Intelligent dual-mode radar system based on terahertz frequency band and imaging method thereof

Abstract

The invention discloses an intelligent dual-mode radar system based on a terahertz frequency band and an imaging method thereof, and relates to the field of terahertz radars, and the system comprises a transmitting module which supports the dynamic switching of a short-distance high-resolution mode and a long-distance low-power-consumption mode; the receiving module is used for receiving an echo signal reflected by the target of the transmitting module; the frequency synthesizer is used for generating adaptive frequency sweeping bandwidth and frequency sweeping time parameters according to a target distance requirement, and presetting at least two waveform modes; the self-adaptive signal processing unit is used for dynamically adjusting filtering parameters and gains according to a target distance working mode and outputting target imaging data; and the control module is used for realizing parameter configuration and mode switching of dual-mode cooperative work. According to the dual-mode radar collaborative architecture, collaborative work of short-distance high-resolution imaging and long-distance low-power-consumption detection can be achieved, the performance bottleneck of a traditional single-mode radar is solved, and the dual-mode radar collaborative architecture is suitable for efficient target detection and imaging requirements of diversified scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of terahertz radar, and particularly to an intelligent dual-mode radar system based on the terahertz band and an imaging method thereof. Background Art

[0002] As an emerging technology, terahertz radar has attracted much attention in recent years due to its unique spectral advantages and potential application values. The radar beam in the terahertz band is narrow and the available bandwidth is relatively large. These characteristics enable the terahertz radar to have significant advantages over the microwave and millimeter-wave bands in terms of resolution, especially in close-range imaging. At the same time, by using gallium nitride amplifier technology, the terahertz band radar can also achieve long-range imaging, which is of great significance for detecting the speed, position and other indicators of low, small and slow targets.

[0003] Due to the different detection requirements in different scenarios, traditional single-mode terahertz radars often cannot dynamically adapt to these requirements and are difficult to balance performance and power consumption. First, in the close-range imaging mode, in order to improve the resolution, large-bandwidth signals need to be used, but the high power consumption limits the continuous working ability of the radar, which is particularly disadvantageous for scenarios that require long-term continuous monitoring. Second, in the long-range detection mode, in order to cover long-range targets, the radar system needs to rely on high transmission power, which not only leads to high system complexity, but also significantly increases energy consumption, increasing the operation cost and maintenance difficulty.

[0004] Therefore, it is necessary to improve the deficiencies in the prior art to solve the above problems. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and provides an intelligent dual-mode radar system based on the terahertz band and an imaging method thereof.

[0006] To achieve the above object, the technical solution adopted by the present invention is: an intelligent dual-mode radar system based on the terahertz band, comprising:

[0007] A transmitting module, configured to generate and transmit terahertz band electromagnetic wave signals, and support dynamic switching between the near-range high-resolution mode and the far-range low-power mode;

[0008] A receiving module, configured to receive the echo signals reflected by the target of the transmitting module, and complete the low-noise amplification and mixing processing of the signals;

[0009] A frequency synthesizer, connected to the transmitting module and the receiving module, configured to generate adapted sweep bandwidth and sweep time parameters according to the target distance requirement, and preset at least two waveform modes;

[0010] An adaptive signal processing unit, connected to the receiving module, for dynamically adjusting filtering parameters and gain according to the target distance working mode, and outputting target imaging data;

[0011] A control module, connected to the receiving module, frequency synthesizer and adaptive signal processing unit, for realizing parameter configuration and mode switching for dual-mode collaborative work.

[0012] In a preferred embodiment of the present invention, the transmit power in the near-distance high-resolution mode is <20 dBm, the sweep bandwidth is ≥15 GHz, the sweep time is ≤1.2 ms, and the range resolution is ≤0.025 m;

[0013] The transmit power in the far-distance low-power mode is ≥20 dBm, the sweep bandwidth is ≤6 GHz, the sweep time is ≤0.48 ms, and the detection range is ≥1000 m.

