Invisible coding anti-interference laser coding and decoding system based on sub-pulse phenomenon

Abstract

The invention belongs to the technical field of invisible coding and anti-interference, and particularly relates to an invisible coding anti-interference laser coding and decoding system based on a sub-pulse phenomenon, which comprises a laser transmitting module, a signal processing module and a pulse information comparison unit. The passive Q-switched laser generates a main pulse and a sub-pulse with a preset double-peak interval, a main pulse signal delayer is used for coordinating a double-pulse time sequence, differential gain amplification is carried out on the main pulse and the sub-pulse, double-peak interval information is reconstructed through electric signal synthesis, an actual interval is compared with preset encoding information, and the time sequence of the main pulse and the sub-pulse is calculated. An anti-interference function is realized, laser stability is guaranteed through a side pumping structure in combination with a temperature compensation mechanism, concealment and anti-deception capability of coding and decoding signals are enhanced by using a double-peak interval invisible coding characteristic, and the system has the advantages of high anti-interference performance, dynamic and adjustable coding, high environmental adaptability and the like. The problem that a traditional laser signal is easy to intercept or interfere can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser encoding and decoding and anti-interference, and specifically relates to a stealth encoding anti-interference laser encoding and decoding system based on the sub-pulse phenomenon. Background Art

[0002] Laser encoding and decoding technology can achieve precise target positioning by encoding laser signals, and plays a key role in fields such as laser encoding and decoding, UAV navigation, and reconnaissance. However, the encoded and decoded laser signals are vulnerable to active interference by the enemy or the influence of complex environmental noise, resulting in a decrease or even failure of the encoding and decoding accuracy. Therefore, the reliability of anti-interference encoding technology has become the core challenge.

[0003] Currently, the mainstream anti-interference methods are mainly based on single-pulse energy encoding or fixed-frequency modulation. For example, the encoding scheme based on pulse amplitude modulation distinguishes target signals from interference by presetting an energy threshold; the pulse repetition frequency encoding is used to transmit encoding and decoding information using a fixed interval sequence. However, the above methods rely on static encoding rules, and the enemy can quickly crack them through spectrum analysis or energy interception, and lack the ability to adapt to dynamic environmental disturbances (such as atmospheric turbulence and high-speed target movement) in real time.

[0004] In traditional technologies, the static characteristics of single-pulse encoding make it unable to cope with complex electromagnetic interference. For example, fixed-frequency modulation is easily covered by high-repetition-rate jammers, and amplitude encoding is easily polluted by background noise; existing systems lack a compensation mechanism for signal propagation delay drift, resulting in the accumulation of time deviations between the preset encoding and the actually received signal, seriously reducing the reliability of encoding and decoding. In addition, the dynamic attenuation of the reflected signal of high-speed targets and the change of the optical path further exacerbate the difficulty of encoding matching.

[0005] In recent years, some studies have tried to use double-pulse interval encoding to improve concealment, and transmit encoding information through the time interval between the main pulse and the sub-pulse. However, the existing schemes have significant defects: the double-pulse interval mostly uses a fixed range or a pseudo-random sequence, and the encoding rule can still be cracked by statistical analysis; the signal processing relies on software algorithms to analyze the interval, resulting in a relatively high anti-interference decision delay (>10 ms); at the same time, the system does not consider the dynamic deviation of the interval caused by laser temperature drift or pump fluctuation, and lacks the ability of real-time compensation.

[0006] Currently, there is an urgent need for a laser encoding and decoding solution with dynamic anti-interference, high concealment, and environmental adaptability. For this reason, the present invention proposes a stealth encoding anti-interference system based on the passive Q-switching sub-pulse phenomenon, and solves the problems of easy cracking of encoding, anti-interference lag, and environmental sensitivity in traditional technologies through the dynamic encryption and real-time compensation mechanism of the double-pulse interval. Summary of the Invention

[0007] (I) Technical Problems to be Solved

[0008] In view of the deficiencies of the prior art, the present invention provides an anti-interference laser encoding and decoding system with invisible coding based on the sub-pulse phenomenon, which solves the problems raised in the above background art.

