Subarray-level time sequence alternate high-duty-ratio wide-coverage pulse waveform design method

Abstract

The invention discloses a sub-array-level time sequence alternate high-duty-ratio wide-coverage pulse waveform design method, and belongs to the technical field of radar detection. According to the invention, the duty ratio of the pulse waveform is improved by adopting sub-array-level time sequence alternate emission, and on the basis, the detection range extension of the wide-coverage pulse waveform is realized through joint optimization design of the pulse width of long and short pulses, the number of coherent pulses and the number of sub-array time sequence alternate emission cycles. The method is mainly used for solving the problem of detection power degradation caused by ERP limitation when a pulse system array radar is in wide-coverage transmitting beam forming.

Description

Technical Field

[0001] The invention belongs to the field of radar detection technology, and in particular relates to a subarray-level sequential high-duty-ratio wide-coverage pulse waveform design method. Background Art

[0002] With the development of science and technology, radar has been applied to many fields such as detection, communication, and reconnaissance. At present, the design of wide coverage pulse waveform is a hot topic in radar waveform design research. The beam pattern with a wide main lobe area can achieve wide coverage of the target area at the same time, improving the target detection performance of the radar system. In addition, wide coverage transmit beamforming technology can also reduce the detection blind area of ​​the radar system, improve signal reception efficiency, increase the radar's observation time on the target, and increase the data rate. At present, everyone's research is mainly focused on the optimization design method of low sidelobe wide coverage waveform, the optimization design of main lobe high gain wide coverage waveform, and precise beam shape control.

[0003] However, in order to achieve wide beam coverage, the number of array elements must be reduced, which will limit the ERP of the array and cause a decrease in the detection distance range. Summary of the invention

[0004] The present invention proposes a subarray-level sequential high-duty-cycle wide-coverage pulse waveform design method, which is mainly used to solve the problem of detection power degradation caused by ERP limitation when pulse array radar is used for wide-coverage transmission beamforming, and can achieve low-transmitting power pulse radar detection range extension.

[0005] The technical solution to achieve the purpose of the present invention is: a sub-array level timing sequence high duty cycle wide coverage pulse waveform design method, the specific steps are:

[0006] Step 1: Determine the short pulse width according to the radar minimum range indicator;

[0007] Step 2: Set the initial coherent pulse number;

[0008] Step 3: Determine the maximum effective range of the short pulse according to the radar equation;

[0009] Step 4: Set the blind pulse detection margin, determine the upper limit of the long pulse width, and make the long pulse width equal to the upper limit of the long pulse width;

[0010] Step 5: Determine the pulse repetition period according to the upper limit of the duty cycle of the radar transmission channel;

[0011] Step 6: Determine the actual pulse repetition period according to the number of subarrays, the short pulse width, and the long pulse width;

[0012] Step 7: Determine the maximum range of the long pulse according to the radar equation;

[0013] Step 8: Determine the number of sub-array timing rotation transmission cycles according to the number of sub-arrays, the maximum effective distance of the long pulse, and the actual pulse repetition period;

[0014] Step 9: Determine the number of coherent pulses according to the number of sub-array timing cycles, and redetermine the maximum range corresponding to the long pulse width according to the radar equation. If it satisfies:

[0015] R' lmax -R max >δ Rl

[0016] In the formula, R' lmax is the recalculated maximum action distance, δ Rl is the long pulse detection margin, R max It is the maximum range indicator of radar;

[0017] Then go to step 10, otherwise add 1 to the initial coherent pulse number and go to step 3;

[0018] Step 10: Output waveform design parameters.

[0019] Preferably, the short pulse width τ is determined short The specific formula is:

[0020] τ short =2R min / C

[0021] In the formula, R min is the minimum effective range indicator of radar, and C is the speed of light.

[0022] Preferably, according to the radar equation, the formula for determining the maximum range of a short pulse is:

[0023]

[0024] Where P t is the radar transmission power, τ short is the radar short pulse width, G t is the antenna transmission gain, G r is the antenna receiving gain, λ is the wavelength, k is the Boltzmann constant, T s Input temperature for the system, D x is the detection factor, and L is the system loss.

[0025] Preferably, the calculation formula for the upper limit of the long pulse width is:

[0026] τ lmax =2(R smax -δ Rs ) / C-τ short

[0027] In the formula, C is the speed of light, R smax is the maximum effective distance of short pulse, δ Rs is the blind pulse detection margin, τ short For short pulse width.

[0028] Preferably, the calculation formula of the pulse repetition period is:

[0029]

[0030] In the formula, τ short is the short pulse width, τ long is the long pulse width, D max It is the upper limit of the radar transmitter duty cycle.