[0014] In a preferred embodiment of the present invention, the frequency synthesizer includes six preset waveform modes, and the preset waveform modes include:

[0015] Near-distance waveform mode: detection range 100 - 300 m, sweep bandwidth 6 - 15 GHz, sweep time 1 - 1.2 ms;

[0016] Far-distance waveform mode: detection range 1000 - 1200 m, sweep bandwidth 0.3 - 0.6 GHz, sweep time 0.2 - 0.48 ms.

[0017] In a preferred embodiment of the present invention, the transmit module includes: a signal generation unit, an amplifier, a power divider, a multiplier chain, and a power amplifier connected in sequence;

[0018] The signal generation unit is used to generate a frequency band of 8.5 - 9.5 GHz;

[0019] The multiplier chain is used to boost the fundamental frequency signal to the 210 - 225 GHz frequency band through X12 multiplication and X2 multiplication;

[0020] The power amplifier is used to output a power ≥20 dBm in the far-distance mode and <20 dBm in the near-distance mode.

[0021] In a preferred embodiment of the present invention, the receiving module includes: a receiving antenna, a low-noise amplifier, a harmonic mixer, and an intermediate-frequency output link connected in sequence;

[0022] The receiving antenna is used to receive the echo signal of 210 - 225 GHz;

[0023] The harmonic mixer is used to mix the echo signal with the local oscillator signal to obtain an intermediate-frequency signal of 100 KHz - 10 MHz;

[0024] The intermediate-frequency output link is used to convert the mixing into an intermediate-frequency signal of 100 KHz - 10 MHz and input it to the adaptive signal processing unit.

[0025] In a preferred embodiment of the present invention, the adaptive signal processing unit includes: a close-range imaging algorithm module and a long-range detection algorithm module;

[0026] The close-range imaging algorithm module is used to implement three-dimensional imaging with centimeter-level resolution by using the fast Fourier transform imaging algorithm;

[0027] The long-range detection algorithm module is used to suppress environmental clutter by using a moving target detection filter and increase the signal-to-noise ratio to ≥10 dB based on dynamic gain adjustment.

[0028] In a preferred embodiment of the present invention, the control module includes: a microprocessor, a control unit, and a radar turntable connected in sequence;

[0029] The microprocessor is used to receive the intermediate-frequency signal from the receiving module through an analog-to-digital converter, perform data processing, and communicate with the control unit and the radar turntable through a communication interface;

[0030] The control unit is used to interact with the frequency synthesizer and the adaptive signal processing unit through a communication interface;

[0031] The radar turntable is used to drive the antenna array to achieve 360° scanning, and the angle accuracy is ≤±0.1°.

[0032] The present invention provides an imaging method for an intelligent dual-mode radar system based on the terahertz band, including the following steps:

[0033] S1. Select the close-range high-resolution or long-range low-power mode according to the target distance, and generate a corresponding frequency-swept signal through the frequency synthesizer;

[0034] S2. In the close-range high-resolution mode, receive the echo signal, and achieve high-resolution three-dimensional reconstruction through the large-bandwidth signal and the FFT imaging algorithm;

[0035] S3. In the long-range low-power mode, receive the echo signal, and achieve low-power target recognition through the narrow-bandwidth signal and the moving target detection algorithm.

[0036] In a preferred embodiment of the present invention, in the step of S2, the distance resolution of the close-range high-resolution mode is:

[0037] ΔR = C / (2f)

[0038] where C is the speed of light; f is the frequency-swept bandwidth; when f≥20 GHz, ΔR≤0.025 m.

[0039] In a preferred embodiment of the present invention, in the step of S3, the detection distance in the long-distance low-power consumption mode is:

[0040] R = (C·T·τ) / (2Δf)

[0041] Wherein, T is the frequency sweep time; τ is the target reflection time delay; Δf is the signal frequency difference; when Δf ≤ 0.6 GHz and T ≤ 0.48 ms, R ≥ 1000 m.

