Radar pulse signal detection system and detection method

Abstract

The invention provides a radar pulse signal detection system and detection method, and belongs to the technical field of radar signal detection. The detection system comprises a square law detection module, a box differential filter module, a modulo module, a constant false alarm detection module and a threshold detection module, thereby completing radar pulse signal detection. According to the detection method, on the basis of the characteristics of a box differential filter and the processing process of radar signals, the change rule of input and output signal distribution of the box differential filter is deduced, then clutter power analysis is carried out on output signals of the box differential filter after modulus taking, a constant false alarm detection threshold value is calculated, and a constant false alarm detection threshold value factor is determined; and the detection probability of the constant false alarm detection algorithm based on the box differential filter is further calculated. The detection method can obtain high detection probability under the conditions of low signal-to-noise ratio and low false alarm probability, and has good environmental adaptability.

Description

Technical Field

[0001] The present application relates to the technical field of radar signal detection, and in particular to a radar pulse signal detection system and detection method. Background Art

[0002] As the information input end of the radar electronic countermeasure system, radar electronic support reconnaissance technology is the basis and premise for implementing radar electronic jamming. The purpose of radar electronic support reconnaissance is to detect, measure and identify the source of enemy radar signals, among which signal detection is the basis and premise for radar electronic reconnaissance receivers to measure signal parameters. Due to the uncertainty of radar signals and environmental noise, radar signal detection is very difficult.

[0003] For radar signals with pulse characteristics, signal detection mainly involves detecting the leading and trailing edges of the pulse and estimating the pulse arrival time ( Time of arrival, TOA ) and pulse width ( Pulse width, PW ) and other pulse description words ( Pulse description words, PDW ) parameters. Classical methods include energy detection in the time domain ( Energy detection, ED ) algorithm and the fast Fourier transform in the frequency domain ( fast Fourier transform, FFT ) algorithm, but the ED algorithm has poor performance at low signal-to-noise ratio, while the FFT algorithm has high complexity and low detection accuracy for pulse edges. In addition, a large number of literatures have proposed a variety of pulse signal detection methods. For joint detection in the time-frequency domain, W. Niczyporuk et al. proposed the use of Radom and Hough transform Algorithm detection ( linear frequency-modulated ) LFM radar signal. E. Swiercz et al. used SCPF ( the sum of the cubic phase function ) and PCPF( the product of the cubic phase function ) hybrid algorithm realizes the detection and parameter measurement of LFM signals. It is difficult to reasonably set the detection threshold in the time-frequency domain detection without or with limited prior information. Based on self-convolution and least squares method, YT Chan et al. obtained the measurement method of baseband pulse parameters by solving linear equations. Based on atomic decomposition and expectation maximization, G. Lopez Risueno The detection of linear mixed signals is realized. However, the above detection methods have the defects of high computational complexity and difficulty in engineering implementation.

[0004] In view of this, it is necessary to study a radar pulse signal detection system and a detection method to solve the above technical problems. Summary of the invention

[0005] In view of the technical problems existing in the background technology, the present application provides a radar pulse signal detection system and detection method. Based on the similarity between the edge of the intermediate frequency sampling pulse signal and the edge characteristics of the digital image, the present invention uses the box differential filter edge detection algorithm according to the "edge detection" concept in image processing to realize the detection of the front and rear edges of the pulse signal. Furthermore, the dynamic detection threshold is obtained through the constant false alarm detection algorithm to ensure the environmental adaptability of the proposed method. The constant false alarm detection method based on the box differential filter is theoretically revealed, and the circuit design is carried out, which lays a good foundation for practical application.

[0006] In order to solve the above technical problems, the present invention provides a radar pulse signal detection system, including a box differential filter module, a constant false alarm detection module and a threshold detection module; The box differential filter module is used to perform incoherent accumulation of the intercepted radar signal, and convert the rising edge into a convex peak, and the falling edge into a concave, and output the detection signal after box differential filtering; The constant false alarm detection module performs clutter power analysis on the detection signal output after differential filtering, calculates the constant false alarm detection threshold, and determines the constant false alarm detection threshold factor; The threshold detection module has an input end connected to the output ends of the constant false alarm detection module and the box differential filter module respectively, and is used to compare the detection signal output by the box differential filter with the constant false alarm detection threshold and calculate the detection probability.

