A kind of battle array lidar measurement device
Technical field
The utility model relates to the laser radar technique in active optics airborne remote sensing load field, the face battle array lidar measurement device that the small-sized remote-sensing flatform in especially a kind of applicable low latitude carries.
Background technology
Lidar measurement is that a kind of having developed rapidly becomes the active optics of focus remote sensing technology, provide important means for obtaining the space three-dimensional data, be applicable to the prospecting of target detection, earth observation, City Building three-dimensional modeling and traffic route, power circuit, oil and gas pipes and planning etc.The lidar measurement device comprises laser ranging unit, position and attitude measuring unit and main control unit.It is to record range information by the laser ranging unit, then associating laser ranging position and attitude information that constantly the position and attitude measuring unit obtains calculate the accurate three-dimensional coordinate of the detection of a target, thereby realizes three-dimensional imaging.These three unit are disconnected from each other in conventional laser radargrammetry device, and each use need to be assembled, be dismantled, and often tear open and once can cause that parameter changes, if wish, collect high-precision data, need before use calibration again.The mode of this employing separate unit combination has not only affected service efficiency, and causes whole lidar measurement device volume and weight to increase, and is difficult to accomplish lightness and miniaturization.
The laser ranging unit is the core of lidar measurement device, it is launched beam of laser by laser transmitter and irradiates object, then by receiver, the echoed signal of target reflection is converted to electric signal, then obtains the distance value of measurement mechanism to object through the laser radar processor.The mode that the conventional laser range cells adopts single-point emission, single-point to receive, high to laser instrument repetition requirement, need the imaging of cooperative mechanical scanister ability, not only volume is large, power consumption is large, and has reduced image taking speed, has limited its range of application.
The deficiency of surveying in order to overcome the scan-type single-point, the face battle array that begins one's study in the world lidar measurement device, at present, mainly adopt ICCD(Intensified Charge-coupled Device) be that image intensifying type charge coupled cell planar array detector carries out three-dimensional imaging.Chinese invention patent instructions CN101498786A and " photoelectric project " periodical the 40th the 2nd phase of volume " staring imaging laser radar based on planar array detector " of February in 2013, the research that the ICCD planar array detector carries out the no-raster three-dimensional imaging is all disclosed, but this mode comes with some shortcomings, one: the ICCD planar array detector can not directly obtain range information, need to adopt modulation demodulation system, and at least two width intensity images just can calculate range image, cause data processing amount large, require very high to processor and storage space simultaneously; Its two: owing to adopting modulation demodulation system, must use the modulator of additional high-pressure modulation power source while receiving echoed signal, need again to use the detuner of processing intensity image during generating three-dimensional information, it is complicated that these additional devices cause this lidar measurement device to be realized, and volume weight is still larger, be difficult to accomplish small-sized; Its three: the range error obtained in top periodical literature has 0.6m, can not meet the higher low-altitude detection occasion of the accuracy requirement of adjusting the distance.
APD(Avalanche Photo Diode) be that the avalanche photodide planar array detector is the N integrated by a plurality of independent APD single-element detectors * N APD detector array, its compact conformation, volume are little, lightweight.Compare the APD single-element detector, can realize non-scanning laser detection, monopulse gets final product three-dimensional imaging; Compare the ICCD detector, the APD detector array can directly obtain three-dimensional information, and image taking speed is faster, and system architecture is simple.
The single-point laser distance measuring method is compared in the laser ranging of face battle array, the single-pulse laser of its emission larger target area of need to throwing light on, while carrying out long-range detection, require single-pulse laser to reach high peak power, these research and development to laser instrument have proposed very high requirement, and can cause laser instrument volume, weight and cost to increase.
Summary of the invention
The purpose of this utility model is the problem existed in order to solve existing lidar measurement device presented above, and a kind of battle array lidar measurement device is provided.Measurement mechanism of the present utility model is without scanning, but the monopulse three-dimensional imaging, image taking speed is fast, measuring accuracy and high efficiency, and also volume weight significantly reduces, and is applicable to the small-sized remote-sensing flatform in low latitude and carries.
