronous signal receiver has the functions of demodulating and detecting the wireless synchronous signals and decoding the wireless synchronous signals into synchronous pulses.

The gate controller is used for controlling the detector to be switched on and off by using a gate signal, and an input source of the gate control signal in the invention is synchronous pulse, namely the gate is controlled by using the synchronous pulse.

The position marker has the function of driving the detector to move and point to a target, and meanwhile, isolating projectile body disturbance.

The laser detector is used for detecting the target reflected laser.

The anti-interference implementation mode described in embodiment 1 is also suitable for the frame laser seeker device, and the universality is strong.

Example 3:

referring to fig. 7, the gate signal is triggered by the synchronization pulse, in conjunction with the encoding.

In order to improve the anti-interference capability of the laser pulse code pattern, the laser pulse at the irradiation end is encoded and triggered by the synchronous pulse signal, and the receiving end decodes according to the synchronous pulse signal. The emitter of the irradiator can select the coding mode at will according to the needs, and the missile-borne seeker does not need a complex hardware platform for decoding, thereby greatly reducing the design difficulty. And because the coding mode of the transmitting terminal can be selected at will, the enemy reconnaissance system is difficult to decode in the battle time, thereby playing the anti-interference effect.

The encoding mode has various options, such as an M sequence, a GOLD sequence, etc., and the generating polynomial and the level can be arbitrarily set according to requirements without considering the decoding complexity.

Example 4:

referring to fig. 8, the wireless synchronization signal is spread with a spreading code.

In order to improve the anti-interference capability during wireless transmission of the synchronous pulse signals and avoid interference of a wireless channel intercepted by an enemy reconnaissance system, a spread spectrum code is added during wireless transmission. When the irradiation end transmits a wireless synchronous signal, spread spectrum is carried out on the synchronous pulse signal by adopting a pseudo-random code; when the wireless synchronization signal is demodulated and detected, pseudo-random codes are adopted to carry out receiving and spreading on the synchronization pulse signal.

Example 5:

referring to fig. 9, the wireless synchronization signal is frequency hopped using a frequency hopping code.

In order to further improve the anti-interference capability during wireless transmission of the synchronous pulse signals and realize the inhibition effect on broadband interference signals, a frequency hopping mechanism is added during wireless transmission. When the irradiation end transmits the wireless synchronization signal, a frequency synthesizer is adopted to carry out frequency hopping on the synchronization pulse signal according to the frequency hopping frequency table; when the wireless synchronization signal is demodulated and detected, the frequency synthesizer is adopted to perform debounce on the synchronization pulse signal according to the frequency hopping frequency table.