Method and system for high-resolution identification of air-launched decoys based on one-dimensional range profile

Abstract

The present invention belongs to the field of electronic information technology, and relates to a method and system for high-resolution identification of air-launched decoys based on one-dimensional range images, the method comprising: emitting a group of pulse signals with agile carrier frequency; sampling in the time dimension; Fourier transforming to obtain a one-dimensional range image of the target corresponding to the sub-pulse; pulse numbering; setting a starting number; two-dimensional FFT processing to obtain a range image of the target once; judging whether the starting number of the coherent pulse is greater than the set ratio of the total number of coherent pulses; judging whether the number of coherent pulses is greater than the number of coherent pulses as the total number of pulses. The present invention can reduce the sampling pressure, and at the same time, perform synthesis of any sub-pulses on the received signal at the receiving end; can synthesize radar detection effects of different carrier frequencies, and can achieve changes in carrier frequency with changes in pulse numbers; can modulate the bandwidth of the synthesized signal by configuring the number of sub-pulses to achieve signal detection effects under different bandwidths.

Description

Technical Field

[0001] The present invention belongs to the field of electronic information technology, and in particular, relates to a method and system for high-resolution identification of air-launched decoys based on one-dimensional range images. Background Art

[0002] The interference signals generated by towed decoys and air-launched decoys will seriously affect the effective detection and tracking of targets by radar. Air-launched decoys refer to decoys launched by fighter jets that simulate the infrared characteristics, radar cross-section reflection characteristics and motion characteristics of fighter jets to deceive target radars and improve the survivability of fighter jets. Air-launched decoys can imitate the flight characteristics and radar signals of fighter jets and bombers, lure air defense radars to track targets, and induce air defense radars to work, thereby guiding anti-radiation weapons to destroy radars, and can also implement close-range interference functions. When necessary, fighter jets can also achieve the purpose of protecting themselves by launching small air-launched decoys. Air-launched decoys with their own power systems have characteristics that are closer to fighter jets in all aspects. Air-launched decoys are air-launched expendable decoy missiles that confuse and deceive the opponent's air defense system by simulating the radar reflection cross-section of various fighter jets or other military aircraft of their own side, causing the air defense system to make wrong judgments.

[0003] Since air-launched decoy bombs can simulate the same echo as actual radar signals and can also simulate characteristics such as aircraft RCS (Radar Cross Section), the current radar system cannot effectively identify decoy bombs.

[0004] Different from the false target information generated by self-defense electronic jamming, air-launched decoy missiles are external decoy jamming that can generate real echo signals in the target radar. Figure 1 The combat flow chart of air-launched decoys is shown in the figure. There are two methods of jamming air-launched decoys. One method is accompanying jamming, which controls the carrier aircraft and the air-launched decoys in the same resolution unit of the radar. The echo of the carrier aircraft and the echo of the air-launched decoys return to the target radar at the same time. The tracking system of the radar cannot distinguish the distance, speed and angle, which increases the tracking error. The other method is separation jamming. After the carrier aircraft and the air-launched decoys are separated, the air-launched decoys continue to fly along the original direction of movement to attract missile attacks, and the carrier aircraft performs large overload maneuvers to avoid. According to the principle of radar superior source response and track association, the missile-borne radar will regard the air-launched decoys as targets and attack them. Since the air-launched decoys themselves have a small RCS, the RCS value needs to be increased through an RCS reflector, but the reflector can only reflect radar signals within a certain range, and the emission characteristics of each angle are different. In order to ensure that the missile-borne radar tracks the air-launched decoy missile after it is dispersed, it is necessary to control the RCS of the carrier aircraft and the air-launched decoy missile relative to the target during the accompanying interference process to increase the relative RCS value of the air-launched decoy missile. Figure 2The air-launched decoy countermeasure flow chart is shown.

[0005] In order to improve the ability to counter air-launched decoy interference, an available strategy is to improve the radar range resolution and improve the imaging capability of the target. However, directly increasing the transmission signal bandwidth will increase the sampling rate and the back-end processing pressure. Using a large broadband signal to detect the target and improving the recognition capability of the air-launched decoy by improving the range resolution has the following disadvantages: the carrier frequency of a broadband signal is fixed, and the carrier frequency is closely related to the reflection of the target. Observing the target reflection characteristics based on only one carrier frequency has the disadvantage of being single; the bandwidth of a broadband signal is fixed, and the target reflection is also related to the radar detection bandwidth. Observing the target reflection characteristics based on only one bandwidth also has the disadvantage of being single, and it is impossible to observe the target reflection characteristics from more dimensions; in addition, irradiating with a large broadband signal will also cause problems such as high sampling rate and high computing pressure, which makes it difficult to apply in actual equipment. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a method for high-resolution identification of air-launched decoys based on one-dimensional range images.

