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

Abstract

The present invention discloses an intelligent dual-mode radar system based on the terahertz frequency band and its imaging method, which relates to the field of terahertz radar. The system includes a transmitter module that supports dynamic switching between a short-range high-resolution mode and a long-range low-power mode, a frequency synthesizer that generates sweep bandwidth and sweep time parameters according to the needs of the target distance and presets at least two waveform modes, an adaptive signal processing unit that outputs target imaging data, and a control module that realizes parameter setting and mode switching for dual-mode cooperative operation.The present invention is a dual-mode radar cooperative structure that can realize the cooperative operation of short-range high-resolution imaging and long-range low-power exploration, and is suitable for the needs of efficient target detection and imaging in diverse scenes.

Description

[Technical Field]

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

[0002] Terahertz radar, an emerging technology, has been attracting attention in recent years due to its unique spectral advantages and potential application value. Terahertz frequency band radar has a narrow beam and a relatively large available bandwidth. These characteristics give terahertz radar a significant advantage over microwave and millimeter wave frequency bands in terms of resolution, especially in short-range imaging. In addition, by utilizing gallium nitride amplifier technology, terahertz frequency band radar can also achieve long-range imaging, which is important for detecting indicators such as the speed and position of low, small, and slow targets.

[0003] Because detection needs vary depending on the scene, conventional single-mode terahertz radars are unable to dynamically respond to these needs and have difficulty balancing performance and power consumption. First, in short-range imaging mode, large-bandwidth signals must be adopted to improve resolution, but high power consumption limits the radar's sustained operating capability, which is particularly disadvantageous in situations requiring long-term, sustained monitoring. Second, in long-range detection mode, radar systems must rely on high transmission power to cover long-range targets, which not only increases system complexity but also significantly increases energy consumption, operating costs, and maintenance difficulties.

[0004] Therefore, there is a need to improve the shortcomings of existing technologies to solve the above problems. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention overcomes the shortcomings of the prior art and provides an intelligent dual-mode radar system and imaging method based on the terahertz frequency band. [Means for solving the problem]

[0006] To achieve the above objectives, the technical solution adopted in the present invention is an intelligent dual-mode radar system based on the terahertz frequency band.

[0007] The transmitter module included in the terahertz frequency band-based intelligent dual-mode radar system is used to generate and transmit terahertz frequency band electromagnetic signals, and supports dynamic switching between a short-range high-resolution mode and a long-range low-power mode.

[0008] The receiving module included in the intelligent dual-mode radar system based on the terahertz frequency band is used to receive the echo signal reflected by the transmitting module of the target, and complete low-noise amplification and mixing processing of the signal.

[0009] The frequency synthesizer included in the intelligent dual-mode radar system based on the terahertz frequency band is connected to the transmitting module and the receiving module, and is used to generate sweep bandwidth and sweep time parameters adapted according to the needs of the target distance, and to preset at least two kinds of waveform modes.

[0010] The adaptive signal processing unit included in the intelligent dual-mode radar system based on the terahertz frequency band is connected to the receiving module and is used to dynamically adjust filter parameters and gain according to the target distance and working mode, and output target imaging data.

[0011] The control module included in the intelligent dual-mode radar system based on the terahertz frequency band is connected to the receiving module, the frequency synthesizer and the adaptive signal processing unit, and is used to realize parameter setting and mode switching for dual-mode cooperative operation.

[0012] In a preferred embodiment of the present invention, the short-distance high-resolution mode has a transmission power of <20 dBm, a sweep bandwidth of ≥15 GHz, a sweep time of ≤1.2 ms, and a distance resolution of ≤0.025 m; The long-distance low-power mode has a transmission power of ≧20 dBm, a sweep bandwidth of ≦6 GHz, a sweep time of ≦0.48 ms, and a detection distance of ≧1000 m.

