Signal optimization method and device

Abstract

The invention relates to a signal optimization method and device. The method comprises the following steps: determining a pulse width required for optimizing a signal according to an observable area of a radar; obtaining the residual effective time of the radar according to the pulse width required by the optimized signal; determining an elevation angle range corresponding to the supplementary area according to the residual effective time; modulating an elevation angle range corresponding to the supplementary area into supplementary sub-pulses, and splicing the supplementary sub-pulses and the original transmitting signal in a time domain to obtain an optimized transmitting signal; and obtaining an optimized echo signal according to the optimized emission signal. According to the technical scheme, the observable area of the radar is analyzed, so that limited pulse energy is accurately positioned to the observable area; and the residual effective time is allocated to the supplementary area through a frequency domain adjustment method, so that the optimized emission signal and echo signal are obtained, imaging can be further carried out according to the optimized echo signal, and optimization of system resources and larger effective imaging breadth are realized.

Description

Technical Field

[0001] The present invention relates to the field of radar signal processing, and in particular to a signal optimization method and device. Background Art

[0002] High-Resolution Wide-Swath (HRWS) imaging has attracted extensive attention in recent years because of its advantages of both high resolution and wide image swath. In co-site radar systems, the inability to receive signals during transmission results in the inability to image certain areas (range blind areas). In the case of a relatively narrow imaging range, the influence of the range blind area can be avoided by appropriate pulse repetition frequency (PRF) design. However, due to the large beam coverage, the imaging range blind area in Time Diverse Array-Synthetic Aperture Radar (TDA-SAR) is unavoidable, and this problem will become more serious under high duty cycle conditions. In addition, the existing frequency scanning radar imaging method ignores the influence of the range blind area and directly designs the signal according to the original desired imaging area. This results in a portion of the radar energy being allocated to the range blind area, resulting in a waste of the limited energy and time resources of the radar system. Summary of the invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a signal optimization method and device.

[0004] According to a first aspect of an embodiment of the present invention, a signal optimization method is provided, the method comprising:

[0005] Determine the pulse width required to optimize the signal based on the radar's observable area;

[0006] Obtaining the remaining effective time of the radar according to the pulse width required by the optimized signal;

[0007] Determine the elevation angle range corresponding to the supplementary area according to the remaining effective time;

[0008] After modulating the elevation angle range corresponding to the supplementary area into a supplementary sub-pulse, the supplementary sub-pulse and the original transmission signal are spliced ​​in the time domain to obtain an optimized transmission signal;

[0009] An optimized echo signal is obtained according to the optimized transmission signal.

[0010] Optionally, before determining the pulse width required for optimizing the signal according to the observable area of ​​the radar, the method further includes:

[0011] Obtaining PRI through a zebra pattern of the radar;

[0012] Obtaining the number of delayed pulses relative to the target's transmitted pulse according to the PRI;

[0013] Obtaining the rising edge time of the echo signal of the target according to the number of delayed pulses;

[0014] An observable area is determined according to the rising edge time.

[0015] Optionally, determining the pulse width required for the optimization signal according to the observable area of ​​the radar includes:

[0016] Obtaining a range frequency bandwidth of the observable area according to the distance frequency of the observable area;

[0017] Obtaining the required time of the observable area according to the range frequency bandwidth of the observable area;

[0018] The pulse width required to optimize the signal is obtained according to the required time of the observable region.

[0019] Optionally, determining the elevation angle range corresponding to the supplementary area according to the remaining effective time includes:

[0020] Obtaining a corresponding supplementary signal bandwidth according to the remaining effective time;

[0021] The elevation angle range corresponding to the supplementary area is determined according to the supplementary signal bandwidth.

[0022] Optionally, the optimized transmission signal is expressed as follows:

[0023]

[0024] Among them, s mnew (t) represents the optimized transmission signal, t represents the fast time, τ m represents the time delay of the mth transmitting element of the radar, T p,i represents the time required for the i-th segment of the observable area, i=1,…,I, I represents the total number of segments of the observable area, rect(·) represents a rectangular window function, exp(·) represents an exponential function, j represents an imaginary unit, T p represents the pulse length, f c represents the carrier frequency, μ represents the modulation frequency;

[0025]

[0026] Among them, T p,q represents the required time of the qth segment of the observable area;

[0027]

[0028] Among them, f rb,i represents the starting distance frequency of the i-th segment of the observable area.