[0007] In a first aspect, the present invention provides a method for high-resolution identification of air-launched decoys based on one-dimensional range profiles, comprising:

[0008] S1: Transmits a set of pulse signals with agile carrier frequency;

[0009] S2: Sample each pulse signal in the time dimension;

[0010] S3: Perform Fourier transform on each pulse signal to obtain a one-dimensional range image of the target corresponding to the sub-pulse;

[0011] S4: setting the number of coherent pulses to a set ratio of the total number of pulses, and numbering each coherent pulse to obtain a pulse number of each coherent pulse;

[0012] S5: Set the starting number of the coherent pulse;

[0013] S6: Perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range to obtain a range image of the primary target;

[0014] S7: add 1 to the starting number of the coherent pulse, and judge whether the starting number of the coherent pulse is greater than the set ratio of the total number of coherent pulses. If yes, add 1 to the number of coherent pulses and go to S8. Otherwise, go to S6 to perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range again, and perform broadband synthesis on all pulses within the selected pulse number range.

[0015] S8: Determine whether the number of coherent pulses is greater than the number of coherent pulses as the total number of pulses. If so, combine all the obtained one-dimensional distance images and end. Otherwise, go to S5 and reset the starting pulse number.

[0016] In a second aspect, the present invention provides a system for high-resolution identification of air-launched decoys based on one-dimensional range profiles, comprising a launching unit, a sampling unit, a first processing unit, a first setting unit, a second setting unit, a second processing unit, a first judging unit, and a second judging unit;

[0017] A transmitting unit, used for transmitting a group of pulse signals with agile carrier frequency;

[0018] A sampling unit, used for sampling each pulse signal in a time dimension;

[0019] A first processing unit is used to perform Fourier transform on each pulse signal to obtain a one-dimensional range image of the target corresponding to the sub-pulse;

[0020] A first setting unit is used to set the number of coherent pulses to a set ratio of the total number of pulses, and to number each coherent pulse to obtain a pulse number of each coherent pulse;

[0021] A second setting unit is used to set the starting number of the coherent pulse;

[0022] The second processing unit is used to perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range to obtain a range image of the primary target;

[0023] The first judgment unit is used to add 1 to the starting number of the coherent pulse, and judge whether the starting number of the coherent pulse is greater than the set ratio of the total number of the coherent pulses. If so, the number of coherent pulses is increased by 1, otherwise, all the coherent pulses within the selected pulse number range are re-processed with two-dimensional FFT, and all the pulses within the selected pulse number range are subjected to broadband synthesis;

[0024] The second judgment unit is used to judge whether the number of coherent pulses is greater than the number of coherent pulses as the total number of pulses. If so, all the obtained one-dimensional distance images are integrated and the process ends. Otherwise, the starting pulse number is reset.

[0025] Based on the above technical solution, the present invention can also be improved as follows.

[0026] Furthermore, the carrier frequency agile pulse signal is a linear frequency modulation agile signal with a bandwidth smaller than a set value, and each sub-pulse transmits a coded signal.

[0027] Furthermore, let the subcode width of the sub-pulse transmitting coded signal be , the frequency agility between sub-pulses, the sub-code bandwidth is , is the speed of light, is the distance resolution corresponding to the total transmitted pulse, and the distance resolution corresponding to the sub-pulse is , all the frequency points of the agile frequency are processed jointly, and all the pulses within the selected pulse number range are synthesized by broadband. The distance resolution obtained is ,but: .

[0028] Furthermore, let the total number of pulses be , set the number of phase pulses to the ratio of the total number of pulses .