[0013] In a preferred embodiment of the present invention, the frequency synthesizer includes six preset waveform modes, which are: A short-distance waveform mode with a search distance of 100 to 300 m, a sweep bandwidth of 6 to 15 GHz, and a sweep time of 1 to 1.2 ms; and a long-distance waveform mode with a detection distance of 1000-1200 m, a sweep bandwidth of 0.3-0.6 GHz, and a sweep time of 0.2-0.48 ms.

[0014] In a preferred embodiment of the present invention, the transmitting module comprises a signal generating unit, an amplifier, a power divider, a frequency multiplier chain and a power amplifier connected in series; The signal generating unit is used to generate a frequency band signal of 8.5 to 9.5 GHz, The frequency multiplier chain is used to increase the base frequency signal to a frequency band of 210-225 GHz by a X12 frequency multiplier module and a X2 frequency multiplier module; The power amplifier is used to ensure that the output power in the long-range mode is ≧20 dBm and the output power in the short-range mode is <20 dBm.

[0015] 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 series; The receiving antenna is used to receive echo signals in the range of 210 to 225 GHz, The harmonic mixer is used to mix the echo signal and the local oscillation signal to obtain an intermediate frequency signal of 100 KHz to 10 MHz; The intermediate frequency output link is used to convert the mixed frequency into an intermediate frequency signal of 100KHz to 10MHz, and input it into the adaptive signal processing unit.

[0016] In a preferred embodiment of the present invention, the adaptive signal processing unit includes a near-field imaging algorithm module and a long-field detection algorithm module; the near-field imaging algorithm module utilizes a fast Fourier transform imaging algorithm to realize centimeter-level resolution three-dimensional imaging; The long-range search algorithm module utilizes a moving target search filter to suppress environmental clutter and is used to improve SINR to ≧10 dB based on dynamic gain adjustment.

[0017] In a preferred embodiment of the present invention, the control module includes a microprocessor, a control unit, and a radar turntable connected in series; 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; the control unit is used to interact with the frequency synthesizer and the adaptive signal processing unit via a communication interface; The radar turntable is used to drive the antenna array to achieve 360° scanning with an angular accuracy of ≦±0.1°.

[0018] The present invention provides an imaging method for an intelligent dual-mode radar system based on the terahertz frequency band, the imaging method comprising: Step S1: selecting a short-distance high-resolution mode or a long-distance low-power mode according to a target distance, and generating a corresponding sweep signal by a frequency synthesizer; In the near-field high-resolution mode, step S2 receives echo signals and realizes high-resolution three-dimensional reconstruction using a large bandwidth signal and an FFT imaging algorithm; In the long-distance low-power mode, the method includes step S3 of receiving an echo signal and realizing low-power target recognition using a narrow-bandwidth signal and a moving target detection algorithm.

[0019] In a preferred embodiment of the present invention, in step S2, the distance resolution in the short-distance high-resolution mode is

[0020]

number

[0021] It is expressed as where C is the speed of light and f is the sweep bandwidth. For f ≥ 20 GHz, ΔR ≤ 0.025 m.

[0022] In a preferred embodiment of the present invention, in step S3, the search distance in the long-distance low-power mode is:

[0023]

number

[0024] It is expressed as where T is the sweep time, τ is the delay of the target reflection, and Δf is the signal frequency difference. If Δf≦0.6 GHz and T≦0.48 ms, then R≧1000 m. [Effects of the Invention]

[0025] The present invention solves the deficiencies existing in the background art and has the following beneficial effects:

[0026] The present invention provides an intelligent dual-mode radar system and imaging method based on the terahertz frequency band. The dual-mode radar cooperative structure of the present invention utilizes a dynamic frequency synthesizer and adaptive signal processing technology to achieve the cooperative operation of close-range high-resolution imaging and long-range low-power exploration. Furthermore, the system employs a dual-mode switching mechanism that combines hardware parameter presets and software algorithms to achieve the cooperative operation of close-range high-resolution imaging and long-range low-power exploration, thereby overcoming the performance bottleneck of traditional single-mode radar and meeting the needs for efficient target detection and imaging in diverse scenes.

