A long-range photon laser radar scanning method and system

Abstract

The present invention relates to a long-range photon laser radar scanning method and system thereof, belonging to the field of laser radar scanning technology, and solves the problem in the prior art that the long-range photon laser radar has a long dead time and cannot receive the target echo signal in real time, resulting in radar space omission. The method includes: obtaining the laser operating frequency, setting the detector operating frequency according to the laser operating frequency, and obtaining the effective detection time of the detector within a detection cycle; determining the unit gating delay of the detector according to the effective detection time of the detector within a detection cycle; setting a plurality of different gating delays according to the unit gating delay and the operating frequency of the detector, and determining the total number of a plurality of different gating delays; within a scanning cycle, the laser continuously emits pulsed lasers, and the detector works in each different gating delay in turn to receive the pulsed laser echo signal. The laser radar system realizes efficient full coverage scanning of the target airspace to be scanned.

Description

Technical Field

[0001] The present invention relates to the field of laser radar scanning technology, and in particular to a long-range photon laser radar scanning method and system thereof. Background Art

[0002] Single-photon detector (SPD) is a highly sensitive photoelectric detector that can respond to photon-level signals and is the basis for single-photon radar detection, quantum communication and other fields. With the continuous development of basic software and hardware technologies, single-photon laser non-scanning lidar 3D imaging detection technology based on Geiger focal plane camera has attracted more and more attention, and many research results have been introduced, which have greatly improved the range and imaging effect, and have high application value.

[0003] However, in order to reduce noise interference and the large amount of detection data transmission requires a long time, the existing Geiger focal plane camera mainly works in a gated state, that is, the camera needs a gated signal to work, otherwise it cannot receive the signal; in addition, after the camera is opened once, it needs a long dead time to recover, and the effective duty cycle of the working time period is relatively low. Therefore, it has the following disadvantages in actual use:

[0004] 1. It is necessary to obtain prior information about the target distance and calculate the accurate arrival time of the echo signal based on the target distance in order to effectively control the delay of the gate signal so that it opens the gate at the moment the echo signal arrives. However, in the actual operation of the LiDAR, the target distance is often unknown and may change at a relatively fast speed, which causes the arrival time of the echo pulse to change in real time, making it unsuitable for detecting high-speed dynamic targets.

[0005] 2. The camera has a long dead time. After completing a detection, it needs a long dead time to restore to the initial state. Taking an existing Geiger focal plane camera as an example, its maximum operating frequency is 25kHz and the longest effective detection time is 4μs. That is, in a working cycle of up to 40μs, only 1 / 10 of the time can receive signals normally, and the rest of the time is dead time, and real-time standby state cannot be achieved. This also causes a large number of spatial omissions in the lidar.

[0006] Therefore, the prior art lacks a long-range photonic laser radar scanning method and system that can achieve full-coverage spatial scanning. Summary of the invention

[0007] In view of the above analysis, an embodiment of the present invention aims to provide a long-range photon laser radar scanning method and system to solve the problem that the existing long-range photon laser radar has a long dead time and cannot receive the target echo signal in real time, resulting in radar spatial omissions.

[0008] On the one hand, an embodiment of the present invention provides a long-range photon laser radar scanning method, comprising:

[0009] Obtaining the laser operating frequency, setting the detector operating frequency according to the laser operating frequency, and obtaining the effective detection time of the detector within a detection cycle;

[0010] Determine the unit gate delay of the detector according to the effective detection time of the detector within the one detection cycle;

[0011] According to the unit gating delay and the working frequency of the detector, a plurality of different gating delays are set, and a total number of the plurality of different gating delays is determined;

[0012] In one scanning cycle, the laser continuously emits pulsed laser, and the detector works in each different gate delay in turn to receive the pulsed laser echo signal.

[0013] Further, determining the unit gating delay of the detector according to the effective detection time of the detector in the one detection cycle includes: setting the unit gating delay Δt of the detector to the effective detection time in the one detection cycle.

[0014] Furthermore, according to the unit gating delay and the working frequency of the detector, a plurality of different gating delays are set, and the total number of the plurality of different gating delays is determined, as follows:

[0015] t i =(i-1)Δt

[0016]

[0017] Among them, t i is the i-th gate delay, i = 1, 2, … m, m is the total number of different gate delays, Δt is the unit gate delay, and f2 is the operating frequency of the detector.