[0029] Optionally, the optimized echo signal is expressed as follows:

[0030]

[0031] Among them, y r (t,t k ) represents the optimized echo signal, M represents the total number of transmitting array elements of the radar, s mnew,i represents the optimized emission signal of the i-th segment of the observable area, τ tr,m represents the time delay between the target, the mth transmitting element and the receiving element.

[0032] Optionally, the signal optimization method further includes:

[0033] Converting the optimized echo signal to the range frequency domain to obtain an optimized echo signal in the range frequency domain;

[0034] The optimized echo signal in the range frequency domain is expressed as follows:

[0035]

[0036] Among them, y r (f r ,t k ) represents the optimized echo signal in the range frequency domain, fr represents the range frequency, represents the radar scanning pattern, B wi represents the frequency bandwidth of the i-th segment of the observable area, f re,i represents the end distance frequency of the i-th segment of the observable area.

[0037] Optionally, the complementary signal bandwidth is expressed as follows:

[0038] B rest =μ·T p,I+1 ;

[0039] Among them, B rest represents the bandwidth of the supplementary signal, μ represents the modulation frequency, T p,I+1 Indicates the remaining effective time, T p,I+1 =T p -T p_new , T p represents the pulse length, T p_newrepresents the pulse width required for the optimization signal.

[0040] According to a second aspect of an embodiment of the present invention, a signal optimization device is provided, the device comprising:

[0041] A pulse width determination module, used to determine the pulse width required for optimizing the signal according to the observable area of ​​the radar;

[0042] An effective time determination module, used to obtain the remaining effective time of the radar according to the pulse width required by the optimization signal;

[0043] An elevation angle determination module, used to determine an elevation angle range corresponding to the supplementary area according to the remaining effective time;

[0044] A transmission signal optimization module, configured to modulate the elevation angle range corresponding to the supplementary area into a supplementary sub-pulse, and then splice the supplementary sub-pulse with the original transmission signal in the time domain to obtain an optimized transmission signal;

[0045] The echo signal optimization module is used to obtain an optimized echo signal according to the optimized transmission signal.

[0046] The technical solution provided by the present invention may include the following beneficial effects:

[0047] Through the above technical scheme, by analyzing the observable area of ​​the radar, the original transmission signal is optimized into a signal with a specific time-frequency structure, so that the limited pulse energy can be accurately located in the observable area; and under the constraint of maintaining the system duty cycle, the remaining effective time is allocated to the supplementary area by adjusting the frequency domain method, thereby obtaining the optimized transmission signal and echo signal, and further imaging can be performed according to the optimized echo signal, thereby achieving optimization of system resources and a larger effective imaging width.

[0048] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0050] Figure 1 It is a schematic diagram of the geometric relationship between a positive side-view TDA-SAR radar platform and a target in a traditional signal model according to an exemplary embodiment.

[0051] Figure 2 The figure is a flow chart of a signal optimization method according to an exemplary embodiment.

[0052] Figure 3 The diagram is a schematic diagram showing optimization of a transmission signal according to an exemplary embodiment.

[0053] Figure 4 It is a schematic diagram showing the geometric relationship between the positive side-view TDA-SAR radar platform and the target in the present invention according to an exemplary embodiment.

[0054] Figure 5a is a schematic diagram of an optimized echo signal in the range-frequency domain according to an exemplary embodiment.

[0055] Figure 5b It is a schematic diagram of a beam main lobe coverage angle corresponding to an optimized echo signal in a range-frequency domain according to an exemplary embodiment.

[0056] Figure 6a It is a schematic diagram of simulation results of an original echo signal according to an exemplary embodiment.

[0057] Figure 6b It is a schematic diagram of simulation results of an original echo signal in the range frequency domain according to an exemplary embodiment.

[0058] Figure 6c According to an exemplary embodiment, a method of k =0 when the distance-frequency profile.

[0059] Figure 6d is a schematic diagram showing the separation result of target 5 in the range frequency domain according to an exemplary embodiment.

[0060] Figure 6e is a schematic diagram of imaging results of target 3 according to an exemplary embodiment.

[0061] Figure 6f is a schematic diagram of imaging results of target 4 according to an exemplary embodiment.

[0062] Figure 6g is a schematic diagram of imaging results of target 5 according to an exemplary embodiment.

