A Dual-Band Radar Anti-Dragging Decoy Interference Method

Abstract

A dual-band radar anti-dragging decoy interference method, in which multi-target tracking and interference type determination are respectively and simultaneously carried out in the C-band and Ku-band of the radar. When both the C-band and Ku-band are not interfered, dual-band time alignment, track association and track fusion are carried out. When only one band is not interfered, it is associated with the system track, and passive angle tracking information fusion is carried out for the interfered band. When both bands are interfered, track extrapolation is carried out, and the interference angle of the band with large interference energy is selected for passive angle tracking information fusion. The present invention is applied to a missile-borne seeker, and can effectively improve the anti-interference performance of the missile-borne radar against dragging decoys.

Description

Technical Field

[0001] The present invention relates to the technical field of anti - interference for missile - borne radar seekers, and in particular to a method for a dual - band radar to resist towed decoy interference. Background Art

[0002] With the development of electronic technology, the electromagnetic environment faced by modern warfare is becoming increasingly complex, and electronic counter - measure technologies are becoming increasingly rich, which poses higher requirements for precision - guided weapons. In terms of resisting towed decoys, most current efforts remain at resisting repeater decoy interference, and there is no corresponding anti - interference ability for towed decoys with modulation capabilities and jamming suppression capabilities.

[0003] The towed decoy forwards the radar signal received by the carrier aircraft through the optical fiber of the carrier aircraft to deceive the guidance radar. Since the towed decoy is close to the carrier aircraft and has the same motion characteristics, it is very difficult for a pulsed - Doppler radar to distinguish and identify the carrier - aircraft echo and the interference echo at medium - and long - range distances. When the missile gradually approaches, since the power of the towed decoy is greater than the power of the carrier - aircraft echo, according to the conventional power - based signal detection criterion, the guidance radar will select the decoy for tracking, resulting in the guidance radar being unable to hit the target. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for a dual - band radar to resist towed decoy interference, which solves the problem in the prior art that the target and the decoy cannot be distinguished in the time - space - frequency domain, so that a single - band seeker tracks the towed decoy based on the conventional signal power detection criterion.

[0005] To achieve the above - mentioned purpose, the present invention provides a method for a dual - band radar to resist towed decoy interference. The C - band and Ku - band of the radar simultaneously perform multi - target tracking and determination of the type of interference respectively. When neither the C - band nor the Ku - band is interfered, dual - band time alignment, track association, and track fusion are performed. When only one band is not interfered, it is associated with the system track, and passive angle - tracking information fusion is performed on the interfered band. When both bands are interfered, track extrapolation is performed, and passive angle - tracking information fusion is performed by selecting the interference angle of the band with greater interference energy.

[0006] The method for the C - band and Ku - band to simultaneously perform multi - target tracking respectively includes the following steps:

[0007] Perform range ambiguity resolution, traverse all possible ambiguity numbers, calculate all possible unambiguous ranges, use histogram statistics, and select the range at the maximum peak as the true missile - target distance;

[0008] Perform time - frequency two - dimensional detection, perform FFT (Fast Fourier Transform) and CFAR (Constant False Alarm Rate) detection, and output possible target dots;

[0009] Perform velocity ambiguity resolution and deception jamming suppression, use angle clustering to distinguish targets in different incoming wave directions, and combine the acceleration criterion to eliminate the deceptive velocity;

[0010] Use the angle clustering center after ambiguity resolution as the angle of this trace.

[0011] The method for performing dual-band time alignment, track association, and track fusion includes the following steps:

[0012] Align the C-band data rate with a lower data rate to the Ku-band data with a higher data rate to retain the higher positioning accuracy of the original Ku-band data;

[0013] Perform velocity association, traverse all tracks in the C-band and Ku-band, calculate the current frame velocity difference between the C-band track and the Ku-band track. If the modulus of the velocity difference is less than or equal to 4, record the C / Ku-band track numbers for velocity association, record the modulus of the velocity difference, and count the number of velocity-associated tracks;

[0014] If there are tracks with successful velocity association, select the track pair with the smallest modulus of the velocity difference, calculate the weighting coefficient based on the missile-target distances observed in each band, perform weighted fusion on the tracks in the two bands, and calculate the system track and target state; otherwise, output the track with more updated frames in the two bands as the fusion output track.

