CN111158010B - Laser active tracking system and tracking method - Google Patents
Laser active tracking system and tracking method Download PDFInfo
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- CN111158010B CN111158010B CN202010010338.0A CN202010010338A CN111158010B CN 111158010 B CN111158010 B CN 111158010B CN 202010010338 A CN202010010338 A CN 202010010338A CN 111158010 B CN111158010 B CN 111158010B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/66—Tracking systems using electromagnetic waves other than radio waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/483—Details of pulse systems
- G01S7/486—Receivers
- G01S7/4861—Circuits for detection, sampling, integration or read-out
- G01S7/4863—Detector arrays, e.g. charge-transfer gates
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Abstract
The invention discloses a laser active tracking system and a tracking method, wherein the system comprises a laser marker, a light spot testing unit and a data transmission unit; the light spot testing unit comprises a receiving mirror, a four-quadrant photoelectric detector, a CCD imaging detector and an acquisition processing circuit; after the pulse laser emitted by the laser irradiates a target, the CCD processing unit processes the CCD imaging detector to obtain a light spot image; the acquisition processing circuit acquires and processes the output electric signals of the four-quadrant photoelectric detector to obtain the coordinates of the centroid of the light spot; the light spot image and the light spot centroid coordinates are sent to a remote control center through a data transmission unit; the active tracking system integrates the four-quadrant detector, the CCD image sensor and the target indicating laser, and the target indicating laser emits pulse laser, so that the comprehensive test and target tracking of laser spots are realized, and target parameters and decision basis reference are provided for the accurate striking of a semi-active guided weapon.
Description
Technical Field
The invention belongs to the technical field of laser tracking, and mainly relates to an active tracking system and a tracking method based on a four-quadrant detector, a CCD (charge coupled device) image sensor and a target indication laser.
Background
The laser active tracking system consists of a four-quadrant Laser Spot Tracking (LST), a laser spot tracking camera (CCD) and a laser target marker. The laser active tracking technology provides real-time information of a target accurate position for a tracking system through laser illumination identification of the target position, and is a closed-loop accurate tracking system which follows a large target and has the function of assisting in enhancing the large target tracking.
In the application of laser semi-active guided weapons, hit targets need to be tracked, and usually a laser active tracking system is installed on a helicopter or a fixed wing aircraft, so that a visual symbol of target indication and important target threat prompt is provided for guided and unguided weapons, a guidance system for accurately hitting is provided for fighters, and the laser semi-active guided weapons is an important link for the accurate hitting and collaborative tactics. The existing laser active tracking technology adopts repetition frequency pulse laser to light a target, adopts a light spot testing unit based on a four-quadrant detector and a CCD image sensor to carry out compound tracking, and sends a light spot image and light spot centroid offset position data to a command operation background in real time, and because the transmitting and receiving channels of the laser are influenced by atmospheric turbulence and wind speed, the system achieves the purpose of correcting the position deviation of a transmitting and tracking point target through detection of a dual-system sensor; the CCD image sensor is used for processing and tracking position information of an imaging bright spot of a laser spot, the four-quadrant detector is used for processing and tracking the position information of the laser spot, and the two systems have different tracking sensitivities, have composite tracking capabilities and increase the use dynamic range of the system.
The core technology in the present laser active tracking is how to obtain a laser peak signal through four-quadrant photoelectric detector measurement, and the 'an optical precision tracking detector based on a double four-quadrant detector (Chinese patent 200910093364.8)' and 'a laser spot and echo tracking monitoring device (Chinese patent 201811336974.1)' both relate to the above applications, and have the common problem that the collected signal is a solid laser pulse signal with a pulse width of 10-20ns and a repetition frequency of 10-20Hz, and the present pulse laser spot detection method based on the photoelectric detector mainly has two modes of peak holding and high-speed collection, wherein the peak holding is to widen the nanosecond pulse signal incident to the detector by microsecond, and then the low-speed collection is adopted for collection, and the problem that the widening is to widen according to the peak intensity of the pulse, thereby reducing the difficulty of data collection, but the linearity and dynamic range of data acquisition cannot be guaranteed, and the real parameters of laser spots cannot be reflected. In comparison, high-speed acquisition is an accurate scheme, but for a pulse signal of 10ns, the ADC sampling rate of a sampling system needs to reach more than 1GS/s, and in addition, a large amount of data of an image sensor brings difficulties to data storage, real-time display and background uploading in continuous work of tens of seconds to minutes, and finally affects the accuracy and real-time performance of spot tracking.