[0063] Figure 6h is a schematic diagram of imaging results of a target 6 according to an exemplary embodiment.

[0064] Figure 7 The figure is a block diagram of a signal optimization device according to an exemplary embodiment. DETAILED DESCRIPTION

[0065] In order to facilitate the understanding of the scheme of the present invention, the relevant state of the prior art and the inventive concept of the present invention are first briefly described.

[0066] In the SCORE (Specific Target and Environment Detection in Synthetic Aperture Radar) operating mode, the radar transmits a wide elevation beam and receives a narrow beam, which effectively suppresses the range ambiguity. In addition, the equivalent phase center method uses azimuth multi-channels to effectively increase the signal sampling rate, thereby reducing the system's PRF requirements and enhancing the unambiguous imaging width. In addition, Multiple-Input Multiple-Output-Synthetic Aperture Radar (MIMO-SAR) converts orthogonal signals between multiple channels to further expand the imaging width. Based on the system degrees of freedom (such as space, time, frequency, and coding dimensions), Waveform Diversity Array (WDA) can more effectively separate clutter with range ambiguity. However, due to the limitations of non-ideal orthogonal waveforms, MIMO-SAR imaging performance is poor.

[0067] In order to avoid the influence of MIMO waveforms, HRWS imaging based on coherent waveforms has achieved remarkable results. The Multi-Frequency Sub-Pulse (MFSP) method divides the pulse into multiple sub-pulses, which are separated in the range frequency domain and point each sub-pulse to a different area, achieving ultra-wide strip imaging. Different from the discrete scanning system of sub-pulse space, the elevation time diversity array radar introduces a time delay between channels, enabling the radar to achieve continuous beam scanning within a single pulse and achieve wide coverage in the range direction.

[0068] Since the energy of a single pulse is dispersed over a large area, TDA-SAR requires a larger transmission signal bandwidth to ensure image quality, which also means a higher duty cycle. The problem of blind spots in the imaging distance is more serious, resulting in a waste of the limited energy and time resources of the radar system.

[0069] Figure 1 FIG1 is a schematic diagram of the geometric relationship between the front-view TDA-SAR radar platform and the target in a conventional signal model according to an exemplary embodiment. As shown in FIG1 , the radar uses M transmitting units in the elevation direction and synthesizes a subarray when receiving. The inclination angle of the array installation is The transmission signal delay between adjacent array elements is Δτ, and the time delay of the mth element is τ m =(m-(M+1) / 2)Δτ. Assuming that there is a coordinate (x0, y0) in the scene and the overlooking angle is θ, the signal received by the target can be expressed as:

[0070]

[0071] Where t is the fast time, T p is the pulse length, μ is the modulation frequency, c is the speed of light, and f c is the carrier frequency, rect(·) represents the fast time window function; is the two-way time delay between the target, the mth transmitting element and the receiving element, and R r (t k ) can be expressed as:

[0072]

[0073] Among them, R B represents the shortest slant distance between the radar and the target, v represents the carrier speed, and x0 represents the transmission slant distance between each array element. is the elevation angle of the target. After down-converting the echo and transforming it to the range frequency domain, we can get:

[0074]

[0075] in, is the TDA radar scanning pattern, which can be expressed as:

[0076]

[0077] From the above formula, it can be seen that the angle of the main lobe is coupled with the range frequency, that is, the beam angle changes with the range frequency. When the signal is transmitted at different range frequencies within the pulse duration, the beam will scan accordingly. Relying on the frequency scanning characteristics, wide beam coverage is achieved. In addition, the range frequency corresponding to a specific main lobe angle can be derived, as shown in the following formula:

[0078]

[0079] The two zero points corresponding to the main lobe can be expressed as: 08 / 5

[0080]

[0081] The effective range bandwidth of the target is expressed as:

[0082]

[0083] Based on the intra-pulse beam scanning characteristics and considering the above frequency coupling relationship, a corresponding bandwidth range imaging framework is designed, ignoring the distance blind area factor. In practice, the distance blind area is unavoidable, which will lead to a waste of time and frequency resources. Therefore, the present invention proposes a signal optimization method to solve this technical problem.

[0084] Figure 2 is a flow chart of a signal optimization method according to an exemplary embodiment. Figure 2 As shown, the method comprises the following steps:

[0085] S101. Determine a pulse width required for optimizing a signal according to an observable area of ​​the radar.