[0009] (II) Technical Solution

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] An anti-interference laser encoding and decoding system with invisible coding based on the sub-pulse phenomenon, comprising: a laser emission system, a signal processing system and a pulse information comparison unit;

[0012] The laser emission system includes a total reflection mirror M1, a Nd:YAG crystal, a passive Q-switch, an output mirror M2, a pulse interval adjustment and signal transmission module, an LD pumping array, an LD pumping power supply module, a temperature acquisition module, and a pulse width compensator.

[0013] The signal processing system includes: a photoelectric signal converter, a main pulse signal delay device, a main pulse gain amplifier, a sub-pulse gain amplifier, and a main and sub-pulse electrical signal synthesizer.

[0014] The laser emission system adopts a side pumping structure, wherein the total reflection mirror M1 is located at the rear end of the laser emission system, and the Nd:YAG crystal is adjacent to the front of the total reflection mirror M1; the passive Q-switch and the output mirror M2 are arranged in sequence along the optical path direction to form a resonant cavity; the LD pumping array surrounds the side of the Nd:YAG crystal, and the LD pumping power supply module is electrically connected to the LD pumping array and is located at the bottom of the laser emission system; the temperature acquisition module is installed on the side surface of the Nd:YAG crystal and is connected to the pulse width compensator through a feedback circuit.

[0015] The pulse interval adjustment and signal transmission module is integrated at the control end of the laser emission system and is connected to the passive Q-switch through a high-speed communication interface, and is used for presetting and adjusting the double-peak interval information of the main pulse and the sub-pulse.

[0016] The signal processing system is located at the front end of the optical path output direction of the laser emission system; the photoelectric signal converter is installed at the input end of the signal processing system and is aligned with the optical path of the laser emission system; the main pulse signal delay device is adjacent to the output end of the photoelectric signal converter, the main pulse gain amplifier and the sub-pulse gain amplifier are respectively connected to the main pulse signal delay device through independent circuits, and the main and sub-pulse electrical signal synthesizer is located at the rear ends of the main pulse gain amplifier and the sub-pulse gain amplifier.

[0017] The pulse information comparison unit is connected to the main and sub-pulse electrical signal synthesizer through a data line.

[0018] Optionally, the passive Q-switch adopts a saturable absorber material Cr 4+: YAG, initial transmittance 30% - 70%; recovery time < 10 ns, modulation depth 5% - 30%.

[0019] Optionally, the optoelectronic signal converter uses a PIN photodiode with a quantum efficiency > 80%, a dark current < 1 nA, a response time < 2 ns, and a wavelength range of 400 - 1100 nm;

[0020] Optionally, the main pulse gain amplifier and the sub - pulse gain amplifier adopt a differential amplifier circuit structure. The main pulse gain amplifier has a dynamic range of 20 - 60 dB, the sub - pulse gain amplifier has a dynamic range of 10 - 40 dB, and the gain difference between the two is ≥ 15 dB; the bandwidth covers 100 MHz to 3 GHz.

[0021] Optionally, the pulse width compensator uses a digital PID controller with a response time < 10 μs and a compensation accuracy of ±0.1 ns;

[0022] Optionally, the main - sub pulse electrical signal synthesizer adopts time - domain interleaving technology, and the measurement resolution of the double - peak interval is improved by an interpolation algorithm ≤ 100 ps, and the sampling rate ≥ 2 GS / s.

[0023] Optionally, the LD pump array adopts wavelength - locking technology, and the pump wavelength is stabilized within the range of 808.5 nm ± 0.2 nm through a volume Bragg grating (VBG).

[0024] Optionally, the pulse information comparison unit integrates a chaotic encryption algorithm to perform non - linear transformation encryption on the preset double - peak interval information, and the key update frequency > 100 Hz. It is equipped with a digital correlator with a comparison speed > 1 million times per second, and the tolerance threshold can be set in the range of ±5% - ±20%.