[0042] The present invention solves the defects existing in the background technology, and the present invention has the following beneficial effects:

[0043] (1) The present invention provides an intelligent dual-mode radar system based on the terahertz frequency band and its imaging method. The dual-mode radar collaborative architecture of the present invention realizes the collaborative work of high-resolution imaging at close range and low-power detection at long range through a dynamic frequency synthesizer and adaptive signal processing technology. The system adopts a dual-mode switching mechanism that combines preset hardware parameters and software algorithms, which can realize the collaborative work of high-resolution imaging at close range and low-power detection at long range, solves the performance bottleneck of traditional single-mode radars, and is suitable for the efficient target detection and imaging requirements in diversified scenarios.

[0044] (2) In the present invention, through the frequency synthesizer, six waveform modes are preset. Combining the real-time filtering and gain adjustment of the adaptive signal processing unit, the optimal frequency sweep bandwidth and frequency range can be automatically matched according to the detection distance requirement, improving the flexibility and response speed of the system, and thus realizing more accurate detection and imaging.

[0045] (3) In the present invention, in the frequency band of 210 - 225 GHz, the transmitted power is controlled within the range of ≤ 20 dBm, and the power output is stable with small fluctuations, indicating that the transmitting module can maintain a stable low-power output under a large bandwidth to ensure that the receiver will not be oversaturated under the condition of low-power dynamic attenuation, thereby optimizing the signal-to-noise ratio and realizing high-resolution imaging.

[0046] (4) In the present invention, in the frequency band of 219 - 225 GHz, by reasonably setting parameters such as the frequency sweep time and bandwidth, the advantages of this frequency band can be fully utilized, so that the weak signals reflected by long-distance targets can be received and amplified more effectively, improving the detection probability and accuracy of the system for low, small, and slow targets, and realizing the effective detection of targets at distances above 1000 meters. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings;

[0048] Figure 1 is the architecture block diagram of the intelligent dual-mode radar system of the present invention;

[0049] Figure 2 is the power test curve graph of Mode A in the preferred embodiment of the present invention;

[0050] Figure 3 is the frequency conversion gain test curve graph of Mode B in the preferred embodiment of the present invention;

[0051] Figure 4 is the noise figure test curve graph of the long-distance mode in the preferred embodiment of the present invention;

[0052] Figure 5 is the three-dimensional imaging interface diagram of the control software in the preferred embodiment of the present invention;

[0053] Figure 6 is the close-range imaging diagram in the preferred embodiment of the present invention;

[0054] Figure 7 is the long-distance imaging diagram in the preferred embodiment of the present invention. Specific Embodiments

[0055] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0056] Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0057] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0058] As Figure 1 shown, an intelligent dual-mode radar system based on the terahertz band includes: a transmitting module for generating and transmitting terahertz band electromagnetic wave signals, supporting dynamic switching between a near-range high-resolution mode and a far-range low-power mode; a receiving module for receiving the echo signals reflected by the target of the transmitting module and completing low-noise amplification and mixing processing of the signals; a frequency synthesizer connected to the transmitting module and the receiving module for generating appropriate sweep bandwidth and sweep time parameters according to the target distance requirement and presetting at least two waveform modes; an adaptive signal processing unit connected to the receiving module for dynamically adjusting the filtering parameters and gain according to the target distance working mode and outputting target imaging data; and a control module connected to the receiving module, the frequency synthesizer, and the adaptive signal processing unit for implementing parameter configuration and mode switching for dual-mode collaborative work.

[0059] It should be noted that in the near-range high-resolution mode, an electronically controlled attenuator is used to achieve a low output power of the transmitted power <20 dBm to ensure that the receiver will not be oversaturated, the sweep bandwidth ≥15 GHz, the sweep time ≤1.2 ms, optimizing the signal-to-noise ratio, and the range resolution ≤0.025 m; in the far-range low-power mode, an electronically controlled attenuator is used to achieve a high output power of the transmitted power ≥20 dBm to ensure long-distance operation, the sweep bandwidth ≤6 GHz, the sweep time ≤0.48 ms, an ultra-short sweep time, improving the power utilization rate, and the detection range ≥1000 m; the system also includes several power supply modules (such as 12 VDC and 48 VDC) to provide the required power for different modules respectively to ensure the normal operation of each module.

