A subarray-level time sequence rotation high-duty-cycle wide-coverage pulse waveform design method

Abstract

The application discloses a kind of subarray level timing round-robin high duty cycle wide coverage pulse waveform design methods, belong to radar detection technical field.The application uses subarray level timing round-robin transmission to improve pulse waveform duty cycle, on the basis of this, through the joint optimization design long-short pulse width, number of coherent pulses, subarray timing round-robin transmission cycle number, the detection range of wide coverage pulse waveform is realized.Problems, such as the degradation of detection power caused by the limitation of ERP when the pulse array radar transmits wide coverage beamforming.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of radar detection, and particularly relates to a subarray-level time sequence rotation high-duty-cycle wide-coverage pulse waveform design method. BACKGROUND

[0002] With the development of science and technology, radars have been applied to detection, communication, reconnaissance and other fields. At present, the design of wide-coverage pulse waveforms is a hotspot in the research of radar waveform design, and a beam pattern with a wide main lobe region can realize wide-range coverage of a target region at the same time, improve the target detection performance of a radar system. In addition, the wide-coverage transmit beam shaping technology can also reduce the detection blind area of the radar system, improve the signal reception efficiency, increase the observation time of the radar on the target, and has other advantages such as improving the data rate. At present, the research of everyone mainly focuses on the low-sidelobe wide-coverage waveform optimization design method, the main lobe high-gain wide-coverage waveform optimization design, and the precise beam shape control.

[0003] However, in order to realize the wide coverage of the beam, the number of array elements will inevitably be reduced, which will cause the limitation of the ERP of the array and thus cause the decline of the detection range. SUMMARY

[0004] The application provides a subarray-level time sequence rotation high-duty-cycle wide-coverage pulse waveform design method, which is mainly used for solving the problem that the detection power is degraded due to the limitation of the ERP when the pulse array radar is in the wide-coverage transmit beam shaping, and can realize the range extension of the low-transmit-power pulse radar detection.

[0005] The technical scheme for realizing the application is as follows: a subarray-level time sequence rotation high-duty-cycle wide-coverage pulse waveform design method, and the specific steps are as follows:

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

[0007] Step 2: setting the initial number of coherent pulses;

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

[0009] Step 4: setting the blind-filling pulse detection margin, determining the upper limit of the long pulse width, and letting the long pulse width be equal to the upper limit of the long pulse width;

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

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

[0012] Step 7: determining the maximum long pulse range according to the radar equation.

[0013] Step 8: Determine the number of subarray time sequence rotation transmission periods according to the number of subarrays, the maximum action distance of long pulse, and the actual pulse repetition period;

[0014] Step 9: Determine the number of coherent pulses according to the number of subarray time sequence rotation transmission periods, and determine the maximum action distance corresponding to the long pulse width according to the radar equation. If the following condition is met:

[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, and R max is the radar maximum action distance index.

[0017] If the condition is not met, go to Step 10, otherwise, increase the initial number of coherent pulses by 1 and go to Step 3.

[0018] Step 10: Output the waveform design parameters.

[0019] Preferably, the specific formula for determining the short pulse width τ short is as follows:

[0020] τ short = 2R min / C

[0021] In the formula, R min is the radar minimum action distance index, and C is the speed of light.

[0022] Preferably, the formula for determining the maximum action distance of the short pulse according to the radar equation is as follows:

[0023]

[0024] In the formula, 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 reception gain, λ is the wavelength, k is the Boltzmann constant, T s is the system input temperature, D x is the detection factor, and L is the system loss.

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

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

[0027] where C is the speed of light, R smax is the maximum range of short pulses, δ Rs is the excess of blind-filling pulse detection, τ short is the pulse width of short pulses.

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

[0029]

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

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

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

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

[0034] Preferably, the maximum range R lmax of long pulses is calculated, and the specific formula is:

[0035]

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

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

[0038]

[0039] where C is the speed of light, F is the number of sub-arrays, R lmax is the maximum range of long pulses, and T r is the actual pulse repetition period.

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

[0041] Preferably, the waveform design parameters include the short pulse width τ. short Long pulse width τ long NP (parametric pulse number) and T (pulse repetition period) r .

[0042] Compared with the prior art, the significant advantages of this invention are:

[0043] 1. In low ERP detection scenarios such as wide-coverage transmission beamforming, detection range can be extended without adopting hardware modification schemes such as increasing radar peak transmission power or increasing transmission duty cycle.

[0044] 2. This invention, combined with a low ERP emission method, has the advantage of covert detection.

[0045] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0046] Figure 1 A block diagram of a subarray-level time-sequential high duty cycle wide coverage pulse waveform design method.

[0047] Figure 2 This is a schematic diagram of a four-subarray long and short pulse transmission waveform arrangement scheme. Detailed Implementation

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

[0049] like Figure 1 As shown, a subarray-level time-sequential high duty cycle wide coverage pulse waveform design method is proposed. This method employs subarray-level time-sequential transmission to increase the pulse waveform duty cycle. Based on this, by jointly optimizing the design of long and short pulse widths, the number of coherent pulses, and the number of time-sequential cycles, the detection range of the wide coverage waveform is extended. A preferred embodiment of this invention includes the following steps:

[0050] Step 1: Based on the radar minimum effective range index 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 phased coherent pulse number N, which can generally be set to N=128 according to the performance specifications of conventional radar;

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

[0054]

[0055] In the formula, P t is the radar transmit power, τ short is the radar short pulse width, G t is the antenna transmit gain, G r is the antenna receive gain, λ is the wavelength, k is the Boltzmann constant, T s is the system input temperature, D x is the detection factor, and L is the system loss.

