Long-distance laser hidden distance measurement method and system and readable storage medium

Abstract

The invention discloses a long-distance laser hidden distance measurement method and system and a readable storage medium, and the method comprises the steps: reading laser emission data of an entity detector through a control processing module, and carrying out the simulation of a target light power condition received by a laser alarm device in simulation software when the target light power of the entity detector is smaller than a set power threshold value, and a frequency spectrum central value is judged according to the emission signal waveform and the spectrogram, and when the frequency spectrum central value is uncertain, the pulse emission frequency of the entity detector cannot be detected by the laser alarm. And finally, the control processing module encodes the pulse signal emitted by the entity detector according to the pulse duty ratio of the analog detector, and sends the encoded data to the entity detector, so that the entity detector emits the debugged pulse signal, and at the moment, the pulse signal emitted by the entity detector is out of the alarm range of the laser alarm. Therefore, the laser ranging device is ensured not to be found by the laser alarm during long-distance laser ranging.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser ranging, and particularly relates to a long-distance laser stealth ranging method, system and readable storage medium. Background Art

[0002] In the prior art, a laser warning device is a device that can identify and intercept laser signals emitted by the enemy in real time. Currently, it has been widely equipped in equipment products, such as vehicle-mounted warning devices, shipborne warning devices, spaceborne warning devices, etc., and has the characteristics of small size, light weight, high detection efficiency, fast response speed, etc. According to the laser radar target distance equation, to achieve active detection of long-distance target equipment, traditional laser ranging devices, such as avalanche APD, need to emit high-energy pulsed lasers to achieve long-distance detection of the target distance when implementing laser ranging. Due to the high single-pulse energy of traditional laser ranging devices, the on-target optical power density is relatively high, which is extremely likely to exceed the power threshold of the laser warning device, thereby causing the laser warning device of the measured equipment to alarm.

[0003] A new laser ranging method is needed to ensure that the laser warning device does not alarm while the laser ranging device accurately measures the distance. Summary of the Invention

[0004] The purpose of the present invention is to provide a long-distance laser stealth ranging method to solve the technical problem that the laser ranging device in the prior art cannot achieve stealth ranging.

[0005] The purpose of the present invention also lies in providing a long-distance laser stealth ranging system.

[0006] The purpose of the present invention also lies in providing a computer-readable storage medium.

[0007] The technical solution for the present invention to solve its technical problems is as follows: A long-distance laser stealth ranging method includes the following steps: S1: The control processing module reads the laser emission data of the entity detector, determines whether the on-target optical power of the entity detector is less than the set power threshold. If so, execute step S2; if not, adjust the laser emission data and execute step S1; S2: Set the pulse emission frequency and signal-to-noise ratio of the analog detector corresponding to the entity detector in the simulation software, simulate the on-target optical power received by the laser warning device, and determine whether the spectral center value is determined according to the transmitted signal waveform and spectrogram. If not, execute step S3; if so, adjust the pulse duty cycle of the analog detector and execute step S2; S3: The control processing module encodes the pulse signal emitted by the entity detector according to the pulse duty cycle of the analog detector, and sends the encoded data to the entity detector.

[0008] Preferably, the calculation formula for the on-target optical power of the entity detector in step S1 is: ; ; ; ; where is the spot radius at the laser warning device; R is the distance between the entity detector and the laser warning device; is the laser divergence angle; is the spot area at the laser warning device; is the on-target optical power of the entity detector; is the peak power of laser emission; is the optical attenuation coefficient of the atmosphere, is the transmission rate of the emission optics; is the transmission rate of the receiving optics; is the area of the receiving optical system; is the target cross-sectional area of reflection; is the reflectivity of the target to the laser; is the two-way transmission rate of the atmosphere; is the optical area of the laser warning device interface; is the detection sensitivity of the entity detector; is the energy attenuation coefficient of the laser.

[0009] Preferably, the set power threshold in step S1 is 35 μW / mm2.

[0010] Preferably, the adjustment of the laser emission data in step S1 specifically includes: Q-switching technology, increasing the pump power technology, mode-locking technology, and power adjustment technology of the optical emission circuit.

[0011] Preferably, the entity detector in step S1 uses a single-photon detector.

