CN113391288B - Satellite-borne DBF processing method and device based on multi-path group delay and storage medium - Google Patents
Satellite-borne DBF processing method and device based on multi-path group delay and storage medium Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
- G01S13/90—Radar or analogous systems specially adapted for specific applications for mapping or imaging using synthetic aperture techniques, e.g. synthetic aperture radar [SAR] techniques
Abstract
The application provides a satellite-borne DBF processing method, a device and a storage medium based on multi-path group delay, wherein the method comprises the following steps: carrying out time-varying phase shift weighting processing on initial echo signals received by each channel to obtain first echo signals corresponding to the initial echo signals; determining a target time delay reference point, and determining the number of time delay paths according to the target time delay reference point; determining the multi-path group delay based on the number of the time delay; performing time delay processing on each first echo signal by adopting the multi-path group time delay to obtain multi-path echo signals after time delay processing; and combining the multi-path echo signals to obtain a target echo signal. In the embodiment of the application, time delay processing is carried out on signals after time-varying phase shift weighting processing is carried out on each channel by adopting multi-channel group time delay, and multi-channel echo signals after time delay processing are obtained; and finally, combining the multi-path echo signals to obtain a target echo signal with less energy loss, thereby avoiding the problem of receiving gain attenuation.
Description
Technical Field
The present disclosure relates to the field of radar signal processing technologies, and in particular, to a satellite-borne DBF processing method and apparatus based on multi-channel group delay, and a storage medium.
Background
Synthetic Aperture Radar (SAR for short) is an active microwave remote sensing Radar which utilizes range-direction pulse compression and azimuth-direction doppler effect to perform imaging, and plays a particularly important role in the field of earth observation. Geometric resolution and swath width are two important indicators of SAR systems. However, limited by the minimum antenna area, conventional SAR systems cannot acquire both high resolution and wide swath images.
The distance direction multi-channel technology is combined with Digital Beam Forming (DBF) and is a key technology for overcoming the limitation of minimum antenna area and realizing high-resolution wide swath imaging of a satellite-borne SAR system. The technique adopts time-varying weighting processing to form a high-gain pencil beam which is swept from the near end of a surveying and mapping band to the far end and tracks a pulse signal in real time so as to compensate gain loss caused by small area of a transmitting aperture, and is also called Scan-On-Receive (SCORE). However, the scan center of the DBF-SCORE always points to the beam center at a given time, and the signals transmitted by the SAR system all have a certain pulse width. Therefore, the narrow beam scanning using the DBF process is affected by Pulse Extension Loss (PEL), deteriorates performance of the DBF processor, reduces a signal-to-noise ratio of the SAR system, and introduces a bias into the SAR image, resulting in that the SAR system cannot receive the echo signal with a maximum reception gain.
To mitigate the effects of PEL, a time delay process is introduced in the conventional DBF. And finally, combining the signals of all channels after time delay processing to obtain radar echo data with high receiving gain. When the mapping bandwidth is small, the DBF-SCORE is less affected by PEL. However, as the application demand continuously increases, the requirements of the satellite-borne SAR system on the mapping bandwidth are higher and higher. Thus, the delayer in the conventional DBF is difficult to alleviate the influence of PEL, resulting in performance degradation of the DBF processor and reduction of the receiving gain of the SAR system.
Disclosure of Invention
In view of the foregoing problems in the prior art, the present application provides a satellite-borne DBF processing method, apparatus and storage medium based on multi-way group delay, and the technical solution adopted in the embodiments of the present application is as follows:
in one aspect, an embodiment of the present application provides a satellite-borne DBF processing method based on multi-path group delay, including:
carrying out time-varying phase shift weighting processing on initial echo signals received by each channel to obtain first echo signals corresponding to the initial echo signals;
determining a target time delay reference point, and determining the number of paths of time delay according to the target time delay reference point;
determining multi-path group delay based on the number of paths of the delay;
performing time delay processing on each first echo signal by adopting the multi-path group time delay to obtain multi-path echo signals after time delay processing;
and combining the multi-path echo signals to obtain a target echo signal.
In some embodiments, the performing time-varying phase shift weighting processing on the initial echo signals received by each channel to obtain a first echo signal corresponding to each initial echo signal includes:
determining the angle of each initial echo signal reaching a radar receiving antenna;
determining a time-varying phase shift function for each channel;
and multiplying each initial echo signal by a time-varying phase shift function of a corresponding channel to obtain the first echo signal.
