阅读说明：本技术 基于偏振调制光注入激光器的激光雷达及其调控方法 (Laser radar based on polarization modulation light injection laser and regulation and control method thereof ) 是由 周沛 张仁恒 李念强 傅剑斌 潘万胜 于 2021-09-07 设计创作，主要内容包括：本发明涉及一种基于偏振调制光注入激光器的激光雷达及其调控方法,包括：激光发生模块,其能够产生光强度可连续调谐的光信号；偏振调制模块,偏振调制模块将光强度可连续调谐的光信号调制成双边带啁啾光信号；第一光耦合器,第一光耦合器将双边带啁啾光信号分路成参考光信号和测试光信号；测试光信号从信号发射端发出并经目标物反射,接收端获取目标物反射的回波信号；第二光耦合器,第二光耦合器将参考光信号与回波信号耦合,获得耦合后的光信号；激光去啁啾模块,激光去啁啾模块将耦合后的光信号下变频为携带目标信息的中频信号。其成本低、结构简单、易于操作、发射的啁啾激光信号质量高且其扫频带宽高达几十GHz。(The invention relates to a laser radar based on a polarization modulation light injection laser and a regulation and control method thereof, wherein the method comprises the following steps: a laser generation module capable of generating an optical signal with continuously tunable optical intensity; the polarization modulation module modulates the optical signal with continuously tunable light intensity into a double-sideband chirp optical signal; a first optical coupler that splits the double-sideband chirped optical signal into a reference optical signal and a test optical signal; the test optical signal is sent from the signal transmitting end and reflected by the target object, and the receiving end acquires an echo signal reflected by the target object; the second optical coupler couples the reference optical signal and the echo signal to obtain a coupled optical signal; and the laser chirp removal module is used for converting the coupled optical signal into an intermediate frequency signal carrying target information in a down-conversion mode. The chirp laser source has the advantages of low cost, simple structure, easy operation, high quality of emitted chirp laser signals and high sweep frequency bandwidth of dozens of GHz.)

1. A lidar based on a polarization modulated light injection laser, comprising:

a laser generation module capable of generating an optical signal with continuously tunable optical intensity;

the polarization modulation module is connected with the laser generation module and modulates the optical signal with continuously tunable light intensity into a double-sideband chirp optical signal;

a first optical coupler connected to the polarization modulation module, the first optical coupler splitting the double sideband chirped optical signal into a reference optical signal and a test optical signal;

the signal transmitting and receiving module is connected with the first optical coupler and comprises a signal transmitting end and a signal receiving end, the test optical signal is transmitted from the signal transmitting end and is reflected by a target object, and the receiving end acquires an echo signal reflected by the target object;

the second optical coupler is connected with the output end of the first optical coupler and the signal transmitting and receiving module, and couples the reference optical signal with the echo signal to obtain a coupled optical signal;

the laser chirp removal module is connected with the output end of the second optical coupler and used for converting the coupled optical signal into an intermediate frequency signal carrying target information in a down-conversion mode;

and the signal processor is connected with the output end of the laser chirp removal module and extracts the distance information and the speed information of the target object from the intermediate frequency signal carrying the target information.

2. The polarization-modulated light injection laser-based lidar of claim 1, wherein the lasing module comprises a primary laser and an optical intensity modulator disposed in sequence, the optical intensity modulator modulating laser light emitted from the primary laser to obtain an optical carrier signal with adjustable optical intensity.

3. The polarization-modulated light injection laser-based lidar of claim 2, further comprising a waveform generator, an output of the waveform generator being coupled to the low-speed rf port of the optical intensity modulator.

4. The polarization-modulated light injection laser-based lidar of claim 1, further comprising:

a third optical coupler disposed between the output of the polarization modulation module and the input of the first optical coupler, the third optical coupler splitting the double sideband chirped optical signal into a first optical signal and a second optical signal, the first optical signal input to the input of the first optical coupler;

a slave laser into which the second optical signal is injected to excite a monocycle oscillation state of the slave laser, the slave laser outputting a linear frequency-swept chirped optical signal;

and the signal feedback module inputs the linear frequency-sweeping chirp optical signal to a high-speed radio frequency port of the polarization modulation module so as to adjust the polarization modulation module to work.

5. The polarization-modulated light injection laser-based lidar of claim 4, further comprising a first optical circulator, the first optical circulator comprising a first port, a second port, and a third port arranged in sequence, the first port being connected to the third optical coupler for receiving a second optical signal, the second port being connected to the slave laser, and the third port being connected to the signal feedback module.