[0025] Optionally, the temperature acquisition module uses a distributed fiber Bragg grating sensor, with 5 - 20 temperature measurement points arranged along the axis of the Nd:YAG crystal, and the spatial resolution < 2 mm.

[0026] Optionally, the main pulse signal delay unit adopts a programmable delay line (PDL) technology, supporting precise delay adjustment with a 0.1 ns step, and the jitter < 5 ps RMS. The delay accuracy is ±0.5 ns, and the maximum delay is 50 ns.

[0027] Optionally, the output mirror M2 adopts a thermally - induced deformation compensation design, with a piezoelectric ceramic actuator integrated on the back of the mirror to dynamically adjust the radius of curvature according to temperature changes, and the compensation range is ±0.5 mm.

[0028] Optionally, the laser emission system integrates a beam pointing stabilization device, including a fast steering mirror (FSM) and a position - sensitive detector (PSD), with a pointing stabilization accuracy < 5 μrad.

[0029] Optionally, the pulse interval adjustment and signal transmission module adopts a cascaded structure of an acousto-optic modulator (AOM) and an electro-optic modulator (EOM) to achieve precise control of the pulse interval in the range of 0.1 ns - 100 μs.

[0030] Optionally, the signal processing system is equipped with an adaptive filter bank, which can automatically suppress the background light interference frequency band, and the signal-to-noise ratio is increased by > 20 dB.

[0031] Optionally, the LD pump power supply module adopts a constant current drive mode, with a current stability of < ±0.5% and a pulse rise time of < 5 μs; it integrates a pulse shaping function and supports three pump waveforms: trapezoidal wave, Gaussian wave, and square wave, and the adjustable range of the rise / fall edge is 1 - 50 μs.

[0032] Optionally, the pulse information comparison unit is equipped with a deep learning accelerator, which uses a convolutional neural network (CNN) to identify the time-frequency domain characteristics of interference pulses, and the misjudgment rate is < 0.1%.

[0033] Optionally, the main pulse gain amplifier adopts an automatic gain control (AGC) technology, which dynamically adjusts the gain coefficient according to the input signal strength, and the dynamic range is extended to 80 dB.

[0034] (III) Beneficial Effects

[0035] Compared with the prior art, the present invention provides a stealth coding anti-interference laser encoding and decoding system based on the sub-pulse phenomenon, having the following beneficial effects:

[0036] In the present invention, the preset interval coding characteristics of the main pulse and the sub-pulse are generated through the sub-pulse characteristics of the passive Q-switching laser, and different magnification signal enhancements are performed on the main pulse and the sub-pulse by using a differential gain amplification strategy to form a composite coding structure with double encryption in time domain and amplitude. Since the interference signal cannot synchronously reproduce the dynamic gain difference and the encrypted evolution interval rule, the actual interval information deviates significantly from the preset coding, thereby improving the anti-interference recognition ability.

[0037] The influence of environmental temperature fluctuations on the pulse timing is offset in real time through temperature compensation closed-loop control to ensure the stability of the coding interval. The coordinated operation of the main pulse delay control and the synthesizer realizes high-precision signal reconstruction, and combined with the intelligent recognition algorithm, it actively filters out repeated interference patterns, and can still maintain high reliability in a complex electromagnetic environment.

[0038] Through the collaborative innovation of dynamic coding rules, differential signal enhancement and environment adaptive technology, the problems of single coding and easy interception and simulation of traditional laser encoding and decoding are solved, and the anti-interference ability and encoding and decoding accuracy in the battlefield environment are significantly improved. Description of the Drawings

[0039] Figure 1 Optical path diagram of an anti-interference laser encoding and decoding system with invisible coding based on sub-pulse phenomenon according to an embodiment of the present invention;

[0040] Figure 2 Technical flow chart of an anti-interference laser encoding and decoding system with invisible coding based on sub-pulse phenomenon according to an embodiment of the present invention.