In some embodiments, the determining the target latency reference point includes:
determining an initial optimization interval, and selecting an initial time delay reference point according to the initial optimization interval;
determining a maximum delay difference based on the initial delay reference point;
determining the difference value of the maximum time delay difference at the two ends of the surveying and mapping belt according to the maximum time delay difference;
and circularly adjusting the initial optimization interval according to preset conditions to adjust the time delay reference point until the difference value meets the preset conditions.
In some embodiments, the cyclically adjusting the initial optimization interval according to a preset condition to adjust the time delay reference point until the difference value meets a preset condition includes:
setting a preset threshold value, and setting the difference value to be less than or equal to the preset threshold value to meet a preset condition; and when the difference is larger than the preset threshold, adjusting the initial optimization interval to correspondingly adjust the time delay reference point according to the adjusted optimization interval so as to update the difference, and circularly adjusting the optimization interval so as to enable the difference to be smaller than or equal to the preset threshold.
In some embodiments, the determining, according to the target delay reference point, the number of paths of the delay includes:
and extracting a maximum value from the maximum time delay difference at the two ends of the mapping belt according to the target time delay reference point, and determining the number of the time delay paths based on the maximum value.
In some embodiments, the determining the multi-way group delay based on the number of paths of the delay comprises:
equally dividing the surveying and mapping band into subintervals with corresponding numbers according to the number of the paths of the time delay;
determining a target sub-time delay reference point of each subinterval;
determining an optimized approximate value of the angle in each subinterval according to the target sub-time delay reference point;
and obtaining the multi-path group delay according to each optimized approximate value.
In some embodiments, the performing, by using the multi-channel group delay, a delay process on each of the first echo signals to obtain a multi-channel echo signal after the delay process includes:
performing distance Fourier transform on each first echo signal to obtain a second echo signal corresponding to each first echo signal;
determining a phase shift function of the multi-path group delay according to the multi-path group delay;
and performing time delay processing on the second echo signal by using the phase shift function of the multi-channel group time delay, and performing inverse Fourier transform on the distance to obtain multi-channel echo signals.
In some embodiments, the combining the multiple echo signals to obtain the target echo signal includes:
summing the echo signals of each channel in the multi-channel echo signals to obtain multi-channel delayed echo signals;
and combining the echo signals after the multiple paths of time delay to obtain a target echo signal.
On the other hand, an embodiment of the present application provides a satellite-borne DBF processing apparatus based on multi-way group delay, including:
the first echo signal processing module is configured to perform time-varying phase shift weighting processing on initial echo signals received by each channel to obtain first echo signals corresponding to each initial echo signal;
the system comprises a path number determining module, a time delay control module and a time delay control module, wherein the path number determining module is configured to determine a target time delay reference point and determine the path number of time delay according to the target time delay reference point;
a multi-path group delay determining module configured to determine a multi-path group delay based on the number of paths of the delay;
and the target echo signal processing module is configured to perform time delay processing on each first echo signal by using the multi-channel group time delay to obtain multi-channel echo signals after time delay processing, and combine the multi-channel echo signals to obtain a target echo signal.
The embodiment of the present application further provides an electronic device, which at least includes a memory, a processor and a bus, where the memory stores machine-readable instructions executable by the processor, and when the electronic device runs, the processor and the memory communicate with each other through the bus, and when the machine-readable instructions are executed by the processor, the steps of the method provided in any embodiment of the present application are performed.
Embodiments of the present application further provide a storage medium, which carries one or more programs and when the one or more programs are executed by a processor, implements the steps of the method provided in any of the above embodiments of the present application.
According to the method, time-varying phase shift weighting processing is carried out on initial echo signals received by each channel to form high-gain beams with narrow beam widths; determining a target time delay reference point, and determining the number of paths of time delay according to the target time delay reference point; then determining the multi-path group delay based on the number of the time delay; then, performing time delay processing on each first echo signal by adopting the multi-channel group time delay to obtain multi-channel echo signals after time delay processing; and finally, combining the multi-path echo signals to obtain a target echo signal, thereby avoiding the problem that the performance of a DBF processor is reduced to attenuate the receiving gain, and enabling the SAR system to receive the echo signal with less loss at high gain.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without any creative effort.