[0007] As a further improvement of the present invention, the radar pulse signal detection system also includes a modulo module, which is used to perform a modulo operation on the detection signal output after the box differential filtering processing, so as to eliminate the influence of the negative signal in the box differential filtering output detection signal on the constant false alarm detection; the input end and output end of the modulo module are respectively connected to the output end of the box differential filter module and the input end of the constant false alarm detection module.

[0008] As a further improvement of the present invention, the radar pulse signal detection system also includes a square-law detection module; the output end of the square-law detection module is connected to the input end of the box differential filter module, which is used to perform square-law detection processing on the intercepted radar signal and then input it into the box differential filter module.

[0009] Based on the above technical purpose, the present invention also provides a radar pulse signal detection method, which uses the above radar pulse signal detection system for detection. The detection method is: for radar signals that generally have pulse characteristics, according to the edge detection idea in image processing, a pulse detection algorithm based on a box differential filter is designed to realize the detection of the front and rear edges of the pulse signal; based on the uncertainty of the radar signal and the environmental noise, it is proposed to use the constant false alarm algorithm to adaptively determine the detection threshold to realize the automatic detection of the output signal of the box differential filter. To this end, based on the characteristics of the box differential filter and the processing process of the radar signal, the change law of the input and output signal distribution of the box differential filter is derived, and then the output signal of the box differential filter after modulo is analyzed for clutter power, the constant false alarm detection threshold is calculated, the constant false alarm detection threshold factor is determined, and the detection probability of the constant false alarm detection algorithm based on the box differential filter is further calculated. Further, based on theoretical analysis, the circuit design and FPGA implementation of the proposed method are completed.

[0010] The detection method mainly includes the analysis of the changing characteristics of the input and output signal distribution of the box differential filter, the design of the constant false alarm detection threshold, the determination of the constant false alarm threshold factor, the calculation of the detection probability and the design of the circuit implementation; for the intercepted radar signal, the signal processing process is as follows: first, the intercepted I / Q channel signal is subjected to square law detection processing, and input into the box differential filter, and the detection signal is output after the box differential filtering; the output signal of the box differential filter is compared with the constant false alarm detection threshold to further detect the radar signal. When estimating the output signal power of the box differential filter, according to the characteristics of the signal, in order to ensure the correct estimation, the output signal of the box differential filter is first modulated. Then, the unit average constant false alarm detection method is used for power estimation. The output signal of the box differential filter obeys the normal distribution, and the signal after the modulo operation obeys the folded normal distribution, and the mean and variance of the signal obeying the folded normal distribution characteristics are obtained. And further determine the detection threshold and threshold factor of the constant false alarm detector. Specifically including the following steps: S1, square-law detection processing: After the intercepted radar signal is processed by square-law detection, it is input into the differential filter; S2, box differential filtering: perform incoherent accumulation on the radar signal after square law detection processing, and convert the rising edge into a convex peak and the falling edge into a concave, and output the detection signal after box differential filtering processing; S3, modulo operation: performing a modulo operation on the detection signal outputted from step S2 to obtain a modulo output signal of the differential filter; S4, constant false alarm detection: perform clutter power analysis on the output signal of the box differential filter after taking the modulus in step S3, calculate the constant false alarm detection threshold, and determine the constant false alarm detection threshold factor; S5, threshold detection: calculate the detection probability of the constant false alarm detection algorithm based on the box difference filter.

[0011] As a further improvement of the present invention, in step S1, after the square law detection processing, the input signal of the differential filter can be expressed as: ; in, I represents the real part of the signal; Q Represents the imaginary part of the signal.

[0012] As a further improvement of the present invention, the box differential filter has an edge detection characteristic. For a causal system, the size is The box differential filter, which Expressed as .

[0013] As a further improvement of the present invention, in step S2, when the input signal is , the length is ,exist In this case, after being processed by the box differential filter, the output signal is expressed as: ; in, L Represents the box difference filter size.

[0014] As a further improvement of the present invention, in step S4, when the intercepted signal is a Gaussian white noise signal, the constant false alarm detection threshold is expressed as ; in, , is the power of the noise signal, is the box difference filter order, is the false alarm probability, whose value is a preset constant. represents the inverse error function; It can be obtained that when the constant false alarm probability is a preset constant, the detection threshold is a function related to the noise variance and the order of the box differential filter. When the order of the box differential filter is determined, the detection threshold is only related to the noise variance.