[0012] Preferably, the simulation software in step S2 uses MATLAB simulation software.

[0013] Preferably, the pulse emission frequency in step S2 is a high-repetition-rate pulse signal.

[0014] A long-distance laser stealth ranging system, comprising: A control and processing module, configured to read the laser emission data of the entity detector, determine whether the on-target optical power of the entity detector is less than the set power threshold; and encode the pulse signal emitted by the entity detector according to the pulse duty cycle of the analog detector; A simulation software for simulating the on-target optical power received by a laser warning device, and determining whether the spectral center value is determined according to the transmitted signal waveform and spectrum diagram; A physical detector for emitting laser signals of corresponding frequencies according to the pulse duty cycle of the simulated detector in the simulation result.

[0015] A computer-readable storage medium storing a computer program, which, when executed by a processor, causes the device where the computer-readable storage medium is located to execute a long-distance laser stealth ranging method.

[0016] The beneficial effects of the present invention are as follows: By controlling the processing module to read the laser emission data of the physical detector, it is determined whether the on-target optical power of the physical detector is less than the set power threshold. When the on-target optical power meets the requirements, the pulse emission frequency and signal-to-noise ratio of the simulated detector corresponding to the physical detector are set in the simulation software, and the on-target optical power received by the laser warning device is simulated. It is determined whether the spectral center value is determined according to the transmitted signal waveform and spectrum diagram. When the spectral center value is uncertain, it means that the laser warning device cannot detect the pulse emission frequency of the physical detector. Finally, the control processing module encodes the pulse signal emitted by the physical detector according to the pulse duty cycle of the simulated detector, and sends the encoded data to the physical detector, so that the physical detector emits the adjusted pulse signal. At this time, the pulse signal emitted by the physical detector is outside the warning range of the laser warning device, that is, it is ensured that the laser ranging device is not detected by the laser warning device during long-distance laser ranging. Description of the Drawings

[0017] Figure 1 is a schematic flow chart of the present invention; Figure 2 is a test result diagram of the present invention taking a 14Km building in actual measurement as an example. Detailed Embodiments

[0018] 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.

[0019] Embodiment 1: As Figure 1 shown, the present invention discloses a long-distance laser stealth ranging method, including the following steps: S1: The control processing module reads the laser emission data of the physical detector, determines whether the on-target optical power of the physical detector is less than the set power threshold. If so, execute step S2; if not, adjust the laser emission data and execute step S1; S2: Set the pulse emission frequency and signal-to-noise ratio of the analog detector corresponding to the entity detector in the simulation software, simulate the target optical power received by the laser warning device, and determine whether the spectral center value is determined according to the transmitted signal waveform and spectrum diagram. If not, execute step S3; if so, adjust the pulse duty cycle of the analog detector and execute step S2; among them, the pulse emission frequency is a high-repetition-rate pulse signal, specifically: the pulse emission frequency is a 100 kHz high-repetition-rate pulse signal, and the signal-to-noise ratio is 10 dB.

[0020] S3: The control processing module encodes the pulse signal emitted by the entity detector according to the pulse duty cycle of the analog detector, and sends the encoded data to the entity detector. The entity detector emits laser with a pulse signal having a set emission pulse duty cycle. After the entity detector receives the echo data, the control processing module processes the echo data, performs multi-frame time correlation accumulation on the received echo data, and calculates the target distance in real time. Among them, when the echo data returns to the detector end, various filtering processing means such as spatial filtering, spectral filtering, and time-gate filtering can be used for comprehensive processing to filter out strong background noise interference, especially sunlight background radiation, so as to realize the all-weather operation of the ranging device.