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

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

[0058] Step 5: Determine the pulse repetition period T max according to the radar transmitter duty cycle upper limit D rmin :

[0059]

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

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

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

[0063]

[0064] In the formula, P t is the radar transmit power, τlong G is the antenna transmit gain, t G is the antenna receive gain, r k is the Boltzmann constant, T is the system input temperature, s D is the system input temperature, x L is the system loss.

[0065] Step 8: According to the number of subarrays F, the maximum action distance R of long pulse, lmax the pulse repetition period T, r these three parameters, determine the subarray timing rotation period number P:

[0066]

[0067] In the formula, C is the speed of light;

[0068] Step 9: Let the number of coherent pulses be NP, R max is the maximum action distance index of the radar, when the number of coherent pulses changes, the detection factor of the radar equation also changes, so according to the radar equation, the long pulse width τ is calculated again long The corresponding maximum action distance R' lmax The long pulse detection margin is δ Rl If it satisfies

[0069] R' lmax -R max > δ Rl (6) Step 10, otherwise let 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 , number of coherent pulses NP, pulse repetition period T r It can be seen that on the basis of maintaining the tracking data rate, the timing rotation high duty cycle waveform can increase the number of target echo coherent pulses, and realize the detection of long-range when the radar ERP is limited.

[0071] Assuming that the number of subarrays is 4, the specific long-short pulse waveform arrangement method can be as shown in Figure 2 .

[0072] The application provides a subarray-level timing round high-duty-cycle wide-coverage pulse waveform design method, and there are many methods and approaches to realize the technical scheme, and the above description is only the preferred embodiment of the application, and it should be pointed out that, for ordinary skilled in the art, some improvements and refinements can be made without departing from the principle of the application, and these improvements and refinements should also be regarded as the protection scope of the application. The components not explicitly described in the embodiment can be realized by using the prior art.

Claims

1. A method for designing a high-duty-cycle wide-coverage pulse waveform in a time-sequential round-robin subarray, characterized in that, The specific steps are as follows: Step 1: determining the short pulse width according to the minimum range of the radar; Step 2: setting the initial number of coherent pulses; Step 3: determining the maximum range of the short pulse according to the radar equation; Step 4: setting the detection margin of the blind filling pulse, determining the upper limit of the long pulse width, and setting the long pulse width equal to the upper limit of the long pulse width; Step 5: determining the pulse repetition period according to the upper limit of the radar transmission channel duty cycle; Step 6: determining the actual pulse repetition period according to the number of subarrays, the short pulse width, and the long pulse width; Step 7: determining the maximum range of the long pulse according to the radar equation; Step 8: determining the number of subarray time sequence round-robin transmission periods according to the number of subarrays, the maximum range of the long pulse, and the actual pulse repetition period; Step 9: determining the number of coherent pulses according to the number of subarray time sequence round-robin transmission periods, and re-determining the maximum range corresponding to the long pulse width according to the radar equation, if the following condition is met: R' lmax - R max > δ Rl where R lmax is the maximum range of the radar Rl is the long pulse detection margin, R max is the radar maximum range index; then turning to Step 10, otherwise setting the initial number of coherent pulses to 1 and turning to Step 3; Step 10: outputting the waveform design parameters.

2. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein determining a short pulse width τ short The specific formula is: τ short = 2R min / C where R min is the radar minimum range index and C is the speed of light.

3. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The formula for determining the maximum range of the short pulse according to the radar equation is: where P t is the radar transmit power, τ short is the radar pulse width, G t is the antenna transmit gain, G r is the antenna receive gain, λ is the wavelength, k is the Boltzmann constant, T s is the system input temperature, D x is the detection factor, and L is the system loss.

4. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The calculation formula of the upper limit of the long pulse width is: τ lmax = 2(R smax - δ Rs ) / C-τ short where C is the speed of light, R smax is the maximum range of the short pulse, δ Rs is the excess of the blind-filling pulse, τ short is the pulse width of the short pulse.

5. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The calculation formula of the pulse repetition period is: where τ short is the short pulse width, τ long is the long pulse width, D max is the radar transmitter duty cycle upper limit.

6. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The actual pulse repetition period T r The calculation formula is: T r = max{F(τ short +τ long ), T rmin} where F is the number of subarrays, τ short is the short pulse width, τ long is the long pulse width, T rmin is the pulse repetition period.

7. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The maximum action distance R of the long pulse is calculated imax The specific formula is: where P t is the radar transmit power, τ long is the radar long pulse width, G t is the antenna transmit gain, G r is the antenna receive gain, λ is the wavelength, k is the Boltzmann constant, T s is the system input temperature, D x is the detection factor, and L is the system loss.

8. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The number of subarray time sequence round-robin transmission periods P is specifically: where C is the speed of light, F is the number of subarrays, R lmax is the maximum range of long pulses, T r is the actual pulse repetition period.

9. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The number of coherent pulses is NP, N is the initial number of coherent pulses, and P is the number of subarray time sequence round-robin transmission periods.

10. The subarray-level timing round-robin high-duty-cycle wide-coverage pulse waveform design method of claim 1, wherein The waveform design parameters include a short pulse width τ short , a long pulse width τ long , a number of coherent pulses NP, a pulse repetition period T r .

Images