CN105445749A - Multi-pulse laser range measuring system and multi-pulse laser range measuring method based on wavelength division - Google Patents

Abstract

A multi-pulse laser ranging system and method based on wavelength division, including a laser, a wavelength divider, a transmitting optical path, a receiving telescope, a wavelength demultiplexer, a ranging module and a data synthesis module, and the laser outputs laser to a wavelength Splitter, which outputs multi-channel wavelength signals, and enters the corresponding transmitting optical path to be collimated and then emits. The receiving telescope converges the returned optical signals and injects them into the wavelength demultiplexer, which divides the multiple wavelength signals according to the corresponding The wavelength extraction is sent to multiple distance measuring modules at the back end, and the distance measurement is realized according to different time intervals respectively. The multi-channel measurement results are finally sent to the data synthesis module, which completes the data synthesis according to the wavelength emission sequence, realizing multi-pulse simultaneous Measurement. The invention improves the measurement efficiency of the laser ranging by multiple times, overcomes the limitation of distance ambiguity to a certain extent, is of great significance for reducing the measurement time, and can promote the industrial application of the laser ranging system.

Description

A multi-pulse laser ranging system and method based on wavelength division

technical field

The invention relates to a multi-pulse laser ranging system and method, in particular to a multi-pulse laser ranging system and method based on wavelength division, belonging to the technical field of laser ranging radar.

Background technique

In the laser ranging system, the time-of-flight measurement method is still widely used at present, that is, the time interval between the emission pulse and the echo pulse is used to measure the transmission distance, so as to realize the accurate measurement of the distance. If there are multiple pulses flying at the same time during the measurement, the echo pulses will be confused, thereby confusing the ranging information. Therefore, the frequency of ranging is usually limited to ensure that no distance ambiguity will occur, thus limiting the efficiency of ranging. . In order to achieve multi-pulse laser ranging and avoid the problem of distance ambiguity, the existing ranging system mainly uses multiple laser light sources of the same wavelength to emit at fixed angular intervals, cooperates with multiple receiving terminals corresponding to different fixed field of view angles, and passes through space Angular relationship enables multi-pulse measurement. Because these methods use multiple laser light sources and multiple detectors, the cost is high. Generally, the number of multi-channels does not exceed 8. Single-channel ranging still has the problem of distance ambiguity, so the efficiency is still not high, the configuration is not flexible enough, and it is difficult to promote commercialization. Application and industrialization promotion.

Contents of the invention

The technical solution of the present invention is to overcome the shortcomings of the existing multi-pulse ranging technology, and provide a multi-pulse laser ranging system and method based on wavelength division. For laser pulses, the receiving end uses demultiplexing technology to extract pulse signals of multiple wavelengths for measurement, thereby increasing the measurement efficiency by multiple times, and to a certain extent overcomes the limitation of distance ambiguity, which is of great significance for reducing measurement time , flexible configuration, high cost performance, and can promote the industrial application of the laser ranging system.

The technical solution of the present invention is: a multi-pulse laser ranging system based on wavelength division, including a laser, a wavelength divider, a transmitting optical path, a receiving telescope, a wavelength demultiplexer, a ranging module and a data synthesis module;

The laser signal generated by the laser is input into the wavelength divider, and the wavelength divider selects the wavelength interval according to the required number of division paths to complete the wavelength division, and the multi-channel wavelength signals generated by the wavelength division are respectively output to the corresponding emission optical paths; The optical path collimates the received laser signal and outputs it;

The receiving telescope receives the collimated laser signal and outputs it to the wavelength demultiplexer after converging; the wavelength demultiplexer extracts the received signal according to the wavelength, and outputs the signal of each wavelength to the corresponding A ranging module, the ranging module completes the measurement of the distance of each signal according to the time interval between the sending and receiving pulses, and outputs the measured data to the data synthesis module;

According to the wavelength sequence corresponding to each channel of measurement data, the data synthesizing module splices the multiple channels of measurement data sequentially, completes the synthesis of multiple channels of measurement data, and finally realizes the multi-pulse laser ranging.

The wavelength demultiplexer is located at the focal point of the receiving telescope.

The laser is a semiconductor, solid or fiber laser.

The emitting optical path is a beam collimating mirror for emitting.

The number of multiple wavelength signals generated by the wavelength division is the same as that of the transmitting optical paths, and the multiple wavelength signals generated by the wavelength division correspond to the transmitting optical paths one by one.