6. The polarization-modulated light injection laser-based lidar of claim 4, wherein the signal feedback module comprises a single-mode fiber, a high-speed photodetector, and an electrical power amplifier arranged in sequence.

7. The polarization-modulated light injection laser-based lidar of claim 4, wherein a first polarization controller is disposed between the lasing module and the polarization modulation module; a second polarization controller is arranged between the output end of the third optical coupler and the input end of the slave laser; and a third polarization controller and a polaroid are sequentially arranged between the output end of the third optical coupler and the input end of the first optical coupler.

8. The polarization-modulated light injection laser-based lidar of claim 1, wherein the laser chirp removal module comprises a low-speed photodetector and a low-pass filter arranged in sequence.

9. A regulation and control method of a laser radar based on a polarization modulation light injection laser is characterized by comprising the following steps:

s1, acquiring an optical signal with continuously tunable optical intensity, and modulating the optical signal with continuously tunable optical intensity into a double-sideband chirped optical signal through a polarization modulation module;

s2, splitting the double-sideband chirped optical signal into a reference optical signal and a test optical signal through a first optical coupler;

s3, transmitting the test light signal to a target object and reflecting the test light signal to obtain an echo signal reflected by the target object;

s4, coupling the reference optical signal with the echo signal to obtain a coupled optical signal;

and S5, down-converting the coupled optical signal into an intermediate frequency signal carrying target information, and extracting the distance information and the speed information of the target object from the intermediate frequency signal carrying the target information.

10. The method for controlling a lidar based on a polarization modulated light injection laser as claimed in claim 9, wherein between S1 and S2 further comprises:

splitting the double sideband chirped optical signal into a first optical signal and a second optical signal;

the first optical signal is input into an input end of a first optical coupler, the second optical signal is injected into a slave laser to excite a single-period oscillation state of the slave laser, and the slave laser outputs a linear frequency-sweeping chirp optical signal;

and inputting the linear frequency sweep chirp optical signal to a high-speed radio frequency port of a polarization modulation module to adjust the polarization modulation module to work.

Technical Field

The invention relates to the technical field of laser radars, in particular to a laser radar based on a polarization modulation light injection laser and a regulation and control method thereof.

Background

The laser radar has the advantages of high resolution, good concealment, stronger anti-interference capability and the like, and is widely applied to the fields of robots, automatic driving, unmanned vehicles and the like. It is widely applied in civil and military fields. Laser radars can be classified into pulse laser radars and frequency modulated continuous wave laser radars according to the system of the transmitted signal. Compared with the pulse laser radar, the frequency modulation continuous wave laser radar has lower peak power, lower interception probability, lower sampling rate and no fuzzy detection capability.

Generally, a frequency modulation continuous wave laser radar realizes linear frequency sweep by modulating the driving current of a semiconductor laser, however, the frequency sweep rate and the frequency sweep linearity are poor, which causes the deterioration of the measurement accuracy; or a baseband microwave chirp signal is modulated onto a beam of optical carrier to realize linear frequency scanning of laser, however, on one hand, an additional radio frequency source is needed to provide the baseband signal, which inevitably increases the volume and cost of the system, and on the other hand, in order to realize larger frequency scanning bandwidth, the frequency doubling or frequency quadrupling is realized by the microwave photon frequency doubling technology, which causes the stray of the baseband signal and the deterioration of the signal-to-noise ratio, and reduces the detection accuracy of the laser radar.

Disclosure of Invention

Therefore, the technical problem to be solved by the invention is to overcome the technical defects of large system volume, high cost and low precision caused by an external radio frequency source in the prior art.

In order to solve the above technical problem, the present invention provides a laser radar based on a polarization modulated light injection laser, including:

a laser generation module capable of generating an optical signal with continuously tunable optical intensity;

the polarization modulation module is connected with the laser generation module and modulates the optical signal with continuously tunable light intensity into a double-sideband chirp optical signal;

a first optical coupler connected to the polarization modulation module, the first optical coupler splitting the double sideband chirped optical signal into a reference optical signal and a test optical signal;

the signal transmitting and receiving module is connected with the first optical coupler and comprises a signal transmitting end and a signal receiving end, the test optical signal is transmitted from the signal transmitting end and is reflected by a target object, and the receiving end acquires an echo signal reflected by the target object;

the second optical coupler is connected with the output end of the first optical coupler and the signal transmitting and receiving module, and couples the reference optical signal with the echo signal to obtain a coupled optical signal;

the laser chirp removal module is connected with the output end of the second optical coupler and used for converting the coupled optical signal into an intermediate frequency signal carrying target information in a down-conversion mode;

and the signal processor is connected with the output end of the laser chirp removal module and extracts the distance information and the speed information of the target object from the intermediate frequency signal carrying the target information.

