A Multi-Mode Radar Composite Detection Method

Abstract

This invention relates to a multi-mode radar composite detection method, belonging to the field of microwave-laser composite detection technology, and solves the problems of inability to achieve all-weather detection, low detection accuracy, and weak adaptability. The method includes: splitting a laser generated by a laser into multiple paths; modulating the first laser path to generate a microwave radar transmission signal and receiving the microwave radar echo signal; modulating the second laser path to generate an intermediate frequency (IF) echo signal; generating a single-photon laser pulse based on the third laser path and receiving the single-photon laser pulse echo signal; generating a laser transmission signal based on the fourth laser path, transmitting the laser transmission signal towards the target and receiving the laser echo signal; using the laser echo signal to coherently process the fifth laser path to obtain a coherent IF signal; and processing the IF echo signal, the laser pulse electrical signal, and the coherent IF signal respectively to obtain target characteristic parameters.

Description

Technical Field

[0001] This invention relates to the field of microwave laser composite detection technology, and in particular to a multi-mode radar composite detection method. Background Technology

[0002] Microwave radar and lidar technologies are becoming increasingly important in various fields such as communications, navigation, power systems, and industrial automation due to their active detection capabilities. Microwave radar detects targets by emitting microwaves and receiving reflected signals, offering advantages such as wide beamwidth and strong penetration, and is widely used in scenarios such as weather monitoring and security surveillance. However, its range and angular resolution are relatively low, making it difficult to meet high-precision requirements for accurate target tracking and measurement. For example, it presents challenges in the accurate identification and localization of small obstacles at close range in autonomous driving.

[0003] LiDAR can be divided into single-photon lidar and coherent lidar. Single-photon lidar utilizes single-photon detection technology, leveraging its narrow beam and narrow pulse width characteristics to achieve extremely high ranging accuracy, making it suitable for detecting weak signals at long distances, such as in deep space exploration. Coherent lidar, through coherent detection technology, can not only acquire target distance information but also accurately measure velocity information, making it indispensable in scenarios such as intelligent transportation and industrial inspection where real-time monitoring of target speed and distance is required. However, lidar is greatly affected by atmospheric transmission. In adverse weather conditions such as heavy rain, sandstorms, and dense fog, the laser signal attenuates severely, leading to a significant decrease in detection performance and limiting its all-weather operation capability.

[0004] Currently, microwave radar and lidar operate in significantly different wavebands, making deep fusion and integration difficult. Existing microwave-laser composite detection technologies cannot fully leverage the advantages of both, hindering their application in fields with high environmental and precision requirements. Summary of the Invention

[0005] The purpose of this invention is to provide a multi-system radar composite detection method. By implementing this invention, the problems of existing detection methods being unable to achieve all-weather detection, having low detection accuracy, and weak adaptability can be solved.

[0006] To achieve the aforementioned objective, in a first aspect, embodiments of the present invention provide a multi-mode radar composite detection method, comprising:

[0007] The laser beam generated by the laser is split into multiple paths;

[0008] The first laser is modulated based on the radio frequency signal to generate a microwave radar transmission signal, which is then transmitted to the target and received by the microwave radar echo signal.

[0009] The second laser beam is modulated using microwave radar echo signals and radio frequency signals to generate an intermediate frequency echo signal.

[0010] Single-photon laser pulses are generated based on the third-path laser, single-photon laser pulses are emitted toward the target and single-photon laser pulse echo signals are received, and the single-photon laser pulse echo signals are converted into laser pulse electrical signals.

[0011] Based on the fourth laser, a laser emission signal is generated, a laser emission signal is emitted towards the target and a laser echo signal is received. The laser echo signal is used to coherently process the fifth laser to obtain a coherent intermediate frequency signal.

[0012] The target's characteristic parameters are obtained by processing the intermediate frequency echo signal, laser pulse electrical signal, and coherent intermediate frequency signal respectively.

[0013] As a further improvement to this application, the feature parameters include: target velocity information and target distance information; the feature parameters of the target generated by processing the intermediate frequency echo signal, laser pulse electrical signal, and coherent intermediate frequency signal include:

[0014] The first velocity information and the first distance information are obtained by processing the intermediate frequency echo signal;

[0015] The second distance information is obtained by processing the laser pulse electrical signal;

[0016] The coherent intermediate frequency signal is processed to obtain the second velocity information and the third distance information. The first velocity information and the second velocity information are weighted and averaged to obtain the target velocity information.

[0017] The target distance information is obtained by performing a weighted average of the first distance information, the second distance information, and the third distance information.

[0018] As a further improvement of this application, the first velocity information obtained based on the intermediate frequency echo signal and the second velocity information obtained based on the coherent intermediate frequency signal are weighted and averaged to obtain the target velocity information, as shown in the calculation formula (1).

[0019] V = αV1 + (1 - α)V2; (1)

[0020] Where V represents the target velocity information, V1 represents the first velocity information, V2 represents the second velocity information, and α represents the velocity weight.

[0021] As a further improvement to this application, it is characterized in that,

[0022] The first velocity information obtained based on the intermediate frequency echo signal includes:

[0023] The Doppler frequency shift is obtained by performing spectral analysis on the intermediate frequency echo signal;

[0024] The first velocity information is shown in calculation formula (2);

[0025]

[0026] Where λ1 is the wavelength of the microwave radar transmitted signal, and Δf1 is the Doppler frequency shift;

[0027] The second velocity information obtained based on the coherent intermediate frequency signal includes:

[0028] Frequency change is obtained by performing frequency analysis on the coherent intermediate frequency signal;

[0029] The second speed information is shown in calculation formula (3);

[0030]

[0031] Where λ2 is the wavelength of the laser emission signal, and Δf2 is the frequency change.