[0086] Optionally, before S101, the method may further include:

[0087] Get PRI through the radar's zebra pattern;

[0088] Obtain the number of delayed pulses relative to the target's transmitted pulse according to PRI;

[0089] The rising edge time of the target echo signal is obtained according to the number of delayed pulses;

[0090] The observable area is determined based on the rising edge time.

[0091] It can be understood that, assuming that the lower viewing angle range of the initial desired imaging area is [θ near ,θ far ], the system protection time is T g , then the desired range resolution and azimuth resolution are expressed as ρ r , ρ a We can select the appropriate PRI by taking into account the zebra pattern of the radar system. Then, the number of delayed pulses relative to the target transmitted pulse can be expressed as:

[0092]

[0093] Among them, floor(·) means rounding down to an integer;

[0094] The rising edge time of the target echo can be expressed as:

[0095]

[0096] when satisfy When the relationship is, the corresponding area is the observable area. Therefore, the downward elevation angle of the observable area can be determined, expressed as;

[0097] θ i ∈(θ b,i ,θ e,i );

[0098] Among them, θ i (i=1,…,I) represents the angle in the i-th segment of the continuous observable area, θ b,i and θ e,i They represent the starting and ending angles of the i-th segment of the observable area respectively.

[0099] Optionally, S101 may include:

[0100] The range frequency bandwidth of the observable area is obtained according to the distance frequency of the observable area;

[0101] The required time of the observable area is obtained according to the range frequency bandwidth of the observable area;

[0102] The pulse width required to optimize the signal is obtained based on the desired time of the observable area.

[0103] It can be understood that the distance frequency of the i-th segment mapped to the observable area can be derived as:

[0104] f ri ∈(f rb,i ,f re,i );

[0105] Among them, f rb,i and f re,i They represent the start and end distance frequencies of the i-th segment of the observable area, respectively. The range frequency bandwidth of this area can be expressed as B wi =f re,i -f rb,i , the time required for the i-th segment of the observable area can be expressed as T p,i =B wi / k r , Figure 3 is a schematic diagram showing a transmission signal optimization according to an exemplary embodiment, such as Figure 3 As shown in the figure, after calculating the time width and distance frequency mapping area corresponding to all valid areas of the observable area, the corresponding sub-pulse signals in the fast time domain are connected in series to construct a new signal that only contains the distance frequency mapped to the observable area. At this time, the pulse width required for the optimized signal can be expressed as:

[0106]

[0107] S102. Obtain the remaining effective time of the radar according to the pulse width required by the optimization signal.

[0108] S103: Determine the elevation angle range corresponding to the supplementary area according to the remaining effective time.

[0109] It is understandable that S103 may include:

[0110] Obtaining the corresponding supplementary signal bandwidth according to the remaining effective time;

[0111] The elevation angle range corresponding to the supplementary area is determined according to the supplementary signal bandwidth.

[0112] Therefore, compared with the original system, the proposed method can effectively reduce the required duty cycle while maintaining the same effective illumination area. By maintaining the radar's duty cycle, the remaining effective time of the radar is given by:

[0113] T p,I+1 =T p -T p_new ;

[0114] Then, this part of energy is allocated to the supplementary area and the effective imaging strip width is increased. At this time, the corresponding supplementary signal bandwidth is:

[0115] Brest = μ·(Tp-Tp_new);

[0116] Where μ represents the modulation frequency, T p represents the pulse length, T p_new Indicates the pulse width required to optimize the signal.

[0117] Assume that the initial pitch angle of the supplementary area is θ rest1 , the corresponding elevation angle is It is worth noting that since the effective frequency bandwidth increases with Therefore, in order to ensure that the supplementary area still meets the distance resolution constraint, the area that satisfies θ should be selected. rest1 <θ near Relational To ensure effective irradiation at this angle, the initial distance frequency f of this area rb,I+1 The traditional model calculates that the upper limit of the distance frequency of the supplementary area is f re,I+1 =f rb,I+1 +B rest , then the other angular boundary of the supplementary region is The following relationship must be satisfied:

[0118]

[0119] Then the elevation angle range corresponding to the supplementary area can be expressed as

[0120] S104, after modulating the elevation angle range corresponding to the supplementary area into a supplementary sub-pulse, the supplementary sub-pulse and the original transmission signal are spliced ​​in the time domain to obtain an optimized transmission signal.