[0018] Further, setting the detector operating frequency according to the laser operating frequency includes: setting the detector operating frequency to an integer multiple of the laser operating frequency;

[0019] The detector synchronization times n corresponding to one working cycle of the laser are determined according to the working frequency of the laser and the working frequency of the detector, wherein the detector synchronization times n is expressed as:

[0020] n=f2 / f1

[0021] Among them, f1 is the operating frequency of the laser, and f2 is the operating frequency of the detector.

[0022] Furthermore, in one scanning cycle, the laser continuously emits pulsed laser, the detector works in turn under each different gate delay, and receiving the pulsed laser echo signal includes:

[0023] At the i-th gate delay, the laser emits N pulse lasers continuously, and the detector emits N pulse lasers at t i =(i-1)Δt gate delay, continuously performing the detection work of the N pulse laser beams, and each pulse laser beam performs n detections;

[0024] Where i = 1, 2, ... m, n is the number of detector synchronizations, and Δt is the unit gate delay;

[0025] N is a constant, and its value is determined according to the scanning accuracy requirements of the long-range photon laser radar.

[0026] Furthermore, the laser emits a laser synchronization signal while emitting pulsed laser, and the detector is synchronized with the operation of the laser according to the laser synchronization signal.

[0027] On the other hand, an embodiment of the present invention provides a long-range photon laser radar scanning system, comprising:

[0028] A laser, for emitting pulsed laser;

[0029] A detector, used for receiving a pulse laser echo signal;

[0030] An operating frequency setting module, used to obtain the operating frequency of the laser, set the operating frequency of the detector according to the operating frequency of the laser, and obtain the effective detection time of the detector within a detection cycle;

[0031] A unit gating delay calculation module, used to determine the unit gating delay of the detector according to the effective detection time of the detector within the one detection cycle;

[0032] A gate delay setting module, used to set a plurality of different gate delays according to the unit gate delay and the working frequency of the detector, and determine the total number of the plurality of different gate delays;

[0033] The scanning control module is used to control the laser to continuously emit pulsed laser within a scanning cycle, control the detector to work in each different gate delay in turn, and receive the pulsed laser echo signal.

[0034] Furthermore, the unit gate delay calculation module is further used to set the unit gate delay Δt of the detector as the effective detection time in the one detection cycle.

[0035] Furthermore, the operating frequency setting module is also used to set the operating frequency of the detector to an integer multiple of the operating frequency of the laser;

[0036] The detector synchronization times n corresponding to a laser working cycle are determined according to the working frequency of the laser and the working frequency of the detector, wherein the detector synchronization times n is expressed as:

[0037] n=f2 / f1

[0038] Among them, f1 is the operating frequency of the laser, and f2 is the operating frequency of the detector.

[0039] Furthermore, the scanning control module is also used to control the laser to continuously emit N pulse lasers under the i-th gate delay, and control the detector to emit N pulse lasers at t i =(i-1)Δt gate delay, continuously performing the detection work of the N pulse laser beams, and each laser beam performs n detections;

[0040] Where i = 1, 2, ... m, n is the number of detector synchronizations, and Δt is the unit gate delay;

[0041] N is a constant, and the value of N is determined according to the scanning accuracy requirements of the long-range photon laser radar.

[0042] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0043] 1. In the present invention, the unit gating delay is set according to the effective detection time of the detector within a detection cycle. According to the unit gating delay, full coverage of all time periods of length T can be achieved, that is, full coverage of the target airspace is achieved, which is suitable for tracking high-speed moving targets;

[0044] 2. The laser and single-photon detector work at a frequency of 1:n, that is, the laser works once and the detector works n times, with high scanning efficiency, which can effectively improve the scanning speed of the target airspace;

[0045] 3. Continuously detect the same target airspace N times, and the detection results have good correlation, which is conducive to the detection of high-speed moving targets.

[0046] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0048] Figure 1 A flow chart of a long-range photon laser radar scanning method shown in one embodiment of the present application;

[0049] Figure 2 A schematic diagram of the number of synchronizations between the laser and the detector shown in one embodiment of the present application;

[0050] Figure 3 This is a schematic diagram of the architecture of a planar single-photon laser radar system shown in one embodiment of the present application;

[0051] Figure 4 A schematic diagram of synchronous control of a laser and a detector shown in one embodiment of the present application;

[0052] Figure 5 This is a schematic diagram of the detector working delay control shown in one embodiment of the present application;

[0053] Figure 6 This is a schematic diagram of spatial scanning shown in an embodiment of the present application. DETAILED DESCRIPTION

[0054] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0055] During the operation of the single-photon laser radar system, the target distance is unknown, and the array detector has a long dead time. During the long dead time, it cannot cover the entire detection space and cannot receive the laser echo signal reflected by the target in real time. This application uses the high frame rate of the laser radar, through strict timing control logic, and uses a spatial splicing method to ensure that the laser radar system can efficiently and fully scan the target airspace to be scanned.