Of the present utility model battle array lidar measurement device realized from following four aspects, one: proposed based on N * N APD(N>=8) the face battle array laser radar distance-finding method of detector array, adopt the APD planar array detector of researching and developing recently in the world, pass through direct detection mode, without scanister, single pulse energy is surveyed N * N point of a rectangular area, and system architecture is compact, image taking speed is fast, detection efficiency is high.Its two: select high resolving power timing chip development multi-channel high-accuracy time interval measurement module, but the N of each parallel measurement laser shuttle flight
2the road time difference, can calculate the range information of N * N target measurement point on search coverage according to the laser ranging formula, the results showed that range error is less than 0.12m.Its three: lidar measurement device of the present utility model is integrated in one position and attitude measurement subsystem, main control subsystem and face battle array laser radar range finding subsystem three, reduced the measurement mechanism volume, removed from and used front assembling and parameter calibration again, improved service efficiency; Its four: the utility model is based on low-altitude remote sensing application, can select peak power be not very high small-sized pulsed laser as light source, further reduced size and the weight of lidar measurement device.
Of the present utility model battle array lidar measurement device, comprise position and attitude measurement subsystem, main control subsystem and face battle array laser radar range finding subsystem.
The position and attitude measurement subsystem is by GPS(Global Positioning System) be that GPS receiver and attitude measurement module form.
The main control subsystem is comprised of microcontroller, timer and storer.
Face battle array laser radar range finding subsystem by pulse laser transmitter module, collimation lens, light splitting piece, total reflective mirror, expand diversing lens, PIN high speed optoelectronic detecting module, receiver lens, focal plane adjustable lens, filter plate, APD array detection module and multi-channel high-accuracy time interval measurement module and form.
The GPS receiver is for providing PPS(pulses per second) be pps pulse per second signal as the enabling signal of this measurement mechanism and the longitude and latitude, elevation and the UTC(Coordinated Universal Time that obtain this measurement mechanism) be the Coordinated Universal Time(UTC) temporal information; The attitude measurement module is for obtaining course angle, the angle of pitch and the angle of roll information of this measurement mechanism.
Microcontroller is as the control center of this measurement mechanism, start the work of this measurement mechanism under the triggering of PPS signal, control the timer timing, read the positional information of GPS receiver, control attitude measurement module work and read its attitude information, trigger pulse laser emitting module Emission Lasers, read multi-channel high-accuracy time interval measurement module time data and be converted into range information again, and these three kinds of information are added to the time synchronized label is kept at storer; Storer is the legerity type mass storage, the data that gather for storing this measurement mechanism; Timer receives that at microcontroller the PPS signal starts timing, record GPS receiver location, attitude measurement module survey appearance, the time difference in these three moment of pulse laser transmitter module Emission Lasers, and using the time difference as three's time synchronized label, the data unification that the UTC time that the GPS of take provides gathers their as benchmark is to UTC on the time, thereby reaches synchronous purpose.
The pulse laser transmitter module need to possess high power, burst pulse, characteristic that output frequency is adjustable, as the transmitting illuminant of this measurement mechanism, its operation wavelength need to filter plate and APD array detection module coupling; Collimation lens and expand diversing lens and form optical transmitting system, receiver lens, focal plane adjustable lens and filter plate form receiving optics, and optical transmitting system and receiving optics adopt the transmission-type telescope mode of light transmitting/receiving parallel optical structure; Optical transmitting system shines target for the laser beam of collimated pulses laser emitting module emission and after expanding, and the requirement that the laser beam divergence size after collimation meets once required detection of a target area according to detection range is determined; Light splitting piece and total reflective mirror form spectroscope and are divided into for the laser by after collimation the two bundle laser that splitting ratio is very large; PIN high speed optoelectronic detecting module is surveyed the compare little mono-road laser that light splitting piece separates, as the sign in the Laser emission moment and the commencing signal of multi-channel high-accuracy time interval measurement module; The laser that receiver lens in receiving optics reflects for receiving target also focuses on the focal plane adjustable lens, need meet the requirement at APD array detection module field of view of receiver angle, wherein the focal plane adjustable lens is assembled position and the size of rear laser focal plane for regulating receiver lens, guarantee that echoed signal covers whole photosurface, coordinate receiver lens to meet optical power density and the requirement of field of view of receiver angle, the laser that filter plate is outer for the filtering operation wavelength, the interference of Background suppression light; APD array detection module is N * N(N of being operated in linear model>=8) array avalanche optoelectronic detecting module, echoed signal produces N after processing by photodetection and signal
2the road stop signal, its avalanche voltage is provided by boosting by low-voltage dc power supply, and bias voltage and comparator reference level are adjustable, and output impedance and multi-channel high-accuracy time interval measurement module meet impedance matching; Multi-channel high-accuracy time interval measurement module is for measuring the N of laser shuttle flight
2the road time interval, then calculate the N that represents a rectangular area according to the laser ranging formula
2individual target measurement point range information, multi-channel high-accuracy time interval measurement module channels number is more than or equal to the unit number of APD array, and for obtaining high-precision range information, each passage need meet the high-precision timing requirement.