[0021] Preferably, the entity detector uses a single-photon detector, specifically: a Geiger-mode avalanche photodiode type single-photon detector, which realizes the conversion from optical signal to analog electrical signal through the photodiode in the single-photon detector, and realizes the conversion from analog electrical signal to digital signal through the high-speed comparator in the single-photon detector, so as to complete the ultra-high-sensitivity detection of the received echo optical signal. The set power threshold of the laser warning device is 35 μW / mm 2 ; The calculation formula for the optical power to the target of the entity detector is: ; ; ; ; Among them, is the spot radius at the laser warning device; R is the distance between the entity detector and the laser warning device; is the laser divergence angle; is the spot area at the laser warning device; is the optical power to the target of the entity detector; is the peak laser emission power; is the atmospheric optical attenuation coefficient, is the transmission optical transmittance; is the reception optical transmittance; is the area of the receiving optical system; is the target cross-sectional area of reflection; is the reflectivity of the target to the laser; is the two-way atmospheric transmittance; is the optical area of the laser warning device interface; is the detection sensitivity of the solid detector; is the energy attenuation coefficient of the laser. It can be seen that the peak power of the laser emission is greater, the signal power received by the warning device is greater. Reducing the laser emission power or increasing can both reduce the power of the laser reaching the target , but both will cause the distance R to become smaller. Therefore, when keeping the ranging distance R unchanged, the detection sensitivity needs to be reduced. And the sensitivity of the single-photon detector is reduced by two orders of magnitude compared with the conventional detector. When ranging on the same distance R target, assuming that the receiving optical areas of the ranging machine with the conventional detection system and the ranging machine with the single-photon detection system are the same, compared with the conventional detection system, the laser emission power required by the single-photon detection system can be reduced by two orders of magnitude. For example, the power of the laser reaching the target of the conventional detection system is 100 μW / mm 2 , while the power of the laser reaching the target of the single-photon detection system is 10 μW / mm 2 . Based on the single-photon detection system, the power of the laser reaching the target is lower than the set power threshold of the laser warning device, which is 35 μW / mm 2 . Therefore, when using the single-photon detection system for ranging, the warning device will not be triggered to give an alarm.

[0022] The emission optical system adopts an inverted Galilean telescope, and the main part uses three lenses. Given that the laser wavelength is 1064 nm, the initial divergence angle is 4 mrad / 5 mrad, the initial spot diameter is 6 mm (beam waist), according to the divergence angle of the outgoing spot, the emission telescope adopts a structure type of 8 times / 10 times, and the output divergence angle is 0.5 mrad. The total length of the emission optical system is 70 mm, and the output beam aperture is 50 mm.

[0023] Adjust the laser emission data, specifically including: Q-switching technology, increasing the pump power technology, mode-locking technology, and power adjustment technology for the optical emission circuit. Taking Q-switching technology as an example: Q-switching working principle: The control processing module sends a signal to the excitation source to emit laser. The laser excitation source generates a current pulse with a specified frequency to drive the pump LD to work, generating pulsed pump light. The doped particles Nd3+ in the Nd:YAG crystal rod absorb the pump light energy of the LD, jump from the lower laser level to the upper laser level and accumulate. At this time, no voltage is applied to the Q-switch crystal. The fluorescence generated by spontaneous emission becomes linearly polarized light with a polarization direction parallel to the incident plane after passing through the polarizer. After passing through the wave plate - Q-switch crystal - total reflector - Q-switch crystal - wave plate back and forth, the polarization direction becomes perpendicular to the incident plane and cannot pass through the polarizer. At this time, the 1.06μm laser resonator is in the closed state and cannot establish a laser oscillation. When the inversion population of Nd3+ reaches the maximum, the Q-switch signal controls the Q-switch drive circuit to generate a pulsed high voltage, which is applied to the Q-switch crystal. At this time, the fluorescence generated by spontaneous emission returns from the total reflector and passes through the Q-switch crystal and the wave plate, and the polarization direction of the polarized light is still parallel to the incident plane and can pass through the polarizer. At this time, the resonator is in the open state, and the 1.06μm fluorescence acts on the Nd3+ accumulated in the upper level, inducing an avalanche transition from the upper laser level to the lower level, generating stimulated emission, and quickly establishing a 1.06μm laser oscillation, which is output from the output mirror to achieve the purpose of adjusting the pulse signal, so that the solid detector generates a low-energy, micro-pulse, high-repetition-rate modulated pulse signal, and this pulse signal is irradiated on the target through the optical beam expander device.