[0015] As a further improvement of the present invention, when the intercepted signal is a radar signal, the constant false alarm detection threshold is expressed as: ; in, , is the variance of the input signal to the box difference filter, is the order of the differential filter. Therefore, it can be obtained that the constant false alarm detection threshold is related to the power of the intercepted signal and the order of the differential filter.

[0016] As a further improvement of the present invention, in step S4, when the intercepted signal is a radar pulse signal that obeys a normal distribution, the square-law detection signal input to the box differential filter obeys a Rice distribution, and when the order of the box differential filter is ≥129, the output signal of the box differential filter obeys a normal distribution.

[0017] As a further improvement of the present invention, in step S4, the clutter power is estimated by taking the modulus of the output signal of the cell differential filter, and its mean value can be expressed as: ; Thus, the constant false alarm detection threshold factor of the constant false alarm detection method can be obtained: ; The threshold factor is only related to the false alarm probability and has nothing to do with the form of the intercepted signal. The false alarm probability has nothing to do with the clutter power value, which reflects the constant false alarm characteristic of the proposed method.

[0018] As a further improvement of the present invention, in step S5, the detection probability is: ; When the signal-to-noise ratio is greater than 3dB, the pulse width 300ns, the false alarm probability is Under the condition of 99%; it verifies that the constant false alarm detection method of the electronic reconnaissance receiver based on the box differential filter can obtain a high detection probability under low signal-to-noise ratio and low false alarm probability conditions, and has good environmental adaptability.

[0019] Beneficial effects: 1. The radar pulse signal detection system provided by the present invention uses a box differential filter to perform incoherent accumulation of radar signals, and converts the rising edge into a convex peak and the falling edge into a concave, thereby realizing the detection of radar pulse signals. The box differential filter is combined with the constant false alarm detection method, so that the radar pulse signal detection has the adaptability to environmental changes, laying a foundation for practical application.

[0020] 2. The radar pulse signal detection system provided by the present invention divides the constant false alarm detection method based on the box differential filter into modules, completes the circuit design, and obtains an integrated detection system including many functional modules such as the change characteristic analysis of the input and output signal distribution of the box differential filter, the constant false alarm detection threshold design, the constant false alarm threshold factor determination, and the detection probability calculation. The detection system can obtain a high detection probability under the conditions of low signal-to-noise ratio and low false alarm probability, and has good environmental adaptability.

[0021] 3. The radar pulse signal detection method provided by the present invention reveals for the first time the theoretical law of the constant false alarm detection method based on the box differential filter: 3dB, pulse width 300ns, the false alarm probability is Under these conditions, the detection probability 99%. It not only has excellent pulse signal detection performance, but also has adaptability to environmental changes and has good engineering application prospects.

[0022] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A structural diagram of the radar pulse signal detection system provided by the present invention; Figure 2 A schematic diagram of a differential filter processing process of a radar pulse signal detection system provided by the present invention; Figure 3 A diagram showing changes in signal distribution characteristics when the radar pulse signal detection system provided by the present invention intercepts a noise signal; Figure 4 A simulation verification diagram of the signal distribution characteristics of the radar pulse signal detection system provided by the present invention when intercepting a noise signal; Figure 5 A diagram showing changes in signal distribution characteristics when the radar pulse signal detection system provided by the present invention intercepts a noise signal; Figure 6 A simulation verification diagram of the signal distribution characteristics of the radar pulse signal detection system provided by the present invention when intercepting a noise signal; Figure 7 A simulation diagram of the detection effect of a radar pulse signal detection system provided by the present invention on a single-carrier frequency radar signal; Figure 8 A comparison diagram of the radar pulse signal detection method provided in Example 1 of the present invention and the detection method provided in Comparative Examples 1-2. DETAILED DESCRIPTION

[0025] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0027] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0028] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0029] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0030] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0031] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0032] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like 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 a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0033] See also Figure 1 As shown, the present invention provides a radar pulse signal detection system of constant false alarm of an electronic reconnaissance receiver based on a box differential filter, including a square law detection module, a box differential filter module, a modulus taking module, a constant false alarm detection module and a threshold detection module, thereby completing radar pulse signal detection.