[0060] Specifically, the dual-mode radar collaborative architecture of the present invention realizes the collaborative work of near-range high-resolution imaging and far-range low-power detection through a dynamic frequency synthesizer and an adaptive signal processing technology. The system adopts a dual-mode switching mechanism of presetting hardware parameters and linking software algorithms, which can realize the collaborative work of near-range high-resolution imaging and far-range low-power detection, solves the performance bottleneck of traditional single-mode radars, and is applicable to the efficient target detection and imaging requirements of diversified scenarios.

[0061] In some embodiments, the frequency synthesizer includes six preset waveform modes, which are: short-range waveform mode: detection range 100 - 300m, sweep bandwidth 6 - 15GHz, sweep time 1 - 1.2ms; long-range waveform mode: detection range 1000 - 1200m, sweep bandwidth 0.3 - 0.6GHz, sweep time 0.2 - 0.48ms.

[0062] It should be noted that through the frequency synthesizer, six preset waveform modes, combined with the real-time filtering and gain adjustment of the adaptive signal processing unit, can automatically match the best sweep bandwidth and frequency range according to the detection range requirements, improving the system flexibility and response speed, so as to achieve more accurate detection and imaging.

[0063] In some embodiments, the transmitting module includes: a signal generating unit, an amplifier, a power divider, a multiplier chain, and a power amplifier connected in sequence; the signal generating unit is used to generate a frequency band of 8.5 - 9.5GHz; the multiplier chain is used to boost the fundamental frequency signal to the 210 - 225GHz frequency band through X12 multiplication and X2 multiplication; the power amplifier is used to output a power ≥20dBm in the long-range mode and <20dBm in the short-range mode.

[0064] In some embodiments, the receiving module includes: a receiving antenna, a low-noise amplifier, a harmonic mixer, and an intermediate-frequency output link connected in sequence; the receiving antenna is used to receive the echo signal of 210 - 225GHz; the harmonic mixer is used to mix the echo signal with the local oscillator signal to obtain an intermediate-frequency signal of 100KHz - 10MHz; the intermediate-frequency output link is used to convert the mixed frequency into an intermediate-frequency signal of 100KHz - 10MHz and input it to the adaptive signal processing unit.

[0065] In some embodiments, the adaptive signal processing unit includes: a short-range imaging algorithm module and a long-range detection algorithm module; the short-range imaging algorithm module is used to implement three-dimensional imaging with centimeter-level resolution by using the fast Fourier transform (FFT) imaging algorithm; the long-range detection algorithm module is used to suppress environmental clutter by using a moving target detection filter and improve the signal-to-noise ratio to ≥10dB based on dynamic gain adjustment.

[0066] In some embodiments, the control module includes: a microprocessor, a control unit, and a radar turntable connected in sequence; the microprocessor is used to receive the intermediate-frequency signal from the receiving module through an analog-to-digital converter (ADC) and perform data processing, and communicate with the control unit and the radar turntable through a communication interface; the control unit is used to interact with the frequency synthesizer and the adaptive signal processing unit through a communication interface; the radar turntable is used to drive the antenna array to achieve 360° scanning, and the angle accuracy ≤±0.1°.