[0032] As a further improvement of this application, the first distance information obtained based on the intermediate frequency echo signal, the second distance information obtained based on the laser pulse electrical signal, and the third distance information obtained based on the coherent intermediate frequency signal are subjected to weighted average processing to obtain the target distance information as shown in the calculation formula (4);

[0033] R=βR1+γR2+(1-β-γ)R3 (4)

[0034] Where R represents the target distance information, R1 represents the first distance information, R2 represents the second distance information, R3 represents the third distance information, and β and γ represent the distance weights.

[0035] As a further improvement to this application, the modulation of the first laser beam based on the radio frequency signal to generate the microwave radar transmission signal includes:

[0036] Control the radio frequency source to generate the first radio frequency signal;

[0037] An intermediate frequency signal is generated by a waveform generator, and the intermediate frequency signal and the first radio frequency signal are mixed to generate a programmable radio frequency signal.

[0038] The first modulated optical signal is obtained by modulating the first laser with the filtered programmable radio frequency signal and the first radio frequency signal.

[0039] The first modulated optical signal is converted into a microwave radar transmission signal by photoelectric conversion.

[0040] As a further improvement to this application, the modulation of the second laser beam using microwave radar echo signals and radio frequency signals to generate intermediate frequency echo signals includes:

[0041] Control the radio frequency source to generate a second radio frequency signal;

[0042] The second laser beam is modulated based on the microwave radar echo signal and the second radio frequency signal to generate a second modulated optical signal;

[0043] The second modulated optical signal is photoelectrically converted to obtain an intermediate frequency echo signal.

[0044] As a further improvement to this application, the microwave radar transmission signal is calculated as shown in equation (5);

[0045] ω Radar =m·ω RF1 -n·ω RF2 -m·[ω IF -BW / 2+BW·t / T] (5)

[0046] Where, ω Radar ω is the angular frequency of the microwave radar transmitted signal. RF1 Let ω be the angular frequency of the first radio frequency signal. RF2 ω is the angular frequency of the second radio frequency signal. IF ω is the angular frequency of the programmable radio frequency signal, m and n are the laser modulation order, BW is the bandwidth of the programmable radio frequency signal, T is the pulse width of the programmable radio frequency signal, and t is the modulation time.

[0047] The intermediate frequency echo signal is calculated as shown in formula (6);

[0048] ω' IF =k·ω RF3 -ω' Radar (6)

[0049] Where, ω RF3 Let ω' be the angular frequency of the third radio frequency signal. Radar Let ω' be the angular frequency of the microwave radar echo signal. IF ω is the angular frequency of the intermediate frequency echo signal, and k is the laser modulation order.

[0050] As a further improvement to this application, the coherent intermediate frequency signal obtained by coherently processing the fifth laser beam using the laser echo signal includes:

[0051] Coherent optical signals are obtained by coherently processing the laser echo signal and the fifth laser beam.

[0052] The coherent optical signal is converted into a coherent intermediate frequency signal by photoelectric conversion.

[0053] As a further improvement of this application, the first distance information is obtained based on the intermediate frequency echo signal as shown in the calculation formula (7);

[0054]

[0055] Where R1 represents the first distance information, c represents the speed of light, t1 represents the arrival time of the microwave radar echo pulse, and t 01 This refers to the transmission time of the microwave radar signal.

[0056] The second distance information obtained based on the laser pulse electrical signal is shown in the calculation formula (8);

[0057]

[0058] Where R2 represents the second distance information, t2 represents the arrival time of the single-photon laser pulse, and t 02 This refers to the emission time of a single-photon laser pulse;

[0059] The third distance information is obtained based on the coherent intermediate frequency signal as shown in the calculation formula (9);

[0060]

[0061] Where R3 is the third distance information and τ2 is the laser pulse width of the laser emission signal.

[0062] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0063] 1. This invention provides unified signal-level control for microwave radar and lidar of different bands and systems, and unified acquisition and processing of echo signals. It can flexibly adjust the working mode according to the actual scenario and perform data-level, feature-level, or decision-level fusion processing, which is conducive to improving target detection and recognition capabilities, realizing high-precision target detection, and thus improving the overall accuracy of detection.

[0064] 2. This invention improves the system's adaptability to various environmental conditions by combining the all-weather operation capability of microwave radar with the high-precision detection capability of lidar. The wide beam and strong penetration of microwave radar ensure detection capability under adverse weather conditions, while lidar provides high-precision detection under good weather conditions, ensuring the effective operation of the system in different environments and improving the system's adaptability to various environmental conditions, thus solving the problem of weak adaptability of existing detection methods.

[0065] 3. The radio frequency signal generator of the present invention generates programmable radio frequency signals through components such as waveform generator, radio frequency source, mixer and bandpass filter. This programmability can flexibly adjust the signal modulation parameters according to different detection task requirements, significantly improving the adaptability and application range of detection.

[0066] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0067] To more clearly illustrate the technical solutions in the embodiments of the present invention or the background art, the accompanying drawings used in the embodiments of the present invention or the background art will be described below.

[0068] Figure 1 This is a flowchart illustrating a multi-mode radar composite detection method in one embodiment of the present invention;

[0069] Figure 2 This is a schematic diagram of the structure of a microwave laser integrated radar composite detection system in one embodiment of the present invention. Detailed Implementation

[0070] To make the technical means, creative features, objectives and effects of the embodiments of the present invention easier to understand, the embodiments of the present invention are further described below in conjunction with the figures and specific embodiments. It should be understood that the specific embodiments described herein are merely for explaining the embodiments of the present invention and are not intended to limit the embodiments of the present invention.

[0071] Example 1

[0072] A specific embodiment of the present invention discloses a multi-system radar composite detection method, such as... Figure 1 As shown.

[0073] A multi-mode radar composite detection method includes:

[0074] Step 1: Divide the laser generated by the laser into multiple paths.