Preferably, the laser generation module includes a main laser and a light intensity modulator, which are sequentially arranged, and the light intensity modulator modulates laser light emitted by the main laser to obtain an optical carrier signal with adjustable light intensity.

Preferably, the optical intensity modulator further comprises a waveform generator, and an output end of the waveform generator is connected with the low-speed radio frequency port of the optical intensity modulator.

Preferably, the method further comprises the following steps:

a third optical coupler disposed between the output of the polarization modulation module and the input of the first optical coupler, the third optical coupler splitting the double sideband chirped optical signal into a first optical signal and a second optical signal, the first optical signal input to the input of the first optical coupler;

a slave laser into which the second optical signal is injected to excite a monocycle oscillation state of the slave laser, the slave laser outputting a linear frequency-swept chirped optical signal;

and the signal feedback module inputs the linear frequency-sweeping chirp optical signal to a high-speed radio frequency port of the polarization modulation module so as to adjust the polarization modulation module to work.

Preferably, the optical fiber coupler further comprises a first optical circulator, the first optical circulator comprises a first port, a second port and a third port, the first port, the second port and the third port are sequentially arranged, the first port is connected with the third optical coupler to receive a second optical signal, the second port is connected with the slave laser, and the third port is connected with the signal feedback module.

Preferably, the signal feedback module comprises a single-mode optical fiber, a high-speed photodetector and an electric power amplifier which are arranged in sequence.

Preferably, a first polarization controller is arranged between the laser generation module and the polarization modulation module; a second polarization controller is arranged between the output end of the third optical coupler and the input end of the slave laser; and a third polarization controller and a polaroid are sequentially arranged between the output end of the third optical coupler and the input end of the first optical coupler.

Preferably, the laser chirp removing module comprises a low-speed photodetector and a low-pass filter which are arranged in sequence.

Preferably, the signal transmitting and receiving module is a telescope.

The invention discloses a regulation and control method of a laser radar based on a polarization modulation light injection laser, which comprises the following steps:

s1, acquiring an optical signal with continuously tunable optical intensity, and modulating the optical signal with continuously tunable optical intensity into a double-sideband chirped optical signal through a polarization modulation module;

s2, splitting the double-sideband chirped optical signal into a reference optical signal and a test optical signal through a first optical coupler;

s3, transmitting the test light signal to a target object and reflecting the test light signal to obtain an echo signal reflected by the target object;

s4, coupling the reference optical signal with the echo signal to obtain a coupled optical signal;

and S5, down-converting the coupled optical signal into an intermediate frequency signal carrying target information, and extracting the distance information and the speed information of the target object from the intermediate frequency signal carrying the target information.

Preferably, the method further comprises the following steps between S1 and S2:

splitting the double sideband chirped optical signal into a first optical signal and a second optical signal;

the first optical signal is input into an input end of a first optical coupler, the second optical signal is injected into a slave laser to excite a single-period oscillation state of the slave laser, and the slave laser outputs a linear frequency-sweeping chirp optical signal;

and inputting the linear frequency sweep chirp optical signal to a high-speed radio frequency port of a polarization modulation module to adjust the polarization modulation module to work. The polarization modulation module outputs a double-sideband chirped optical signal.

Compared with the prior art, the technical scheme of the invention has the following advantages:

1. the device core device is a commercial single-mode semiconductor laser, a high-speed radio frequency source is not needed, and the device has the advantages of simple structure, low cost and easiness in operation and control.

2. The double-chirp optical signal generated by the invention has the advantages of large scanning frequency bandwidth, high scanning speed and flexible tuning, the signal-to-noise ratio is low, and the detection precision of the laser radar is improved.

3. All modules in the invention can be miniaturized and integrated and packaged, and can be remotely controlled through a computer program, so that the laser radar system can be integrated.

Drawings

FIG. 1 is a schematic block diagram of the present invention;

FIG. 2 is a diagram of an apparatus according to an embodiment of the present invention;

fig. 3 is a schematic optical spectrum diagram of a dual chirp optical signal generated according to the present invention;

fig. 4 is a schematic diagram of the principle of object detection based on the device of the present invention.