Fig. 1 is a flowchart of a multi-way group delay-based satellite-borne DBF processing method according to an embodiment of the present disclosure;
fig. 2 is a schematic flowchart of a multi-way group delay-based satellite-borne DBF processing method according to an embodiment of the present disclosure;
fig. 3 is a block diagram of a satellite-borne DBF processing apparatus based on multi-way group delay according to an embodiment of the present disclosure;
fig. 4 is a schematic structural diagram of an electronic device according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings of the embodiments of the present application. It should be apparent that the described embodiments are only some of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the application without any inventive step, are within the scope of protection of the application.
Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs. As used in this application, the terms "first," "second," and the like do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element or item preceding the word comprises the element or item listed after the word and its equivalent, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.
To maintain the following description of the embodiments of the present application clear and concise, detailed descriptions of known functions and components are omitted.
An embodiment of the present application provides a satellite-borne DBF processing method based on multi-way group delay, as shown in fig. 1 and fig. 2, the method includes the following steps:
s1, performing time-varying phase shift weighting processing on initial echo signals received by each channel to obtain first echo signals corresponding to the initial echo signals;
s2, determining a target time delay reference point, and determining the number of time delay paths according to the target time delay reference point;
s3, determining multi-path group delay based on the number of paths of the delay;
s4, performing time delay processing on each first echo signal by adopting the multi-channel group time delay to obtain multi-channel echo signals after time delay processing;
and S5, combining the multiple echo signals to obtain a target echo signal.
According to the method, the time-varying phase shift weighting processing is carried out on the initial echo signals received by each channel, so that a high-gain beam with narrow beam width is formed; determining a target time delay reference point, and determining the number of paths of time delay according to the target time delay reference point; then determining the multi-path group delay based on the number of paths of the delay; then, performing time delay processing on each first echo signal by adopting the multi-path group time delay to obtain multi-path echo signals after time delay processing; and finally, combining the multiple echo signals to obtain a target echo signal, thereby avoiding the problem of receiving gain attenuation caused by performance reduction of a DBF processor, and enabling the SAR system to receive the echo signal with less loss at high gain.
In some embodiments, the step S1 may be implemented as the following steps:
step S11: and determining the angle of each initial echo signal reaching a radar receiving antenna. In some specific embodiments, the following formula (1) may be used to calculate the angle θ (t) at which each of the initial echo signals reaches the radar receiving antenna at the time t.
In the formula (1), H represents the height of the load platform, R e Representing the radius of the earth, R (t) representing the slant distance at which the beam points to the target within the swath at time t, R (t) = c.t 2, c represents the speed of light, and t ∈ [ t ] near ,t far ]Wherein t is near Representing the echo time, t, corresponding to the near end of the swath far Representing the corresponding echo time at the far end of the swath.
Step S12: a time-varying phase shift function is determined for each channel. For the nth receiving channel, the following formula (2) can be used to determine the time-varying phase shift function w n (t)。
w n (t)＝exp{-j2π·(n-1)·d·sin[θ(t)-β]/λ} (2)
In the formula (2), N =1, \8230;, N, where N represents the number of receiving channels from the direction, d represents the distance between adjacent sub-apertures from the direction, β represents the angle between the normal line of the antenna and the vertical direction, and λ represents the wavelength of the radar carrier.
Step S13: and multiplying each initial echo signal by a time-varying phase shift function of a corresponding channel to obtain the first echo signal. In some specific embodiments, for the nth receiving channel, the following formula (3) may be used to receive the initial echo signal s of the nth channel n (t) time-varying phase shift function w with the nth channel n (t) multiplying to obtain the signal s of the initial echo n (t) the corresponding first echo signal S n (t)。
S n (t)＝s n (t)·w n (t) (3)
In some embodiments, the determining the target time delay reference point in the step S2 may be implemented as the following steps:
step S21: and determining an initial optimization interval, and selecting an initial time delay reference point according to the initial optimization interval. When determining the initial optimization interval, the echo time t of the near end of the surveying and mapping belt is made near Left end time t as interval left Let the echo time t at the far end of the surveying and mapping strip far Right end time t as interval right Then the optimization interval can be represented as (t) left ,t right ). In some embodiments, the optimization interval (t) is determined according to left ,t right ) Can adopt t ref ＝(t left +t right ) Selecting an initial time delay reference point t ref 。
Step S22: and determining the maximum time delay difference based on the initial time delay reference point. In some embodiments, if the SAR system receives the echo signal using N channels, the first channel is taken as a referenceWhen the nth channel has the maximum delay difference, the following formula (4) may be used to calculate the maximum delay difference Δ D of the nth channel N (t)。
In the formula (4), the symbol of taking the absolute value, t ref Indicating the selected reference point of time delay, which can be based on t ref ＝(t left +t right ) /2 calculation of k r Representing the range chirp, θ (t) ref ) Indicating that t is calculated from the function θ (t) ref Angle value of (d), θ' (t) ref ) Representing function θ (t) at t ref The first derivative value of (a).