A multi-pulse laser ranging method, the steps are as follows:

(1) After the laser pulse signal output by the laser passes through the 1×N wavelength splitter, it forms N-channel laser pulse signals with equal intervals of center wavelength, and outputs them to the transmitting optical path;

(2) The transmitting optical path simultaneously transmits the input laser pulse signals of N wavelengths to realize the parallel transmission of multi-wavelength and multi-pulse laser signals;

(3) The receiving telescope converges the returned N-channel multi-pulse laser signals to the input end of the 1×N-channel wavelength demultiplexer, and the wavelength demultiplexer extracts the N-channel wavelength signals simultaneously according to different central wavelengths during transmission, Realize the division of the receiving wavelength and output it to the ranging module;

(4) The ranging module completes the measurement of the distance of each signal according to the time interval between the sending and receiving pulses, that is, the pulse flight time, according to the input N laser echo pulse signals, and realizes the simultaneous ranging of multi-pulse laser signals;

(5) According to the pulsed laser signal ranging results corresponding to the N wavelengths obtained in step (4), the data synthesis module splices the multi-channel measurement data in sequence according to the wavelength sequence corresponding to the distance measurement results of each channel, and completes the multi-channel measurement data. Synthesis, thus realizing the multi-pulse parallel laser ranging.

The beneficial effect of the present invention compared with prior art is:

(1) The present invention adopts the multi-pulse emission scheme based on wavelength division, and both the wavelength division device and the wavelength demultiplexer can adopt the commercialized wavelength demultiplexer with mature technology, so as to realize the separation of emission wavelength and the separation of reception wavelength respectively. Separation, when it is necessary to further increase the number of multi-pulse channels, it is only necessary to replace the demultiplexer with a different number of demultiplexing channels. System expansion and upgrade are easy and cost-effective;

(2) The present invention adopts multi-pulse laser ranging technology based on wavelength division, which solves the problems of limited measurement frequency and difficult improvement of measurement efficiency in existing laser ranging systems, and can be widely used in laser ranging and scanning systems. Can meet the needs of low-cost system construction.

Description of drawings

Fig. 1 is a system block diagram of the present invention;

Fig. 2 is the working flow diagram of the present invention.

detailed description

Specific embodiments of the present invention will be further described in detail below in conjunction with the accompanying drawings.

Wavelength division and multiplexing technology is already a widely used technology in optical fiber communication, and belongs to the key technology in the field of optical communication technology. Laser ranging belongs to the professional field of laser radar. Based on the technical accumulation in two related fields, the present invention innovatively introduces wavelength division multiplexing technology into the multi-channel laser ranging system, and analyzes the existing multi-pulse laser ranging data The synthesis method has been improved to some extent, and the data synthesis basis has been improved based on the wavelength, thereby realizing a new and more efficient multi-pulse laser ranging device and method based on wavelength division.

Fig. 1 is a system block diagram of the present invention. It can be seen from Fig. 1 that the multi-pulse laser ranging system based on wavelength division in the present invention includes a laser 1, a wavelength divider 2, a transmitting optical path 3, a receiving telescope 4, a wavelength demultiplexer 5, a ranging module 6 and a data synthesis module 7 .

Among them, the laser 1 is a semiconductor, solid-state or fiber laser, which is used to provide the light source required for distance measurement; the wavelength divider 2 is to divide the laser signal emitted by the laser into multiple wavelength lasers according to a certain wavelength interval; the transmitting optical path 3 is for transmitting The beam collimating mirror transmits the laser signals of multiple wavelengths generated by the wavelength splitter at the same time, and the receiving telescope 4 is used to gather and receive the returned laser pulse signals; the wavelength demultiplexer 5 is used to collect the echo signals collected by the receiving telescope Segmentation and extraction are carried out according to the different wavelengths emitted; the distance measurement module 6 performs time and distance measurement and distance measurement on the multiple wavelength signals extracted by the wavelength demultiplexer respectively; the data synthesis module 7 is based on the distance measurement information obtained by multiple distance measurement modules, The distance measurement information is synthesized and stored according to the order of the emitted wavelengths, so as to realize the measurement of multiple targets at the same time and greatly improve the measurement efficiency.