The specification reference numbers indicate: 10. a laser generation module; 11. a main laser; 12. a first optical attenuator; 13. a light intensity modulator; 14. a waveform generator; 20. a polarization modulation module; 30. a first optical coupler; 31. a second optical coupler; 32. a third optical coupler; 40. a signal transmitting and receiving module; 41. a telescope; 42. a target object; 50. a laser chirp removal module; 51. a low-speed photodetector; 52. a low-pass filter; 60. a signal processor; 61. an analog-to-digital converter; 70. a slave laser; 71. a first optical circulator; 72. a second optical circulator; 80. a signal feedback module; 81. a single mode optical fiber; 82. a second optical attenuator; 83. a high-speed photodetector; 84. an electric power amplifier; 90. a first polarization controller; 91. a second polarization controller; 92. a third polarization controller; 93. a polarizing plate; a. a first port; b. a second port; c. a third port.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

Referring to fig. 1 to 4, the present invention discloses a polarization-modulated light injection laser-based lidar comprising a laser generation module 10, a polarization modulation module 20, a first optical coupler 30, a signal transmitting and receiving module 40, a second optical coupler 31, a laser chirp removal module 50, a signal processor 60, and a slave laser 70.

The laser generating module 10 is capable of generating an optical signal with continuously tunable optical intensity. The laser generation module 10 includes a main laser 11 and a light intensity modulator 13, which are sequentially disposed, and the light intensity modulator 13 modulates laser light emitted from the main laser 11 to obtain an optical carrier signal with adjustable light intensity. A first optical attenuator 12 may also be provided between main laser 11 and optical intensity modulator 13 to adjust the optical intensity of the output laser light of main laser 11. The invention further comprises a waveform generator, the output of which is connected to the low-speed rf port of the optical intensity modulator 13. The waveform generator can generate a voltage signal having a particular waveform, amplitude, period to control the sweep range, sweep period, and duty cycle of the transmitted dual chirped light signal.

The polarization modulation module 20 is connected to the laser generation module 10, and the polarization modulation module 20 modulates the optical signal with continuously tunable optical intensity into a double-sideband chirped optical signal. The polarization modulation module 20 may be configured as an optical polarization modulator.

The first optical coupler 30 is connected to the polarization modulation module 20, and the first optical coupler 30 splits the double-sideband chirped optical signal into a reference optical signal and a test optical signal.

The signal transmitting and receiving module 40 is connected to the first optical coupler 30, the signal transmitting and receiving module 40 includes a signal transmitting end and a signal receiving end, the test optical signal is transmitted from the signal transmitting end and reflected by the target 42, and the receiving end obtains the echo signal reflected by the target 42. The signal transmitting and receiving module 40 may be a telescope 41 capable of transmitting the test light signal and receiving the echo signal.

The second optical coupler 31 is connected to the output end of the first optical coupler 30 and the signal transmitting and receiving module 40, and the second optical coupler 31 couples the reference optical signal and the echo signal to obtain a coupled optical signal.

The laser chirp removing module 50 is connected to an output end of the second optical coupler 31, and the laser chirp removing module 50 down-converts the coupled optical signal into an intermediate frequency signal carrying target information. The laser chirp removal module 50 includes a low-speed photodetector 51 and a low-pass filter 52, which are sequentially disposed.

The signal processor 60 is connected to an output end of the laser chirp removal module 50, and the signal processor 60 extracts distance information and speed information of the target 42 from the intermediate frequency signal carrying the target information. When the signal processor 60 is a digital signal processor 60, an analog-to-digital converter 61 may be disposed between the digital processor and the low pass filter 52.

To achieve a linear sweep of the laser, the present invention further includes a third optical coupler 32, a slave laser 70, and a signal feedback module 80. The third optical coupler 32 is disposed between the output end of the polarization modulation module 20 and the input end of the first optical coupler 30, and the third optical coupler 32 splits the optical signal output by the polarization modulation module 20 into a first optical signal and a second optical signal, and the first optical signal is input to the input end of the first optical coupler 30. A second optical signal is injected into the slave laser 70 to excite a monocycle oscillation state of the slave laser 70, and a linear frequency-swept chirped optical signal is output from the slave laser 70. The slave laser 70 is a single mode distributed feedback semiconductor laser or a distributed bragg reflector laser without an isolator at its output.