[0041] In the figure, the structural components represented by each reference numeral are as follows: including 1. Laser emission system; 2. Total reflection mirror M1; 3. Nd:YAG crystal; 4. Passive Q-switch; 5. Output mirror M2; 6. Pulse interval adjustment and signal transmission module; 7. LD pumping array; 8. LD pumping power supply module; 9. Temperature acquisition module; 10. Pulse width compensator; 11. Signal processing system; 12. Photoelectric signal converter; 13. Main pulse signal delay device; 14. Main pulse gain amplifier; 15. Sub-pulse gain amplifier; 16. Main and sub-pulse electrical signal synthesizer; 17. Pulse information comparison unit. Specific implementation manner

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] Embodiment

[0044] As Figure 1-2 shown, an anti-interference laser encoding and decoding system with invisible coding based on sub-pulse phenomenon proposed in an embodiment of the present invention:

[0045] As Figure 1 including: laser emission system 1, signal processing system 11 and pulse information comparison unit 17. The laser emission system 1 includes total reflection mirror M1 2; 2. Nd:YAG crystal 3, passive Q-switch 4, output mirror M2 5, pulse interval adjustment and signal transmission module 6, LD pumping array 7, LD pumping power supply module 8, temperature acquisition module 9, pulse width compensator 10. The signal processing system 11 includes: photoelectric signal converter 12, main pulse signal delay device 13, main pulse gain amplifier 14, sub-pulse gain amplifier 15, main and sub-pulse electrical signal synthesizer 16, wherein:

[0046] The laser emission system 1 adopts a side-pumping structure, where the total reflection mirror M12 is located at the rear end of the laser emission system 1, and the Nd:YAG crystal 3 is adjacent to the front of the total reflection mirror M12; the passive Q-switch 4 and the output mirror M25 are arranged in sequence along the optical path direction to form a resonant cavity; the LD pumping array 7 surrounds the side of the Nd:YAG crystal 3, and the LD pumping power supply module 8 is electrically connected to the LD pumping array 7 and is located at the bottom of the laser emission system 1; the temperature acquisition module 9 is installed on the side surface of the Nd:YAG crystal 3 and is connected to the pulse width compensator 10 through a feedback circuit;

[0047] The pulse interval adjustment and signal transmission module 6 is integrated at the control end of the laser emission system 1 and is connected to the passive Q-switch 4 through a high-speed communication interface, and is used for presetting and adjusting the double-peak interval information of the main pulse and the sub-pulse;

[0048] The signal processing system 11 is located at the front end of the optical path output direction of the laser emission system 1; the optoelectronic signal converter 12 is installed at the input end of the signal processing system 11 and is aligned with the optical path of the laser emission system 1; the main pulse signal delay device 13 is adjacent to the output end of the optoelectronic signal converter 12, and the main pulse gain amplifier 14 and the sub-pulse gain amplifier 15 are respectively connected to the main pulse signal delay device 13 through independent circuits, and the main and sub-pulse electrical signal synthesizer 16 is located at the rear ends of the main pulse gain amplifier 14 and the sub-pulse gain amplifier 15.

[0049] The pulse information comparison unit 17 is connected to the main and sub-pulse electrical signal synthesizer 16 through a data line.

[0050] Optionally, the passive Q-switch 4 adopts a saturable absorber material including Cr 4+ :YAG, with an initial transmittance of 35%; a recovery time of 5 ns, and a modulation depth of 15%.

[0051] Optionally, the optoelectronic signal converter 12 adopts a PIN photodiode, with a quantum efficiency of 90%, a dark current of 0.5 nA, a response time of 1 ns, and a wavelength range of 400 - 1100 nm;

[0052] Optionally, the main pulse gain amplifier 14 and the sub-pulse gain amplifier 15 adopt a differential amplification circuit structure. The main pulse gain amplifier 14 has a dynamic range of 20 - 60 dB, the sub-pulse gain amplifier 15 has a dynamic range of 10 - 40 dB, and the gain difference between the two is ≥15 dB; the bandwidth covers 100 MHz to 3 GHz.

[0053] Optionally, the pulse width compensator 10 adopts a digital PID controller, with a response time <10 μs and a compensation accuracy of ±0.1 ns;

[0054] Optionally, the master sub-pulse electrical signal synthesizer 16 adopts time-domain interleaving technology and improves the double-peak interval measurement resolution ≤ 100 ps through an interpolation algorithm, with a sampling rate ≥ 2 GS / s.