[0024] In the actual application process, adjust the laser emission peak power of the solid detector through the control processing module, use simulation software to simulate the on-target light power received by the laser warning device, obtain the duty cycle of the emission pulse that cannot be calculated by the laser warning device, and encode the duty cycle of the emission pulse, so that the single-photon detector emits laser with a pulse signal of the set emission pulse duty cycle. As Figure 2 shown, taking the 14Km building test as an example, after the solid detector emits laser with a pulse signal of the set emission pulse duty cycle, regardless of how the test time and optical attenuation value change, the on-target light power of the emission pulse laser is less than 35 μw / mm2. At this time, the laser warning device does not give an alarm, realizing long-distance laser stealth ranging.

[0025] Embodiment 2: A long-distance laser stealth ranging system, including: A control processing module, used to read the laser emission data of the solid detector, and judge whether the on-target light power of the solid detector is less than the set power threshold; encode the pulse signal emitted by the solid detector according to the pulse duty cycle of the analog detector; A simulation software, which is used to simulate the received target optical power of a laser warning device, and determine whether the spectral center value is determined according to the transmitted signal waveform and spectrum diagram; An entity detector, which is used to emit laser signals of corresponding frequencies according to the pulse duty cycle of the simulated detector in the simulation result.

[0026] Embodiment 3: A computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the device where the computer-readable storage medium is located is caused to execute a long-distance laser stealth ranging method.

[0027] 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.

Claims

1. A long-distance laser stealth ranging method, characterized in that, It includes the following steps: S1: The control processing module reads the laser emission data of the entity detector, determines whether the on-target optical power of the entity detector is less than the set power threshold. If so, execute step S2. If not, adjust the laser emission data and execute step S1; S2: Set the pulse emission frequency and signal-to-noise ratio of the analog detector corresponding to the entity detector in the simulation software, simulate the on-target optical power situation received by the laser warning device, and determine whether the spectral center value is determined according to the emission signal waveform and spectrogram. If not, execute step S3; if so, adjust the pulse duty cycle of the analog detector and execute step S2; S3: The control processing module encodes the pulse signal emitted by the entity detector according to the pulse duty cycle of the analog detector, and sends the encoded data to the entity detector.

2. The long-distance laser stealth ranging method according to claim 1, wherein: The calculation formula for the on-target optical power of the entity detector in step S1 is: ； ； ； ； Where r is the spot radius at the laser warning device; R is the distance between the entity detector and the laser warning device; is the laser divergence angle; is the spot area at the laser warning device; is the on-target optical power of the entity detector; is the peak power of the laser emission; is the optical attenuation coefficient of the atmosphere, is the transmission of the emitting optics; is the transmission of the receiving optics; is the area of the receiving optical system; is the cross-sectional area of the target reflection; is the reflectivity of the target to the laser; is the two-way atmospheric transmittance; is the optical area of the laser warning device interface; is the detection sensitivity of the entity detector; is the energy attenuation coefficient of the laser.

3. The long-distance laser stealth ranging method according to claim 2, wherein: The set power threshold in the step S1 is 35 μW / mm 2 .

4. The long-distance laser stealth ranging method according to claim 1, wherein In step S1, the adjustment of the laser emission data specifically includes: Q-switching technology, increasing the pump power technology, mode-locking technology, and power adjustment technology of the optical emission circuit.

5. The long-distance laser stealth ranging method according to claim 1, characterized in that: In step S1, the entity detector uses a single-photon detector.

6. The long-distance laser stealth ranging method according to claim 1, characterized in that: In step S2, the simulation software uses MATLAB simulation software.

7. The long-distance laser stealth ranging method according to claim 1, characterized in that: The pulse emission frequency in step S2 is a high-repetition-rate pulse signal.

8. A long-distance laser stealth ranging system, characterized in that, It includes: A control processing module, configured to read the laser emission data of the entity detector and determine whether the on-target optical power of the entity detector is less than the set power threshold; Encode the pulse signal emitted by the entity detector according to the pulse duty cycle of the analog detector; A simulation software, configured to simulate the on-target optical power situation received by the laser warning device and determine whether the spectral center value is determined according to the emission signal waveform and spectrogram; An entity detector, configured to emit a laser signal with a corresponding frequency according to the pulse duty cycle of the analog detector in the simulation result.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it causes the device where the computer-readable storage medium is located to execute the method according to any one of claims 1-7.

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