[0015] The calculation formula for the weighting coefficient is:

[0016]

[0017]

[0018]

[0019] In the formula, represents the missile-target distance measured by the C-band at the k-th moment, represents the missile-target distance measured by the Ku-band at the k-th moment, α m (k) is the weighting coefficient of the measurement data of the C-band active radar, β m (k) is the weighting coefficient of the Ku-band measurement data, θ is the target azimuth angle, is the target elevation angle, ν is the target velocity, and r is the missile-target distance;

[0020] The calculation formula for the measurement data after fusion is:

[0021]

[0022] In the formula, is the measurement data of the C-band, is the measurement data of the Ku-band.

[0023] A method for associating with the system track and performing passive angle tracking information fusion on the interfered waveband comprises the following steps:

[0024] If the track in the C band or Ku band is associated with the system track, output the track of this band;

[0025] For the interfered waveband, output that the distance and speed are invalid, and adopt passive angle tracking as the interference angle.

[0026] A method for performing track extrapolation and selecting the interference angle of the waveband with large interference energy for passive angle tracking information fusion comprises the following steps:

[0027] When both the C band and Ku band are interfered, perform track extrapolation;

[0028] Select the waveband angle with large interference energy of the two wavebands as the interference angle, perform passive angle tracking, and output that the distance and speed are invalid.

[0029] When the missile is in the head-on posture, the distance R′ after time t is inferred based on the distance R, speed ν, and acceleration a of the last frame of the target track as:

[0030]

[0031] The speed ν′ is:

[0032] ν′ = ν + at

[0033] Filter the point traces by distance, perform speed association between the point traces of the current frame and the speed ν′, and if the speed association is successful, re-capture the track.

[0034] The present invention is applied to an on-board seeker, and can effectively improve the anti-jamming performance of the on-board radar against towed decoys. Brief Description of the Drawings

[0035] Figure 1 It is a flowchart of a method for a dual-band radar to resist towed decoy interference provided by the present invention. Detailed Embodiment

[0036] The following is based on Figure 1 Specifically illustrate the preferred embodiments of the present invention.

[0037] Traditional single-band radars mainly identify targets from the time domain, frequency domain, spatial domain, and power domain. However, towed decoys deceive the radar in terms of speed, distance, and angle, and it is not easy to identify them from characteristics such as ship speed and track. Therefore, traditional single-band seekers do not have the ability to resist towed decoy interference. Since the instantaneous bandwidth of current jammers is generally not greater than a few GHz, it is considered that they cannot interfere with dual-band radars with a frequency difference of several GHz simultaneously. Therefore, dual-band radars can be used to counter towed decoy interference.

[0038] As Figure 1 shown, the present invention provides a method for a dual-band radar to resist towed decoy interference, which includes the following steps:

[0039] Step S1: The C-band and Ku-band of the radar simultaneously perform multi-target tracking and determination of interference types. When there is a jump in speed or distance, there is interference. When both the C-band and Ku-band are not interfered, step S2 is performed. When only one band is not interfered, step S3 is performed. When both bands are interfered, step S4 is performed;

[0040] Step S2: Dual-band time alignment, track association, and track fusion;

[0041] Step S3: Associate with the system track and perform passive angle tracking information fusion on the interfered band;

[0042] Step S4: Perform track extrapolation and select the interference angle of the band with high interference energy for passive angle tracking information fusion.

[0043] In the above step S1, the method for the C-band and Ku-band to simultaneously perform multi-target tracking includes the following steps:

[0044] Step S1.1: Perform range deambiguation, traverse all possible ambiguity numbers, calculate all possible unambiguous ranges, use histogram statistics, and select the range with the largest peak as the true missile-target range;

[0045] Step S1.2: Perform time-frequency two-dimensional detection, perform FFT (Fast Fourier Transform) and CFAR (Constant False Alarm Rate) detection, and output possible target traces;

[0046] Step S1.3: Perform velocity deambiguation and deception interference suppression, use angle clustering to distinguish targets in different incoming wave directions, and combine the acceleration criterion to eliminate deceptive velocities;

[0047] Step S1.4: Use the angle clustering center after deambiguation as the angle of the trace.