[0031] Preferably, the actual pulse repetition period T r The calculation formula is:

[0032] T r =max{F(τ short +τ long ),T rmin}

[0033] In the formula, F is the number of sub-arrays, τ short is the short pulse width, τ long is the long pulse width, T rmin is the pulse repetition period.

[0034] Preferably, the maximum effective distance R of the long pulse is calculated lmax , the specific formula is:

[0035]

[0036] Where P t is the radar transmission power, τ long is the radar long pulse width, G t is the antenna transmission gain, G r is the antenna receiving gain, λ is the wavelength, k is the Boltzmann constant, T s Input temperature for the system, D x is the detection factor, and L is the system loss.

[0037] Preferably, the number of sub-array sequential transmission cycles P is specifically:

[0038]

[0039] In the formula, C is the speed of light, F is the number of subarrays, R lmax is the maximum effective distance of long pulse, T r is the actual pulse repetition period.

[0040] Preferably, the number of coherent pulses is NP, N is the initial number of coherent pulses, and P is the number of sub-array sequential transmission cycles.

[0041] Preferably, the waveform design parameters include the short pulse width τ short , long pulse width τ long , coherent pulse number NP, pulse repetition period T r .

[0042] Compared with the prior art, the present invention has the following significant advantages:

[0043] 1. In low ERP detection scenarios such as wide coverage transmit beamforming, detection range extension can be achieved without adopting hardware change solutions such as increasing radar peak transmit power and increasing transmit duty cycle.

[0044] 2. The present invention has the advantage of covert detection when combined with a low ERP emission method.

[0045] The present invention is described in further detail below in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The block diagram is a method for designing a high duty cycle and wide coverage pulse waveform with sub-array-level sequential timing.

[0047] Figure 2 This is a schematic diagram of a 4-subarray long and short pulse transmission waveform arrangement scheme. DETAILED DESCRIPTION

[0048] The present invention will be further described in detail below in conjunction with the accompanying drawings and preferred embodiments, but the protection scope of the present invention is not limited by the implementing regulations.

[0049] like Figure 1 As shown, a sub-array level timing alternation high duty cycle wide coverage pulse waveform design method adopts sub-array level timing alternation to improve the pulse waveform duty cycle, and on this basis, by jointly optimizing the design of long and short pulse widths, the number of coherent pulses, and the number of timing alternation cycles, the detection range extension of the wide coverage waveform is achieved. The preferred embodiment of the present invention includes the following steps:

[0050] Step 1: According to the radar minimum range indicator R min , determine the short pulse width τ short :

[0051] τ short =2R min / C(1); where C is the speed of light;

[0052] Step 2: Set the initial coherent pulse number N, which can generally be set to N = 128 according to conventional radar performance indicators;

[0053] Step 3: Determine the maximum range R of the short pulse according to the radar equation smax , the specific formula is:

[0054]

[0055] Where P t is the radar transmission power, τ short is the radar short pulse width, G t is the antenna transmission gain, G r is the antenna receiving gain, λ is the wavelength, k is the Boltzmann constant, T s Input temperature for the system, D x is the detection factor, and L is the system loss.

[0056] Step 4: Set the blind pulse (short pulse) detection margin δ Rs , determine the upper limit of the long pulse width τ lmax , and take the long pulse width τ long =τ lmax :

[0057] τ lmax =2(R smax -δ Rs ) / C-τ short (2); where C is the speed of light;

[0058] Step 5: According to the upper limit D of the radar transmitter duty cycle max , determine the pulse repetition period T rmin :

[0059]

[0060] Step 6: According to the number of subarrays F, the short pulse width τ short , long pulse width τ long , the actual T r :

[0061] T r =max{F(τ short +τ long ),T rmin} (4);

[0062] Step 7: Determine the maximum range R of the long pulse according to the radar equation lmax , the specific formula is:

[0063]

[0064] Where P t is the radar transmission power, τ longis the radar long pulse width, G t is the antenna transmission gain, G r is the antenna receiving gain, λ is the wavelength, k is the Boltzmann constant, T s Input temperature for the system, D x is the detection factor, and L is the system loss.

[0065] Step 8: According to the number of sub-arrays F and the maximum effective distance of long pulses R lmax , pulse repetition period T r These three parameters determine the number of sub-array timing cycles P:

[0066]

[0067] Where C is the speed of light;

[0068] Step 9: Let the number of coherent pulses be NP, R max is the maximum range indicator of the radar. When the number of coherent pulses changes, the detection factor substituted into the radar equation also changes. Therefore, the long pulse width τ is calculated again according to the radar equation. long The corresponding maximum range R' lmax , the long pulse detection margin is δ Rl , if satisfied

[0069] R' lmax -R max >δ Rl (6) Then go to step 10, otherwise set N=N+1 and go to step 3;

[0070] Step 10: Output waveform design parameters: short pulse width τ short , long pulse width τ long , coherent pulse number NP, pulse repetition period T r It can be seen that on the basis of maintaining the tracking data rate, the timing alternation of high duty cycle waveforms can increase the number of target echo coherent pulses and achieve detection range extension when the radar ERP is limited.