[0027] In this invention, six types of waveform modes can be preset through the frequency synthesizer, and combined with real-time filtering and gain adjustment by the adaptive signal processing unit, the optimal sweep bandwidth and frequency range can be automatically matched according to the needs of the detection distance, improving the flexibility and response speed of the system and achieving more accurate detection and imaging.

[0028] In the present invention, in the 210-225 GHz frequency band, the transmission power is controlled to be less than 20 dBm, and the power output is stable with small fluctuations. This allows the transmitter module to maintain a stable low power output over a large bandwidth. Under the condition of low power dynamic attenuation, this ensures that the receiver does not become oversaturated, thereby optimizing the SINR and realizing high-resolution imaging.

[0029] In the present invention, by rationally setting parameters such as sweep time and bandwidth in the 219-225 GHz frequency band, the advantages of this frequency band can be fully utilized, and weak signals reflected by distant targets can be more efficiently received and amplified, improving the system's detection probability and accuracy for low, small, and slow targets, and achieving effective detection of targets at distances of 1,000 meters or more. [Brief explanation of the drawings]

[0030] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces drawings necessary for describing the embodiments or the prior art. However, the drawings in the following description are only some embodiments described in the present invention, and it is obvious to those skilled in the art that other drawings can be obtained based on these drawings without paying creative labor. [Figure 1] 1 is a structural block diagram of an intelligent dual-mode radar system according to the present invention; FIG. [Figure 2] 1 is a power test graph of Mode A in a preferred embodiment of the present invention. [Figure 3] 10 is a frequency conversion gain test graph of Mode B in a preferred embodiment of the present invention. [Figure 4] 10 is a noise factor test graph for the long-distance mode in a preferred embodiment of the present invention. [Figure 5] FIG. 10 is a three-dimensional imaging interface diagram of the control software in the preferred embodiment of the present invention. [Figure 6] FIG. 1 is a diagram illustrating close-range imaging in a preferred embodiment of the present invention. [Figure 7] FIG. 1 is a diagram of long-distance imaging in a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, but it is clear that the described embodiments are only a part of the embodiments of the present invention, and are not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present invention.

[0032] In the following description, numerous specific details are set forth to facilitate a thorough understanding of the present invention; however, the present invention may be practiced in other ways than those described in the present invention, and therefore the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, unless otherwise expressly specified and limited, the terms "attach," "connect," and "connect" should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection. They may also refer to a mechanical connection or an electrical connection. They may also refer to a direct connection, an indirect connection via an intermediate medium, or an internal connection between two elements. The specific meanings of the above terms in this application can be understood by those skilled in the art depending on the specific circumstances.

[0034] As shown in FIG. 1, the intelligent dual-mode radar system is based on the terahertz frequency band, and includes: a transmitting module for generating and transmitting terahertz frequency band electromagnetic signals, supporting dynamic switching between a short-range high-resolution mode and a long-range low-power mode; a receiving module for receiving echo signals reflected by the transmitting module from the target and completing low-noise signal amplification and mixing; a frequency synthesizer connected to the transmitting module and the receiving module for generating adaptive sweep bandwidth and sweep time parameters according to the needs of the target distance and presetting at least two waveform modes; an adaptive signal processing unit connected to the receiving module for dynamically adjusting filter parameters and gain according to the target distance and 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 realizing parameter setting and mode switching for dual-mode cooperative working.

[0035] The short-distance, high-resolution mode uses an electronically controlled attenuator to achieve low output power (<20dBm), ensuring no receiver oversaturation. It also features a sweep bandwidth of ≥15GHz, a sweep time of ≤1.2ms, optimized SINR, and a range resolution of ≤0.025m. The long-distance, low-power mode uses an electronically controlled attenuator to achieve high output power (≥20dBm), ensuring long-distance operation. It features a sweep bandwidth of ≤6GHz, a sweep time of ≤0.48ms, and an ultra-short sweep time, improving power utilization and enabling a detection range of ≥1000m. The system also includes several power supply modules (e.g., 12VDC and 48VDC) to provide the necessary power for each module and ensure its normal operation.