[0075] Lasers are used to generate continuous laser light of a specific wavelength. The continuous laser light generated by a laser can be split into multiple paths by a beam splitter. A beam splitter is an optical element used to split the laser light emitted by the laser into five paths. The power and phase of each laser path can be set according to the working requirements to meet the needs of subsequent processing.

[0076] Step 2: Modulate the first laser based on the radio frequency signal to generate a microwave radar transmission signal, transmit the microwave radar transmission signal to the target and receive the microwave radar echo signal.

[0077] Radio frequency (RF) signals can be generated by an RF source, which is a device capable of generating high-frequency alternating current signals. Its output frequency and power can be adjusted according to the operating frequency band and detection requirements of the microwave radar. For example, in some close-range, high-precision detection scenarios, a higher frequency RF signal can be selected to improve range resolution; while in long-range detection scenarios, the power needs to be adjusted appropriately to ensure that the signal can effectively propagate to the target and return.

[0078] A modulator is used to modulate the first laser beam based on a radio frequency (RF) signal to generate a microwave radar transmission signal, which is then transmitted towards the target. The modulator can be an electro-optic modulator, which utilizes the electro-optic effect to change the intensity, frequency, or phase of the laser beam by altering the electric field strength of the RF signal applied to it, thereby loading the RF signal onto the laser. The modulated optical signal carries RF information related to the target.

[0079] Furthermore, the modulation of the first laser beam based on the radio frequency signal to generate the microwave radar transmission signal includes:

[0080] Step 201: Control the radio frequency source to generate the first radio frequency signal.

[0081] The radio frequency (RF) source can be selected based on the operating frequency band requirements of the microwave radar. If the microwave radar operates in the 8-12 GHz band, a high-performance RF source that can cover this band can be selected.

[0082] Step 202: Generate an intermediate frequency signal using a waveform generator, and mix the intermediate frequency signal with the first radio frequency signal to generate a programmable radio frequency signal.

[0083] The waveform generator can be an arbitrary waveform generator (AWG), allowing parameter settings for the generated intermediate frequency (IF) signal, including waveform shape, frequency, and amplitude. The IF signal generated by the waveform generator is mixed with a first radio frequency (RF) signal generated by an RF source in a mixer. The mixer multiplies the IF signals of different frequencies with the first RF signal to produce a programmable RF signal containing multiple frequency components, including the sum and difference of the original signal frequencies. During the mixing process, it is essential to ensure that the mixer's operating frequency range covers the frequency range of the input signal.

[0084] Step 203: Modulate the first laser beam based on the filtered programmable radio frequency signal and the first radio frequency signal to obtain the first modulated optical signal.

[0085] The programmable radio frequency signal obtained after mixing contains multiple frequency components. A filter can be used to filter the mixed signal. Based on the filtered programmable radio frequency signal and the first radio frequency signal, the first laser is modulated to obtain the first modulated optical signal. The modulator can be a dual-drive Mach-Zehnder modulator or a dual-parallel Mach-Zehnder modulator.

[0086] Step 204: The first modulated optical signal is converted into a microwave radar transmission signal by photoelectric conversion.

[0087] The photodetector can be either a PIN photodiode or an avalanche photodiode (APD). PIN photodiodes are characterized by fast response speed and good linearity, making them suitable for detecting low to medium power optical signals; avalanche photodiodes have higher gain and are suitable for detecting weak optical signals. The first modulated optical signal is converted into a microwave radar transmission signal by the photodetector.

[0088] Step 3: Modulate the second laser beam using microwave radar echo signal and radio frequency signal to generate intermediate frequency echo signal.

[0089] A modulator is used to modulate the microwave radar echo signal and the second laser beam based on the radio frequency (RF) signal, generating a microwave radar transmission signal. The modulation parameters can be adjusted according to the requirements of the intermediate frequency (IF) echo signal. After modulation, a modulated optical signal carrying target information is obtained. The modulated optical signal is then converted into an electrical signal through photoelectric conversion, yielding the IF echo signal.

[0090] The microwave radar transmit signal is calculated as shown in equation (1):

[0091] ω Radar =m·ω RF1 -n·ω RF2 -m·[ω IF -BW / 2+BW·t / T] (1)

[0092] Where, ω Radar ω is the angular frequency of the microwave radar transmitted signal. RF1 Let ω be the angular frequency of the first radio frequency signal. RF2 ω is the angular frequency of the second radio frequency signal. IF ω is the angular frequency of the programmable radio frequency signal, m and n are the laser modulation order, BW is the bandwidth of the programmable radio frequency signal, T is the pulse width of the programmable radio frequency signal, and t is the modulation time.

[0093] The generation of an intermediate frequency echo signal by modulating a second laser beam using microwave radar echo signals and radio frequency signals includes:

[0094] Step 301: Control the radio frequency source to generate a second radio frequency signal.

[0095] The settings of parameters such as frequency and power of the second radio frequency signal need to be combined with the characteristics of the microwave radar echo signal. The frequency of the second radio frequency signal needs to form a specific difference or proportional relationship with the frequency of the microwave radar echo signal, and the intensity of the second radio frequency signal acting together with the microwave radar echo signal to modulate the laser should be matched. It should not be too large, which will cause signal distortion, nor too small, which will make the modulation effect insignificant.

[0096] Step 302: Modulate the second laser beam based on the microwave radar echo signal and the second radio frequency signal to generate a second modulated optical signal.

[0097] The microwave radar echo signal and the generated second radio frequency signal are simultaneously applied to the electrodes of the modulator. The second laser enters from the optical input port of the modulator and propagates in the electro-optic crystal. Due to the electric field generated by the radio frequency signal and the microwave radar echo signal applied to the electrodes, the optical properties of the laser (such as intensity and phase) can change according to the laws of these two electrical signals, thereby generating a second modulated optical signal carrying target-related information.

[0098] Step 303: The second modulated optical signal is photoelectrically converted to obtain an intermediate frequency echo signal.