Disclosure of Invention
The invention provides a technical scheme of a laser active tracking system, aiming at overcoming the defects of large data collection quantity of a photoelectric detector and an image sensor and difficulty in real-time display and uploading in the existing laser active tracking.
The specific technical scheme of the invention is as follows:
a laser active tracking system comprises a laser marker, a light spot testing unit and a data transmission unit; the laser marker comprises a transmitting mirror, a laser and a laser driver; the light spot testing unit comprises a receiving mirror, a four-quadrant photoelectric detector, a CCD imaging detector, a CCD processing unit and an acquisition processing circuit; after pulse laser emitted by the laser irradiates a target, reflected light spots of the laser synchronously enter a four-quadrant photoelectric detector and a CCD imaging detector through a receiving mirror, and a CCD processing unit processes the CCD imaging detector to obtain a light spot image; the acquisition processing circuit acquires and processes the output electric signals of the four-quadrant photoelectric detector to obtain a light spot centroid coordinate; the light spot image and the light spot centroid coordinate are sent to a remote control center through a data transmission unit; the laser outputs repetition frequency pulse laser;
the acquisition processing circuit comprises a core control unit, an adder, a total signal AD unit, four conditioning amplification units and four quadrant AD units, wherein the four conditioning amplification units and the four quadrant AD units respectively correspond to four quadrants of the four-quadrant photoelectric detector; the core control unit comprises a processor, a memory and a plurality of ports; the input end of the adder is connected with the output ends of the four conditioning and amplifying units, and the output end of the adder is connected with the sampling end of the total signal AD unit; the output ends of the four conditioning amplifying units are respectively connected with the sampling ends of the corresponding four quadrant AD units; the output end and the trigger end of the total signal AD unit and the output end and the trigger end of the four-quadrant AD unit are respectively connected with a port of the core control unit;
after receiving the active tracking start instruction, a processor of the core control unit synchronously sends a trigger instruction to a laser driver and a trigger end of the total signal AD unit, and the laser sends repetition frequency pulse laser until the tracking is finished; meanwhile, the AD conversion is carried out by the total signal AD unit, the front n laser pulse data after the starting instruction are processed to obtain the leading edge starting time, the pulse width and the period of the laser pulse signal, the triggering time and the triggering duration are set according to the processing result, and then the CCD processing unit and the four quadrant AD units are synchronously triggered to carry out acquisition conversion to obtain the light spot and the coordinates of the mass center of the light spot; the trigger time is advanced and the arrival time of the pulse, and the trigger time length is longer than the pulse width.
In the laser active tracking system, the collection frequency of the spot image and the centroid coordinate is consistent with the frequency of the laser pulse.
In the laser active tracking system, the laser output pulse width is 10-20ns, and the repetition frequency is 1-50 Hz.
In the laser active tracking system, the sampling frequency of the total signal AD unit and the four-quadrant AD unit is not less than 1 GS/s.
In the laser active tracking system, the coordinates of the center of mass of the light spot in the image display unit are displayed in the same display interface by the cross hairs and the light spot image.
In the laser active tracking system, the receiving mirror comprises a single lens and a semi-transparent semi-reflecting mirror arranged behind the single lens, a focused light beam passes through the semi-transparent semi-reflecting mirror and is divided into two beams of reflected light and transmitted light, one beam is imaged to the four-quadrant photoelectric detector, and the other beam is imaged to the CCD imaging detector.