[0036] Specifically, the dual-mode radar cooperative structure of the present invention utilizes dynamic frequency synthesizers and adaptive signal processing technology to achieve the cooperative operation of close-range high-resolution imaging and long-range low-power exploration. Furthermore, the system employs a dual-mode switching mechanism that combines hardware parameter presets and software algorithms to achieve the cooperative operation of close-range high-resolution imaging and long-range low-power exploration, solving the performance bottleneck of traditional single-mode radar and meeting the needs of efficient target detection and imaging in diverse scenes.

[0037] In some embodiments, the frequency synthesizer includes six preset waveform modes, including a short-range waveform mode with a detection distance of 100-300 m, a sweep bandwidth of 6-15 GHz, and a sweep time of 1-1.2 ms, and a long-range waveform mode with a detection distance of 1000-1200 m, a sweep bandwidth of 0.3-0.6 GHz, and a sweep time of 0.2-0.48 ms.

[0038] It should be noted that the frequency synthesizer can preset six waveform modes, combined with the adaptive signal processing unit's real-time filtering and gain adjustment, to automatically match the optimal sweep bandwidth and frequency range according to the needs of the detection distance, improving the system's flexibility and response speed and achieving more accurate detection and imaging.

[0039] In some embodiments, the transmitter module includes a signal generating unit, an amplifier, a power divider, a frequency multiplier chain, and a power amplifier connected in series, wherein the signal generating unit is used to generate a 8.5-9.5 GHz frequency band signal, the frequency multiplier chain is used to upscale the base frequency signal to a 210-225 GHz frequency band through a X12 frequency multiplier module and a X2 frequency multiplier module, and the power amplifier is used to ensure that the output power in long-range mode is ≧20 dBm and the output power in short-range mode is <20 dBm.

[0040] 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 series, wherein the receiving antenna is used to receive an echo signal of 210-225 GHz, the harmonic mixer is used to mix the echo signal with a local oscillator signal to obtain an intermediate frequency signal of 100 KHz-10 MHz, and the intermediate frequency output link is used to convert the mixed frequency into an intermediate frequency signal of 100 KHz-10 MHz, which is input to the adaptive signal processing unit.

[0041] In some embodiments, the adaptive signal processing unit includes a near-field imaging algorithm module and a long-field search algorithm module, wherein the near-field imaging algorithm module utilizes a fast Fourier transform imaging algorithm (FFT) to achieve centimeter-level resolution three-dimensional imaging, and the long-field search algorithm module utilizes a moving target search filter to suppress environmental clutter and to improve SINR to ≧10 dB based on dynamic gain adjustment.

[0042] In some embodiments, the control module includes a microprocessor, a control unit, and a radar turntable connected in series, wherein the microprocessor receives an intermediate frequency signal from the receiving module using an analog-to-digital converter (ADC), performs data processing, and communicates with the control unit and the radar turntable via a communication interface; the control unit interacts with the frequency synthesizer and the adaptive signal processing unit via a communication interface; and the radar turntable drives an antenna array to achieve 360° scanning with an angle accuracy of ≦±0.1°.