[0048] The above step S2 includes the following steps:

[0049] Step S2.1: Align the C-band data rate with a lower data rate to the Ku-band data with a higher data rate to retain the higher positioning accuracy of the original Ku-band data;

[0050] Since data fusion can only be performed on data at the same moment, and the sampling frequencies of the two bands are inconsistent, time alignment is required;

[0051] Step S2.2: Perform velocity correlation. Traverse all tracks in the C-band and Ku-band, calculate the velocity difference between the current frames of the C-band track and the Ku-band track. If the modulus of the velocity difference is less than or equal to 4, record the C / Ku-band track numbers for velocity correlation, record the modulus of the velocity difference, and count the number of tracks with velocity correlation;

[0052] Step S2.3: If there are tracks with successful velocity correlation, select the pair of tracks with the smallest modulus of velocity difference, calculate the weighting coefficient based on the missile-target distances observed in each band, perform weighted fusion on the tracks of the two bands, and calculate the system track X(k) and the target state; otherwise, output the tracks with more updated frames in the two bands as the fusion output tracks;

[0053] The closer the sensor is to the target, the greater the weight of its measurement data in the fused data. That is to say, the more measurement data of this sensor is adopted by the fusion center, and the more it believes in the measurement data of this sensor.

[0054] The calculation formula for the weighting coefficient is:

[0055]

[0056]

[0057]

[0058] In the formula, represents the missile-target distance measured by the C-band at the k-th moment, represents the missile-target distance measured by the Ku-band at the k-th moment, α m (k) is the weighting coefficient of the measurement data of the C-band active radar, β m (k) is the weighting coefficient of the Ku-band measurement data, θ is the target azimuth angle, is the target elevation angle, ν is the target velocity, and r is the missile-target distance;

[0059] The calculation formula for the fused measurement data is:

[0060]

[0061] In the formula, is the measurement data of the C-band, is the measurement data of the Ku-band.

[0062] Step S3 includes the following steps:

[0063] Step S3.1: If the track in the C-band or Ku-band is associated with the system track, output the track of this band;

[0064] Step S3.2: For the interfered band, output that the distance and speed are invalid, and adopt passive angle tracking as the interference angle.

[0065] Step S4 includes the following steps:

[0066] Step S4.1: When both the C-band and Ku-band are interfered, conduct track extrapolation; when the missile is in a head-on posture, use the distance R, speed ν, and acceleration a of the last frame of the target track to estimate the distance R′ after time t as:

[0067]

[0068] The speed ν′ is:

[0069] ν′ = ν + at

[0070] Screen the point traces by distance, associate the point traces of the current frame with the speed ν′. If the speed association is successful, re-capture the track;

[0071] Step S4.2: Select the band angle with large interference energy in the two bands as the interference angle, conduct passive angle tracking, and output that the distance and speed are invalid.

[0072] In an embodiment of the present invention, if the C-band receives towed interference and there is no interference in the Ku-band, then multi-target tracking is first performed simultaneously in the C-band and Ku-band respectively: perform distance deblurring, traverse all possible ambiguity numbers, calculate all possible unambiguous distances, use histogram statistics, and select the distance at the maximum peak as the true missile-target distance; perform time-frequency two-dimensional detection, perform FFT and CFAR detection, and output possible target point traces; perform speed deblurring and deception interference suppression, use angle clustering to distinguish targets in different incoming wave directions, and combine the acceleration criterion to eliminate the deception speed; use the angle clustering center after deblurring as the angle of this point trace. Since it is known through interference type judgment that there is interference in the C-band, when only the Ku-band is not interfered, the track in the Ku-band is associated with the system track, and the track in the Ku-band is output. For the C-band, output that the distance and speed are invalid, and adopt passive angle tracking as the interference angle.

[0073] The present invention brings the following beneficial effects:

[0074] Adopt a dual - band composite guidance system and a distributed, feature - level fusion scheme. Each single - band seeker completes its own signal acquisition, pre - processing, multi - target tracking and state estimation, and sends the obtained target track information to the fusion center. The fusion center completes the fusion of the same target track and the fusion of passive angle tracking information, so as to output interference angle information when one band is subjected to towed interference, and the other band outputs the angle information of the target.