A laser active tracking method comprises the following steps:
【1】 Powering up the system and performing self-checking;
【2】 Rotating and searching a turret on the fixed platform, finding a target through a CCD imaging detector, and sending a target image to a remote control center through a data transmission unit;
【3】 The instruction control center sends an active tracking instruction to the core control unit through the data transmission unit, the core control unit synchronously sends a trigger instruction to the laser driver and the trigger end of the total signal AD unit, and the laser sends repetition frequency pulse laser; meanwhile, the AD unit of the total signal carries out AD conversion, processes the front n laser pulse data after the starting instruction to obtain the leading edge starting time, the pulse width and the period of the laser pulse signal, and calculates to obtain the coming time of the subsequent laser pulse;
【4】 Before the next pulse arrives, the core control unit sends a trigger instruction of which the trigger time is ahead of the arrival time of the pulse to the trigger ends of the four-quadrant AD unit and the CCD processing unit, the four-quadrant AD unit and the CCD processing unit are triggered to acquire signals, and image facula and centroid data are sent to a remote control center, wherein the acquisition time length of the four-quadrant AD unit is set to be longer than the pulse width of the laser signal obtained by the calculation in the step (3);
【5】 And the finger control center (17) performs fusion display on the obtained image facula and mass center data on the image display unit, and performs striking decision according to the test result.
In the active laser tracking method, the triggering time of the four quadrant AD units in the step (4) is 1.2-1.5 times of the laser pulse width calculated in the step (3).
In the laser active tracking method, the triggering time of the four quadrant AD units in the step (4) is more than 10ns ahead of the coming time of the laser pulse calculated in the step (3).
In the laser active tracking method, n in the step (3) is 2 to 10.
The invention has the following beneficial technical effects:
1. the active tracking system integrates the four-quadrant detector, the CCD image sensor and the target indicating laser, the target indicating laser emits pulse laser, data and images obtained by the two sensors are fused together, the laser spot mass center, the peak power of a signal and a spot image are obtained, the comprehensive test and target tracking of the laser spot are realized, and target parameters and decision basis reference are provided for accurate striking of a semi-active guided weapon.
2. In the light spot test, the four-quadrant detector is adopted to collect and process the first pulses irradiating laser in a full period, the initial time, the pulse width and the period of the light pulse of the repetition frequency laser under the current atmospheric condition are obtained, the reaching time and the pulse width of the subsequent pulse are obtained through calculation and are used for synchronous triggering of the subsequent four-quadrant detector and the image sensor, the width of the triggering pulse is specially set to be slightly larger than the pulse width of the laser, the time is slightly advanced, and the subsequent light pulse is ensured to be collected only in the effective light pulse. For laser pulse with pulse width of 10-20ns and repetition frequency of 1-50Hz, the effective optical pulse signal ratio is very small, and the acquisition time and data volume are greatly reduced, so that the overhead of a circuit and a memory can be reduced, the work heating of high-speed AD is reduced, and the subsequent data processing is facilitated so as to display light spots in real time. The working mode does not need to require the laser to provide a synchronous trigger signal, has a certain adaptive range for different laser parameters, and also meets the light spot test requirement under the influence of light pulse parameters when atmospheric changes.
3. When the optical pulse signal parameters are obtained, the four-quadrant pulse signals are collected by the adder and then processed and calculated, so that the signal input deviation caused by the position deviation of light spots when the optical pulse signal parameters are calculated by adopting a single quadrant is avoided, the collected signals are subjected to data processing, the calculation precision of the pulse parameters can be greatly improved, and the reliability of follow-up light spot tracking is ensured.
Drawings
FIG. 1 is a schematic diagram of the components of the laser active tracking system of the present invention;
FIG. 2 is a schematic diagram of a laser active tracking system mounted on an unmanned aerial vehicle;
FIG. 3 is a schematic diagram of the acquisition processing circuit of the laser active tracking system of the present invention;
fig. 4 is a schematic diagram of the working timing principle of the acquisition processing circuit of the present invention.
FIG. 5 is a schematic illustration of a data and image fusion display according to the present invention;
fig. 6 is a schematic diagram of the receiver mirror of the present invention.
The reference numbers are as follows: 1-light spot active tracking system; 2-fixing the platform; 3-target; 4-emitting a light beam; 5-reflected beam; 6-a receiving mirror; 7-four quadrant photodetector; 8, an acquisition processing circuit; 9-a data transmission unit; 10-a reflector; 11-a laser; 12-reflecting the light spot; 14-a CCD imaging detector; 15-a CCD processing unit; 16-a laser driver; 17-a center of command; 35-a semi-transparent and semi-reflective mirror; 38-a single lens; 42-a laser marker; 43-a turret; 44-a light spot testing unit; 50-displaying an interface; 51-target plate image; 52-light spot image; 53-coordinates of the centroid of the spot; 54-parameter display area; 55-spot center.