The laser 1 can provide a broadband laser light source that meets the needs of wavelength division;

The wavelength divider 2 selects the wavelength interval according to the number of divisions required, and can simultaneously divide the laser light provided by the laser into a plurality of different wavelengths according to a certain wavelength interval;

The transmitting optical path 3 can simultaneously transmit multiple laser signals of different wavelengths according to the needs of multi-pulse ranging;

The receiving telescope 4 can simultaneously receive the returned pulse signals of multiple wavelengths, and converge them to the wavelength demultiplexer 5;

The wavelength demultiplexer 5 can simultaneously extract the signals of multiple wavelengths according to the wavelength interval and the center wavelength when transmitting;

The distance measuring module 6 can measure distance simultaneously for the received multi-channel wavelength signals respectively, and complete the measurement of the distance of each signal according to the time interval between the sending and receiving pulses, that is, the pulse time of flight;

The data synthesizing module 7 can synthesize multi-channel ranging information according to the wavelength sequence when sending, so as to realize multi-pulse simultaneous measurement;

The multi-pulse laser ranging system based on wavelength division uses wavelength division technology, and realizes multi-pulse simultaneous measurement by realizing simultaneous transmission of multiple wavelength signals at the transmitting end and simultaneous reception of multiple wavelength signals at the receiving end. It has the characteristics of easy realization and high measurement efficiency.

Fig. 2 is a working flow diagram of the present invention. It can be seen from Figure 2 that the distance measurement corresponding to a single wavelength is exactly the same as the ordinary laser distance measurement, multiple wavelengths are emitted at the same time, the distance measurement information of each wavelength is accurately recorded, and the distance measurement information corresponding to multiple wavelengths The final synthesis forms multi-pulse simultaneous measurement results. The method and steps of applying the above-mentioned multi-pulse laser ranging system based on wavelength division to perform multi-pulse laser ranging are as follows:

①Laser wavelength division: after the laser signal output by the ranging light source laser 1 passes through the 1×N wavelength divider 2, according to the wavelength interval △λ=the emission laser line width B/N, N channels of equally spaced laser pulse signals of the center wavelength are formed ;

② Multi-wavelength emission: the emission optical path 3 emits the input laser pulse signals of N wavelengths at the same time, so as to realize multi-wavelength multi-pulse signal emission;

③ Receiving wavelength division: the receiving telescope 4 converges the returned laser signals of N wavelengths to the input end of the 1×N wavelength demultiplexer 5, and the wavelength demultiplexer 5 separates the laser signals of each channel according to the wavelength interval and central wavelength when transmitting. The wavelength signal is extracted at the same time to realize the division of the receiving wavelength;

④Multi-pulse measurement: The distance measuring unit 6 completes the measurement of the distance of each signal according to the input N laser echo pulse signals and the time interval between sending and receiving pulses, that is, the pulse flight time △τ, and the measurement distance=light speed C×flight time △τ/2, simultaneously measure the distance of multiple pulses, and realize the simultaneous measurement of multiple pulse signals;

⑤ Data synthesis: The data synthesis unit performs data synthesis according to the obtained multiple ranging results and according to the wavelength relationship at the time of emission, thus realizing efficient laser ranging for measuring multiple targets at one time.

Example

The specific devices used in this embodiment are: the laser selects the 1550nm fiber laser of CLP 34, the wavelength divider and the wavelength demultiplexer all select the 1550nm band 8-way wave demultiplexer corresponding to CLP 34, and the transmitting optical path The collimating mirror of Thorlabs' optical fiber input interface was selected, the receiving telescope was selected from Thorlabs' 4" aperture, and the optical fiber output interface telescope was selected. The ranging module was selected from the laser pulse flight measurement module developed by Zhongke Tianwei. The data synthesis module was selected from Advantech's industrial control module.