[0121] Optionally, the optimized transmission signal is expressed as follows:

[0122]

[0123] Among them, s mnew (t) represents the optimized transmission signal, t represents the fast time, τ mrepresents the time delay of the mth transmitting element of the radar, T p,i represents the time required for the i-th segment of the observable area, i = 1, ..., I, I represents the total number of segments in the observable area, rect(·) represents the rectangular window function, exp(·) represents the exponential function, j represents the imaginary unit, T p represents the pulse length, f c represents the carrier frequency, μ represents the modulation frequency;

[0124]

[0125] Among them, T p,q represents the required time for the qth segment of the observable area;

[0126]

[0127] Among them, f rb,i Represents the start distance frequency of the th segment of the observable area.

[0128] S105. Obtain an optimized echo signal according to the optimized transmission signal.

[0129] Optionally, the optimized echo signal is expressed as follows:

[0130]

[0131] Among them, y r (t,t k ) represents the optimized echo signal, M represents the total number of radar transmitting array elements, s mnew,i represents the optimized emission signal of the i-th segment of the observable area, τ tr,m represents the time delay between the target, the mth transmitting element and the receiving element.

[0132] Optionally, the method may further include:

[0133] Converting the optimized echo signal to the range frequency domain to obtain the optimized echo signal in the range frequency domain;

[0134] The optimized echo signal in the range frequency domain is expressed as follows:

[0135]

[0136] Among them, y r (f r ,t k ) represents the optimized echo signal in the range frequency domain, fr represents the range frequency, represents the radar scanning pattern, B wi represents the frequency bandwidth of the i-th segment of the observable area, f re,iRepresents the end distance frequency of the i-th segment of the observable area.

[0137] Through the above design, limited radar energy can be allocated to specific supplementary areas. Figure 4 FIG. 1 is a schematic diagram showing the geometric relationship between the positive side-view TDA-SAR radar platform and the target in the present invention according to an exemplary embodiment. Figure 4 As shown, accordingly, compared with the original imaging system, the optimized echo signal can effectively expand the imaging width of the system through a flexible energy allocation strategy.

[0138] In one embodiment, the angular beam coupling characteristic enables it to separate echoes from different regions in the range frequency domain. To achieve this, a specific bandpass filter can be constructed in the range frequency domain, as shown below:

[0139]

[0140] Since the echo signals from different regions are only bandpass filtered and windowed in the range frequency domain, the traditional imaging algorithm is still valid. Therefore, the range Doppler imaging algorithm can be used to process the bandpass filtered data. After range compression, range pixel migration correction and azimuth matching, the imaging result can be expressed as:

[0141]

[0142] Where Δf a is the Doppler bandwidth of the target. Then, the bandpass filtering and imaging process is applied to other targets located in different areas, and finally a clear imaging result can be obtained.

[0143] In one implementation, the effectiveness of the present invention is verified by simulation, assuming that the radar operates in a side-view mode, and other system parameters are listed in Table 1.

[0144] Table 1

[0145]

[0146] Then the range blind area map is obtained. In the required large coverage area, the range blind area is inevitable. After considering the azimuth resolution requirements, the PRF is selected as 3395Hz. Therefore, the top-down angle of the observable area is θ1∈(42°,44.395°), θ2∈(45.55°,47.77°), θ3∈(48.74°,50°), accounting for 73.44% of the total observation area. If the original linear frequency modulation (LFM) signal is transmitted, part of the energy will be wasted because the echo data in some areas cannot be received.

[0147] To solve this problem, the corresponding distance-frequency discrete observable region can be obtained as f r1 ∈(-223.05,-168.72)MHz, f r2 ∈(-125.67,-250.59)MHz, f r3 ∈(29.25,144.75)MHz corresponds to a sub-pulse length of T p,i =[8.469,16.017,18.386]μs,(i=1,2,3).T p,4 and B rest They are 36.476μs and 229MHz respectively. The initial downward angle of the supplementary area is selected to be 39°, and the corresponding initial distance frequency is 271.04MHz. Therefore, it can be obtained that the downward viewing angle corresponding to the supplementary finite spectrum under the extended imaging range is θ4∈(35.625°,39°).