[0043] When using this invention, a frequency synthesizer presets a short-range waveform mode and a long-range waveform mode, and selects a short-range high-resolution mode or a long-range low-power mode depending on the target distance. The signal generating unit generates a signal in the 8.5-9.5 GHz band, which is then amplified by an amplifier to provide a signal of sufficient strength for subsequent frequency multiplication and other tasks. A power divider then divides the amplified signal into two parts. The first circuit multiplies the signal to the 100-112.5 GHz frequency band through the X12 frequency multiplier module in the frequency multiplier chain, and the second circuit multiplies the signal to the 210-225 GHz frequency band through the X2 frequency multiplier module, which amplifies the power of the power amplifier and finally transmits it through the transmitting antenna. The second circuit multiplies the signal to the 100-112.5 GHz frequency band through the X12 frequency multiplier chain, which is used as a local oscillator signal. At the same time, the receiving antenna receives the 210-225GHz echo signal, which is then low-noise amplified by a low-noise amplifier. The received echo signal is then mixed with the local oscillator signal by a harmonic mixer to obtain an IF signal in the frequency range of 100KHz to 10MHz, which is then output to the adaptive signal processing unit and control module via an intermediate frequency output link. The control module then receives the IF signal through an ADC, and the microprocessor performs data processing and other tasks. At the same time, the control unit communicates with the radar turntable via various interfaces (e.g., RS232, RS422, J30J, etc.), whereby the radar turntable and antenna array achieve multi-angle scanning, and combine it with the adaptive signal processing unit's short-range imaging algorithm module or long-range detection algorithm module to achieve high-precision target positioning and imaging, improving the efficiency and accuracy of imaging.

[0044] An imaging method for an intelligent dual-mode radar system based on terahertz frequency band, Step S1: selecting a short-distance high-resolution mode or a long-distance low-power mode according to a target distance, and generating a corresponding sweep signal by a frequency synthesizer; In the near-field high-resolution mode, step S2 receives echo signals and realizes high-resolution three-dimensional reconstruction using a large bandwidth signal and an FFT imaging algorithm; In the long-distance low-power mode, the method includes step S3 of receiving an echo signal and realizing low-power target recognition using a narrow-bandwidth signal and a moving target detection algorithm.

[0045] The FFT imaging algorithm is based on frequency domain analysis of radar echo signals, converting time domain signals into frequency domain information to extract target distance and azimuth characteristics, achieving centimeter-level real-time imaging. Meanwhile, the moving target detection algorithm uses signal Doppler frequency shift and clutter suppression technology to distinguish moving targets from stationary backgrounds, achieving efficient identification of kilometer-level targets under low power consumption conditions. Its application principles and coding are both conventional techniques known to those skilled in the art and belong to the common knowledge in the art, and will not be described in detail in this application.

[0046] In some embodiments, in step S2, the distance resolution in the near-field high-resolution mode is:

[0047]

number

[0048] It is expressed as where C is the speed of light and f is the sweep bandwidth. For f ≥ 20 GHz, ΔR ≤ 0.025 m.

[0049] In some embodiments, in step S3, the search distance of the long-distance low-power mode is:

[0050]

number

[0051] It is expressed as where T is the sweep time, τ is the delay of the target reflection, and Δf is the signal frequency difference. If Δf≦0.6 GHz and T≦0.48 ms, then R≧1000 m.

[0052] In order to make the objects and advantages of the present invention more easily understandable, the present invention will be further described with reference to the following embodiments.

[0053] (Embodiment) The intelligent dual-mode radar system of this embodiment supports a large bandwidth, short-range, high-resolution mode (Mode A) and a small bandwidth, long-range, low-power mode (Mode B), the details of which are shown in Table 1.

[0054] [Table 1]

[0055] The results of measuring the transmit power characteristics of Mode A using a VDI / PM5 power meter are shown in Figure 2. In the 210-225 GHz frequency band, the transmit power is controlled to below 20 dBm, with stable power output and little fluctuation. This allows the transmitter module to maintain stable low power output over a wide bandwidth, ensuring that the receiver does not oversaturate under low-power dynamic attenuation conditions, optimizing the SINR and enabling high-resolution imaging.