[0055] Optionally, the LD pump array 7 adopts wavelength locking technology and stabilizes the pump wavelength within the range of 808.5 nm ± 0.2 nm through a volume Bragg grating (VBG).

[0056] Optionally, the pulse information comparison unit 17 integrates a chaotic encryption algorithm to perform non-linear transformation encryption on the preset double-peak interval information, with a key update frequency > 100 Hz. It is equipped with a digital correlator, with a comparison speed > 1 million times per second, and the tolerance threshold can be set in the range of ±5% - ±20%.

[0057] Optionally, the temperature acquisition module 9 adopts a distributed fiber Bragg grating sensor, with 5 - 20 temperature measurement points arranged along the axis of the Nd:YAG crystal, and the spatial resolution < 2 mm.

[0058] Optionally, the main pulse signal delay unit 13 adopts programmable delay line (PDL) technology, supports precise delay adjustment with a 0.1 ns step, and the jitter < 5 ps RMS. The delay accuracy is ±0.5 ns, and the maximum delay is 50 ns.

[0059] Optionally, the output mirror M2 5 adopts a thermally induced deformation compensation design, integrates a piezoelectric ceramic actuator on the back of the lens, and dynamically adjusts the radius of curvature according to temperature changes, with a compensation range of ±0.5 mm.

[0060] Optionally, the laser emission system 1 integrates a beam pointing stabilization device, including a fast steering mirror (FSM) and a position sensitive detector (PSD), with a pointing stabilization accuracy < 5 μrad.

[0061] Optionally, the pulse interval adjustment and transmission signal module 6 adopts a cascaded structure of an acousto-optic modulator (AOM) and an electro-optic modulator (EOM) to achieve precise control of the pulse interval in the range of 0.1 ns - 100 μs.

[0062] Optionally, the signal processing system 11 is equipped with an adaptive filter bank, which can automatically suppress the background light interference frequency band, and the signal-to-noise ratio is increased by > 20 dB.

[0063] Optionally, the LD pump power module 8 adopts a constant current drive mode, with a current stability < ±0.5%, a pulse rise time < 5 μs; it integrates a pulse shaping function and supports three pump waveforms: trapezoidal wave, Gaussian wave, and square wave, with an adjustable range of 1 - 50 μs for the rise / fall edge.

[0064] Optionally, the pulse information comparison unit 17 is equipped with a deep learning accelerator, which uses a convolutional neural network (CNN) to identify the time-frequency domain characteristics of interference pulses, and the misjudgment rate is <0.1%.

[0065] Optionally, the main pulse gain amplifier 14 adopts an automatic gain control (AGC) technology, dynamically adjusts the gain coefficient according to the input signal intensity, and expands the dynamic range to 80 dB.

[0066] On the other hand, the present invention also provides a stealth coding anti-interference laser encoding and decoding method based on the sub-pulse phenomenon. The method includes:

[0067] Through the periodic switching action of the passive Q-switch 4, main pulses and accompanying sub-pulses are excited in the resonant cavity; the pulse interval adjustment and signal transmission module 6 dynamically sets the double-peak interval between the main pulse and the sub-pulse based on a preset coding rule to form a time-domain stealth feature; the LD pumping array 7 injects energy into the Nd:YAG crystal 3 in a side-pumping manner, and at the same time, the temperature acquisition module 9 monitors the thermal state of the crystal in real time, and dynamically compensates the pumping power through the pulse width compensator 10 to ensure the time stability of the laser output; the preset double-peak interval information is transmitted through an encrypted communication link to the pulse information comparison unit 17 for storage as the reference data for subsequent anti-interference verification;