The job step of of the present utility model battle array lidar measurement device is:
(1) after microcontroller is received the PPS signal of GPS receiver generation, the triggering timing device starts timing.
(2) microcontroller reads the GPS receiver positional information and UTC temporal information are kept in storer, then control the work of attitude measurement module, read the attitude information of its output and add that the time synchronized label is saved in storer.
(3) microprocessor controls peripheral drive circuit output Transistor-Transistor Logic level, trigger pulse laser emitting module Emission Lasers, the laser sent produces the two-way laser signal by light splitting piece after the collimation lens collimation, the fraction laser of reflection enters PIN high speed optoelectronic detecting module by total reflective mirror and produces commencing signal and Laser emission moment supervisory signal, and the START that inputs respectively multi-channel high-accuracy time interval measurement module holds and the middle fracture of microcontroller, most of laser of transmission irradiates target through expanding diversing lens, the laser that target reflects focuses on the focal plane adjustable lens through receiver lens, then converge to APD array detection module by filter plate and produce N
2the road stop signal, input respectively the N of multi-channel high-accuracy time interval measurement module
2individual STOP end, the N that the duplex high precision timing obtains
2the road time data is transferred to microcontroller by serial ports, then is converted into by the laser ranging formula N that represents a rectangular area
2individual distance value, be saved in storer after adding the time synchronized label.
(4) repeating step (2) and step (3) work, until obtain the original three-dimensional information of whole imaging region.
(5) treat that remote-sensing flatform landing ground, through Data Post, generates accurate 3-D view.
The relative prior art of the utility model mainly contains following advantage:
1) the utility model selects high resolving power timing chip to develop multi-channel high-accuracy time interval measurement module, but each parallel measurement N
2the road laser shuttle flight time difference, can obtain the range information that target detection zone error is about 0.12m.
2) compare the simple scan laser radar, the utility model has been realized non-scanning laser detection, and single laser pulse gets final product the generating three-dimensional image, and imaging efficiency is high, to the laser instrument repetition, requires low; Compare ICCD face battle array detecting laser radar, the utility model, without modulation /demodulation, has been simplified system architecture, but fast direct obtain and get three-dimensional information, meet small-sized remote-sensing flatform and carry requirement.
3) the utility model is integrated in one position and attitude measurement subsystem, main control subsystem and face battle array laser radar range finding subsystem three, can be on remote-sensing flatform the original three-dimensional information of Real-time Obtaining, and exempted each subsystem assembling and parameter calibration again while using.
4) the utility model is based on the low-altitude remote sensing application, can select peak power is not that very high small-sized pulsed laser is as light source, size and the weight of lidar measurement device have further been reduced, in addition, during low idle job, the impact of climate condition is less, the spatial domain application is convenient, can more fast come into operation.
The accompanying drawing explanation
Fig. 1 is that of the present utility model battle array lidar measurement device carries the work schematic diagram on unmanned plane.
Fig. 2 is of the present utility model battle array lidar measurement apparatus structure theory diagram.
Mark in figure: 1-position and attitude measurement subsystem; The 101-GPS receiver; 102-attitude measurement module.
2-main control subsystem; The 201-microcontroller; The 202-timer; The 203-storer.
3-face battle array laser radar range finding subsystem; 301-pulse laser transmitter module; The 302-collimation lens; The 303-light splitting piece; The 304-total reflective mirror; 305-expands diversing lens; 306-PIN high speed optoelectronic detecting module; The 307-receiver lens; 308-focal plane adjustable lens; The 309-filter plate; 310-APD array detection module; 311-multi-channel high-accuracy time interval measurement module.