Detailed Description
The invention is described in further detail below with reference to the drawings and preferred examples.
As shown in fig. 1 and 2, the laser active tracking system of the present invention includes a laser marker 42, a spot test unit 44, and a number transmission unit 9; the laser marker 42 includes a transmitting mirror 10, a laser 11, and a laser driver 16; the light spot testing unit 44 comprises a receiving mirror 6, a four-quadrant photoelectric detector 7, a CCD imaging detector 14, a CCD processing unit 15 and an acquisition processing circuit 8;
after pulse laser emitted by a laser 11 irradiates a target 3 beyond a few km, a reflected light spot 12 of the pulse laser is incident on a four-quadrant photoelectric detector 7 and a CCD imaging detector 14 through a receiving mirror 6, and a CCD processing unit 15 processes the CCD imaging detector 14 to obtain a light spot image; the acquisition processing circuit 8 acquires and processes the output electric signals of the four-quadrant photoelectric detector 7 to obtain the coordinates of the centroid of the light spot; the light spot image and the light spot centroid coordinate are sent to a remote control center 17 through a data transmission unit 9.
The laser 11 outputs repetition frequency pulse laser with the wavelength of 1064nm or 532nm, the output pulse width of 10-20ns and the repetition frequency of 1-50 Hz. Narrow-band filters matched with laser wavelength are arranged between the receiving mirror 6 and the four-quadrant photoelectric detector 7 and between the receiving mirror 6 and the CCD imaging detector 14, and the four-quadrant photoelectric detector 6 and the CCD imaging detector 14 are located near the focal plane of the receiving mirror 6.
As shown in fig. 2, the light spot active tracking system 1 is mounted on an unmanned aerial vehicle or other fixed platform 2 through a turret 43, and the turret 43 can be rotated in a multi-angle servo manner to realize tracking and locking of a target. The receiver mirror 6 and the transmitter mirror 10 are arranged side by side below the turret 43 with their optical axes parallel, and may be approximately coaxial for long-distance targets beyond a few km.
The receiving mirror 6 receives the laser pulse signal reflected on the target 3, converts the laser pulse signal incident on the photosensitive surface of the four-quadrant photoelectric detector 6 into an electric pulse signal, outputs the electric pulse signal in four paths A, B, C, D, and obtains the coordinate position of a light spot incident on the four-quadrant detector by calculating the amplitude of the output signal. The four-quadrant photoelectric detector 7 is made of InGaAs, PIN or APD photoelectric detectors, and the response rate reaches more than ns level. By constructing X-axis and Y-axis coordinates with the center of the four-quadrant photodetector as the coordinate O point, the centroid coordinates (X, Y) of the spot can be expressed as:
x＝(VA+VB-VC-VD)/(VA+VB+VC+VD)
y＝(VA+VD-VB-VC)/(VA+VB+VC+VD)
wherein VA, VB, VC and VD are output voltage signals of four quadrants respectively.
In the application of the laser semi-active guided weapon, a target spot image and a spot centroid coordinate tracked by a laser active tracking system need to be sent to a remote control center 17 in real time, that is, data of the four-quadrant photoelectric detector 7 and the CCD imaging detector 14 need to be sent to a background in real time, the duration time is about tens of seconds, and target information is provided for the guided weapon.
Due to the fact that the pulse width of the laser is 10ns, if the pulse amplitude of the light spot is obtained in a high-speed acquisition mode and then the position of the light spot is calculated and displayed in real time, the four-quadrant photoelectric detector 7 needs a high-speed ADC sampling system with a sampling rate of more than 1GS/s, the data volume is too large, great expenses are brought to circuit and software storage, the heating of a high-speed AD module is high, the circuit is complex, the operation data volume is too large in processing and real-time display of the data, in addition, image data obtained by the CCD imaging detector 14 are too large, and the accuracy and the real-time performance of light spot display are affected finally.