The signal feedback module 80 inputs the linear swept-frequency chirped optical signal to the high-speed rf port of the polarization modulation module 20 to adjust the operation of the polarization modulation module 20. The polarization modulation module 20 outputs a double sideband chirped optical signal. The feedback module 80 is used for maintaining the stability of the double-sideband chirped optical signal, and the signal feedback module 80 comprises a single-mode optical fiber 81, a second optical attenuator 82, a high-speed photodetector 83 and an electric power amplifier 84 which are sequentially arranged.

The present invention further includes a first optical circulator 71, where the first optical circulator 71 includes a first port a, a second port b, and a third port c, which are sequentially arranged, the first port a is connected to the third optical coupler 32 to receive the second optical signal, the second port b is connected to the slave laser 70, and the third port c is connected to the signal feedback module 80.

A first polarization controller 90 is arranged between the laser generation module 10 and the polarization modulation module 20; a second polarization controller 91 is arranged between the output end of the third optical coupler 32 and the input end of the slave laser 70; a third polarization controller 92 and a polarizing plate 93 are sequentially disposed between the output end of the third optical coupler 32 and the input end of the first optical coupler 30.

In an embodiment, both master laser 11 and slave laser 70 have center wavelengths around 1550 nm.

The laser radar in the invention has the following advantages:

1. the present invention outputs a monocycle oscillation state from the laser 70 module, rather than injecting a lock-in state, by properly tuning the frequency detuning between the laser generating module 10 and the free-running slave laser 70, and the optical power injected into the slave laser 70.

2. The laser radar system transmits a signal which is a double-chirp optical signal with simultaneous linear frequency sweeping, and the frequency sweeping slope of the double-chirp optical signal is positive and negative; compared with a triangular frequency modulation chirp optical signal with alternate frequency sweeping in time, the laser radar device can directly measure the distance and speed information of the target without an additional complex signal processing process.

3. The voltage signal with a specific waveform is designed by the waveform generator 14, so that the sweep linearity of the dual chirped optical signal can be accurately controlled, and the amplitude and the period of the voltage signal are adjusted by the waveform generator, so that the sweep range, the sweep period and the duty ratio of the chirped optical signal can be simply and accurately tuned.

4. The power distribution ratio of the first optical coupler 30, the second optical coupler 31 and the third optical coupler 32 in the invention is not fixed, and can be adjusted according to the working requirement, so that the flexibility of the whole laser radar is higher.

5. The lidar includes a signal feedback module 80, and the feedback delay in the signal feedback module 80 needs to be equal to the period of the emitted optical signal, which can be strictly guaranteed by carefully tuning the length of the single mode fiber 81 in the feedback control module.

The invention also discloses a regulation and control method of the laser radar based on the polarization modulation light injection laser, which comprises the following steps:

step one, acquiring an optical signal with continuously tunable light intensity, and modulating the optical signal with continuously tunable light intensity into a double-sideband chirp optical signal through a polarization modulation module 20;

step two, the double-sideband chirped optical signal is divided into a reference optical signal and a test optical signal through a first optical coupler 30;

step three, the test optical signal is transmitted to the target 42 and reflected, and an echo signal reflected by the target 42 is obtained;

coupling the reference optical signal with the echo signal to obtain a coupled optical signal;

and step five, down-converting the coupled optical signal into an intermediate frequency signal carrying target information, and extracting the distance information and the speed information of the target 42 from the intermediate frequency signal carrying the target information.

Wherein, still include between step one and step two: splitting the double sideband chirped optical signal into a first optical signal and a second optical signal; the first optical signal is input to the input end of the first optical coupler 30, the second optical signal is injected into the slave laser 70 to excite the single-period oscillation state of the slave laser 70, and the linear frequency-sweep chirped optical signal is output from the laser 70; the linear swept-frequency chirped optical signal is input to a high-speed radio frequency port of the polarization modulation module 20 to adjust the operation of the polarization modulation module 20.

Referring to fig. 2 to 4, the specific operation principle of the laser radar device based on the modulated light injection laser according to the present invention is as follows:

the main laser outputs a frequency f after passing through a first optical attenuator 12 and a light intensity modulator 13_MLOf a free-running output frequency f from laser 70_SLAs shown in fig. 3 (a). The waveform generator 14 generates a voltage signal with a specific waveform, and modulates the intensity of the optical carrier signal through the optical intensity modulator, the optical carrier after intensity modulation is input into the optical polarization modulator 20 after the polarization state is adjusted by the first polarization controller 90, and the output light is divided into two paths by the third optical coupler 32: one path passes through the second polarization controller 91, the first port a and the second port b of the first optical circulator 71 in sequence, and then is injected into the slave laser 70, under appropriate injection power, the slave laser 70 works in a single-period oscillation state, and the output optical signal thereof not only includes the frequency component f of the master laser 11_MLAlso included is a frequency range of Δ f ═ f_s2-f_s1As shown in fig. 3 (b). The linear frequency-swept optical signal is converted into a microwave chirp signal after passing through the single-mode fiber 81, the second optical attenuator 82 and the high-speed photodetector 83 in sequence, the microwave chirp signal is amplified by the electric power amplifier 84 and then fed back to the high-speed radio frequency port of the optical polarization modulator 20 to perform double sideband modulation on the optical carrier, and the chirp optical signal of the double sideband linear frequency sweep is derived from the other port of the third optical coupler 32, as shown in fig. 3(c), the frequency sweep bandwidths of the two sidebands are both Δ f (Δ f), and the frequency sweep bandwidths of the two sidebands are both Δ f (Δ f)_s2-f_s1＝f_s4-f_s3). The double sideband linear frequency sweepThe chirped optical signal is analyzed and polarized by the third polarization controller 92 and the polarizer 93 to realize a carrier suppression state, as shown in fig. 3 (d). The first optical coupler 30 divides the chirp signal of the double-sideband linear frequency sweep in the carrier suppression state into two paths: one path passes through the first port a and the second port b of the second optical circulator 72 in sequence, then is collimated by the telescope 41 and then is transmitted to the free space, echo signals are collected by the telescope 41 after being reflected by a target, then enter the second port b of the second optical circulator 72, and echo signals are led out from the third port c of the second optical circulator 72. The other path of the reference signal and the echo signal are coupled into a path of optical signal through the second optical coupler 31, and input to the low-speed photodetector 51 to complete photoelectric conversion, the low-speed photodetector 51 outputs an intermediate-frequency electrical signal carrying target information, the low-pass filter 52 filters out the intermediate-frequency electrical signal, the analog-to-digital converter 61 digitizes the intermediate-frequency electrical signal, and the digital signal processor 60 extracts the target information.

The target detection principle of the laser radar system based on the modulated light injection semiconductor laser device comprises the following steps: the emission signal is a double-chirp linear sweep frequency optical signal, and the sweep frequency bandwidth is delta f (delta f is f)_s2-f_s1＝f_s4-f_s3) The sweep period is T, as shown in FIG. 4, which comprises a chirped optical signal (from f) that is swept positively₃Linear scan to f₄) And a negatively swept chirped optical signal (from f)₂Linear scan to f₁). After the reflection of the target, the echo signal and the emission signal have a delay time Δ τ, so the distance of the target can be calculated by d ═ c Δ τ/2, where c is the speed of light in vacuum. Since the transmission signal is a linearly chirped optical signal, information of the target can be acquired by directly calculating a frequency difference between the transmission signal and the echo signal. As shown in FIG. 4(b), when the target is in a static state, i.e. the velocity of the target is zero, the frequency difference between the positive and negative sweep portions is f_IFSo that only one intermediate frequency signal is present. When the target is in motion, as shown in fig. 4(c), the relative motion between the target and the lidar introduces a doppler frequency f_dResulting in a frequency difference of the positive swept frequency part and a negative swept frequencyThe frequency differences of the sections are not uniform. The frequency difference of the positive swept frequency portion is f_IF2And the frequency difference of the negative swept frequency portion is f_IF1The distance information of the object can be passed through f_IF2And f_IF1Adding to obtain: f. of_IF＝(f_IF2+f_IF1) (ii)/2, the speed information can be passed through f_IF2And f_IF1Subtracting to obtain: f. of_d＝(f_IF2-f_IF1)/2. The distance of the target is therefore: r ═ f_IFTc/2(Δ f), speed: v ═ f_dc/2f_ML。

Compared with the prior art, the technical scheme of the invention has the following advantages:

compared with the prior art, the laser radar based on the polarization modulation light injection laser has the advantages that firstly, the core device of the laser radar is a commercial single-mode semiconductor laser, a high-speed radio frequency source is not needed, and the laser radar has the advantages of simple structure, low cost and easiness in operation and control; secondly, the slave laser works in a single-period oscillation state, so that the generated double-chirp optical signal has the advantages of large scanning bandwidth, high scanning speed and flexible tuning; finally, the laser generation module, the polarization modulation module, the signal feedback module, the slave laser, the signal transmitting and receiving module, the laser chirp removal module and the signal processing module can be miniaturized and integrated and packaged, and can be remotely controlled through a computer program, so that the laser radar system can be integrated.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.