[0067] When the present invention is in use, the frequency synthesizer presets the near - range waveform mode and the far - range waveform mode, selects the near - range high - resolution or far - range low - power mode according to the target distance. The signal generation unit generates a signal of 8.5 - 9.5 GHz, and the generated signal is amplified by an amplifier to provide a signal with sufficient intensity for subsequent frequency multiplication and other operations. The power divider divides the amplified signal into two paths. The first path is multiplied by X12 through the frequency multiplier chain, and the signal is raised to the 100 - 112.5 GHz band, then multiplied by X2 to output a signal in the 210 - 225 GHz band, and is power - amplified by the power amplifier, and finally transmitted through the transmitting antenna. The second path is multiplied by X12 through the frequency multiplier chain, and the signal is raised to the 100 - 112.5 GHz band as the local oscillator signal. At the same time, the receiving antenna receives the echo signal of 210 - 225 GHz, which is low - noise amplified by the low - noise amplifier. The harmonic mixer mixes the received echo signal with the local oscillator signal to obtain an IF signal with a frequency range of 100 KHz - 10 MHz, and the IF signal is output to the adaptive signal processing unit and the control module through the intermediate - frequency output link. In the control module, the IF signal is received by the ADC, and data processing and other operations are performed by the microprocessor. At the same time, communication is carried out with the control unit and the radar turntable through various interfaces (such as RS232, RS422, J30J, etc.). The radar turntable and the antenna array perform multi - angle scanning, and in combination with the close - range imaging algorithm module or the far - range detection algorithm module of the adaptive signal processing unit, high - precision positioning and imaging of the target are achieved, improving the imaging efficiency and accuracy.

[0068] An imaging method for an intelligent dual - mode radar system based on the terahertz band, comprising the following steps:

[0069] S1. Select the near - range high - resolution or far - range low - power mode according to the target distance, and generate a corresponding swept - frequency signal through the frequency synthesizer;

[0070] S2. In the near - range high - resolution mode, receive the echo signal, and achieve high - resolution three - dimensional reconstruction through the large - bandwidth signal and the FFT imaging algorithm;

[0071] S3. In the far - range low - power mode, receive the echo signal, and achieve low - power target recognition through the narrow - bandwidth signal and the moving - target detection algorithm.

[0072] It should be noted that the FFT imaging algorithm is based on the frequency-domain analysis of radar echo signals. By converting the time-domain signal into frequency-domain information, the range and azimuth features of the target are extracted to achieve real-time imaging with centimeter-level resolution. The moving target detection algorithm distinguishes the stationary background from the moving target through the Doppler frequency shift of the signal and clutter suppression technology, and realizes the efficient recognition of kilometer-level targets under low-power conditions. Its application principles and coding are all well-known prior art means in this field and belong to the common general knowledge in this field. Therefore, this application will not be explained in detail and will not be elaborated here.

[0073] In some embodiments, in the step of S2, the range resolution of the near-range high-resolution mode is:

[0074] ΔR = C / (2f)

[0075] Where C is the speed of light; f is the swept frequency bandwidth; when f ≥ 20 GHz, ΔR ≤ 0.025 m.

[0076] In some embodiments, in the step of S3, the detection range of the far-range low-power mode is:

[0077] R = (C·T·τ) / (2Δf)

[0078] Where T is the swept frequency time; τ is the target reflection time delay; Δf is the signal frequency difference; when Δf ≤ 0.6 GHz and T ≤ 0.48 ms, R ≥ 1000 m.

[0079] To further make the purpose and effect of the present invention simple and easy to understand, the present invention will be further elaborated in combination with the following embodiments.

[0080] Embodiment

[0081] The intelligent dual-mode radar system of this embodiment: supports the large-bandwidth near-range high-resolution mode (Mode A) and the small-bandwidth far-range low-power mode (Mode B), as shown in Table 1 specifically.

[0082] Table 1:

[0083]

[0084]

[0085] Using a VDI / PM5 power meter, the measured transmit power characteristics of Mode A are as Figure 2 shown. In the frequency band of 210 - 225 GHz, the transmit power is controlled within the range of ≤ 20 dBm, the power output is stable and the fluctuation is small, indicating that the transmit module can maintain a stable low-power output under large bandwidth to ensure that the receiver will not be oversaturated under the condition of low-power dynamic attenuation, thereby optimizing the signal-to-noise ratio and achieving high-resolution imaging.

[0086] Using a PNA network analyzer, the frequency conversion gain characteristics of mode B were measured, and the results are as follows Figure 3 shown. In the frequency band of 219 - 225 GHz, although the gain fluctuates, the overall frequency conversion ability is still available. By reasonably setting parameters such as the sweep time and bandwidth, the advantages of this frequency band can be fully utilized, enabling weak signals reflected by distant targets to be received and amplified more effectively, improving the detection probability and accuracy of the system for low, small, and slow targets, and achieving effective detection of targets at distances over 1000 meters.