To overcome the aboveThe problem is that the invention deeply analyzes the pulse characteristics of the laser, and takes the repetition frequency of 10Hz and the pulse width of 10ns as an example, the whole effective pulse only occupies 1/10 of the whole pulse duration7If only the effective pulse is acquired at a high speed, the data volume and the acquisition time are greatly reduced, so that a high-speed AD trigger signal needs to be provided, the AD is triggered to be acquired before the light pulse comes, and the AD acquisition is stopped after the effective pulse is finished. Considering that the change of atmospheric transmission characteristics can be ignored within a working time period of tens of seconds, the invention provides a priori acquisition triggering scheme, wherein the first n laser pulses are completely acquired in advance in a full period and are used for calculating the pulse width T, the period T and the time T0 of the leading edge of the pulse of the repetition laser, and then the acquisition time and the acquisition time of the subsequent pulse are set according to the calculation result, so that the purpose of high-speed acquisition only at the effective pulse time is achieved. In the actual processing, if the AD in one quadrant is adopted for prior acquisition, signal loss in the quadrant is easily caused when the position of a light spot is subjected to offset irradiation, so that the output signals of 4 quadrants are superposed and then calculated, and the effectiveness of prior acquisition is ensured.
As shown in fig. 3, the acquisition processing circuit 8 includes a core control unit, an adder, a total signal AD unit, and four conditioning and amplifying units and four quadrant AD units respectively corresponding to four quadrants of the four-quadrant photodetector 7, where the four quadrant AD units are an a quadrant AD, a B quadrant AD, a C quadrant AD, and a D quadrant AD. The core control unit is a single chip microcomputer or FPGA and comprises a processor, a memory and a plurality of I/O ports. A. B, C, D the output signals of four quadrants are conditioned and amplified to proper amplitudes, and divided into two paths, one path enters into an adder for signal superposition, the input end of the adder is connected with the output ends of the four conditioning and amplifying units, the output end of the adder is connected with the sampling end of a total signal AD unit, and the total signal AD unit is adopted to carry out prior acquisition on the signals. And the other path is respectively connected with the sampling ends of the four corresponding quadrant AD units, and after the prior collection is finished, the light spot collection processing is normally carried out.
The output ends of the A-quadrant AD, the B-quadrant AD, the C-quadrant AD, the D-quadrant AD and the total signal AD unit are coupled to a GTX port of the core control unit FPGA, and the A-quadrant trigger, the B-quadrant trigger, the C-quadrant trigger, the D-quadrant trigger and the total signal AD trigger ends are coupled to an I/O port of the core control unit. After a processor in a core control unit receives a light spot tracking start instruction, firstly triggering a total signal AD unit to perform AD conversion, processing conversion data to obtain the starting time T0, the pulse width T and the period T of the leading edge of a laser pulse, then setting the triggering time and the duration of a subsequent pulse according to the processing result, then synchronously triggering a CCD processing unit 15 and an A quadrant AD, a B quadrant AD, a C quadrant AD and a D quadrant AD to perform acquisition conversion, and storing the conversion data in a memory by the core control unit and performing light spot centroid coordinate conversion; the converted light spot centroid coordinates and the CCD processing unit 15 acquire a light spot image, and the light spot image is sent to a remote control center 17 through a data transmission unit 9 for background decision processing. The CCD processing unit 15 adopts a ready-made VGA image acquisition card, can synchronously acquire CCD signals according to the trigger signals, and uploads facula images. The start-stop instruction of laser emission and light spot detection is issued by the instruction control center 17 through the data transmission unit 9, for example, the high level is light spot tracking, the low level is light spot tracking stopping or a narrow pulse trigger signal is given, and the acquisition is carried out according to the set time length. The data transmission unit 9 adopts a mature wireless data transmission module or a radio station to transmit signal data. When the system receives a laser active tracking command through the data transmission unit, the core control unit sends a command to the laser driver 16 to drive the laser 11 to emit repetition frequency pulse laser to mark a target, and simultaneously drives the light spot testing unit 44 to perform light spot acquisition and light spot mass center coordinate acquisition.