[0099] The second modulated optical signal is converted into an intermediate frequency echo signal by a photodetector. In addition, in order to suppress noise interference, the intermediate frequency echo signal can be filtered to remove high-frequency noise and impurity signals.

[0100] The intermediate frequency echo signal is calculated as shown in formula (2);

[0101] ω' IF =k·ω RF3 -ω' Radar

[0102] Where, ω RF3 Let ω' be the angular frequency of the third radio frequency signal. Radar Let ω' be the angular frequency of the microwave radar echo signal. IF ω is the angular frequency of the intermediate frequency echo signal, and k is the laser modulation order.

[0103] Step 4: Generate single-photon laser pulses based on the third laser path, emit single-photon laser pulses towards the target and receive single-photon laser pulse echo signals, and convert the single-photon laser pulse echo signals into laser pulse electrical signals.

[0104] Based on the third-path laser, single-photon laser pulses can be generated using a single-photon pulse generator. This generator can be a pulsed laser or an optical pulse modulator, producing a single-photon laser pulse through nonlinear optical effects. The pulse width, repetition frequency, and other parameters of the single-photon laser pulse can be adjusted according to the target distance and detection accuracy requirements. For high-precision detection of long-range targets, single-photon laser pulses with narrower pulse widths and lower repetition frequencies are required to improve ranging accuracy.

[0105] A single photon is the smallest unit of energy in light. Single-photon laser pulses are emitted by single-photon lidar modules and are characterized by extremely narrow pulse widths, typically in the picosecond to nanosecond range. When this narrow-pulse laser illuminates a target, the target reflects the photon back. A single-photon detector is used to receive the echo signal of the single-photon laser pulse. The probability of the detector triggering (detecting at least one photon) between times t1 and t2 is:

[0106]

[0107] Where, η e Let be the quantum efficiency of the detector photocathode, nb(t) be the rate function of the ambient background light, ns(t) be the rate function of the laser echo photon count, and nd(t) be the rate function of the detector dark count.

[0108] Step 5: Generate a laser emission signal based on the fourth laser, emit the laser emission signal towards the target and receive the laser echo signal, and use the laser echo signal to coherently process the fifth laser to obtain a coherent intermediate frequency signal.

[0109] Specifically, the coherent intermediate frequency signal obtained by coherently processing the fifth laser beam using the laser echo signal includes:

[0110] Step 501: Perform coherent processing on the laser echo signal and the fifth laser to obtain a coherent optical signal;

[0111] Step 502: The coherent optical signal is converted into a coherent intermediate frequency signal by photoelectric conversion.

[0112] By performing power adjustment and waveform shaping on the fourth laser beam, a laser emission signal that meets the emission requirements can be generated. Coherent processing refers to causing interference between the laser echo signal and the fifth laser beam. The electric fields of the two beams superimpose, and interference fringes are generated when their frequencies, polarization directions are similar, and a stable phase relationship exists. The target's distance and velocity information can be reflected in the phase changes of the coherent intermediate frequency signal.

[0113] Step 6: Process the intermediate frequency echo signal, laser pulse electrical signal and coherent intermediate frequency signal respectively to obtain the characteristic parameters of the target.

[0114] Furthermore, the characteristic parameters include: target velocity information and target range information; the characteristic parameters of the target generated by processing the intermediate frequency echo signal, laser pulse electrical signal, and coherent intermediate frequency signal include:

[0115] The first velocity information and the first distance information are obtained by processing the intermediate frequency echo signal;

[0116] The second distance information is obtained by processing the laser pulse electrical signal;

[0117] The coherent intermediate frequency signal is processed to obtain the second velocity information and the third distance information. The first velocity information and the second velocity information are weighted and averaged to obtain the target velocity information.

[0118] The target distance information is obtained by performing a weighted average of the first distance information, the second distance information, and the third distance information.

[0119] The target velocity information is obtained by weighted averaging the first velocity information obtained based on the intermediate frequency echo signal and the second velocity information obtained based on the coherent intermediate frequency signal, as shown in the calculation formula (4).

[0120] V = αV1 + (1 - α)V2; (4)

[0121] Where V represents the target velocity information, V1 represents the first velocity information, V2 represents the second velocity information, and α represents the velocity weight.

[0122] The first velocity information obtained based on the intermediate frequency echo signal includes:

[0123] The Doppler frequency shift is obtained by performing spectral analysis on the intermediate frequency echo signal;

[0124] The first velocity information is shown in calculation formula (5);

[0125]

[0126] Where λ1 is the wavelength of the microwave radar transmitted signal, and Δf1 is the Doppler frequency shift;

[0127] The second velocity information obtained based on the coherent intermediate frequency signal includes:

[0128] Frequency change is obtained by performing frequency analysis on the coherent intermediate frequency signal;

[0129] The second speed information is shown in the calculation formula (6);

[0130]

[0131] Where λ2 is the wavelength of the laser emission signal, and Δf2 is the frequency change.

[0132] The target distance information is obtained by weighted averaging the first distance information obtained from the intermediate frequency echo signal, the second distance information obtained from the laser pulse electrical signal, and the third distance information obtained from the coherent intermediate frequency signal, as shown in the calculation formula (7).

[0133] R=βR1+γR2+(1-β-γ)R3 (7)

[0134] Where R represents the target distance information, R1 represents the first distance information, R2 represents the second distance information, R3 represents the third distance information, and β and γ represent the distance weights.

[0135] The first distance information is obtained based on the intermediate frequency echo signal as shown in the calculation formula (8);

[0136]

[0137] Where R1 represents the first distance information, c represents the speed of light, t1 represents the arrival time of the microwave radar echo pulse, and t 01 This refers to the transmission time of the microwave radar signal.