[0029] The beneficial effects of the present invention are:

[0030] (1) The present invention splits a long pulse into multiple sub-pulses, each of which transmits a signal with a smaller bandwidth, thereby reducing the sampling pressure, and at the same time, the received signal is synthesized at the receiving end for any sub-pulse;

[0031] (2) The present invention can integrate the detection effects of radars with different carrier frequencies, and the carrier frequency can be changed as the pulse number changes;

[0032] (3) The present invention can modulate the bandwidth of the integrated signal by configuring the number of sub-pulses to achieve signal detection effects under different bandwidths. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the operational flow chart for air-launched decoys;

[0034] Figure 2 Provide a flowchart for air-launched decoy countermeasures;

[0035] Figure 3 This is a schematic diagram of the air-launched decoy countermeasure waveform;

[0036] Figure 4 This is a simulation diagram of the matched filter output;

[0037] Figure 5 Output an enlarged simulation image for the target distance segment;

[0038] Figure 6 This is a simulation diagram of the output of the matched filter for the mixed coded signal;

[0039] Figure 7 It is a processing schematic diagram based on multi-pulse frequency agility;

[0040] Figure 8 A schematic diagram of a specific implementation of a method for high-resolution identification of air-launched decoys based on one-dimensional range profiles;

[0041] Fig. 9 This is the schematic diagram of a system for high-resolution identification of air-launched decoys based on one-dimensional range profiles. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0043] Example 1

[0044] As an embodiment, in order to solve the above technical problems, this embodiment provides a method for high-resolution identification of air-launched decoys based on one-dimensional range profiles, including:

[0045] S1: Transmits a set of pulse signals with agile carrier frequency;

[0046] S2: Sample each pulse signal in the time dimension;

[0047] S3: Perform Fourier transform on each pulse signal to obtain a one-dimensional range image of the target corresponding to the sub-pulse;

[0048] S4: setting the number of coherent pulses to a set ratio of the total number of pulses, and numbering each coherent pulse to obtain a pulse number of each coherent pulse;

[0049] S5: Set the starting number of the coherent pulse;

[0050] S6: Perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range to obtain a range image of the primary target;

[0051] S7: add 1 to the starting number of the coherent pulse, and judge whether the starting number of the coherent pulse is greater than the set ratio of the total number of coherent pulses. If yes, add 1 to the number of coherent pulses and go to S8. Otherwise, go to S6 to perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range again, and perform broadband synthesis on all pulses within the selected pulse number range.

[0052] S8: Determine whether the number of coherent pulses is greater than the number of coherent pulses as the total number of pulses. If so, combine all the obtained one-dimensional distance images and end. Otherwise, go to S5 and reset the starting pulse number.

[0053] The present invention can realize the simultaneous observation of multiple groups of carrier frequencies and multiple groups of bandwidths on the same target, and improves the dimension of observing the reflection characteristics of the target, so that the simulated echo of the air-launched decoy that can deceive the traditional radar can be identified as a decoy signal, and the target can be effectively detected at the same time.

[0054] Through combination coding, the bandwidth is small for each moment or sub-pulse, so the sampling rate requirement for the pulse signal is not high. However, after the broadband synthesis of multiple pulse signals, the signal bandwidth can be greatly improved without increasing the sampling rate.

[0055] Optionally, the carrier frequency agile pulse signal is a linear frequency modulation agile signal with a bandwidth smaller than a set value, and each sub-pulse transmits a coded signal.

[0056] As attached Figure 3 The waveform diagram of a linear frequency agility and coding signal combination is shown in FIG. 1 , where each sub-pulse transmits a coding signal and the sub-code width is , the frequency agility between sub-pulses is , the total transmit pulse width is , the bandwidth occupied by the total frequency points is .

[0057] Optionally, the subcode width of the sub-pulse transmitting coded signal is , the frequency agility between sub-pulses, the sub-code bandwidth is , is the speed of light, is the distance resolution corresponding to the total transmitted pulse, and the distance resolution corresponding to the sub-pulse is , all the frequency points of the agile frequency are processed jointly, and all the pulses within the selected pulse number range are synthesized by broadband. The distance resolution obtained is ,but: .

[0058] As attached Figure 4 The simulation diagram of the matched filter output is shown in the figure. The horizontal axis is the distance point, the unit is number, and the vertical axis is the power, the unit is dB. The simulation parameters are set as follows: each sub-pulse coding signal, bandwidth 10MHz; number of sub-pulses: 50; frequency step between sub-pulses: 10MHz; carrier frequency: 17GHz; target 1 distance: 10km; target 2 distance: 10km+0.5m.

[0059] As attached Figure 5 The enlarged simulation diagram of the target range output is shown in the figure. The horizontal axis is the distance point, the unit is number, and the vertical axis is the power, the unit is dB. It can be seen that a single pulse cannot distinguish the target by matching filtering.

[0060] As attached Figure 6As shown in the simulation diagram of the output of the mixed coding signal matched filter, the horizontal axis is the distance point and the vertical axis is the amplitude. Two targets with a distance of only 0.5 meters are clearly distinguished. Figure 7 As shown, a processing schematic diagram based on multi-pulse frequency agility.