Fig. 4 shows a schematic diagram of the working timing principle of the light spot acquisition processing circuit. When finding a target, the CCD imaging detector 14 sends the target image to a remote control center 17 through a data transmission unit 9; the command center 17 sends an active tracking command to the core control unit through the data transmission unit 9, the core control unit synchronously sends a trigger command to the laser driver 16 and the trigger end of the total signal AD unit, and the laser sends repetition frequency pulse laser until the tracking is finished; meanwhile, the AD unit of the total signal carries out AD conversion, processes the front n laser pulse data after the starting instruction to obtain the leading edge starting time, the pulse width and the period of the laser pulse signal, and calculates to obtain the coming time of the subsequent laser pulse; in the figure, the pulse emitted by the laser is delayed for a period of time after long-distance transmission, and then is received by the receiving mirror 6.
In fig. 3, after receiving a tracking start instruction, the core control unit sends a narrow pulse trigger signal, the total trigger signal AD unit continuously collects signals of the adder, generally requiring 2-10 pulses of duration, the collected data enters the core control unit, the processor calculates the time sequence of the first n pulses, obtains the starting time, pulse width and period of the laser pulse, and estimates the arrival time and pulse width of the subsequent pulses in the time period of the atmospheric condition; then, the acquisition time and duration of the CCD processing unit 15 and the four-quadrant AD unit are set again, so as to ensure that only signals of the incoming optical pulses are acquired synchronously, for example, the pulse width of the subsequent pulse is calculated to be t, and the actual setting time can be lengthened to t1, where t1 is (1.2-1.5) t; the time of triggering collection is earlier than the calculated time by more than 10ns, for example, 15ns, so as to ensure that all the effective optical signals are collected and acquired, and then the core control unit stores the converted data in the memory until receiving the instruction of stopping the light spot tracking. As shown in fig. 3, the trigger signals of the CCD and the four quadrants AD are narrow pulse trigger signals, and after each quadrant AD unit receives the trigger signal, it performs high-speed acquisition according to a set acquisition duration, and the CCD processing unit 15 performs image acquisition according to a set integration time by using the pulse signal as the trigger signal, where an image in each integration time is a frame, and the integration time is set according to different parameters of the camera, and is usually 1-100 microseconds.
For the four-path digital signals of A, B, C, D four quadrants collected, the central control unit FPGA calculates the position of the light spot after obtaining output voltage signals of VA, VB, VC, VD which are four quadrants respectively and corresponding time relations, and the centroid coordinates (x, y) of the light spot can be expressed as:
x＝(VA+VB-VC-VD)/(VA+VB+VC+VD)
y＝(VA+VD-VB-VC)/(VA+VB+VC+VD)。
the core control unit FPGA sends data information such as light spot coordinates, laser frequency, peak power, pulse width and the like to the command control center through the data transmission unit 9 according to the refresh rate (1-50Hz) with the same laser pulse frequency, and simultaneously the CCD processing unit 15 sends the acquired light spot image data to the command control center, so that the real-time display of light spot positions and parameters is realized after the two are fused, and the complete synchronization of the light spot display result and the actual light pulse time is ensured. The coordinates of the light spots in the display are represented on the coordinate positions by cross or diamond symbols, under the influence of atmospheric transmission and the difference of the time resolution of the two, the cross or diamond symbols can rapidly change the positions around the light spot image, and the change represents the current atmospheric transmission condition, so that accurate light spot tracking parameters and decision bases are provided for the hitting of weapons and the judgment of an atmospheric emission window.
As shown in fig. 5, a target plate image 51, a light spot image 52 captured by the CCD detector 6, and a light spot centroid coordinate 53 detected by the four-quadrant photo-detecting unit and a parameter display area 54 for displaying pulse peak power, frequency code signals and the like are displayed in a display interface 50 of the display, wherein the CCD light spot image 52 is inside the target plate image 51, the centroid thereof is represented by a light spot center 55, and the light spot centroid coordinate 53 is represented by a cross-hair symbol. Under the influence of atmospheric transmission, a cross-hair symbol may appear at a position closer to the spot center 55, as a cross-shaped symbol drawn by a solid line; and may also occur at a location further from the spot center 55 as indicated by the cross-symbol drawn by the dashed line in the figure.