Step S23: and determining the difference value of the time delay differences at the two ends of the surveying and mapping belt according to the maximum time delay difference. In some embodiments, equation (4) may be used to calculate the maximum delay difference Δ D of the Nth channel at the near end of the swath based on the selected delay reference point N (t near ) And maximum time delay difference deltad at the far end of the swath N (t far ) Then, the difference Δ of the maximum delay differences across the swath for the nth channel with the largest delay difference is determined using equation (5) below.
Δ＝|ΔD N (t near )-ΔD N (t far )| (5)
Step S24: and circularly adjusting the initial optimization interval according to a preset condition to adjust the time delay reference point until the difference value meets the preset condition.
In some specific embodiments, a preset threshold may be preset, and the difference value smaller than or equal to the preset threshold is set to satisfy a preset condition; according to the preset condition, when the difference value is greater than the preset threshold value, adjusting the initial optimization interval (t) left ,t right ) The time of the two ends is adjusted according to the adjusted optimization interval so as to correspondingly adjust the time delay reference point, and the difference value is recalculated according to the adjusted time delay reference point, so that the optimization interval is adjusted in a circulating mannerAnd when the difference value is less than or equal to a preset threshold value, taking the time delay reference point at the moment as a target time delay reference point, thereby determining the target time delay reference point.
In some specific embodiments, a preset threshold δ = 1/(2Q · B) may be set r ) In the formula B r Representing the radar's transmitted signal bandwidth, Q e (2, 100), typically taken as Q =5,
when said difference is greater than a preset threshold, i.e. Δ > δ:
if Δ D N (t near ) Greater than Δ D N (t far ) Let the original region (t) left ,t right ) Inner t left T as a new interval left Let the selected time delay reference point t in the original region ref Time t on the right hand side as new interval right And selecting a new time delay reference point t ref ＝(t left +t right )/2；
If Δ D N (t near ) Less than Δ D N (t far ) Let the original region (t) left ,t right ) Internal selected time delay reference point t ref Is the left end time t of the new interval left Let t in the original interval right T as a new interval right And selecting a new time delay reference point t ref ＝(t left +t right )/2；
Circularly executing the steps S22, S23 and S24 according to the new time delay reference point until the difference is not greater than the preset threshold value, namely delta is not greater than delta, namely the preset condition is met, and then selecting the time delay reference point t at the moment ref Is selected as the target delay reference point.
In the method, the echo signals have different time delays in the surveying and mapping band, for more accurate time delay processing of the echo signals received by each channel, the surveying and mapping band is divided into multiple paths of intervals from the near end to the far end, and then the time delays corresponding to the multiple paths of intervals are respectively calculated to obtain multiple paths of group time delays, and then the echo signals in the corresponding intervals are subjected to time delay processing by utilizing the multiple paths of group time delays, so that the echo signals among the channels have good correlation, and the SAR system is enabled to overcome the influence of pulse expansion loss.
In some embodiments, the determining, according to the target delay reference point, the number of paths of the delay includes: and extracting a maximum value from the maximum time delay difference at the two ends of the mapping belt according to the target time delay reference point, and determining the number of the time delay paths based on the maximum value. In this embodiment, to determine the number of paths of the time delay, the maximum time delay difference Δ D at the near end of the swath is calculated by using the formula (4) N (t near ) And maximum delay difference deltad of the far end N (t far ) From Δ D N (t near ) And Δ D N (t far ) To determine the maximum value DeltaD max Namely:
let Delta D max ＝max{ΔD N (t near ),ΔD N (t far ) Where max { } denotes taking the maximum value, Δ D N (t near ) The maximum time delay difference, delta D, of the Nth receiving channel at the near end obtained by adopting the target time delay reference point N (t far ) And the maximum time delay difference of the Nth receiving channel at the far end obtained by adopting the target time delay reference point is shown.
Then, determining the number of delayed paths K according to the determined maximum value, and enabling
Wherein
Denotes a rounded-down sign, K denotes the number of paths of the delay, η is a variable coefficient and η ∈ (1, 50), and for a general SAR system, η =6 is taken.