[0087] The frequency synthesizer presets six waveform modes, as shown in Table 2 specifically, for automatically matching the detection distance requirements.

[0088] Table 2:

[0089]

[0090]

[0091] The adaptive signal processing unit dynamically adjusts the filtering parameters and gain according to the target distance;

[0092] The three-dimensional radar turntable and antenna array support 360° scanning and multi-angle imaging.

[0093] Operating principle

[0094] Mode A: Frequency band: 210 - 225 GHz (large bandwidth 20 GHz); Power: ≤20 dBm (low power dynamic attenuation); Resolution: Range resolution ≤0.025 m (based on the range resolution formula); Applicable scenarios: High-precision imaging within 100 meters (such as personnel positioning, small object detection); Using an electronic control attenuator to achieve a low output power of <20 dBm to ensure that the receiver will not be oversaturated, with a 15 GHz bandwidth and a 1 ms sweep time to optimize the signal-to-noise ratio.

[0095] Mode B: Frequency band: 219 - 225 GHz (small bandwidth 6 GHz); Power: ≥20 dBm (high power dynamic compensation); Scanning range: Over 1000 meters; Applicable scenarios: Long-distance target detection (such as building outlines, terrain mapping), low, small, and slow targets; Using an electronic control attenuator with a high output power of ≥20 dBm to ensure long-distance operation, and through a 0.3 GHz narrow bandwidth and a 0.2 ms ultra-short sweep time to improve the power utilization rate.

[0096] Adaptive noise suppression algorithm: Using Y-factor method noise test data, as shown Figure 4 below, dynamically adjust the intermediate frequency gain in the far-distance mode to reduce the influence of thermal noise.

[0097] Hardware-algorithm collaboration: As shown Figure 5As shown, based on the turntable angle accuracy (±0.1°) and the sampling rate (8192 pps), high-precision three-dimensional imaging reconstruction is achieved.

[0098] Field test:

[0099] As Figure 6 shown, for close-range imaging (100 m): the horizontal resolution is ±0.1°, and the pitch resolution is ±0.1°.

[0100] As Figure 7 shown, for long-range imaging (1200 m): the signal-to-noise ratio is ≥10 dB, and the target recognition rate is ≥95%.

[0101] In summary, through dynamic switching and hardware collaboration, the present invention enables the system to have the capabilities of "seeing clearly" and "seeing far" in complex environments, significantly expanding the application boundary of the terahertz radar.

[0102] Based on the ideal embodiments of the present invention as an inspiration, through the above description, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed rights.

[0103] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An intelligent dual-mode radar system based on the terahertz frequency band, characterized in that: include: The transmitting module is used to generate and transmit electromagnetic wave signals in the terahertz frequency band, and supports dynamic switching between short-range high-resolution mode and long-range low-power consumption mode; A receiving module is used to receive the echo signal reflected by the target of the transmitting module and complete the low-noise amplification and mixing processing of the signal; A frequency synthesizer, connected to the transmitting module and the receiving module, for generating adaptive sweep bandwidth and sweep time parameters according to target distance requirements, and presetting at least two waveform modes; An adaptive signal processing unit, connected to the receiving module, for dynamically adjusting the filtering parameters and gain according to the target distance working mode, and outputting the target imaging data; The control module is connected with the receiving module, the frequency synthesizer and the adaptive signal processing unit, and is used to realize parameter configuration and mode switching of the dual-mode collaborative work.

2. The intelligent dual-mode radar system based on the terahertz frequency band according to claim 1, characterized in that: The transmission power of the close-range high-resolution mode is <20dBm, the sweep bandwidth is ≥15GHz, the sweep time is ≤1.2ms, and the distance resolution is ≤0.025m; The transmission power of the long-range low-power mode is ≥20dBm, the sweep bandwidth is ≤6GHz, the sweep time is ≤0.48ms, and the detection distance is ≥1000m.