In conjunction with Fig. 1 and Fig. 2, the specific process of the present invention's implementation of multi-pulse laser ranging based on wavelength division is:

①Laser wavelength division: the laser signal output by the ranging light source laser with a line width of 80nm in the 1550nm band is divided by a 1×8 wavelength divider, and the resulting wavelengths are 1515nm, 1525nm and 1535nm according to the wavelength interval of 80nm/8=10nm , 1545nm, 1555nm, 1565nm, 1575nm and 1585nm, a total of 8 wavelength pulses enter 8 corresponding emission light paths;

②Multi-wavelength emission: 8 emission optical paths 2 transmit the input laser pulse signals of 8 wavelengths at the same time, realizing the simultaneous emission of 8 wavelengths and 8 pulse signals;

③ Receiving wavelength division: the receiving telescope converges the returned 8-wavelength laser signals to the input end of the wavelength demultiplexer, and the wavelength demultiplexer extracts 8 wavelength signals at the same time according to the wavelength interval during transmission to realize the division of the receiving wavelength , these signals of different wavelengths are simultaneously sent to the subsequent ranging modules for distance measurement;

④Multi-pulse measurement: 8 ranging modules calculate the ranging information respectively according to the input 8 laser echo pulse signals, and measure the distance of 8 pulses at the same time to realize the simultaneous measurement of 8 pulses;

⑤ Data synthesis: The data synthesis module performs data synthesis sequentially according to the obtained 8 ranging results and according to the order of wavelengths at the time of emission, thus realizing the efficient laser ranging of 8 targets at a time, combining the existing single-pulse laser measuring The system efficiency has been improved by 8 times.

The content that is not described in detail in the specification of the present invention belongs to the well-known technology of those skilled in the art.

Claims (6)

1. A multi-pulse laser ranging system based on wavelength division, characterized in that: comprising a laser, a wavelength divider, a transmitting optical path, a receiving telescope, a wavelength demultiplexer, a ranging module and a data synthesis module; The laser signal generated by the laser is input into the wavelength divider, and the wavelength divider selects the wavelength interval according to the required number of division paths to complete the wavelength division, and the multi-channel wavelength signals generated by the wavelength division are respectively output to the corresponding emission optical paths; The optical path collimates the received laser signal and outputs it; The receiving telescope receives the collimated laser signal and outputs it to the wavelength demultiplexer after converging; the wavelength demultiplexer extracts the received signal according to the wavelength, and outputs the signal of each wavelength to the corresponding A ranging module, the ranging module completes the measurement of the distance of each signal according to the time interval between the sending and receiving pulses, and outputs the measured data to the data synthesis module; According to the wavelength sequence corresponding to each channel of measurement data, the data synthesizing module splices the multiple channels of measurement data sequentially, completes the synthesis of multiple channels of measurement data, and finally realizes the multi-pulse laser ranging. 2. A multi-pulse laser ranging system based on wavelength division according to claim 1, wherein the wavelength demultiplexer is located at the focal point of the receiving telescope. 3. A multi-pulse laser ranging system based on wavelength division according to claim 1, characterized in that: said laser is a semiconductor, solid-state or fiber laser. 4. A multi-pulse laser ranging system based on wavelength division according to claim 1, characterized in that: the transmitting optical path is a beam collimating mirror for transmitting. 5. A kind of multi-pulse laser ranging system based on wavelength division according to claim 1, characterized in that: the number of multi-channel wavelength signals generated by the wavelength division is the same as that of the emission optical path, and the wavelength division The generated multi-channel wavelength signals are in one-to-one correspondence with the transmitting optical paths. 6. a multi-pulse laser ranging method adopting the multi-pulse laser ranging system based on wavelength division according to claim 1, is characterized in that the steps are as follows: (1) After the laser pulse signal output by the laser passes through the 1×N wavelength splitter, it forms N-channel laser pulse signals with equal intervals of center wavelength, and outputs them to the transmitting optical path; (2) The transmitting optical path simultaneously transmits the input laser pulse signals of N wavelengths to realize the parallel transmission of multi-wavelength and multi-pulse laser signals; (3) The receiving telescope converges the returned N-channel multi-pulse laser signals to the input end of the 1×N-channel wavelength demultiplexer, and the wavelength demultiplexer extracts the N-channel wavelength signals simultaneously according to different central wavelengths during transmission, Realize the division of the receiving wavelength and output it to the ranging module; (4) The ranging module completes the measurement of the distance of each signal according to the time interval between the sending and receiving pulses, that is, the pulse flight time, according to the input N laser echo pulse signals, and realizes the simultaneous ranging of multi-pulse laser signals; (5) According to the pulsed laser signal ranging results corresponding to the N wavelengths obtained in step (4), the data synthesis module splices the multi-channel measurement data in sequence according to the wavelength sequence corresponding to the distance measurement results of each channel, and completes the multi-channel measurement data. Synthesis, thus realizing the multi-pulse parallel laser ranging.