[0056] The frequency conversion gain characteristics of Mode B were measured using a PNA network analyzer, and the results are shown in Figure 3. Although the gain fluctuates in the 219-225 GHz frequency band, overall, frequency conversion capability is maintained. By rationally setting parameters such as sweep time and bandwidth, the advantages of this frequency band can be fully utilized, allowing weak signals reflected by distant targets to be more efficiently received and amplified, improving the system's detection probability and accuracy for low, small, and slow targets, and achieving effective detection of targets at distances of over 1,000 meters.

[0057] The frequency synthesizer includes six preset waveform modes, which can be used to automatically match the search distance requirements, as shown in Table 2.

[0058] [Table 2]

[0059] The adaptive signal processing unit dynamically adjusts the filter parameters and gain depending on the target distance.

[0060] The three-dimensional radar turntable and antenna array supports 360° scanning and multi-angle imaging.

[0061] (Working principle) Mode A: Frequency band: 210~225GHz (large bandwidth 20GHz); Power: ≦20dBm (low power dynamic attenuation); Resolution: Distance resolution ≦0.025m (based on distance resolution formula); Applicable scene: High-precision imaging within 100 meters (people location, small object detection, etc.); Additionally, an electronically controlled attenuator is adopted to achieve a low output power of <20dBm, a bandwidth of 15GHz, a sweep time of 1ms, and optimize the SINR to ensure that the receiver is not oversaturated.

[0062] Mode B: Frequency band: 219~225GHz (narrow bandwidth 6GHz); power: ≥20dBm (high power dynamic compensation); scanning range: 1000m or more; applicable scenarios: long-distance target detection (building outlines, terrain mapping, etc.), low, small, and slow targets; and an electronically controlled attenuator is used to achieve a high output power of ≥20dBm to ensure long-distance operation. The narrow bandwidth of 0.3GHz and ultra-short sweep time of 0.2ms improve power utilization.

[0063] Adaptive noise suppression algorithm: As shown in Figure 4, noise test data from the Y-factor method is used to dynamically adjust the IF gain in long-distance mode to reduce the impact of thermal noise.

[0064] Hardware - Algorithm: As shown in Figure 5, high-precision 3D imaging reconstruction is achieved based on the turntable angle accuracy (±0.1°) and sampling rate (8192 pps).

[0065] (Field Test) As Figure 6 shows, close-range imaging (100 m): horizontal resolution ±0.1°, pitch resolution ±0.1°.

[0066] As shown in Figure 7, long-distance imaging (1200 m): SINR ≥ 10 dB, target recognition rate ≥ 95%.

[0067] As described above, the present invention utilizes dynamic switching and hardware cooperation to enable the system to combine the capabilities of "clear vision" and "far vision" in complex environments, significantly expanding the application boundaries of terahertz radar.

[0068] The above-described ideal embodiment of the present invention is a revelation, and from the contents of the foregoing description, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiment set forth above, and that the present invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, in all respects, the embodiments are to be considered as illustrative and not restrictive, and the scope of the present invention is to be limited not by the above description but by the appended claims, and all changes that come within the meaning and scope of the claims are to be embraced therein. Any reference signs in the claims should not be considered as limiting the claims.

[0069] Furthermore, although the present specification is described in terms of embodiments, each embodiment does not include only a single independent technical solution, and this description style is merely for the sake of clarity. Those skilled in the art should view the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that are understandable to those skilled in the art.

Claims

1. a transmitting module used to generate and transmit an electromagnetic wave signal in the terahertz frequency band, and supporting dynamic switching between a short-distance high-resolution mode and a long-distance low-power mode; a receiving module used to receive the echo signal reflected by the transmitting module of the target and complete low-noise amplification and mixing of the signal; a frequency synthesizer connected to the transmitting module and the receiving module, for generating a sweep bandwidth and a sweep time parameter according to the demands of a target distance, and for presetting at least two kinds of waveform modes; an adaptive signal processing unit connected to the receiving module, adapted to dynamically adjust filter parameters and gains according to a target distance and a working mode, and output target imaging data; a control module connected to the receiving module, the frequency synthesizer and the adaptive signal processing unit, and used to realize parameter setting and mode switching of dual-mode cooperative operation; the transmitting module includes a signal generating unit, an amplifier, a power divider, a frequency multiplier chain, and a power amplifier connected in this order; The signal generating unit is used to generate a frequency band signal of 8.5 to 9.5 GHz; the frequency multiplier chain is used to increase the base frequency signal to the 210-225 GHz frequency band by an X12 frequency multiplier module and an X2 frequency multiplier module; The power amplifier is used to ensure that the output power in the long-range mode is ≧20 dBm and the output power in the short-range mode is <20 dBm.