3. The intelligent dual-mode radar system based on the terahertz frequency band according to claim 1, characterized in that: The frequency synthesizer includes six preset waveform modes, and the preset waveform modes include: Close range waveform mode: detection distance 100-300m, sweep bandwidth 6-15GHz, sweep time 1-1.2ms; Long-range waveform mode: detection distance 1000-1200m, sweep bandwidth 0.3-0.6GHz, sweep time 0.2-0.48ms.

4. The intelligent dual-mode radar system based on the terahertz frequency band according to claim 1, characterized in that: The transmitting module comprises: a signal generating unit, an amplifier, a power divider, a frequency multiplier chain and a power amplifier connected in sequence; The signal generating unit is used to generate a frequency band of 8.5-9.5 GHz; The frequency multiplier chain is used to increase the baseband signal to the 210-225 GHz frequency band through X12 frequency multiplication and X2 frequency multiplication; The power amplifier is used to output power ≥ 20dBm in long-range mode and < 20dBm in short-range mode.

5. The intelligent dual-mode radar system based on the terahertz frequency band according to claim 1, characterized in that: The receiving module comprises: a receiving antenna, a low noise amplifier, a harmonic mixer and an intermediate frequency output link connected in sequence; The receiving antenna is used to receive echo signals of 210-225 GHz; The harmonic mixer is used to mix the echo signal with the local oscillator signal to obtain an intermediate frequency signal of 100KHz-10MHz; The intermediate frequency output link is used to convert the mixed frequency into an intermediate frequency signal of 100KHz-10 MHz, and input it into the adaptive signal processing unit.

6. The intelligent dual-mode radar system based on the terahertz frequency band according to claim 1, characterized in that: The adaptive signal processing unit includes: a short-range imaging algorithm module and a long-range detection algorithm module; The close-range imaging algorithm module is used to implement three-dimensional imaging with centimeter-level resolution by using a fast Fourier transform imaging algorithm; The long-distance detection algorithm module is used to suppress environmental clutter using a moving target detection filter and improve the signal-to-noise ratio to ≥10dB based on dynamic gain adjustment.

7. The intelligent dual-mode radar system based on the terahertz frequency band according to claim 1, characterized in that: The control module includes: a microprocessor, a control unit and a radar turntable connected in sequence; The microprocessor is used to receive the intermediate frequency signal from the receiving module through an analog-to-digital converter, perform data processing, and communicate with the control unit and the radar turret through a communication interface; The control unit is used to interact with the frequency synthesizer and the adaptive signal processing unit through a communication interface; The radar turntable is used to drive the antenna array to achieve 360° scanning with an angle accuracy of ≤±0.1°.

8. An imaging method of an intelligent dual-mode radar system based on the terahertz frequency band according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1, select short-range high-resolution or long-range low-power consumption mode according to the target distance, and generate the corresponding sweep signal through the frequency synthesizer; S2, in close-range high-resolution mode, receives echo signals and achieves high-resolution 3D reconstruction through large-bandwidth signals and FFT imaging algorithms; S3, in the long-range high-low power mode, receives the echo signal and realizes low-power target recognition through narrow bandwidth signal and moving target detection algorithm.

9. The imaging method of the intelligent dual-mode radar system based on the terahertz frequency band according to claim 8, characterized in that: In step S2, the distance resolution of the close-range high-resolution mode is: ΔR=C / (2f) Where, C is the speed of light; f is the frequency sweep bandwidth; when f≥20GHz, ΔR≤0.025m.

10. The imaging method of the intelligent dual-mode radar system based on the terahertz frequency band according to claim 8, characterized in that: In the step S3, the detection distance of the long-range low power consumption mode is: R=(C·T·τ) / (2Δf) Wherein, T is the frequency sweep time; τ is the target reflection delay; Δf is the signal frequency difference; when Δf≤0.6GHz and T≤0.48ms, R≥1000m.

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