[0138] The second distance information obtained based on the laser pulse electrical signal is shown in the calculation formula (9);

[0139]

[0140] Where R2 represents the second distance information, t2 represents the arrival time of the single-photon laser pulse, and t 02 This refers to the emission time of a single-photon laser pulse;

[0141] The third distance information is obtained based on the coherent intermediate frequency signal as shown in the calculation formula (10);

[0142]

[0143] Where R3 is the third distance information and τ2 is the laser pulse width of the laser emission signal.

[0144] The intermediate frequency echo signal is calculated as shown in equation (11);

[0145] s(t)=A1cos2πf0t+πkt 2 (11)

[0146] Where A1 is the amplitude of the intermediate frequency echo signal, t is the time variable, f0 is the center frequency of the intermediate frequency echo signal, and k is the modulation coefficient;

[0147] The coherent intermediate frequency signal is calculated as shown in equation (12);

[0148]

[0149] Where A2 is the amplitude of the coherent intermediate frequency signal, t is the time variable, and f IF The frequency of the coherent intermediate frequency signal. This represents the phase offset of the coherent intermediate frequency signal;

[0150] The laser pulse electrical signal is calculated as shown in equation (13);

[0151] s(t)=A3cos(2πf LP t+Δθ) (13)

[0152] Where A3 is the amplitude of the laser pulse electrical signal, t is the time variable, and f LP The oscillation frequency of the laser pulse electrical signal, and the phase shift of the laser pulse electrical signal Δθ.

[0153] The above embodiments of the present invention have the following beneficial effects: The microwave radar transmit signal is generated by modulating the first laser based on the radio frequency signal; simultaneously, the second laser is generated by modulating the microwave radar echo signal and the radio frequency signal to generate the intermediate frequency echo signal; a single-photon laser pulse is generated based on the third laser; and a laser transmit signal is generated based on the fourth laser, enabling the microwave radar, coherent laser, and single-photon laser to work collaboratively. This effectively solves the problem of poor coordination in existing detection methods, achieving high-precision detection of the target and thus improving the overall detection accuracy. By comprehensively processing the intermediate frequency echo signal, laser pulse electrical signal, and coherent intermediate frequency signal, characteristic parameters of the target are generated, changing the current situation of a single data processing method and improving detection accuracy. Combining the all-weather working capability of the microwave radar and the high-precision detection capability of the lidar, the microwave radar has a wide beam and strong penetration, ensuring the system's detection capability. The lidar, with its high angular resolution and ranging accuracy, can provide high-precision detection in good weather conditions, effectively improving the system's adaptability to various environmental conditions and solving the problem of weak adaptability in existing detection methods.

[0154] Example 2

[0155] A specific embodiment of the present invention discloses a microwave-laser integrated radar composite detection system, such as... Figure 2 As shown.

[0156] A microwave-laser integrated radar composite detection system, comprising:

[0157] Laser, used to generate laser light;

[0158] A beam splitter is used to receive the laser emitted by the laser and split the laser into multiple paths, which are then transmitted to a microwave radar module, a single-photon lidar module, and a coherent lidar module, respectively.

[0159] The microwave radar module is used to receive the first and second laser beams emitted by the beam splitter, modulate the first laser beam with radio frequency signals to generate a microwave radar transmission signal and transmit it to the target; it is also used to receive microwave radar echo signals, and modulate the second laser beam with microwave radar echo signals and radio frequency signals to generate an intermediate frequency echo signal, which is then transmitted to the control and acquisition processing module.

[0160] The single-photon lidar module is used to receive the third laser beam emitted by the beam splitter, generate a single-photon laser pulse based on the third laser beam and emit it; it is also used to receive the single-photon laser pulse echo signal and convert it into an electrical signal before transmitting it to the control and acquisition processing module.

[0161] The coherent lidar module is used to receive the fourth and fifth laser beams after beam splitting, generate a laser emission signal based on the fourth laser beam and emit it; receive the laser echo signal, and obtain a coherent intermediate frequency signal based on the laser echo signal and the fifth laser beam, which is then transmitted to the control and acquisition processing module.

[0162] The control and acquisition processing module is used to process the received intermediate frequency echo signal from the microwave radar module, the electrical signal from the single-photon lidar module, and the coherent intermediate frequency signal from the coherent lidar module to generate the target's characteristic parameters.

[0163] like Figure 2 As shown, laser 1 generates continuous laser light of a specific wavelength. The continuous laser light generated by laser 1 is split into multiple paths by beam splitter 2, which are then transmitted to a microwave radar module, a single-photon lidar module, and a coherent lidar module, respectively. Beam splitter 2 is an optical element used to split the laser light emitted by laser 1 into five paths. The first and second laser paths are transmitted to the microwave radar module, the third laser path is transmitted to the single-photon lidar module, and the fourth and fifth laser paths are transmitted to the coherent lidar module.

[0164] The microwave radar module receives the first and second laser beams emitted by beam splitter 2. It modulates the first laser beam using radio frequency signals to generate a microwave radar transmission signal, which is then transmitted to the target. It also receives microwave radar echo signals and modulates the second laser beam using the microwave radar echo signal and radio frequency signals to generate an intermediate frequency echo signal, which is then transmitted to the control and acquisition processing module.

[0165] Specifically, the microwave radar module includes: a radio frequency signal generator, a first optoelectronic modulator, a second optoelectronic modulator, a first optoelectronic conversion unit, a second optoelectronic conversion unit, and a transceiver unit;

[0166] The radio frequency signal generator is used to generate a first radio frequency signal and a programmable radio frequency signal and send them to a first optoelectronic modulator; it is also used to generate a second radio frequency signal and send it to a second optoelectronic modulator.

[0167] The radio frequency (RF) signal generator is used to generate RF signals for radar detection. The RF signal generator includes: a waveform generator 4, an RF source 3, a mixer 5, and a first bandpass filter 6. The RF source 3 generates a first RF signal which is transmitted to the mixer 5, and generates a second RF signal which is transmitted to the second optoelectronic modulator 13 for modulating a second laser beam.