[0034] The box differential filter module is used to perform incoherent accumulation of the intercepted radar signal, and convert the rising edge into a convex peak, and the falling edge into a concave, and output the detection signal after box differential filtering; The constant false alarm detection module performs clutter power analysis on the detection signal output after differential filtering, calculates the constant false alarm detection threshold, and determines the constant false alarm detection threshold factor; The threshold detection module has an input end connected to the output ends of the constant false alarm detection module and the box differential filter module respectively, and is used to compare the detection signal output by the box differential filter with the constant false alarm detection threshold and calculate the detection probability.

[0035] The modulo module is used to perform modulo operation on the detection signal output after the box differential filtering process; the input end and output end of the modulo module are respectively connected to the output end of the box differential filter module and the input end of the constant false alarm detection module.

[0036] The output end of the square-law detection module is connected to the input end of the box differential filter module, and is used to perform square-law detection processing on the intercepted radar signal before inputting it into the box differential filter module.

[0037] Example 1 Based on the above radar pulse signal detection system, embodiment 1 of the present invention provides a radar pulse signal detection method, which mainly includes the analysis of the change characteristics of the input and output signal distribution of the box differential filter, the design of the constant false alarm detection threshold, the determination of the constant false alarm threshold factor, the detection probability calculation and the circuit implementation design. Among them, for the intercepted radar signal, the signal processing process is as follows: first, the intercepted I / Q channel signal is subjected to square law detection processing, and input into the box differential filter, and the detection signal is output after the box differential filtering; the output signal of the box differential filter is compared with the constant false alarm detection threshold to further detect the radar signal. When estimating the power of the output signal of the box differential filter, according to the characteristics of the signal, in order to ensure the correct estimation, the output signal of the box differential filter is first modulated. Then, the unit average constant false alarm detection method is used for power estimation. The output signal of the box differential filter obeys the normal distribution, and the signal after the modulo operation obeys the folded normal distribution, and the mean and variance of the signal obeying the folded normal distribution characteristics are obtained. And further determine the detection threshold and threshold factor of the constant false alarm detector. Specifically including the following steps: S1, square-law detection processing: After the intercepted radar signal is processed by square-law detection, it is input into the differential filter; In step S1, after the square law detection process, the input signal of the differential filter can be expressed as: ; in, I represents the real part of the signal; Q Represents the imaginary part of the signal.

[0038] S2, box difference filtering: see Figure 2 As shown, the radar signal after the square-law detection processing is non-coherently accumulated, and the rising edge is converted into a convex peak, and the falling edge is converted into a concave, and the detection signal is output after the box differential filtering processing; The box differential filter has an edge detection characteristic, and for a causal system, the size is The box differential filter, which Expressed as .

[0039] In step S2, when the input signal is , the length is ,exist In this case, after being processed by the box differential filter, the output signal is expressed as: ; in, L Represents the box difference filter size.

[0040] S3, modulo operation: performing a modulo operation on the detection signal outputted from step S2 to obtain a modulo output signal of the differential filter; S4, constant false alarm detection: perform clutter power analysis on the output signal of the box differential filter after taking the modulus in step S3, calculate the constant false alarm detection threshold, and determine the constant false alarm detection threshold factor; In step S4, when the intercepted signal is a Gaussian white noise signal, the constant false alarm detection threshold is expressed as ; in, , is the power of the noise signal, is the box difference filter order, is the false alarm probability, whose value is a preset constant. represents the inverse error function; It can be obtained that when the constant false alarm probability is a preset constant, the detection threshold is a function related to the noise variance and the order of the box differential filter. When the order of the box differential filter is determined, the detection threshold is only related to the noise variance.

[0041] As a further improvement of the present invention, when the intercepted signal is a radar signal, the constant false alarm detection threshold is expressed as: ; in, , is the variance of the input signal to the box difference filter, is the box difference filter order.

[0042] In step S4, when the intercepted signal is a radar pulse signal that obeys a normal distribution, the square-law detection signal input to the box differential filter obeys a Rice distribution, and when the order of the box differential filter is ≥129, the output signal of the box differential filter obeys a normal distribution.

[0043] In step S4, the clutter power is estimated by taking the modulus of the output signal of the cell differential filter, and its mean value can be expressed as: ; Thus, the constant false alarm detection threshold factor of the constant false alarm detection method can be obtained: ; The threshold factor is only related to the false alarm probability and has nothing to do with the form of the intercepted signal. The false alarm probability has nothing to do with the clutter power value, which reflects the constant false alarm characteristic of the proposed method.