[0071] Assuming the number of sub-arrays is 4, the specific arrangement of long and short pulse waveforms can be as follows: Figure 2 shown.

[0072] The present invention provides a sub-array level timing alternating high duty cycle wide coverage pulse waveform design method. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A method for designing a high duty cycle and wide coverage pulse waveform with sub-array-level sequential rotation, characterized in that: The specific steps are: Step 1: Determine the short pulse width according to the radar minimum range indicator; Step 2: Set the initial coherent pulse number; Step 3: Determine the maximum effective range of the short pulse according to the radar equation; Step 4: Set the blind pulse detection margin, determine the upper limit of the long pulse width, and make the long pulse width equal to the upper limit of the long pulse width; Step 5: Determine the pulse repetition period according to the upper limit of the duty cycle of the radar transmission channel; Step 6: Determine the actual pulse repetition period according to the number of subarrays, the short pulse width, and the long pulse width; Step 7: Determine the maximum range of the long pulse according to the radar equation; Step 8: Determine the number of sub-array timing rotation transmission cycles according to the number of sub-arrays, the maximum effective distance of the long pulse, and the actual pulse repetition period; Step 9: Determine the number of coherent pulses according to the number of sub-array timing cycles, and redetermine the maximum range corresponding to the long pulse width according to the radar equation. If it satisfies: R' lmax -R max >d Rl In the formula, R' lmax is the recalculated maximum action distance, δ Rl is the long pulse detection margin, R max It is the maximum range indicator of radar; Then go to step 10, otherwise add 1 to the initial coherent pulse number and go to step 3; Step 10: Output waveform design parameters.

2. The subarray-level sequential high duty cycle wide coverage pulse waveform design method according to claim 1 is characterized in that: Determine the short pulse width τ short The specific formula is: τ short =2R min / C In the formula, R min is the minimum effective range indicator of radar, and C is the speed of light.

3. The method for designing a subarray-level sequential high duty cycle wide coverage pulse waveform according to claim 1, characterized in that: According to the radar equation, the formula for determining the maximum range of a short pulse is: Where P t is the radar transmission power, τ short is the radar short pulse width, G t is the antenna transmission gain, G r is the antenna receiving gain, λ is the wavelength, k is the Boltzmann constant, T s Input temperature for the system, D x is the detection factor, and L is the system loss.

4. The method for designing a subarray-level sequential high duty cycle wide coverage pulse waveform according to claim 1, characterized in that: The calculation formula for the upper limit of long pulse width is: t lmax =2(R smax -d Rs ) / C-τ short In the formula, C is the speed of light, R smax is the maximum effective distance of short pulse, δ Rs is the blind pulse detection margin, τ short For short pulse width.

5. The method for designing a subarray-level sequential high duty cycle wide coverage pulse waveform according to claim 1, characterized in that: The pulse repetition period is calculated as: In the formula, τ short is the short pulse width, τ long is the long pulse width, D max It is the upper limit of the radar transmitter duty cycle.

6. The subarray-level sequential high duty cycle wide coverage pulse waveform design method according to claim 1, characterized in that: The actual pulse repetition period T r The calculation formula is: T r =max{F(τ short +t long ),T rmin } Where F is the number of sub-arrays, τ short is the short pulse width, τ long is the long pulse width, T rmin is the pulse repetition period.

7. The method for designing a subarray-level sequential high duty cycle wide coverage pulse waveform according to claim 1, characterized in that: Calculate the maximum range R of long pulse imax , the specific formula is: Where P t is the radar transmission power, τ long is the radar long pulse width, G t is the antenna transmission gain, G r is the antenna receiving gain, λ is the wavelength, k is the Boltzmann constant, T s Input temperature for the system, D x is the detection factor, and L is the system loss.

8. The method for designing a subarray-level sequential high duty cycle wide coverage pulse waveform according to claim 1, characterized in that: The specific number of sub-array timing rotation transmission cycles P is: In the formula, C is the speed of light, F is the number of subarrays, R lmax is the maximum effective distance of long pulse, T r is the actual pulse repetition period.

9. The method for designing a subarray-level sequential high duty cycle wide coverage pulse waveform according to claim 1, characterized in that: The number of coherent pulses is NP, N is the initial number of coherent pulses, and P is the number of sub-array sequential transmission cycles.

10. The method for designing a subarray-level sequential high duty cycle wide coverage pulse waveform according to claim 1, characterized in that: The waveform design parameters include the short pulse width τ short , long pulse width τ long , coherent pulse number NP, pulse repetition period T r .

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