In some embodiments, the step S3 may be implemented as the following steps:
step S31: according to the determined number K of paths of the time delay, the surveying and mapping band is equally divided into K subintervals, wherein the time t of the kth subinterval k ∈[t k,start ,t k,end )，t k,start And t k,end Respectively representing the echo time corresponding to the minimum value and the maximum value of theta (t) in the kth subinterval.
Step S32: determining a target sub-interval for each sub-intervalA reference point is extended. Specifically, let t be in the kth sub-interval k,start As the time t near the interval near And let t k,end As the interval remote time t far Obtaining a target sub-time delay reference point of the kth sub-interval by executing the step S2, and enabling the time delay reference point t of the kth sub-interval ref As t ref,k For calculating t within the kth sub-interval according to the function θ (t) ref,k Angle value of theta (t) ref,k ) Where K =1, \ 8230;, K.
Step S33: and determining an optimized approximate value of the angle theta (t) in each subinterval according to the target sub-time delay reference point. Within the kth sub-interval, the following equation (6) may be employed to calculate an approximation θ (t) k (t)。
θ(t)≈θ k (t)＝θ(t ref,k )+θ′(t ref,k )·(t-t ref,k ) (6)
In the formula (6), θ' (t) ref,k ) Representing function θ (t) at t ref,k The first derivative value of (a).
Step S34: according to each optimized approximate value theta k (t) obtaining a multi-way group delay D k,n . In some embodiments, the following equation (7) may be used to determine θ k (t) calculating to obtain the optimized multi-path group delay D k,n 。
In some embodiments, the step S4 may be implemented as the following steps:
step S41: the following formula (8) can be adopted for each first echo signal S n (t) performing a range Fourier transform to obtain frequency domain signals corresponding to each of the first echo signals, i.e. to obtain a second echo signal S n (f)。
S n (f)＝FFT{S n (t)} (8)
FFT { } in the formula represents a distance-to-fourier transform.
Step S42: according to the multi-way group delay D k,n Determining a function H for implementing multi-way group delay k,n (f) .1. The Using the multi-way group delay D using the following equation (9) k,n Calculating to obtain a time delay function H k,n (f)。
In the formula (9), f is the sampling frequency of the radar, c represents the speed of light, k r Indicating the range chirp.
Step S43: using said delay function H k,n (f) For the second echo signal S n (f) And performing time delay processing, and performing inverse Fourier transform on the distance to obtain a plurality of paths of echo signals.
In some embodiments, the delay function H is first utilized by equation (10) k,n (f) For the second echo signal S n (f) Performing time delay processing, namely: by H k,n (f) And belongs to the frequency domain form S of the echo signal in the kth subinterval n (f) Multiplying to obtain a frequency domain signal S after time delay processing k,n (f)。
S k,n (f)＝S n (f)·H k,n (f) (10)
Then, the following formula (11) is adopted to process the time-delayed frequency domain signal S k,n (f) Carrying out range inverse Fourier transform to obtain a multi-path echo signal r k,n (t)。
r k,n (t)＝IFFT{S k,n (f)} (11)
IFFT { } in equation (11) represents inverse fourier transform of the distance.
In some embodiments, the step S5 may be implemented as the following steps:
step S51: and summing the echo signals of each channel in the multi-channel echo signals to obtain multi-channel delayed echo signals. In some specific embodiments, equation (12) may be applied to each channel echo signal r in the kth subinterval k,n (t) summing to obtain echo signal r delayed by kth group k (t) of (d). Processing each channel echo signal in each subinterval in the K subintervals according to the mode, and obtaining K delayed echo signals r 1 (t),…,r k (t),…,r K (t)。
Σ in equation (12) represents a summation sign.
Step S52: for multiple signals r k (t) combining, taking r k (t) at time t k Internal signal, where t k ∈[t k,start ,t k,end )，t k,start And t k,end Respectively representing the echo time corresponding to the minimum value and the maximum value of theta (t) in the kth subinterval. And combining the acquired K paths of delayed echo signals according to the time sequence of each subinterval to finally obtain a radar echo signal r (t) under a high-resolution wide swath, namely obtaining a target echo signal.