[0044] S5, threshold detection: calculate the detection probability of the constant false alarm detection algorithm based on the box difference filter.

[0045] In step S5, the detection probability is: ; When the signal-to-noise ratio is greater than 3dB, the pulse width 300ns, the false alarm probability is Under the condition of 99%; it verifies that the constant false alarm detection method of the electronic reconnaissance receiver based on the box differential filter can obtain a high detection probability under low signal-to-noise ratio and low false alarm probability conditions, and has good environmental adaptability.

[0046] Comparative Example 1 A conventional time-domain energy detection method is used for signal detection.

[0047] Comparative Example 2 The conventional double-threshold time-domain correlation method is used for signal detection.

[0048] See also Figure 3 The signal distribution change law before and after the box differential filter processing shown in the figure, when the intercepted signal is a Gaussian white noise signal, the intercepted signal is input into the box differential filter after the square law detection operation, and the input signal of the box differential filter obeys the Rayleigh distribution. According to the central limit theorem, when the order of the box differential filter is large enough, the output signal obeys the normal distribution.

[0049] See also Figure 4 The simulation diagrams shown when the intercepted signal is a noise signal respectively represent the simulation results of the distribution characteristics of the input signal and output signal of the box differential filter. It can be seen from the simulation diagram that the input signal of the box differential filter obeys the Rayleigh distribution, and the output signal obeys the normal distribution. The simulation results are consistent with the theoretical analysis.

[0050] See also Figure 5 The diagram of the change of signal distribution characteristics before and after the box differential filter processing when intercepting a radar signal that obeys a normal distribution is shown in FIG. After the intercepted radar signal is processed by square rate detection, the input signal of the box differential filter obeys the Rice distribution, and the output signal obeys the normal distribution.

[0051] See also Figure 6 The simulation diagram of intercepting radar signals is shown in FIG. 1 . It can be obtained from the simulation diagram that the input signal of the box differential filter obeys the Rice distribution and the output signal obeys the normal distribution. The simulation results are consistent with the theoretical analysis.

[0052] See also Figure 7 The pulse detection result of the single carrier signal is shown in FIG. The frequency of the single carrier signal is set to 600 MHz and the pulse arrival time is us, us, the pulse end time is us, us, then the pulse width us. The sampling rate is set to GHz, the number of sampling points of the pulse signal is , the signal-to-noise ratio is set to 10dB. It can be seen that the output of the box differential filter forms a peak and a depression at the front and rear edges of the pulse, respectively, which can well locate the pulse arrival time. The detection results based on the signal threshold illustrate the effectiveness of the constant false alarm detection method based on the box differential filter.

[0053] See also Figure 8 As shown, the detection method of Example 1 of the present invention (red) is compared with the detection methods of Comparative Example 1 (blue) and Comparative Example 2 (green). It can be seen that the detection probability of the detection method of Example 1 of the present invention is significantly better than that of Comparative Example 1 and Comparative Example 2. When the signal-to-noise ratio is 1.5 dB, the detection probability of the detection method of the present invention is ≥90%, and when the signal-to-noise ratio is ≥3 dB, the detection probability is ≥99%, which proves the excellent pulse signal detection performance of the present invention.

[0054] In summary, the present invention discloses a radar pulse signal detection system and detection method for detecting radar pulse signals. The method comprises the following steps: for radar signals generally having pulse characteristics, according to the edge detection idea in image processing, a pulse detection algorithm based on a box differential filter is designed to detect the front and rear edges of the pulse signal; based on the uncertainty of the radar signal and the environmental noise, it is proposed to use a constant false alarm algorithm to adaptively determine the detection threshold to realize the automatic detection of the output signal of the box differential filter. To this end, based on the characteristics of the box differential filter and the processing process of the radar signal, the change law of the input and output signal distribution of the box differential filter is derived, and then the output signal of the box differential filter after modulo is subjected to clutter power analysis, the constant false alarm detection threshold is calculated, the constant false alarm detection threshold factor is determined, and the detection probability of the constant false alarm detection algorithm based on the box differential filter is further calculated. Further, based on theoretical analysis, the circuit design and FPGA implementation of the proposed method are completed. The present invention not only has excellent pulse signal detection performance, but also has adaptability to environmental changes, and has good engineering application prospects.