Embodiment
Below in conjunction with drawings and the specific embodiments, the utility model is further described.
Embodiment:
Work schematic diagram as shown in Figure 1, the lidar measurement device of the present embodiment carries and carry out 3-D data collection work on the SUAV (small unmanned aerial vehicle) of 200m low latitude, launching single laser pulse is the target area of detectable 5m * 5 m, the 3-D view distance error generated is less than 0.12m, and pel spacing is 0.625m.
As shown in Figure 2, face battle array lidar measurement device comprises position and attitude measurement subsystem 1, main control subsystem 2 and face battle array laser radar range finding subsystem 3.
Position and attitude measurement subsystem 1 is comprised of GPS receiver 101 and attitude measurement module 102.
Main control subsystem 2 is comprised of microcontroller 201, timer 202 and storer 203.
Face battle array laser radar range finding subsystem 3 by pulse laser transmitter module 301, collimation lens 302, light splitting piece 303, total reflective mirror 304, expand diversing lens 305, PIN high speed optoelectronic detecting module 306, receiver lens 307, focal plane adjustable lens 308, filter plate 309, APD array detection module 310 and multi-channel high-accuracy time interval measurement module 311 and form.
Collimation lens 302 and expand diversing lens 305 and form optical transmitting systems, receiver lens 307, focal plane adjustable lens 308 and filter plate 309 form receiving optics, and optical transmitting system and receiving optics adopt the transmission-type telescope mode of light transmitting/receiving parallel optical structure.
Described GPS receiver 101, for the PPS signal is provided, the positional information of UTC temporal information and this measurement mechanism, adopt the DGPS Receiver of the Canadian NovAtel OEMV-2 of company model, the horizontal level precision is 0.45m, renewal frequency can reach 50HZ, uses the RS232 serial line interface to communicate by letter with microcontroller 201.
Described attitude measurement module 102, for obtaining this measurement mechanism attitude information, adopt Inertial Measurement Unit IMU(Inertial measurement unit) be Inertial Measurement Unit, the Data Update frequency can reach 100HZ, guarantee that at the auxiliary lower of GPS receiver its three attitude errors obtaining are less than 0.08 °, use the RS232 serial line interface to communicate by letter with microcontroller 201.
The microcontroller that described microcontroller 201 is 32 ARM cores, control center as this measurement mechanism, adopt the high phenotype low-power consumption of the STM32 product of ST Microelectronics, clock frequency is up to 120MHZ, 2 USB (Universal Serial BUS) are USB (universal serial bus), nearly 15 of communication interfaces, nearly 17 of 16 and 32 bit timers, carry flash capacity and can reach 1MHZ and energy easy expansion memory capacity.
Described timer 202 starts timing receive the PPS signal of GPS receiver 101 at microcontroller after, record the poor time synchronized label as the three of working time of GPS receiver 101, attitude measurement module 102, pulse laser transmitter module 301, thereby the data unification of their three's collections is reached to synchronous purpose to UTC, the 32 bit timing devices that adopt described microcontroller 201 to carry on the time.
Described storer 203 is the legerity type mass storage, the data that gather for storing this measurement mechanism.Adopting SD card (Secure Digital Memory Card) is safe digital card, and its weight only has 1.5g, and capacity reaches 32GB, and access speed is up to 30MB/s.
Described pulse laser transmitter module 301, as the transmitting illuminant of this measurement mechanism, adopt output center wavelength 905nm, pulsewidth 8ns, peak power 29kw, the pulse microchip laser module that repetition frequency is adjustable.
Described collimation lens 302 and the transmission-type optical transmitting system that expands diversing lens 305 compositions, shine target for the laser beam of collimated pulses laser emitting module emission and after expanding, laser beam divergence after collimation is 35mrad, for improving the described collimation lens 302 of emission efficiency, needs plating 905nm anti-reflection film.
Described light splitting piece 303, by the two bundle laser that to be divided into the ratio of reflected light and transmitted light be 1:999 of the laser after collimation.
Described total reflective mirror 304, the compare little mono-road laser that light splitting piece 303 is separated incides PIN high speed optoelectronic detecting module 306.