[0148] Figure 5a is a schematic diagram of an optimized echo signal in the range frequency domain according to an exemplary embodiment. Figure 5b is a schematic diagram of a beam main lobe coverage angle corresponding to an optimized echo signal in a range frequency domain according to an exemplary embodiment, such as Figure 5a As shown, the designed echo signal is divided into four discrete range-frequency support regions in the range-frequency domain and each frequency domain region corresponds to one of the four observable regions. In addition, the beam pattern corresponding to the optimized signal is obtained, as shown in Figure 5b After time-frequency optimization, the signal design can flexibly allocate limited energy to different observable areas, thereby improving the energy utilization efficiency of the radar system.

[0149] To further illustrate the effectiveness of the proposed method, six objectives can be set. Figure 6a is a schematic diagram of a simulation result of an original echo signal according to an exemplary embodiment. Figure 6b is a schematic diagram of simulation results of an original echo signal in a range frequency domain according to an exemplary embodiment. Figure 6c According to an exemplary embodiment, a method of k = 0 when the distance-frequency profile, Figure 6d is a schematic diagram showing the separation result of target 5 in the range frequency domain according to an exemplary embodiment, Figure 6e is a schematic diagram of imaging results of target 3 according to an exemplary embodiment. Figure 6f is a schematic diagram of imaging results of target 4 according to an exemplary embodiment. Figure 6g is a schematic diagram of imaging results of a target 5 according to an exemplary embodiment. Figure 6h: is a schematic diagram of the imaging result of target 6 according to an exemplary embodiment. The angles of the following five targets are 45.009°, 48.285°, 46.697°, 49.857°, 43.102° and 38° respectively. The first two targets are located in the range blind area. The third, fourth and fifth targets are all located in the observable area, and these three targets are located in different range fuzzy areas. The fifth target is located in the supplementary area. Figure 6a The echo of the original echo signal is shown. Target 1 and Target 2 cannot be effectively received because they are in the range blind zone. It should be noted that even though the theoretical envelope rising edge for Targets 3, 4, and 5 differs by only 25 meters, it is observed that the different targets show obvious range differences due to the range modulation caused by the transmit beam pattern. Figure 6b It can be seen from the figure that after converting the echo signal into the range-frequency domain, targets at different distances occupy different range-frequency regions. This feature can remove gaps in the range-frequency domain because target 4 is located at the edge of the scene. Figure 6c The range-frequency distribution of the azimuth center time is shown, and the frequency domain support region is aligned with the theoretical analysis. Subsequently, the corresponding range-frequency bandpass filter can be constructed to separate the echoes. Figure 6d The separation result of target 5 is shown. After bandpass filtering, the data of target 5 is retained. The other targets are suppressed. Similarly, all these targets can be separated by constructing corresponding filters. Next, imaging processing is performed using an imaging algorithm. Figure 6e-Figure 6h The imaging results of targets 3-6 are shown. After the signal optimization design, the pulse energy is effectively allocated to the observable area. The coverage can be expanded to the area corresponding to target 6, thereby increasing the imaging width. However, due to the waste of energy in the range blind area and the fact that target 6 is not in the originally designated imaging area, the conventional TDA system cannot observe the area where target 6 is located.

[0150] The present invention can flexibly allocate limited pulse energy to the observable area, effectively improving the utilization efficiency of radar resources, and the optimized echo signal can increase the imaging width. The effectiveness of the proposed method is verified through simulation experiments.

[0151] Figure 7 is a block diagram of a signal optimization device according to an exemplary embodiment. Figure 7 , the signal optimization device 700 may include.

[0152] A pulse width determination module 701 is used to determine the pulse width required for the optimization signal according to the observable area of ​​the radar;

[0153] An effective time determination module 702 is used to obtain the remaining effective time of the radar according to the pulse width required by the optimization signal;

[0154] An elevation angle determination module 703 is used to determine an elevation angle range corresponding to the supplementary area according to the remaining effective time;

[0155] The transmission signal optimization module 704 is used to modulate the elevation angle range corresponding to the supplementary area into a supplementary sub-pulse, and then splice the supplementary sub-pulse with the original transmission signal in the time domain to obtain an optimized transmission signal;

[0156] The echo signal optimization module 705 is used to obtain an optimized echo signal according to the optimized transmission signal.