[0055] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A radar pulse signal detection system, characterized in that: It includes a box differential filter module, a constant false alarm detection module and a threshold detection module; The box differential filter module is used to perform incoherent accumulation of the intercepted radar signal, and convert the rising edge into a convex peak, and the falling edge into a concave, and output the detection signal after box differential filtering; The constant false alarm detection module performs clutter power analysis on the detection signal output after differential filtering, calculates the constant false alarm detection threshold, and determines the constant false alarm detection threshold factor; The threshold detection module has an input end connected to the output ends of the constant false alarm detection module and the box differential filter module respectively, and is used to compare the detection signal output by the box differential filter with the constant false alarm detection threshold and calculate the detection probability.

2. The radar pulse signal detection system according to claim 1, characterized in that: The radar pulse signal detection system also includes a modulus module, which is used to perform a modulus operation on the detection signal output after the box differential filtering processing, so as to eliminate the influence of the negative signal in the box differential filtering output detection signal on the constant false alarm detection; the input end and the output end of the modulus module are respectively connected to the output end of the box differential filter module and the input end of the constant false alarm detection module.

3. The radar pulse signal detection system according to claim 1, characterized in that: The radar pulse signal detection system also includes a square-law detection module; the output end of the square-law detection module is connected to the input end of the box differential filter module, which is used to perform square-law detection processing on the intercepted radar signal and then input it into the box differential filter module.

4. A radar pulse signal detection method, characterized in that: The radar pulse signal detection system according to any one of claims 1 to 3 is used for detection, comprising the following steps: S1, square-law detection processing: After the intercepted radar signal is processed by square-law detection, it is input into the differential filter; S2, box differential filtering: perform incoherent accumulation on the radar signal after square law detection processing, and convert the rising edge into a convex peak and the falling edge into a concave, and output the detection signal after box differential filtering processing; S3, modulo operation: performing a modulo operation on the detection signal outputted from step S2 to obtain a modulo output signal of the differential filter; S4, constant false alarm detection: perform clutter power analysis on the output signal of the box differential filter after taking the modulus in step S3, calculate the constant false alarm detection threshold, and determine the constant false alarm detection threshold factor; S5, threshold detection: calculate the detection probability of the constant false alarm detection algorithm based on the box difference filter.

5. The radar pulse signal detection method according to claim 4, characterized in that: In step S1, after the square law detection process, the input signal of the differential filter can be expressed as: ； in, I represents the real part of the signal; Q Represents the imaginary part of the signal.

6. The radar pulse signal detection method according to claim 4, characterized in that: In step S2, when the input signal is , the length is ,exist In this case, after being processed by the box differential filter, the output signal is expressed as: ； in, L Represents the box difference filter size.

7. The radar pulse signal detection method according to claim 4, characterized in that: In step S4, when the intercepted signal is a Gaussian white noise signal, the constant false alarm detection threshold is expressed as ； in, , is the power of the noise signal, is the box difference filter order, is the false alarm probability, whose value is a preset constant. represents the inverse error function; Alternatively, when the intercepted signal is a radar signal, the constant false alarm detection threshold is expressed as: ； in, , is the variance of the input signal to the box difference filter, is the box difference filter order; Therefore, it can be obtained that the constant false alarm detection threshold is related to the power of the intercepted signal and the order of the differential filter.

8. The radar pulse signal detection method according to claim 7, characterized in that: In step S4, when the intercepted signal is a radar pulse signal that obeys a normal distribution, the square-law detection signal input to the box differential filter obeys a Rice distribution, and when the order of the box differential filter is ≥129, the output signal of the box differential filter obeys a normal distribution.

9. The radar pulse signal detection method according to claim 7, characterized in that: In step S4, the clutter power is estimated by taking the modulus of the output signal of the cell differential filter, and its mean value can be expressed as: ； Thus, the threshold factor of the constant false alarm detection method can be obtained: ； The threshold factor is only related to the false alarm probability and has nothing to do with the form of the intercepted signal. The false alarm probability has nothing to do with the clutter power value.

10. The radar pulse signal detection method according to claim 4, characterized in that: In step S5, the detection probability is: 。

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