Described PIN high speed optoelectronic detecting module 306, for surveying the laser by total reflective mirror 304 incidents, the electric impulse signal produced is as the sign in the Laser emission moment and the commencing signal of multi-channel high-accuracy time interval measurement module 311, in employing, the GT106 high speed PIN photodiode of 44 of electric sections is surveyed the laser of incident, then by trans-impedance amplifier circuit and the required electric impulse signal of high-speed comparator circuit evolving.
The non-spherical lens that described receiver lens 307 is bore 120mm, focal length 100mm, the laser reflected for receiving target also focuses on focal plane adjustable lens 308, for improving the described receiver lens 307 plating 905nm anti-reflection films of receiving efficiency.
Laser focal plane position and size that described focal plane adjustable lens 308 is assembled for regulating receiver lens 307, guarantee that echoed signal covers whole photosurface, meet optical power density and the requirement of field of view of receiver angle, for improving the described focal plane of receiving efficiency adjustable lens 308 plating 905nm anti-reflection films.
Described filter plate 309 is bandwidth ± 10nm, and the 905nm filter plate that transmitance is greater than 85%, for the laser outside the filtering operation wavelength, the interference of Background suppression light.
Described APD array detection module 310 is the avalanche optoelectronic detecting module of the N that is operated in linear model * N array, the echoed signal of field of view of receiver scope, APD array by 8 * 8 carries out independently processing generation 64 tunnel stop signals across resistance operational amplifier and comparer two-stage circuit at a high speed by 64 after photodetection, realizes the photodetection of a face.Adopt 8 * 8 APD arrays of first sensor company, the responsiveness at the 905nm place is 60A/W, and its avalanche voltage is 200V, and HVB high voltage bias voltage is boosted and obtained by the 5V power supply, and bias voltage and comparator reference level are adjustable, 50 ohm of output impedance.
50 ohm of described multi-channel high-accuracy time interval measurement module 311 input impedance, for measuring the multichannel time difference of laser shuttle flight, and then obtain the target measurement point range information that represents a rectangular area.Adopt 8 passage TDC-GPX chips of timing resolution 81 psecs of German ACAM company, at ARM core micro-control unit or FPGA(Field-Programmable Gate Array) be by sheet, to select under the control of field programmable gate array, use 8 TDC-GPX chips to develop, but in the time interval of the relative commencing signal of 64 tunnel stop signal of parallel measurement APD array detection module 310 outputs, this module adopts USB interface to communicate by letter with microcontroller 201.
The job step of this measurement mechanism is:
(1) after microcontroller is received the PPS signal of GPS receiver 101 generations, triggering timing device 202 starts timing.
(2) microcontroller 201 reads GPS receiver 101 positional information and UTC temporal information are kept in storer 203, then control 102 work of attitude measurement module, read the attitude information of its output and add that the time synchronized label is saved in storer 203.
(3) microcontroller 201 is controlled peripheral drive circuit output Transistor-Transistor Logic level trigger pulse laser emitting module 301 Emission Lasers, the laser sent produces the two-way laser signal by light splitting piece 303 after collimation lens 302 collimations, the fraction laser of reflection enters PIN high speed optoelectronic detecting module 306 by total reflective mirror 304 and produces commencing signal and Laser emission moment supervisory signal and input respectively the START end of multi-channel high-accuracy time interval measurement module 311 and the middle fracture of microcontroller 201, most of laser of transmission irradiates target through expanding after diversing lens 305 expands, the laser that target reflects focuses on focal plane adjustable lens 308 through receiver lens 307, then converge to APD array detection module 310 by filter plate 309 and produce 64 STOP ends that 64 tunnel stop signals are inputted respectively multi-channel high-accuracy time interval measurement module 311, the 64 road time datas that the duplex high precision timing obtains are transferred to microcontroller 201 by serial ports, be converted into by the laser ranging formula the 64 road distance values that represent the square target area of 5m * 5m again, after adding the time synchronized label, be saved in storer 203.
(4) repeating step (2) and step (3) work, until obtain the original three-dimensional information of the desired imaging region of task.
(5) treat that unmanned plane landing ground, through Data Post, generates accurate 3-D view.
Above disclosed be only an embodiment of the present utility model; but the utility model is not limited thereto; for the person of ordinary skill of the art, under the prerequisite that does not break away from the utility model principle, the distortion of making should be considered as belonging to the utility model protection domain.