[0056] Embodiment 1:

[0057] A specific embodiment of the present invention discloses a long-range photon laser radar scanning method, such as Figure 1 As shown, including:

[0058] S10, obtaining a laser operating frequency, setting a detector operating frequency according to the laser operating frequency, and obtaining an effective detection time of the detector within a detection cycle; specifically, setting the detector operating frequency according to the laser operating frequency includes: setting the detector operating frequency to an integer multiple of the laser operating frequency;

[0059] Specifically, Figure 2 As shown, the detector synchronization times n corresponding to one working cycle of the laser are determined according to the working frequency of the laser and the working frequency of the detector, that is, after the laser emits a laser pulse, the detector works synchronously n times; wherein, the detector synchronization times n is expressed as:

[0060] n=f2 / f1

[0061] Among them, f1 is the operating frequency of the laser, and f2 is the operating frequency of the detector.

[0062] S20 , determining a unit gating delay of the detector according to the effective detection time of the detector in the one detection cycle, including: setting the unit gating delay Δt of the detector as the effective detection time in the one detection cycle.

[0063] S30, according to the unit gating delay and the working frequency of the detector, setting a plurality of different gating delays, and determining the total number of the plurality of different gating delays, as follows:

[0064] t i =(i-1)Δt

[0065]

[0066] Among them, t i is the i-th gate delay, i = 1, 2, … m, m is the total number of different gate delays, Δt is the unit gate delay, and f2 is the operating frequency of the detector.

[0067] Specifically, the laser emits a laser synchronization signal while emitting a pulsed laser, and the detector is synchronized with the laser according to the laser synchronization signal. More specifically, Figure 3 As shown, the long-range photon laser radar scanning system includes a laser, a laser receiving module, a single photon array detector, and a control and data processing module, and the control and data processing module includes: an operating frequency setting module, a unit gated delay calculation module, a gated delay setting module, and a scanning control module. The functions of each module will be described in detail in Example 2.

[0068] The laser and detector work synchronously. The laser emits light at a certain frequency, and the detector also opens at a certain frequency, such as Figure 4As shown, the laser emits light at the rising edge of the light output signal, and the detector starts working at the rising edge of the detector gate signal. The time interval between the rising edge of the laser light output signal and the rising edge of the detector trigger signal is t, and the time difference t between the laser light output and the detector door opening is controllable. Optionally, Δt can be changed according to the effective working time of the detector during operation. More specifically, by controlling the gate delay t of the single-photon detector i , which enables the detector to receive echo data of the target in different time periods.

[0069] Specifically, Figure 5 As shown, taking m = 4 as an example, after the laser emits light, the gate delay t i Then the detector starts to receive the echo signal. After receiving the gate signal, the detector works continuously for T / 4, where T is the frame period of the array detector T = 1 / f2. By controlling the gate delay t of the array detector i 0, T / 4, T / 2, 3T / 4, thereby achieving full coverage of all time periods with a length of T.

[0070] S40, in one scanning cycle, the laser continuously emits pulsed laser, and the detector works in each different gate delay in turn to receive the pulsed laser echo signal, including:

[0071] At the i-th gate delay, the laser emits N pulse lasers continuously, and the detector emits N pulse lasers at t i =(i-1)Δt gate delay, continuously perform N pulse laser detection work, and each pulse laser realizes n detections;

[0072] Where i = 1, 2, ... m, n is the number of detector synchronizations, and Δt is the unit gate delay;

[0073] N is a constant. The value of N is determined according to the scanning accuracy requirements of the long-range photon lidar. The system repeats N consecutive detections on the same delay to obtain N detection results with good correlation.

