A method and system for improving the ranging accuracy of radar seekers

Abstract

This invention relates to a method and system for improving the ranging accuracy of a radar seeker. The method utilizes existing SF (frequency step) ranging results, i.e., the initial missile-target distance, and calculates the fine-resolution periodic ambiguity factor based on this. Then, the ambiguous distance is calculated according to the ambiguity factor. Simultaneously, the distance residual is calculated using a formula based on the fine-resolution value of the target's strongest point. Finally, the ambiguous distance and the distance residual are added to obtain the final missile-target distance value. This invention primarily utilizes improvements in software algorithms to enhance the accuracy of radar seeker range measurement to a certain extent, has low dependence on hardware resources, and is highly adaptable to radar seekers with already fixed hardware.

Description

Technical Field

[0001] This invention relates to the field of radar ranging technology, and specifically to a method and system for improving the ranging accuracy of a radar seeker. Background Technology

[0002] 1. Distance measurement accuracy

[0003] Ranging is a significant feature that distinguishes active radar from other detection devices and is one of the fundamental tasks of radar. Since the speed of radio waves propagation in a uniform medium is constant, the essence of ranging is measuring the time delay of the echo relative to the transmitted signal. Common methods for measuring time delay include the pulse method, phase method, and frequency method. For pulse-based radars, narrower pulses generally result in higher range resolution, while for pulse compression radars, wider effective bandwidth generally results in higher range resolution. Theoretically, the range resolution Δr of a radar can be expressed by the following formula:

[0004]

[0005] Where c is the speed of light, usually c = 3 × 10 8 m / s, τ is the pulse width, and B is the signal bandwidth.

[0006] Radar seekers are miniature radars mounted on missiles. Currently, radar seekers used on missile platforms need to simultaneously perform search, identification, interception, tracking, ranging, velocity measurement, and anti-jamming functions. Therefore, their systems and signal waveforms are often more complex than traditional radars, and the ranging methods used are relatively fixed, with few ways to improve ranging accuracy. Under the premise of unambiguous ranging, for a pulse compression radar seeker, the range resolution includes not only the theoretical resolution Δr mentioned above, but also the sampling resolution Δr'. The former represents the seeker's ability to separate objects and is mainly constrained by bandwidth, while the latter represents the range scale of the sampling unit after AD sampling by the seeker's signal processor and is constrained by the sampling rate. The sampling resolution Δr' can be expressed as:

[0007]

[0008] During the design phase of the seeker, the sampling resolution Δr' (i.e., the sampling unit) is mainly selected based on the target size. However, traditional seekers measure missile-target distance (distance between the missile and the target) with relatively low accuracy requirements, so distance calculations typically use the sampling resolution Δr' directly. If Δr' is fixed, the accuracy of the distance calculation is fixed; distance changes smaller than Δr' are not reflected in the calculated distance value. Furthermore, Δr, which reflects detailed target distance information, is usually not used in range measurement. The traditional algorithm for measuring missile-target distance R0 using a seeker can be expressed as:

[0009] R0=Δr'×(N1-N0) (3)

[0010] Where N1 is the range cell number of the strongest point of the target as processed by the signal processor, N0 is the correction amount of the range cell number, which is caused by the processing delay of the signal processor, and the missile-target distance R0 usually refers to the distance from the position of the strongest target echo to the seeker.

[0011] 2. Frequency step signal

[0012] Pulse compression radar employs wide-pulse transmission to increase average transmitted power and ensure a sufficiently long range. During reception, a corresponding pulse compression algorithm is used to obtain narrow pulses, improving range resolution. This effectively resolves the conflict between radar range and range resolution, simultaneously enhancing both. Currently, the commonly used modulation signal for pulse compression is Linear Frequency Modulation (LFM). In Earth observation, Stepped Frequency (SF) signals are frequently used. SF signals are an important high-resolution range radar signal. They transmit a series of linearly varying carrier frequency radar pulses, and then use IFFT (Inverse Fourier Transform) processing on the pulse echoes to achieve a synthesized high-resolution range. This type of signal can achieve high resolution while reducing the instantaneous bandwidth requirements of the digital signal processor.