Fig. 6 is a schematic diagram of a principle of a receiving mirror 6 with a single-tube structure, the receiving mirror 6 includes a single lens 38 and a semi-transparent and semi-reflective mirror 35 arranged behind the single lens 38, a light beam focused by the single lens 38 passes through the semi-transparent and semi-reflective mirror 35 and is divided into two beams of reflected light and transmitted light, one beam is imaged to the four-quadrant photodetector 7, and the other beam is imaged to the CCD imaging detector 14, so that the consistency of the two sets of measuring units for imaging light spots is ensured.
The laser active tracking method comprises the following steps:
【1】 Powering up the system, performing self-inspection, and preparing a laser marker 42, a four-quadrant photoelectric detector 7, an acquisition processing circuit 8 and a CCD imaging detector 14;
【2】 Rotating and searching a turret on a fixed platform, finding a target through a CCD imaging detector 14, and sending a target image to a remote control center 17 through a data transmission unit 9;
【3】 The instruction control center 17 sends an active tracking instruction to the core control unit through the data transmission unit 9, the core control unit synchronously sends a trigger instruction to the laser driver 16 and the trigger end of the total signal AD unit, and the laser sends repetition frequency pulse laser; meanwhile, the AD unit of the total signal carries out AD conversion, processes the front n laser pulse data after the starting instruction to obtain the leading edge starting time, the pulse width and the period of the laser pulse signal, and calculates to obtain the coming time of the subsequent laser pulse;
【4】 Before the next pulse arrives, the core control unit sends a trigger instruction of which the trigger time is ahead of the arrival time of the pulse to the trigger ends of the four-quadrant AD unit and the CCD processing unit, the four-quadrant AD unit and the CCD processing unit are triggered to acquire signals, and image facula and centroid data are sent to a remote control center, wherein the acquisition time length of the four-quadrant AD unit is set to be longer than the pulse width of the laser signal obtained by the calculation in the step (3);
【5】 And the command center 17 performs fusion display on the obtained image facula and the obtained centroid data on an image display unit, and performs striking decision according to the test result.
In the processing method of the invention, the CCD imaging detector 14 and the 4 AD only carry out high-speed acquisition on effective light pulse signals. For laser pulse with pulse width of 10-20ns and repetition frequency of 1-50Hz, effective optical pulse signal ratio is very small, so that acquisition time and data volume are greatly reduced, thereby reducing the expenditure of circuits and memories, reducing the work heating of high-speed AD, and facilitating the subsequent data processing uploading and real-time spot display.
It should be noted that, in the present invention, prior measurement and statistical calculation are performed on laser pulse time sequence characteristics before acquisition, and time sequence parameters of laser are obtained, because even if laser with known time sequence parameters of the same platform is affected by the change of the tracking distance and the current atmospheric parameters, time parameters arriving at a detector are different, a method of prior measurement and calculation is adopted, so that it can be ensured that sample parameters are obtained within the current small segment of atmospheric basic stable time, and subsequent AD parameter adjustment is performed according to the sample parameters, so as to ensure that effective optical pulse signals are obtained, thereby overcoming the influence of the current atmospheric environment on laser pulse characteristics, and having certain adaptability to different laser parameters.