[0074] Specifically, through the close coordination of several control signals f1, f2, and Δt, seamless scanning of the target airspace is achieved, such as Figure 6As shown in the figure, the arrow indicates that the laser emits a pulse laser, and the rectangular box indicates that the detector outputs a frame of data, that is, completes a detection. The gray part in the rectangular box indicates the effective working time of the detector, and the white part indicates the dead time of the detector. The effective working time accounts for 1 / m of the entire frame period T. The photon counting detector needs to detect N beams of pulse lasers before it can achieve the target detection required by the scanning accuracy. The working frequency f2 of the detector is n times the working frequency f1 of the laser. n, m, N, are all positive integers. In a scanning cycle, the detector works in each gated delay in turn to receive the pulse laser echo signal. The specific steps are as follows:

[0075] (1) As shown in the first group of data, in the initial state, the detector gate delay t1 is set to 0, the laser emits 1 laser pulse, the detector detects n times, and the effective working time of each detection is T / m;

[0076] (2) maintaining the gate delay setting in (1), repeatedly detecting the N beams of pulsed laser light, and obtaining the detection results of the N beams of pulsed laser light under the delay state;

[0077] (3) As shown in the second group of data, the laser outputs the N+1th laser pulse, the gate delay t2 of the detector is set to T / m, and the setting is maintained until the 2Nth laser pulse, and the detection results of the Nth pulse laser under the delay state are obtained;

[0078] (4) The gate delays of the 3rd, 4th, ..., mth groups of data detectors are set to t3 = 2T / m, t4 = 3T / m, ...t m =(m-1)T / m, repeat the above operation until the mth group of data is finished, thus completing a full coverage scan of the space;

[0079] (5) Reset the detector gate delay to 0, repeat the above (1) to (4) operations, and start the next round of scanning of the space.

[0080] Compared with the prior art, the long-range photon laser radar scanning method of the present invention sets the unit gating delay according to the effective detection time of the detector within a detection cycle. According to the unit gating delay, full coverage of all time periods with a length of T can be achieved, that is, full coverage of the target airspace is achieved, which is suitable for tracking high-speed moving targets; the laser and the single-photon detector have a 1:n operating frequency, that is, the laser works once and the detector works n times, and the scanning efficiency is high, which can effectively improve the scanning speed of the target airspace; continuous N repeated detections are achieved on the same target airspace, and the detection results have good correlation, which is conducive to the detection of high-speed moving targets.

[0081] Embodiment 2:

[0082] A specific embodiment of the present invention discloses a long-range photon laser radar scanning system, such as Figure 3 As shown, including:

[0083] A laser, for emitting pulsed laser;

[0084] A detector, used for receiving a pulse laser echo signal;

[0085] The control and data processing module is used to control the laser and detector and perform data processing.

[0086] The control and data processing module includes: an operating frequency setting module, a unit gate delay calculation module, a gate delay setting module, and a scanning control module.

[0087] In order to receive the pulse laser echo signal, the scanning system further includes a laser receiving module. The laser receiving module uses an optical system to receive the laser echo and sends the received laser echo signal to the detector.

[0088] The working frequency setting module 10 is used to obtain the working frequency of the laser, set the working frequency of the detector according to the working frequency of the laser, and obtain the effective detection time of the detector within a detection cycle; more specifically, the working frequency setting module is used to set the working frequency of the detector to an integer multiple of the working frequency of the laser; determine the corresponding number of detector synchronizations n within a laser working cycle according to the working frequency of the laser and the working frequency of the detector, wherein the number of detector synchronizations n is expressed as:

[0089] n=f2 / f1

[0090] Among them, f1 is the operating frequency of the laser, and f2 is the operating frequency of the detector.

[0091] The unit gating delay calculation module 20 is used to determine the unit gating delay of the detector according to the effective detection time of the detector within the one detection cycle; more specifically, the unit gating delay calculation module is used to set the unit gating delay Δt of the detector to the effective detection time within the one detection cycle.

[0092] A gate delay setting module 30, for setting a plurality of different gate delays according to the unit gate delay and the working frequency of the detector, and determining the total number of the plurality of different gate delays;

[0093] The scanning control module 40 is used to control the laser to continuously emit pulsed lasers in a scanning cycle, and control the detector to work in each different gate delay in turn to receive the pulsed laser echo signal. More specifically, the detection module is used to control the laser to continuously emit N pulsed lasers at the i-th gate delay, and control the detector to work at t i =(i-1)Δt gate delay, continuously perform N laser beam detection work, and each laser beam realizes n detections;

[0094] Where i = 1, 2, ... m, n is the number of detector synchronizations, and Δt is the unit gate delay;

[0095] N is a constant, and the value of N is determined according to the scanning accuracy requirements of the long-range photon laser radar.