[0013] Let the repetition period of the signal pulse be T. r Given a pulse width of τ, a frequency step of Δf, a fundamental transmission frequency of f0, and N coherent accumulation points, the SF transmission signal can be expressed as:

[0014]

[0015] The echo signal of a target at a distance of R is:

[0016]

[0017] SF signals can be described as transmitting discrete frequency domain spectra with a frequency domain sampling interval of Δf, and the total bandwidth can be expressed as:

[0018] B=NΔf(6)

[0019] Therefore, the SF signal has a high range resolution effect after IFFT, and the theoretical range resolution (SF fine resolution) can be expressed as:

[0020]

[0021] Because SF signals have a wide bandwidth and theoretically high resolution, they can achieve meter-level or even sub-meter-level distance image accuracy, providing richer target detail information. Therefore, theoretically, ranging accuracy can also be improved through finer resolution. The relationship between SF fine resolution and distance is calculated as follows: Figure 1 As shown. Therefore, the fine-resolution information of the range image can be fully utilized to improve the accuracy of missile-to-eye range measurement.

[0022] 3. Technical Objectives

[0023] Therefore, to improve ranging accuracy, the sampling resolution Δr' can be increased, i.e., the AD (analog-to-digital) sampling rate can be increased. However, increasing the AD sampling rate inevitably leads to increased hardware costs and processing complexity. Thus, increasing sampling resolution and reducing hardware costs are contradictory, and replacing the AD chip in a seeker with already fixed hardware is virtually impossible. Furthermore, since many current ground detection radar seekers already use SF signal waveforms, the large bandwidth provided by SF can theoretically improve theoretical range resolution and refine target radial detail information. Therefore, theoretically, this information can be used to assist in improving the accuracy of range measurement.

[0024] In summary, in order to make full use of existing hardware resources, there is a need for a ranging algorithm that is compatible with existing sampling resolutions while incorporating theoretical resolutions to improve the distance measurement accuracy of the seeker. This would make it more feasible and cost-effective to improve the ranging accuracy and perform subsequent upgrades for seekers with already fixed hardware systems. Summary of the Invention

[0025] The technical problem to be solved by this invention is:

[0026] To avoid the shortcomings of existing technologies, this invention provides a method for improving the ranging accuracy of radar seekers, wherein the target-missile distance in this method refers to the straight-line distance between the radar seeker and the point on the target with the strongest echo.

[0027] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0028] A method for improving the ranging accuracy of a radar seeker, characterized by the following steps:

[0029] Step 1: Calculate the initial distance between the missile and the target; the initial distance between the missile and the target is the straight-line distance between the radar seeker and the point on the target with the strongest echo.

[0030] Step 2: Calculate the multiple of the fine-resolution periodic blur in SF;

[0031] Step 3: Calculate the blur distance based on the blur factor;

[0032] Step 4: Calculate the distance residual;

[0033] Step 5: Calculate the corrected distance based on the fuzzy distance and the distance residual.

[0034] A further technical solution of the present invention: Step 1 is specifically: calculate the initial distance R0 = (N1-N0)×Δr' of the target according to the existing sampling resolution Δr', where N1 is the distance unit number of the strongest point of the target processed by the signal processor, and N0 is the correction amount of the distance unit number.

[0035] A further technical solution of the present invention: Step 2 is specifically as follows: Calculate the fine resolution blur factor M = floor(R0 / ΔR') based on the initial distance R0 between the projectile and the target, where ΔR' is the actual distance corresponding to one complete cycle of the SF fine resolution change, and floor(·) represents rounding down.

[0036] A further technical solution of the present invention: Step 3 specifically involves: calculating the fuzzy distance R based on the fuzziness factor M. M =M·ΔR'.

[0037] A further technical solution of the present invention: Step 4 specifically involves: calculating the distance residual ΔR = (k1-k0) × (ΔR' / N) based on the fine resolution information, where ΔR represents R M The difference between the actual distance to the target and the distance to the target is where k1 is the fine resolution sign of the point where the target echo is strongest, k0 is the fine resolution sign of the point at distance 0, ΔR' / N is the fine resolution scale, and ΔR is called the "distance residual".