[0061] Optionally, let the total number of pulses be , set the number of phase pulses to the ratio of the total number of pulses .

[0062] As attached Figure 8 As shown, a flow chart of a specific implementation method of a method for high-resolution identification of air-launched decoys based on one-dimensional range profiles is as follows:

[0063] S1: Transmits a set of linear frequency modulation signals with agile carrier frequency, and the frequency between sub-pulses is agile;

[0064] S2: For each pulse signal, sampling is performed in the time dimension

[0065] S3: Perform Fourier transform on each pulse signal to obtain a one-dimensional range image of the target corresponding to the sub-pulse;

[0066] S4: Set the number of pulses to , number each coherent pulse to obtain the pulse number of each coherent pulse;

[0067] S5: Set the starting pulse number to 1;

[0068] S6: Perform two-dimensional FFT processing on all pulses within the selected pulse number range to obtain a range image of the primary target;

[0069] S6: Add 1 to the starting pulse number to determine whether the starting pulse number is greater than ;

[0070] S7: If the start pulse number is greater than , then set the number of coherent pulses plus 1, if it is not greater than , then go to S5 and perform broadband synthesis again on all pulses within the selected pulse number range;

[0071] S8: Determine whether the number of coherent pulses is greater than M. If so, integrate all the obtained one-dimensional distance images and end. If not, go to S4 and reset the starting pulse number to 1.

[0072] The present invention proposes a method based on transmitting multi-sub-pulse broadband signals and performing broadband synthesis on arbitrary sub-band signals after reception. The method can simultaneously simulate multiple carrier frequency signals to illuminate the target, and can also simulate multiple bandwidths to illuminate the target. The detection performance of the target under multiple carrier frequencies and multiple bandwidths can be observed, forming a one-dimensional range image of the target with extremely high fineness and high resolution, which can realize accurate identification of the target and air-launched decoys.

[0073] The existing method can only form a bandwidth signal to detect the echo of the target by transmitting a broadband signal. The present invention splits a long pulse into multiple sub-pulses, each of which transmits a signal with a smaller bandwidth, thereby reducing the sampling pressure. At the same time, the received signal is synthesized at the receiving end.

[0074] The present invention can integrate radar detection effects of different carrier frequencies, because the numbers of the starting sub-pulse and the last sub-pulse of the coherent synthesis can be configured, so the equivalent signal carrier frequency is the carrier frequency of the middle sub-pulse, so the carrier frequency can be changed as the pulse number changes; the number of each group of coherent sub-pulses can be configured arbitrarily, and the more the number of coherent sub-pulses, the larger the synthesized bandwidth, so the synthesized signal bandwidth can be modulated by configuring the number of sub-pulses to achieve signal detection effects under different bandwidths.

[0075] Example 2

[0076] Based on the same principle as the method shown in Example 1 of the present invention, as shown in the attached Fig. 9 As shown, an embodiment of the present invention also provides a system for high-resolution identification of air-launched decoys based on one-dimensional range profiles, including a launching unit, a sampling unit, a first processing unit, a first setting unit, a second setting unit, a second processing unit, a first judging unit, and a second judging unit;

[0077] A transmitting unit, used for transmitting a group of pulse signals with agile carrier frequency;

[0078] A sampling unit, used for sampling each pulse signal in a time dimension;

[0079] A first processing unit is used to perform Fourier transform on each pulse signal to obtain a one-dimensional range image of the target corresponding to the sub-pulse;

[0080] A first setting unit is used to set the number of coherent pulses to a set ratio of the total number of pulses, and to number each coherent pulse to obtain a pulse number of each coherent pulse;

[0081] A second setting unit is used to set the starting number of the coherent pulse;

[0082] The second processing unit is used to perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range to obtain a range image of the primary target;

[0083] The first judgment unit is used to add 1 to the starting number of the coherent pulse, and judge whether the starting number of the coherent pulse is greater than the set ratio of the total number of the coherent pulses. If so, the number of coherent pulses is increased by 1, otherwise, all the coherent pulses within the selected pulse number range are re-processed with two-dimensional FFT, and all the pulses within the selected pulse number range are subjected to broadband synthesis;

[0084] The second judgment unit is used to judge whether the number of coherent pulses is greater than the number of coherent pulses as the total number of pulses. If so, all the obtained one-dimensional distance images are integrated and the process ends. Otherwise, the starting pulse number is reset.

[0085] Optionally, the carrier frequency agile pulse signal is a linear frequency modulation agile signal with a bandwidth smaller than a set value, and each sub-pulse transmits a coded signal.