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

3. The frequency synthesizer includes six preset waveform modes, which are: a short-distance waveform mode in which the search distance is 100 to 300 m, the sweep bandwidth is 6 to 15 GHz, and the sweep time is 1 to 1.2 ms; and a long-distance waveform mode, the long-distance waveform mode having a detection distance of 1000-1200 m, a sweep bandwidth of 0.3-0.6 GHz, and a sweep time of 0.2-0.48 ms.

4. the receiving module includes a receiving antenna, a low noise amplifier, a harmonic mixer, and an intermediate frequency output link, connected in this order; the receiving antenna is used to receive echo signals in the range of 210 to 225 GHz; the harmonic mixer is used to mix the echo signal with the local oscillator signal to obtain an intermediate frequency signal of 100 KHz to 10 MHz; 2. The intelligent dual-mode radar system based on the terahertz frequency band as claimed in claim 1, wherein the intermediate frequency output link is used to convert the mixed frequency into an intermediate frequency signal of 100 KHz to 10 MHz, and input it into the adaptive signal processing unit.

5. the adaptive signal processing unit includes a near-field imaging algorithm module and a long-field detection algorithm module; The short-range imaging algorithm module uses a fast Fourier transform imaging algorithm, which is based on frequency domain analysis of radar echo signals, converts time domain signals into frequency domain information, extracts target distance and azimuth characteristics, and realizes centimeter-level resolution three-dimensional imaging; 2. The intelligent dual-mode radar system based on the terahertz frequency band according to claim 1, wherein the long-range detection algorithm module uses a moving target detection algorithm, and uses Doppler frequency shift and a moving target detection filter to suppress environmental clutter, and improves SINR to ≧10 dB based on dynamic gain adjustment by the power amplifier to distinguish moving targets from stationary backgrounds, and uses an electronically controlled attenuator to adjust the power attenuation amount, thereby achieving efficient identification of kilometers-level targets under low power consumption conditions.

6. Step S1: selecting a short-distance high-resolution mode or a long-distance low-power mode according to a target distance, and generating a corresponding sweep signal by a frequency synthesizer; In a short-distance high-resolution mode, step S2 receives echo signals and realizes high-resolution three-dimensional reconstruction using a large bandwidth signal and an FFT imaging algorithm; The imaging method for the intelligent dual-mode radar system based on the terahertz frequency band according to any one of claims 1 to 5, further comprising: step S3 in the long-distance low-power mode, receiving an echo signal and realizing low-power target recognition by using a narrow-bandwidth signal and a moving target detection algorithm.

7. In step S2, the distance resolution in the short-distance high-resolution mode is [Equation 5] It is expressed as 7. The imaging method for an intelligent dual-mode radar system based on terahertz frequency band as claimed in claim 6, wherein C is the speed of light, f is the sweep bandwidth, and ΔR≦0.025 m when f≧20 GHz.

8. In step S3, the search distance in the long-distance low-power consumption mode is [Equation 6] It is expressed as 7. The imaging method for an intelligent dual-mode radar system based on terahertz frequency band as claimed in claim 6, wherein T is the sweep time, τ is the delay of the target reflection, Δf is the difference in signal frequency, and R≧1000 m when Δf≦0.6 GHz and T≦0.48 ms.

Images