Claims (4)
1. A laser active tracking method is characterized by comprising the following steps:
【1】 Powering up the laser active tracking system, and performing self-checking;
the laser active tracking system comprises a laser marker (42), a light spot testing unit (44) and a data transmission unit (9); the laser marker (42) comprises a transmitting mirror (10), a laser (11) and a laser driver (16); the light spot testing unit (44) comprises a receiving mirror (6), a four-quadrant photoelectric detector (7), a CCD imaging detector (14), a CCD processing unit (15) and an acquisition processing circuit (8); after pulse laser emitted by a laser (11) marks a target (3), a reflected light spot (12) of the target is synchronously incident to a four-quadrant photoelectric detector (7) and a CCD imaging detector (14) through a receiving mirror (6), and a CCD processing unit (15) processes the CCD imaging detector (14) to obtain a light spot image; the acquisition processing circuit (8) acquires and processes the output electric signals of the four-quadrant photoelectric detector (7) to obtain the coordinates of the centroid of the light spot; the spot image and the spot centroid coordinates are sent to a remote control center (17) through a data transmission unit (9); the laser (11) outputs repetition frequency pulse laser to mark the target (3); the laser output pulse width is 10-20ns, and the repetition frequency is 1-50 Hz;
the acquisition processing circuit (8) comprises a core control unit, an adder, a total signal AD unit, four conditioning amplification units and four quadrant AD units, wherein the four conditioning amplification units and the four quadrant AD units respectively correspond to four quadrants of the four-quadrant photoelectric detector (7); the core control unit comprises a processor, a memory and a plurality of ports; the input end of the adder is connected with the output ends of the four conditioning and amplifying units, and the output end of the adder is connected with the sampling end of the total signal AD unit; the output ends of the four conditioning amplifying units are respectively connected with the sampling ends of the corresponding four quadrant AD units; the output end and the trigger end of the total signal AD unit and the output end and the trigger end of the four-quadrant AD unit are respectively connected with a port of the core control unit;
after receiving the active tracking start instruction, a processor of the core control unit synchronously sends a trigger instruction to a laser driver (16) and a trigger end of a total signal AD unit, and the laser sends repetition frequency pulse laser until the tracking is finished; meanwhile, the AD conversion is carried out on the total signal AD unit, the front n laser pulse data after the starting instruction are processed to obtain the leading edge starting time, the pulse width and the period of the laser pulse signal, the triggering time and the triggering duration are set according to the processing result, and then the CCD processing unit (15) and the four-quadrant AD unit are synchronously triggered to carry out acquisition conversion to obtain the light spot and the coordinates of the mass center of the light spot; wherein the triggering time is 1.2-1.5 times of the calculated laser pulse width, and the triggering time is more than 10ns ahead of the calculated laser pulse coming time; the sampling frequency of the total signal AD unit and the four-quadrant AD unit is not less than 1 GS/s;
【2】 Rotating and searching a turret on a fixed platform, finding a target through a CCD imaging detector (14), and sending a target image to a remote control center (17) through a data transmission unit (9);
【3】 The instruction control center (17) sends an active tracking instruction to the core control unit through the data transmission unit (9), the core control unit synchronously sends a trigger instruction to the laser driver (16) and the trigger end of the total signal AD unit, and the laser sends repetition frequency pulse laser to mark the target (3); meanwhile, the AD unit of the total signal carries out AD conversion, processes the front n laser pulse data after the starting instruction to obtain the leading edge starting time, the pulse width and the period of the laser pulse signal, and calculates to obtain the coming time of the subsequent laser pulse;
【4】 Before the next pulse arrives, the core control unit sends a trigger instruction of which the trigger time is ahead of the arrival time of the pulse to the trigger ends of the four-quadrant AD unit and the CCD processing unit, the four-quadrant AD unit and the CCD processing unit are triggered to acquire signals, and image facula and centroid data are sent to a remote control center, wherein the acquisition time length of the four-quadrant AD unit is set to be longer than the pulse width of the laser signal obtained by the calculation in the step (3);
【5】 The finger control center (17) performs fusion display on the obtained image facula and mass center data on an image display unit, and performs striking decision according to a test result;
wherein n is 2 to 10.
2. The laser active tracking method of claim 1, wherein: the collection frequency of the spot image and the centroid coordinate is consistent with the frequency of the laser pulse.
3. The laser active tracking method of claim 1, wherein: the spot centroid coordinates (53) in the image display unit are displayed in a cross-hair with the spot image (52) in the same display interface (50).
4. The laser active tracking method of claim 1, wherein: the receiving mirror (6) comprises a single lens (38) and a semi-transparent semi-reflecting mirror (35) arranged behind the single lens, a focused light beam passes through the semi-transparent semi-reflecting mirror (35) and is divided into two beams of reflected light and transmitted light, one beam is imaged to the four-quadrant photoelectric detector (7), and the other beam is imaged to the CCD imaging detector (14).
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| CN114152189B (en) * | 2021-11-09 | 2022-10-04 | 武汉大学 | Four-quadrant detector light spot positioning method based on feedforward neural network |
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| CN118466595B (en) * | 2024-07-10 | 2024-10-01 | 常州华达科捷光电仪器有限公司 | Automatic laser tracking device and method |
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