[0157] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0158] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0159] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0160] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A signal optimization method, characterized in that: The method comprises: Determine the pulse width required to optimize the signal based on the radar's observable area; Obtaining the remaining effective time of the radar according to the pulse width required by the optimized signal; Determine the elevation angle range corresponding to the supplementary area according to the remaining effective time; After modulating the elevation angle range corresponding to the supplementary area into a supplementary sub-pulse, the supplementary sub-pulse and the original transmission signal are spliced ​​in the time domain to obtain an optimized transmission signal; An optimized echo signal is obtained according to the optimized transmission signal.

2. The signal optimization method according to claim 1, characterized in that: Before determining the pulse width required for optimizing the signal according to the observable area of ​​the radar, the method further includes: Obtaining PRI through a zebra pattern of the radar; Obtaining the number of delayed pulses relative to the target's transmitted pulse according to the PRI; Obtaining the rising edge time of the echo signal of the target according to the number of delayed pulses; An observable area is determined according to the rising edge time.

3. The signal optimization method according to claim 1, characterized in that: The step of determining the pulse width required for optimizing the signal according to the observable area of ​​the radar comprises: Obtaining a range frequency bandwidth of the observable area according to the distance frequency of the observable area; Obtaining the required time of the observable area according to the range frequency bandwidth of the observable area; The pulse width required to optimize the signal is obtained according to the required time of the observable region.

4. The signal optimization method according to claim 1, characterized in that: The determining, according to the remaining effective time, the elevation angle range corresponding to the supplementary area comprises: Obtaining a corresponding supplementary signal bandwidth according to the remaining effective time; The elevation angle range corresponding to the supplementary area is determined according to the supplementary signal bandwidth.

5. The signal optimization method according to claim 1, characterized in that: The optimized transmission signal is expressed as follows: Among them, s mnew (t) represents the optimized transmission signal, t represents the fast time, τ m represents the time delay of the mth transmitting element of the radar, T p,i represents the time required for the i-th segment of the observable area, i=1,…,I, I represents the total number of segments of the observable area, rect(·) represents a rectangular window function, exp(·) represents an exponential function, j represents an imaginary unit, T p represents the pulse length, f c represents the carrier frequency, μ represents the modulation frequency; Among them, T p,q represents the required time of the qth segment of the observable area; Among them, f rb,i represents the starting distance frequency of the i-th segment of the observable area.

6. The signal optimization method according to claim 5, characterized in that: The optimized echo signal is expressed as follows: Among them, y r (t,t k ) represents the optimized echo signal, M represents the total number of transmitting array elements of the radar, s mnew,i represents the optimized emission signal of the i-th segment of the observable area, τ tr,m represents the time delay between the target, the mth transmitting element and the receiving element.

7. The signal optimization method according to claim 6, characterized in that: The signal optimization method further comprises: Converting the optimized echo signal to the range frequency domain to obtain an optimized echo signal in the range frequency domain; The optimized echo signal in the range frequency domain is expressed as follows: Among them, y r (f r ,t k ) represents the optimized echo signal in the range frequency domain, fr represents the range frequency, represents the radar scanning pattern, B wi represents the frequency bandwidth of the i-th segment of the observable area, f re,i represents the end distance frequency of the i-th segment of the observable area.

8. The signal optimization method according to claim 4, characterized in that: The complementary signal bandwidth is expressed as follows: B rest =μ·T p,I+1 ; Among them, B rest represents the bandwidth of the supplementary signal, μ represents the modulation frequency, T p,I+1 Indicates the remaining effective time, T p,I+1 =T p -T p_new , T p represents the pulse length, T p_new represents the pulse width required for the optimization signal.

9. A signal optimization device, characterized in that: The device comprises: A pulse width determination module, used to determine the pulse width required for optimizing the signal according to the observable area of ​​the radar; An effective time determination module, used to obtain the remaining effective time of the radar according to the pulse width required by the optimization signal; An elevation angle determination module, used to determine an elevation angle range corresponding to the supplementary area according to the remaining effective time; A transmission signal optimization module, configured to modulate the elevation angle range corresponding to the supplementary area into a supplementary sub-pulse, and then splice the supplementary sub-pulse with the original transmission signal in the time domain to obtain an optimized transmission signal; The echo signal optimization module is used to obtain an optimized echo signal according to the optimized transmission signal.

Images