Based on the same inventive concept, an embodiment of the present application further provides a satellite-borne DBF processing apparatus based on multi-way group delay, as shown in fig. 3, the processing apparatus includes:
a first echo signal processing module 10, configured to perform time-varying phase shift weighting processing on initial echo signals received by each channel, so as to obtain first echo signals corresponding to each of the initial echo signals;
a path number determining module 20, configured to determine a target time delay reference point, and determine the path number of the time delay according to the target time delay reference point;
a multi-way group delay determining module 30 configured to determine a multi-way group delay based on the number of ways of the delay;
and a target echo signal processing module 40 configured to perform delay processing on each of the first echo signals by using the multi-channel group delay to obtain multi-channel echo signals after the delay processing, and combine the multi-channel echo signals to obtain a target echo signal.
In the multi-path group delay-based satellite-borne DBF processing apparatus in the embodiment of the present application, the configured functional modules can implement the steps of the multi-path group delay-based satellite-borne DBF processing method mentioned in any embodiment of the present application.
An electronic device is further provided in this embodiment of this application, and includes at least a memory 901, a processor 902, and a bus (not shown), where a schematic structural diagram of the electronic device may be as shown in fig. 4, the memory 901 stores machine-readable instructions executable by the processor 902, when the electronic device runs, the processor 902 communicates with the memory 901 through the bus, and the machine-readable instructions, when executed by the processor, perform the steps of the multi-way group delay based on-board DBF processing method provided in any embodiment of this application.
Since the electronic device described in the embodiment of the present application is an electronic device provided with a memory for implementing the multi-path group delay-based satellite-borne DBF processing method disclosed in the embodiment of the present application, a person skilled in the art can understand the structure and the deformation of the electronic device described in the embodiment of the present application based on the multi-path group delay-based satellite-borne DBF processing method described in the embodiment of the present application, and thus, no further description is given here.
The embodiment of the present application further provides a storage medium, where the storage medium carries one or more programs, and when the one or more programs are executed by a processor, the steps of the multi-group delay-based satellite-borne DBF processing method provided in any embodiment of the present application are implemented.
The storage medium in the present embodiment may be contained in an electronic device/system; or may exist alone without being assembled into an electronic device/system. The storage medium carries one or more programs, and when the one or more programs are executed, the steps of the method for processing the satellite-borne DBF based on the multi-way group delay provided by the embodiment of the present application are implemented.
According to embodiments of the present application, the computer readable storage medium may be a non-volatile computer readable storage medium, which may include, for example but is not limited to: a portable computer diskette, a hard disk, a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. Optionally, the specific examples in this embodiment may refer to examples described in any embodiment of this application, and this embodiment is not described herein again. It will be apparent to those skilled in the art that the modules or steps of the present application described above may be implemented by a general purpose computing device, they may be centralized on a single computing device or distributed across a network of multiple computing devices, and alternatively, they may be implemented by program code executable by a computing device, such that they may be stored in a storage device and executed by a computing device, and in some cases, the steps shown or described may be performed in an order different than that described herein, or they may be separately fabricated into individual integrated circuit modules, or multiple ones of them may be fabricated into a single integrated circuit module. Thus, the present application is not limited to any specific combination of hardware and software.
Moreover, although exemplary embodiments have been described herein, the scope thereof includes any and all embodiments based on the present application with equivalent elements, modifications, omissions, combinations (e.g., of various embodiments across), adaptations or alterations. The elements of the claims are to be interpreted broadly based on the language employed in the claims and not limited to examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive. It is intended, therefore, that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims and their full scope of equivalents.
The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more versions thereof) may be used in combination with each other. For example, other embodiments may be used by those of ordinary skill in the art upon reading the above description. In addition, in the above detailed description, various features may be grouped together to streamline the application. This should not be interpreted as an intention that a disclosed feature not claimed is essential to any claim. Rather, subject matter of the present application may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that the embodiments can be combined with each other in various combinations or permutations. The scope of the application should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
The embodiments of the present application have been described in detail, but the present application is not limited to these specific embodiments, and those skilled in the art can make various modifications and modified embodiments based on the concept of the present application, and these modifications and modified embodiments should fall within the scope of the present application.