[0168] Waveform generator 4 is used to generate intermediate frequency (IF) signals and transmit them to mixer 5. The IF signal is a fixed frequency signal used for signal processing and modulation in the radar system, with a frequency between that of radio frequency (RF) signals and baseband signals.

[0169] Mixer 5 mixes the first radio frequency signal and the intermediate frequency signal to generate a programmable radio frequency signal, which is then transmitted to the first bandpass filter 6. The programmable radio frequency signal can be programmed as needed to adapt to different detection conditions and target characteristics.

[0170] The first bandpass filter 6 is used to filter the programmable radio frequency signal to ensure that the frequency characteristics of the signal meet the system requirements. The filtered programmable radio frequency signal is then transmitted to the first modulation unit.

[0171] The first optoelectronic modulator 7 modulates the first laser beam based on the programmable radio frequency signal and the first radio frequency signal, and sends the modulated optical signal to the first optoelectronic conversion unit for optoelectronic conversion to obtain a microwave radar transmission signal, which is then transmitted by the transceiver unit. The second optoelectronic modulator 13 modulates the second laser beam based on the microwave radar echo signal and the second radio frequency signal to generate a modulated optical signal, which is then sent to the second optoelectronic conversion unit for optoelectronic conversion to obtain an intermediate frequency echo signal, which is then transmitted to the control and acquisition processing module 29.

[0172] The first optoelectronic modulator 7 modulates the first laser beam with a programmable radio frequency signal generated by the radio frequency signal generator and a first radio frequency signal, changing the phase or amplitude of the laser to carry the information required for radar detection. The second optoelectronic modulator 13 receives the target-reflected microwave radar echo signal from the transceiver unit and modulates the second laser beam together with the second radio frequency signal, changing the phase or amplitude of the laser. Modulation is the process of encoding information onto a carrier wave in a radar signal. In the optoelectronic modulator, the characteristics of the laser, such as amplitude, frequency, or phase, are changed to carry the information to be transmitted.

[0173] Furthermore, the first photoelectric conversion unit includes:

[0174] The first optical amplifier 8 amplifies the modulated optical signal sent by the first photoelectric modulator 7 before transmitting it to the first optical filter. The first optical amplifier 8 amplifies the modulated optical signal to increase its intensity.

[0175] The first optical filter 9 is used to filter the amplified optical signal before transmitting it to the first photodetector, removing unwanted frequency components to improve signal quality.

[0176] The first photodetector 10 is used to convert the filtered optical signal into a corresponding electrical signal, namely the microwave radar transmission signal, and transmit the microwave radar transmission signal to the transceiver unit for transmission.

[0177] The transceiver unit includes a TR component 11 and an antenna 12. The TR component 11 includes a transmitter and a receiver. In transmit mode, the TR component 11 transmits microwave radar signals to the target via the antenna 12. In receive mode, the TR component 11 receives echo signals reflected from the target.

[0178] The second photoelectric conversion unit includes: a second optical filter 14, a second photodetector 15, and a second bandpass filter 16.

[0179] The second optical filter 14 is used to receive the optical signal modulated by the second photoelectric modulator 13, filter the optical signal to remove unwanted frequency components or noise, and transmit the filtered signal to the second photodetector.

[0180] The second photodetector 15 is used to convert the filtered optical signal into an electrical signal, namely an intermediate frequency echo signal, and transmit it to the second bandpass filter 16.

[0181] The second bandpass filter 16 is used to further filter the intermediate frequency echo signal to extract useful signal components, remove unwanted frequencies or noise, and transmit the signal to the control and acquisition processing module 29.

[0182] Furthermore, the coherent lidar module includes:

[0183] Laser modulation unit, transceiver optical system, coherent detection unit;

[0184] The laser modulation unit is used to receive the fourth laser beam emitted by the beam splitter, modulate the fourth laser beam to generate a laser emission signal, and emit the laser emission signal through the transceiver optical system.

[0185] The transceiver optical system receives the laser echo signal and transmits it to the coherent detection unit.

[0186] The coherent detection unit is used to receive the laser echo signal and the fifth laser beam. Based on the laser echo signal and the fifth laser beam, a coherent intermediate frequency signal is obtained and transmitted to the control and acquisition processing module.

[0187] Coherent lasers refer to two or more beams of light that maintain the same phase difference, have the same frequency, or have completely identical waveforms during propagation. Coherent lasers can produce stable interference phenomena during propagation, namely constructive interference and destructive interference.

[0188] Specifically, the laser modulation unit includes:

[0189] The fourth optoelectronic modulator 22 is used to receive the fourth laser emitted by the beam splitter 2, modulate the fourth laser, change the phase, frequency or amplitude of the fourth laser to generate a laser emission signal for detection and transmit it to the third optical amplifier 23.

[0190] The third optical amplifier 23 is used to amplify the laser emission signal to ensure that the laser emission signal has a sufficient power level and to transmit the amplified laser emission signal to the transceiver optical system.

[0191] The coherent detection unit includes: an optical coupler 27 and a fourth photodetector 28;

[0192] Optical coupler 27 is used to receive the laser echo signal and the fifth laser emitted by beam splitter 2, obtain a coherent optical signal based on the laser echo signal and the fifth laser, and transmit the coherent optical signal to the fourth photodetector 28. Optical coupler 27 mixes the laser echo signal and the fifth laser, and uses the phase difference between the laser echo signal and the fifth laser to generate a coherent optical signal.

[0193] The fourth photodetector 28 is used to convert coherent optical signals into electrical signals and transmit them to the control and acquisition processing module.

[0194] The transceiver optical system includes: an optical circulator 24, an optical transmission system 25, and a galvanometer 26;

[0195] The optical circulator 24 is used to receive laser emission signals and transmit them to the optical transmission system; and to transmit the laser echo signals transmitted by the optical transmission system to the coherent detection unit.