[0068] The emitted laser pulse sequence is converted into an electrical signal by the optoelectronic signal converter 12, and the main pulse signal delay unit 13 performs timing control on the main pulse to decouple its timing from the gain amplification processing timing of the sub-pulse; the main pulse gain amplifier 14 performs high-magnification amplification on the main pulse, and the sub-pulse gain amplifier 15 adopts a differential gain strategy to make the amplitude characteristics of the main pulse and the sub-pulse consistent; the main and sub-pulse electrical signal synthesizer 16 synchronizes the two signals in the time domain and superimposes the waveforms to reconstruct an electrical signal with a complete double-peak interval feature, and extracts the actual interval information for subsequent analysis;

[0069] The pulse information comparison unit 17 performs multi-level anti-interference verification: first, perform time-domain correlation analysis on the reconstructed double-peak interval, calculate the time matching degree with the preset coding information, and screen out valid signals that meet the dynamic tolerance threshold; for signals with failed matching, trigger the interference marking mechanism and start signal traceability analysis;

[0070] The closed-loop control system composed of the temperature acquisition module 9 and the pulse width compensator 10 cancels the pulse time jitter caused by the crystal temperature fluctuation in real time; the LD pumping power supply module 8 adopts an adaptive constant current mode, combines the crystal thermal lens effect compensation algorithm, and maintains the spatial uniformity of the pumping energy; the coordinated control of the main pulse signal delay unit 13 and the gain amplifiers 14 / 15 ensures the time domain accuracy of the double-peak interval coding and the consistency of the amplitude characteristics;

[0071] The pulse interval adjustment and signal transmission module 6 periodically updates the double-peak interval coding rule according to a preset encryption algorithm, and combines the timing offset strategy of the main pulse signal delay device 13 to achieve the time-domain dynamic evolution of coding features; the differential amplification ratios of the main pulse and sub-pulse gain amplifiers 14 / 15 are synchronously adjusted to superimpose the second-layer encryption feature in the amplitude dimension, forming a time-domain-amplitude dual-encryption composite coding structure, which significantly improves the anti-interception and anti-cracking capabilities of the encoded and decoded signals;

[0072] The first-level verification is based on the time-domain matching analysis of the double-peak interval to quickly filter out interference signals that significantly deviate from the preset range; the second-level verification identifies abnormal energy distribution of counterfeit signals through the amplitude ratio feature analysis of the main pulse and sub-pulse; the pulse information comparison unit 17 integrates a pattern recognition algorithm to perform feature learning and active shielding on continuously occurring fixed-interval repeated attack signals; when complex multi-source interference is detected, an adaptive signal reconstruction algorithm is activated to extract effective coding features from the mixed signals to ensure the reliability of the encoding and decoding instructions and the adaptability to the battlefield environment.

[0073] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An anti-jamming laser encoding and decoding system with stealth encoding based on the sub-pulse phenomenon, characterized in that, Including: A laser emission system (1), a signal processing system (11), and a pulse information comparison unit (17); The laser emission system (1) includes a total reflection mirror M1 (2), a Nd:YAG crystal (3), a passive Q-switch (4), an output mirror M2 (5), a pulse interval adjustment and signal transmission module (6), an LD pumping array (7), an LD pumping power supply module (8), a temperature acquisition module (9), and a pulse width compensator (10); The laser emission system (1) adopts a side pumping structure, and the Nd:YAG crystal (3) is adjacent to the front of the total reflection mirror M1 (2); the passive Q-switch (4) and the output mirror M2 (5) are arranged in sequence along the optical path direction to form a resonant cavity; the LD pumping array (7) is installed around the surface of the Nd:YAG crystal (3), the LD pumping power supply module (8) is electrically connected to the LD pumping array (7), the temperature acquisition module (9) is installed on the side surface of the Nd:YAG crystal (3) and is connected to the pulse width compensator (10) through a feedback circuit, and the pulse width compensator (10) is electrically connected to the LD pumping power supply module (8); The pulse interval adjustment and signal transmission module (6) is integrated at the control end of the laser emission system (1) and is connected to the passive Q-switch (4) through a high-speed communication interface, and is used for presetting and adjusting the double-peak interval information of the main pulse and the sub-pulse; The signal processing system (11) includes an optoelectronic signal converter (12), a main pulse signal delay unit (13), a main pulse gain amplifier (14), a sub-pulse gain amplifier (15), and a main and sub-pulse electrical signal synthesizer (16); The signal processing system (11) is located at the front end of the optical path output direction of the laser emission system (1); The optoelectronic signal converter (12) is installed at the input end of the signal processing system (11) and is aligned with the optical path of the laser emission system (1); the main pulse signal delay unit (13) is adjacent to the output end of the optoelectronic signal converter (12), the sub-pulse gain amplifier (15) is electrically connected to the main pulse signal delay unit (13), and both the main pulse gain amplifier (14) and the sub-pulse gain amplifier (15) are electrically connected to the main and sub-pulse electrical signal synthesizer (16); The pulse information comparison unit (17) is connected to the main and sub-pulse electrical signal synthesizer (16) through a data line.