[0038] A further technical solution of the present invention: Step 5 specifically involves: at the fuzzy distance R M Based on this, adding the "distance residual" ΔR, we obtain the fine-resolution corrected distance R = R M +ΔR.

[0039] A system for improving the ranging accuracy of a radar seeker is characterized by comprising a projectile-target initial distance calculation module, a fine-resolution ambiguity multiplier calculation module, an ambiguity distance calculation module, a distance residual calculation module, and a correction module;

[0040] The initial distance calculation module calculates the initial distance between the projectile and the target based on the sampling resolution and outputs it to the fine-resolution ambiguity multiplier calculation module; the fine-resolution ambiguity multiplier calculation module calculates the fine-resolution ambiguity multiplier based on the initial distance between the projectile and the target and outputs it to the ambiguity distance calculation module; the ambiguity distance calculation module calculates the ambiguity distance based on the fine-resolution ambiguity multiplier and outputs it to the correction module; the distance residual calculation module calculates the distance residual based on the fine-resolution information and outputs it to the correction module; the correction module adds the ambiguity distance and the distance residual to obtain the corrected distance.

[0041] A computer system is characterized by comprising: one or more processors, and a computer-readable storage medium for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method described above.

[0042] A computer-readable storage medium is characterized by storing computer-executable instructions, which, when executed, are used to implement the above-described method.

[0043] The beneficial effects of this invention are as follows:

[0044] This invention proposes a method to improve the ranging accuracy of a radar seeker. The method first calculates the initial distance between the target and the target using the sampling resolution. Then, it introduces the information of the fine-resolution (SF) system and calculates the fuzzy distance by the period multiple of the fuzzy resolution. Next, it calculates the distance residual by using the fine-resolution signal of the target's strongest scattering point and the fine-resolution signal of the distance 0 point. Finally, it adds the fuzzy distance and the distance residual to obtain the target-target distance calculated by the fine resolution. Its accuracy is consistent with the fine-resolution scale and is higher than the accuracy expressed by the original sampling resolution.

[0045] This invention improves the accuracy of radar seeker range display. It does not require increasing the AD sampling rate or changing the system's hardware structure; it simply utilizes the existing range calculation method while incorporating fine-resolution information from the radar detector (SF). By modifying the range calculation algorithm during data processing, the accuracy of range calculation can be improved. Since this method only requires changing the software algorithm and not altering the hardware configuration, it demonstrates strong applicability and versatility, possessing significant engineering application value. Attached Figure Description

[0046] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0047] Figure 1 This is a schematic diagram illustrating the relationship between SF fine resolution, its blur factor, and distance;

[0048] Figure 2 This is a flowchart of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0050] like Figure 2 As shown, the present invention proposes a method for improving the ranging accuracy of a radar seeker, comprising the following steps:

[0051] (1) The initial distance between the projectile and the target is calculated according to the original method of calculating the distance between the projectile and the target, and the calculation accuracy is consistent with the sampling resolution;

[0052] (2) Based on the relationship between SF fine resolution and its periodic ambiguity multiple and the actual distance, calculate the ambiguity multiple of SF fine resolution traversing the complete cycle (from 1 to N), that is, the number of fine resolution variation cycles from 1 to N contained in the initial distance between the projectile and the target.

[0053] (3) Calculate the fuzzy distance based on the fuzziness factor;

[0054] (4) Calculate the distance residual by using the fine resolution of the point where the target echo is strongest and the fine resolution of the distance from 0.

[0055] (5) Add the fuzzy distance to the distance residual to obtain the distance after fine resolution correction. The distance calculation accuracy is consistent with the fine resolution scale.

[0056] Specifically:

[0057] Step 1: Calculate the initial distance between the projectile and the target R0 = (N1-N0) × Δr' based on the existing sampling resolution Δr', which is the distance with the original accuracy;

[0058] Step 2: Calculate the fine resolution blur factor M = floor(R0 / ΔR') based on the initial distance R0 between the projectile and the target, where ΔR' is the actual distance corresponding to one complete cycle of the SF fine resolution change (from 1 to N), and floor(·) represents rounding down;

[0059] Step 3: Calculate the fuzzy distance R based on the fuzziness factor M. M =M·ΔR';

[0060] Step 4: Calculate the distance residual ΔR = (k1-k0) × (ΔR' / N) based on the fine resolution information, where ΔR represents R. M The difference between the actual distance to the target and the actual distance, where k1 is the fine resolution sign of the point where the target echo is strongest, k0 is the fine resolution sign of the point at distance 0, ΔR' / N is the fine resolution scale, and ΔR is called the "distance residual".