[0196] The optical circulator 24 is a non-reciprocal optical element that allows light signals to travel in one direction without reflection. The optical circulator 24 receives the laser emission signal from the third optical amplifier 23 and transmits it to the optical transmission system. When the laser echo signal is reflected back from the target, the optical circulator 24 transmits the laser echo signal to the coherent detection unit for coherent detection and signal processing.

[0197] Optical transmission system 25 is used to collimate the laser emission signal and transmit it to galvanometer 26; and to converge the laser echo signal and transmit it to optical circulator 24. Optical transmission system 25 collimates the laser emission signal, that is, it focuses the laser beam into a parallel beam to improve its directional stability and energy concentration during propagation.

[0198] Galvanometer 26 is used to scan the target based on the collimated laser emission signal and to receive the laser echo signal returned from the target and transmit it to the optical transmission system 25. Galvanometer 26 is a fast-response optical scanner that guides the direction of the laser beam by controlling the deflection angle of a mirror. Galvanometer 26 receives the collimated laser emission signal and scans the target according to the instructions of the control and acquisition processing module 29. Galvanometer 26 also reflects the laser echo signal returned from the target back to the optical transmission system 25 for subsequent signal processing.

[0199] Furthermore, the single-photon lidar module includes: a third optoelectronic modulator 17, a second optical amplifier 18, a third photodetector 19, an optical transmitting system 20, and an optical receiving system 21.

[0200] The third optoelectronic modulator 17 receives the third laser beam after beam splitting, modulates the third laser beam to generate single-photon laser pulses, and transmits them to the second optical amplifier. The third optoelectronic modulator 17 receives the third laser beam from the beam splitter 2, performs electro-optic effects on the third laser beam to generate the required pulse sequence, and generates single-photon level laser pulses. Each single-photon laser pulse contains only one photon, which has the characteristics of high time resolution and sensitivity, and can accurately measure the arrival time of photons in a very short time.

[0201] The second optical amplifier 18 is used to amplify the single-photon laser pulse and transmit the amplified single-photon laser pulse to the optical emission system 20 for emission. The optical emission system 20 includes lenses or other optical elements for focusing and directional emission of the laser pulse toward the target area.

[0202] The optical receiving system 21 receives the echo signal of a single-photon laser pulse and transmits it to the third photodetector 19. The optical receiving system 21 includes a receiving lens or optical antenna for collecting the scattered laser pulse and focusing it onto the third photodetector 29.

[0203] The third photodetector 19 is used to convert the single-photon laser pulse echo signal into an electrical signal and transmit it to the control and acquisition processing module. The sensitivity of the third photodetector 19 needs to be set to be able to detect signals at the single photon level. The converted electrical signal is transmitted to the control and acquisition processing module 29.

[0204] Furthermore, the control and acquisition processing module 29 is used to process the received intermediate frequency echo signal from the microwave radar module, the electrical signal from the single-photon lidar module, and the coherent intermediate frequency signal from the coherent lidar module to generate the characteristic parameters of the target.

[0205] Specifically, for the intermediate frequency (IF) echo signal of the microwave radar module, the control and acquisition processing module 29 can analyze the spectrum of the IF echo signal transmitted by the microwave radar module using the Fast Fourier Transform (FFT) algorithm to identify the Doppler frequency shift of the target, thereby identifying the target's velocity. By analyzing the amplitude changes of the signal, the relative distance to the target is inferred. Through time-domain analysis of the IF echo signal, the vibration mode of the target is identified.

[0206] For the electrical signal of the single-photon lidar module, the control and acquisition processing module 29 determines the photon return time by recording the timestamp of the electrical signal of the single-photon lidar module, thereby calculating the target distance. By analyzing the statistical characteristics of the signal, such as the photon arrival time distribution, the surface characteristics and size of the target are calculated.

[0207] For the coherent intermediate frequency signal of the coherent lidar module, the control and acquisition processing module 29 extracts the target's distance and velocity information by coherently demodulating the received coherent intermediate frequency signal.

[0208] The above embodiments of the present invention have the following beneficial effects: The present invention provides unified signal-level control for microwave radar and lidar of different bands and systems, and performs unified acquisition and processing of echo signals. It can flexibly adjust the working mode according to the actual scenario and perform data-level, feature-level, or decision-level fusion processing, which is beneficial to improving target detection and identification capabilities, achieving high-precision target detection, and thus improving the overall detection accuracy. The present invention improves the system's adaptability to various environmental conditions by combining the all-weather working capability of microwave radar and the high-precision detection capability of lidar. The wide beamwidth and strong penetration of microwave radar ensure detection capability under adverse weather conditions, while lidar provides high-precision detection in good weather conditions, ensuring the effective operation of the system in different environments, improving the system's adaptability to various environmental conditions, and solving the problem of weak adaptability of existing detection methods. The radio frequency signal generator of the present invention generates programmable radio frequency signals through components such as waveform generators, radio frequency sources, mixers, and bandpass filters. This programmability allows for flexible adjustment of signal modulation parameters according to different detection task requirements, significantly improving the adaptability and application range of detection.

[0209] Those skilled in the art will understand that the above embodiments can be implemented by a computer program instructing related hardware, and the program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a disk, optical disk, read-only memory, or random access memory, etc.

[0210] The above description is merely a specific embodiment of the present invention, but the protection scope of the embodiments of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of the present invention should be included within the protection scope of the embodiments of the present invention. Therefore, the protection scope of the embodiments of the present invention should be determined by the protection scope of the claims.