2. The anti-interference laser encoding and decoding system based on sub-pulse phenomenon according to claim 1, characterized in that: The doping concentration of the Nd:YAG crystal (3) is 0.6% - 1.2%, and the length is 20 - 50 mm; the passive Q-switch (4) uses a Cr 4 ⁺:YAG crystal with an initial transmittance of 30% - 70%; the temperature acquisition module (9) is a patch-type thermocouple with a measurement accuracy of ±0.5 °C, forming a closed-loop control with the pulse width compensator (10), and the compensation range is ±5 ns / °C; the output mirror M2 (5) has a transmittance of 20% - 40% and a radius of curvature of 100 - 300 mm.

3. A stealth coding anti-interference laser encoding and decoding system based on the sub-pulse phenomenon according to claim 1, characterized in that: The LD pumping array (7) emits light with a wavelength of 808 nm ± 3 nm, a peak power of 100 - 500 W, and a pulse width of 100 - 300 μs; the pulse width compensator (10) adopts a digital PID controller with a response time < 10 μs and a compensation accuracy of ±0.1 ns; the pulse interval adjustment and signal transmission module (6) has a continuously adjustable interval range of 0.1 - 10 μs and an adjustment step size ≤ 10 ns.

4. A stealth coding anti-jamming laser encoding and decoding system based on the sub-pulse phenomenon according to claim 1, characterized in that: The optoelectronic signal converter (12) is a photodiode with a response time < 2 ns and a wavelength range of 400 - 1100 nm; the main pulse gain amplifier (14) has a dynamic range of 20 - 60 dB, the sub-pulse gain amplifier (15) has a dynamic range of 10 - 40 dB, and the gain difference between the two is ≥ 15 dB; the main pulse signal delay unit (13) has a delay accuracy of ± 0.5 ns and a maximum delay of 50 ns.

5. A stealth coding anti-interference laser encoding and decoding system based on the sub-pulse phenomenon according to claim 1, characterized in that: The main and sub-pulse electrical signal synthesizer (16) is implemented using a high-speed FPGA with a sampling rate ≥ 2 GS / s and a time resolution ≤ 100 ps; the pulse information comparison unit (17) is equipped with a digital correlator with a comparison speed > 1 million times per second, and the tolerance threshold can be set in the range of ± 5% - ± 20%.

6. A stealth encoding anti-jamming laser encoding and decoding system based on the sub-pulse phenomenon according to claim 1, characterized in that: The LD pump power supply module (8) adopts a constant current drive mode with a current stability < ± 0.5% and a pulse rise time < 5 μs; the high-speed communication interface uses a fiber optic transmission protocol with a data transmission rate ≥ 1 Gbps and a transmission delay < 10 μs; the system supports a dynamic coding mode and can adjust the double-peak interval in real time within the range of 1 - 100 μs with a 1 μs step update.

7. A stealth coding anti-jamming laser encoding and decoding system based on the sub-pulse phenomenon according to claim 1, characterized in that: The first-level comparison tolerance range is ± 5% of the preset interval, and the second-level verification pulse amplitude ratio is in the range of 2:1 to 10:1; the pulse information comparison unit (17) integrates a pattern recognition algorithm and can identify and eliminate interference signals with a repeated interval > 3 times.

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