[0075] It should be noted that in the embodiments of the present invention, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0076] In the present invention, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication 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 present invention can be understood according to specific circumstances.

[0077] Although the content of the present invention has been introduced in detail through the above - mentioned preferred embodiments, it should be recognized that the above description should not be regarded as a limitation of the present invention. After those skilled in the art have read the above content, various modifications and substitutions of the present invention will be obvious. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims

1. A method for a dual-band radar to resist towed decoy interference, characterized in that The C-band and Ku-band of the radar simultaneously perform multi-target tracking and determination of interference types respectively. When both the C-band and Ku-band are not interfered, dual-band time alignment, track association, and track fusion are carried out. When only one band is not interfered, the non-interfered band is associated with the system track, and the interfered band performs passive angle tracking information fusion. When both bands are interfered, track extrapolation is carried out, and the interference angle of the band with greater interference energy is selected for passive angle tracking information fusion; The method for simultaneously performing multi-target tracking in the C-band and Ku-band respectively includes the following steps: Perform range de-ambiguation, traverse all possible ambiguity numbers, calculate all possible non-ambiguous ranges, use histogram statistics, and select the range at the maximum peak as the true missile-target range; Perform time-frequency two-dimensional detection, perform FFT fast Fourier transform and CFAR constant false alarm detection, and output possible target traces; Perform velocity de-ambiguation and deception interference suppression, use angle clustering to distinguish targets in different incoming wave directions, and combine the acceleration criterion to eliminate deceptive velocities; Use the de-ambiguated angle clustering center as the angle of the trace; The method for associating with the system track and performing passive angle tracking information fusion for the interfered band includes the following steps: If the track of the C-band or Ku-band is associated with the system track, output the track of that band; For the interfered band, output that the range and velocity are invalid, and use passive angle tracking as the interference angle; The method for performing track extrapolation and selecting the interference angle of the band with greater interference energy for passive angle tracking information fusion includes the following steps: When both the C-band and Ku-band are interfered, perform track extrapolation; Select the band angle with greater interference energy of the two bands as the interference angle, perform passive angle tracking, and output that the range and velocity are invalid; When the missile is in a head-on posture, the range R′ after time t is speculated based on the range R, velocity ν, and acceleration a of the last frame of the target track as: The velocity ν′ is: ν′ = ν + at Screen the traces by range, perform velocity association between the traces of the current frame and the velocity ν′. If the velocity association is successful, re-capture the track.

2. The dual-band radar anti-dragging decoy interference method according to claim 1, wherein The method for performing dual-band time alignment, track association, and track fusion includes the following steps: Align the data rate of the lower data rate C-band to the higher data rate Ku-band to retain the higher positioning accuracy of the original Ku-band data; Perform velocity association, traverse all tracks of the C-band and Ku-band, calculate the current frame velocity difference between the C-band track and the Ku-band track. If the modulus of the velocity difference is less than or equal to 4, record the C / Ku-band track numbers of the velocity association, record the modulus of the velocity difference, and count the number of velocity-associated tracks; If there are tracks with successful velocity association, select the track pair with the minimum modulus of the velocity difference, calculate the weighting coefficient based on the missile-target ranges observed in each band, perform weighted fusion on the tracks of the two bands, and calculate the system track and target state; otherwise, output the tracks with more updated frames of the two bands as the fusion output tracks.

3. The dual-band radar anti-dragging decoy interference method according to claim 2, characterized in that, The calculation formula for the said weighting coefficient is: In the formula, represents the missile-target distance measured in the C-band at the k-th moment, represents the missile-target distance measured in the Ku-band at the k-th moment, and α m (k) is the weight coefficient of the measurement data of the C-band active radar, and β m (k) is the weight coefficient of the Ku-band measurement data, θ is the target azimuth angle, is the target elevation angle, ν is the target speed, and r is the missile-target distance; The calculation formula for the measured data after fusion is: In the formula, is the measurement data in the C band, is the measurement data in the Ku band.

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