Claims

1. A multi-mode radar composite detection method, characterized in that, include: The laser beam generated by the laser is split into multiple paths; The first laser is modulated based on the radio frequency signal to generate a microwave radar transmission signal, which is then transmitted to the target and received by the microwave radar echo signal. The second laser beam is modulated using microwave radar echo signals and radio frequency signals to generate an intermediate frequency echo signal. Single-photon laser pulses are generated based on the third-path laser, single-photon laser pulses are emitted toward the target and single-photon laser pulse echo signals are received, and the single-photon laser pulse echo signals are converted into laser pulse electrical signals. Based on the fourth laser, a laser emission signal is generated, a laser emission signal is emitted towards the target and a laser echo signal is received. The laser echo signal is used to coherently process the fifth laser to obtain a coherent intermediate frequency signal. The target's characteristic parameters are obtained by processing the intermediate frequency echo signal, laser pulse electrical signal, and coherent intermediate frequency signal respectively.

2. The method according to claim 1, characterized in that, The characteristic parameters include: target velocity information and target distance information; the characteristic parameters of the target generated by processing the intermediate frequency echo signal, laser pulse electrical signal, and coherent intermediate frequency signal include: The first velocity information and the first distance information are obtained by processing the intermediate frequency echo signal; The second distance information is obtained by processing the laser pulse electrical signal; The coherent intermediate frequency signal is processed to obtain the second velocity information and the third distance information. The first velocity information and the second velocity information are weighted and averaged to obtain the target velocity information. The target distance information is obtained by performing a weighted average of the first distance information, the second distance information, and the third distance information.

3. The method according to claim 2, characterized in that, The target velocity information is obtained by weighted averaging the first velocity information obtained based on the intermediate frequency echo signal and the second velocity information obtained based on the coherent intermediate frequency signal, as shown in the calculation formula (1). V = αV1 + (1 - α)V2; (1) Where V represents the target velocity information, V1 represents the first velocity information, V2 represents the second velocity information, and α represents the velocity weight.

4. The method according to claim 3, characterized in that, The first velocity information obtained based on the intermediate frequency echo signal includes: The Doppler frequency shift is obtained by performing spectral analysis on the intermediate frequency echo signal; The first velocity information is shown in calculation formula (2); Where λ1 is the wavelength of the microwave radar transmitted signal, and Δf1 is the Doppler frequency shift; The second velocity information obtained based on the coherent intermediate frequency signal includes: Frequency change is obtained by performing frequency analysis on the coherent intermediate frequency signal; The second speed information is shown in calculation formula (3); Where λ2 is the wavelength of the laser emission signal, and Δf2 is the frequency change.

5. The method according to claim 4, characterized in that, The target distance information is obtained by weighted averaging the first distance information obtained from the intermediate frequency echo signal, the second distance information obtained from the laser pulse electrical signal, and the third distance information obtained from the coherent intermediate frequency signal, as shown in the calculation formula (4). R=βR1+γR2+(1-β-γ)R3 (4) Where R represents the target distance information, R1 represents the first distance information, R2 represents the second distance information, R3 represents the third distance information, and β and γ represent the distance weights.

6. The method according to claim 5, characterized in that, The process of modulating the first laser beam using radio frequency signals to generate a microwave radar transmission signal includes: Control the radio frequency source to generate the first radio frequency signal; An intermediate frequency signal is generated by a waveform generator, and the intermediate frequency signal and the first radio frequency signal are mixed to generate a programmable radio frequency signal. The first modulated optical signal is obtained by modulating the first laser with the filtered programmable radio frequency signal and the first radio frequency signal. The first modulated optical signal is converted into a microwave radar transmission signal by photoelectric conversion.

7. The method according to claim 6, characterized in that, The generation of an intermediate frequency echo signal by modulating a second laser beam using microwave radar echo signals and radio frequency signals includes: Control the radio frequency source to generate a second radio frequency signal; The second laser beam is modulated based on the microwave radar echo signal and the second radio frequency signal to generate a second modulated optical signal; The second modulated optical signal is photoelectrically converted to obtain an intermediate frequency echo signal.

8. The method according to claim 7, characterized in that, The microwave radar transmits signals as shown in calculation formula (5); oh Radar =m·ω RF1 -n·ω RF2 -m·[ω IF -BW / 2+BW·t / T] (5) Where, ω Radar ω is the angular frequency of the microwave radar transmitted signal. RF1 Let ω be the angular frequency of the first radio frequency signal. RF2 ω is the angular frequency of the second radio frequency signal. IF ω is the angular frequency of the programmable radio frequency signal, m and n are the laser modulation order, BW is the bandwidth of the programmable radio frequency signal, T is the pulse width of the programmable radio frequency signal, and t is the modulation time. The intermediate frequency echo signal is calculated as shown in formula (6); oh IF =k·ω RF3 -oh' Radar (6) Where, ω RF3 Let ω' be the angular frequency of the third radio frequency signal. Radar Let ω' be the angular frequency of the microwave radar echo signal. IF ω is the angular frequency of the intermediate frequency echo signal, and k is the laser modulation order.

9. The method according to claim 1, characterized in that, The coherent intermediate frequency signal obtained by coherently processing the fifth laser beam using the laser echo signal includes: Coherent optical signals are obtained by coherently processing the laser echo signal and the fifth laser beam. The coherent optical signal is converted into a coherent intermediate frequency signal by photoelectric conversion.

10. The method according to claim 5, characterized in that, The first distance information is obtained based on the intermediate frequency echo signal as shown in the calculation formula (7); Where R1 represents the first distance information, c represents the speed of light, t1 represents the arrival time of the microwave radar echo pulse, and t 01 This refers to the transmission time of the microwave radar signal. The second distance information obtained based on the laser pulse electrical signal is shown in the calculation formula (8); Where R2 represents the second distance information, t2 represents the arrival time of the single-photon laser pulse, and t 02 This refers to the emission time of a single-photon laser pulse; The third distance information is obtained based on the coherent intermediate frequency signal as shown in the calculation formula (9); Where R3 is the third distance information and τ2 is the laser pulse width of the laser emission signal.

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