Claims (8)
1. A satellite-borne DBF processing method based on multi-path group delay comprises the following steps:
performing time-varying phase shift weighting processing on initial echo signals received by each channel to obtain first echo signals corresponding to the initial echo signals;
determining a target time delay reference point, and determining the number of time delay paths according to the target time delay reference point; wherein, include: extracting a maximum value from the maximum time delay difference at the two ends of the mapping belt according to the target time delay reference point, and determining the number of paths of time delay based on the maximum value; wherein the content of the first and second substances,
the determining the target time delay reference point includes:
determining an initial optimization interval, and selecting an initial time delay reference point according to the initial optimization interval;
determining a maximum delay difference based on the initial delay reference point;
determining the difference value of the maximum time delay difference at the two ends of the surveying and mapping belt according to the maximum time delay difference;
circularly adjusting the initial optimization interval according to a preset condition to adjust a time delay reference point until the difference value meets a preset condition;
determining the multi-path group delay based on the number of the time delay;
performing time delay processing on each first echo signal by adopting the multi-path group time delay to obtain multi-path echo signals after time delay processing;
and combining the multi-path echo signals to obtain a target echo signal.
2. The method according to claim 1, wherein the performing time-varying phase shift weighting processing on the initial echo signals received by each channel to obtain a first echo signal corresponding to each initial echo signal comprises:
determining the angle of each initial echo signal reaching a radar receiving antenna;
determining a time-varying phase shift function for each channel;
and multiplying each initial echo signal by the time-varying phase shift function of the corresponding channel to obtain the first echo signal.
3. The method of claim 1, wherein the cyclically adjusting the initial optimization interval according to a preset condition to adjust a time delay reference point until the difference value satisfies a preset condition comprises:
setting a preset threshold value, and setting the difference value smaller than or equal to the preset threshold value as meeting a preset condition; and when the difference is larger than the preset threshold, adjusting the initial optimization interval to correspondingly adjust the time delay reference point according to the adjusted optimization interval so as to update the difference, and circularly adjusting the optimization interval so as to enable the difference to be smaller than or equal to the preset threshold.
4. The method of claim 1, wherein the determining the multi-way group delay based on the number of paths of the delay comprises:
equally dividing the surveying and mapping band into subintervals with corresponding numbers according to the number of the paths of the time delay;
determining a target sub-time delay reference point of each subinterval;
determining an optimized approximate value of the time delay in each subinterval according to the target sub-time delay reference point;
and obtaining the multi-path group delay according to the optimized approximate values.
5. The method of claim 1, wherein the performing, by using the multi-group delay, the delay processing on each of the first echo signals to obtain multi-path echo signals after the delay processing includes:
performing range Fourier transform on each first echo signal to obtain a second echo signal corresponding to each first echo signal;
determining a phase shift function of the multi-path group delay according to the multi-path group delay;
and performing time delay processing on the second echo signal by using the phase shift function of the multi-channel group time delay, and performing distance inverse Fourier transform to obtain a multi-channel echo signal.
6. The method of claim 1 or 4, wherein said combining the multi-path echo signals to obtain a target echo signal comprises:
summing the echo signals of each channel in the multi-channel echo signals to obtain multi-channel delayed echo signals;
and combining the multiple delayed echo signals to obtain a target echo signal.
7. A satellite-borne DBF processing device based on multi-path group delay comprises:
the first echo signal processing module is configured to perform time-varying phase shift weighting processing on initial echo signals received by each channel to obtain first echo signals corresponding to each initial echo signal;
the device comprises a path number determining module, a delay time calculating module and a delay time calculating module, wherein the path number determining module is configured to determine a target delay reference point and determine the path number of the delay according to the target delay reference point; wherein, include: extracting a maximum value from the maximum time delay difference at the two ends of the surveying and mapping belt according to the target time delay reference point, and determining the number of time delay paths based on the maximum value; wherein, the first and the second end of the pipe are connected with each other,
the determining the target time delay reference point includes:
determining an initial optimization interval, and selecting an initial time delay reference point according to the initial optimization interval;
determining a maximum delay difference based on the initial delay reference point;
determining the difference value of the maximum time delay difference at the two ends of the surveying and mapping belt according to the maximum time delay difference;
circularly adjusting the initial optimization interval according to preset conditions to adjust a time delay reference point until the difference value meets the preset conditions;
the multi-path group delay determining module is configured to determine the multi-path group delay based on the number of paths of the delay;
and the target echo signal processing module is configured to perform time delay processing on each first echo signal by adopting the multi-channel group time delay to obtain multi-channel echo signals after the time delay processing, and combine the multi-channel echo signals to obtain a target echo signal.
8. A storage medium carrying one or more programs which, when executed by a processor, perform the steps of the method of any of claims 1-6.
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