[0086] Optionally, the subcode width of the sub-pulse transmitting coded signal is set to , the frequency agility between sub-pulses, the sub-code bandwidth is , is the speed of light, is the distance resolution corresponding to the total transmitted pulse, and the distance resolution corresponding to the sub-pulse is , all the frequency points of the agile frequency are processed jointly, and all the pulses within the selected pulse number range are synthesized by broadband. The distance resolution obtained is ,but: .

[0087] Optionally, let the total number of pulses be , set the number of phase pulses to the ratio of the total number of pulses .

[0088] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for high-resolution identification of air-launched decoys based on one-dimensional range profiles, characterized in that: include: S1: Transmits a set of pulse signals with agile carrier frequency; The carrier frequency agile pulse signal is a linear frequency modulation agile signal with a bandwidth less than a set value, and each sub-pulse transmits a coded signal; S2: Sample each pulse signal in the time dimension; S3: Perform Fourier transform on each pulse signal to obtain a one-dimensional range image of the target corresponding to the sub-pulse; S4: setting the number of coherent pulses to a set ratio of the total number of pulses, and numbering each coherent pulse to obtain a pulse number of each coherent pulse; S5: Set the starting number of the coherent pulse; S6: Perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range to obtain a range image of the primary target; S7: add 1 to the starting number of the coherent pulse, and judge whether the starting number of the coherent pulse is greater than the set ratio of the total number of coherent pulses. If so, add 1 to the number of coherent pulses and go to S8. Otherwise, go to S6 to re-perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range, and perform broadband synthesis on all pulses within the selected pulse number range; suppose the sub-code width of the sub-pulse transmission coded signal is , the frequency agility between sub-pulses, the sub-code bandwidth is , is the speed of light, is the distance resolution corresponding to the total transmitted pulse, and the distance resolution corresponding to the sub-pulse is , all the frequency points of the agile frequency are processed jointly, and all the pulses within the selected pulse number range are synthesized by broadband. The distance resolution obtained is ,but: ; S8: Determine whether the number of coherent pulses is greater than the number of coherent pulses as the total number of pulses. If so, combine all the obtained one-dimensional distance images and end. Otherwise, go to S5 and reset the starting pulse number.

2. The method for high-resolution identification of air-launched decoys based on one-dimensional range profile according to claim 1 is characterized in that: The total number of pulses is , set the number of phase pulses to the ratio of the total number of pulses .

3. A system for high-resolution identification of air-launched decoys based on one-dimensional range profiles, characterized in that: It includes a transmitting unit, a sampling unit, a first processing unit, a first setting unit, a second setting unit, a second processing unit, a first judging unit and a second judging unit; A transmitting unit, used for transmitting a group of carrier frequency agile pulse signals; the carrier frequency agile pulse signal is a linear frequency modulation agile signal with a bandwidth less than a set value, and each sub-pulse transmits a coded signal; A sampling unit, used for sampling each pulse signal in a time dimension; A first processing unit is used to perform Fourier transform on each pulse signal to obtain a one-dimensional range image of the target corresponding to the sub-pulse; A first setting unit is used to set the number of coherent pulses to a set ratio of the total number of pulses, and to number each coherent pulse to obtain a pulse number of each coherent pulse; A second setting unit is used to set the starting number of the coherent pulse; The second processing unit is used to perform two-dimensional FFT processing on all coherent pulses within the selected pulse number range to obtain a range image of the primary target; The first judgment unit is used to add 1 to the starting number of the coherent pulse to determine whether the starting number of the coherent pulse is greater than the set ratio of the total number of coherent pulses. If so, the number of coherent pulses is increased by 1; otherwise, all coherent pulses within the selected pulse number range are re-processed with two-dimensional FFT, and all pulses within the selected pulse number range are synthesized with broadband; the sub-code width of the sub-pulse transmission coded signal is set to , the frequency agility between sub-pulses, the sub-code bandwidth is , is the speed of light, is the distance resolution corresponding to the total transmitted pulse, and the distance resolution corresponding to the sub-pulse is , all the frequency points of the agile frequency are processed jointly, and all the pulses within the selected pulse number range are synthesized by broadband. The distance resolution obtained is ,but: ; The second judgment unit is used to judge whether the number of coherent pulses is greater than the number of coherent pulses as the total number of pulses. If so, all the obtained one-dimensional distance images are integrated and the process ends. Otherwise, the starting pulse number is reset.

Images