[0061] Step 5: At the fuzzy distance R M Based on this, adding the "distance residual" ΔR, we obtain the fine-resolution corrected distance R = R M +ΔR.

[0062] To enable those skilled in the art to better understand the present invention, the present invention will be described in detail below with reference to specific embodiments.

[0063] Example 1:

[0064] (1) Assuming the distance cell where the strongest point of the target echo is located is N1 = 300, the distance correction is N0 = 100, and the sampling resolution is Δr' = 7.5m, then the original accuracy distance R0 = (301-100) × 7.5 = 1507.5m;

[0065] (2) Assuming ΔR' = 30m, calculate the fine resolution blur factor M = floor(R0 / ΔR') = 50;

[0066] (3) Calculate the fuzzy distance R M =M·ΔR'=1500m;

[0067] (4) Assuming k1 = 50, k0 = 10, N = 128, then the distance residual ΔR = (k1 - k0) × (ΔR′ / N) = 9.375m;

[0068] (5) Calculate the corrected distance R = R M +ΔR=1509.375m.

[0069] Through experimental verification and comparison with traditional methods, the present invention demonstrates higher accuracy in calculating the target distance compared to traditional methods, as shown in Table 1:

[0070] Table 1 Comparison of the method of the present invention with traditional methods

[0071]

[0072] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the scope of the technology disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention.

Claims

1. A method for improving the ranging accuracy of a radar seeker, characterized in that... The steps are as follows: Step 1: Calculate the initial distance between the missile and the target; the initial distance between the missile and the target is the straight-line distance between the radar seeker and the point on the target with the strongest echo; specifically, based on the existing sampling resolution... Calculate the initial distance between the target and the target. ,in N 1 represents the distance cell number of the strongest point of the target as determined by the signal processor. N 0 represents the correction amount for the distance cell number; Step 2: Calculate the multiple of the SF fine-resolution periodic blur; specifically: based on the initial distance between the projectile and the target. Calculate the multiple of fine resolution blur. ,in The actual distance corresponding to a complete cycle of SF fine-resolution variation. Indicates rounding down; Step 3: Calculate the fuzzy distance based on the fuzziness factor; specifically: based on the fuzziness factor... M Calculate fuzzy distance ; Step 4: Calculate the distance residual; specifically: calculate the distance residual based on the fine-resolution information. , express The difference between the actual distance to the target, where It is the fine resolution sign where the strongest point of the target echo is located. It is the fine resolution sign at the distance from 0. To refine the scale; Step 5: Calculate the corrected distance based on the fuzzy distance and the distance residual; specifically: in the fuzzy distance... Based on this, plus distance residual That is, to obtain the distance after fine resolution correction. .

2. A system for implementing the method for improving the ranging accuracy of a radar seeker as described in claim 1, characterized in that... It includes a projectile-target initial distance calculation module, a fine-resolution ambiguity multiplier calculation module, an ambiguity distance calculation module, a distance residual calculation module, and a correction module; The initial distance calculation module for the projectile and the target is calculated based on the sampling resolution and output to the fine resolution ambiguity factor calculation module; the fine resolution ambiguity factor calculation module is calculated based on the initial distance for the projectile and the target and output to the ambiguity distance calculation module. The fuzzy distance calculation module calculates the fuzzy distance based on the fine resolution fuzziness factor and outputs it to the correction module; The distance residual calculation module calculates the distance residual based on the fine resolution information and outputs it to the correction module; The correction module adds the fuzzy distance and the distance residual to obtain the corrected distance.

3. A computer system, characterized in that... include: One or more processors, a computer-readable storage medium for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to implement the method of claim 1.

4. A computer-readable storage medium, characterized in that... The device stores computer-executable instructions, which, when executed, are used to implement the method of claim 1.

Images