[0096] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0097] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A long-range photon laser radar scanning method, characterized in that: include: Obtaining the laser operating frequency, setting the detector operating frequency according to the laser operating frequency, and obtaining the effective detection time of the detector within a detection cycle; Determine the unit gate delay of the detector according to the effective detection time of the detector within the one detection cycle; According to the unit gating delay and the working frequency of the detector, a plurality of different gating delays are set, and a total number of the plurality of different gating delays is determined; In one scanning cycle, the laser continuously emits pulsed laser, and the detector works in each different gate delay in turn to receive the pulsed laser echo signal; The method of setting a plurality of different gating delays according to the unit gating delay and the working frequency of the detector and determining the total number of the plurality of different gating delays is as follows: t i =(i-1)Δt Among them, t i is the i-th gate delay, i = 1, 2, … m, m is the total number of different gate delays, Δt is the unit gate delay, and f2 is the operating frequency of the detector.

2. The long-range photon laser radar scanning method according to claim 1, characterized in that: Determining the unit gating delay of the detector according to the effective detection time of the detector in the one detection cycle includes: setting the unit gating delay Δt of the detector as the effective detection time in the one detection cycle.

3. The long-range photon laser radar scanning method according to claim 2, characterized in that: The step of setting the detector operating frequency according to the laser operating frequency comprises: setting the detector operating frequency to an integer multiple of the laser operating frequency; The detector synchronization times n corresponding to one working cycle of the laser are determined according to the working frequency of the laser and the working frequency of the detector, wherein the detector synchronization times n is expressed as: n=f2 / f1 Among them, f1 is the operating frequency of the laser, and f2 is the operating frequency of the detector.

4. The long-range photon laser radar scanning method according to claim 3, characterized in that: In one scanning cycle, the laser continuously emits pulsed laser, the detector works in each different gate delay in turn, and receiving the pulsed laser echo signal includes: At the i-th gate delay, the laser emits N pulse lasers continuously, and the detector emits N pulse lasers at t i =(i-1)Δt gate delay, continuously performing the detection work of the N pulse laser beams, and each pulse laser beam performs n detections; Where i = 1, 2, ... m, n is the number of detector synchronizations, and Δt is the unit gate delay; N is a constant, and its value is determined according to the scanning accuracy requirements of the long-range photon laser radar.

5. The long-range photon laser radar scanning method according to claim 4, characterized in that: The laser emits a laser synchronization signal while emitting pulsed laser, and the detector realizes operation synchronization with the laser according to the laser synchronization signal.

6. A long-range photon laser radar scanning system, characterized in that: include: A laser, for emitting pulsed laser; A detector, used for receiving a pulse laser echo signal; An operating frequency setting module, used to obtain the operating frequency of the laser, set the operating frequency of the detector according to the operating frequency of the laser, and obtain the effective detection time of the detector within a detection cycle; A unit gating delay calculation module, used to determine the unit gating delay of the detector according to the effective detection time of the detector within the one detection cycle; The method of setting a plurality of different gating delays according to the unit gating delay and the working frequency of the detector and determining the total number of the plurality of different gating delays is as follows: t i =(i-1)Δt Among them, t i is the i-th gate delay, i = 1, 2, ... m, m is the total number of different gate delays, Δt is the unit gate delay, and f2 is the operating frequency of the detector; A gate delay setting module, used to set a plurality of different gate delays according to the unit gate delay and the working frequency of the detector, and determine the total number of the plurality of different gate delays; The scanning control module is used to control the laser to continuously emit pulsed laser within a scanning cycle, control the detector to work in each different gate delay in turn, and receive the pulsed laser echo signal.

7. The long-range photon laser radar scanning system according to claim 6, characterized in that: The unit gate delay calculation module is further used to set the unit gate delay Δt of the detector as the effective detection time within the one detection cycle.

8. The long-range photon laser radar scanning system according to claim 6, characterized in that: The operating frequency setting module is also used to set the operating frequency of the detector to an integer multiple of the operating frequency of the laser; The detector synchronization times n corresponding to a laser working cycle are determined according to the working frequency of the laser and the working frequency of the detector, wherein the detector synchronization times n is expressed as: n=f2 / f1 Among them, f1 is the operating frequency of the laser, and f2 is the operating frequency of the detector.

9. The long-range photon laser radar scanning system according to claim 6, characterized in that: The scanning control module is also used to control the laser to continuously emit N pulse lasers under the i-th gate delay, and control the detector to emit N pulse lasers at t i =(i-1)Δt gate delay, continuously performing the detection work of the N pulse laser beams, and each laser beam performs n detections; Where i = 1, 2, ... m, n is the number of detector synchronizations, and Δt is the unit gate delay; N is a constant, and the value of N is determined according to the scanning accuracy requirements of the long-range photon laser radar.

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