Methods, devices, and storage media for processing monopulse radar echo signals
By using non-uniformly spaced transmit jitter sequences and Pearson correlation coefficient R in monopulse radar to identify and eliminate interference signals, the problems of misjudgment and measurement error caused by interference in traditional monopulse radar are solved, thus improving the accuracy of the radar system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XIAMEN XINNUO ELECTRONICS CO LTD
- Filing Date
- 2023-09-06
- Publication Date
- 2026-07-17
AI Technical Summary
In traditional monopulse radar, the return signal interference from the previous pulse is superimposed on the current sampled signal, causing the radar to misidentify false targets and making distance measurement errors, thus reducing the performance of the radar system.
Using non-equal interval transmit jitter sequences, the correlation between the time series of the target signal and the transmit jitter sequence is calculated using the Pearson correlation coefficient R, thereby identifying and eliminating interference signals from the previous pulse.
It accurately eliminates the interference of the previous pulse echo signal on the target of the current pulse echo signal, avoids the radar's misjudgment of false targets and range measurement errors, and improves the performance of the radar system.
Smart Images
Figure CN117169845B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of radar echo signal processing, and in particular to a method, apparatus, and storage medium for processing single-pulse radar echo signals. Background Technology
[0002] Monopulse radar is a type of precision tracking radar, boasting advantages such as high tracking accuracy, high data acquisition rate, and good anti-jamming performance. However, in traditional monopulse radar, after the radar transmits a pulse signal, subsequent sampling signals may contain not only the echo from the current target but also the return signal from the previous pulse. This echo interference is superimposed on the current sampling signal, leading to misjudgment of false targets and errors in range measurement, thus degrading the performance of the radar system. Summary of the Invention
[0003] Embodiments of the present invention provide a method, apparatus and storage medium for processing single-pulse radar echo signals to identify interference signals caused by the return signal of the previous pulse.
[0004] To achieve the above objectives, one aspect is to provide a signal processing method for a monopulse radar, comprising: transmitting pulses using a predetermined transmission pulse interval time sequence, wherein the transmission pulse interval time sequence is a transmission jitter sequence with unequal intervals; performing target identification on the signal returned from each pulse transmission; and determining that the target signal is an interference signal from the previous pulse when the time sequence of the target signal identified as the same target appearing in each returned signal is related to the transmission jitter sequence.
[0005] Preferably, when the time sequence of the target signal identified as the same target appearing in each returned signal has a predetermined correlation with the transmission jitter sequence, the target signal is determined to be an interference signal from the previous pulse.
[0006] Preferably, when the time sequence of the target signal identified as the same target appearing in each returned signal has a predetermined negative correlation with the transmission jitter sequence, the target signal is determined to be an interference signal from the previous pulse.
[0007] Preferably, in the signal processing method, the transmission pulse intervals in the transmission jitter sequence are all different or at least adjacent transmission pulse intervals are different.
[0008] Preferably, in the signal processing method, the transmission pulse interval time in the transmission jitter sequence is generated by increasing, decreasing or randomly according to the transmission order.
[0009] Preferably, the signal processing method determines whether the targets corresponding to the target signals are the same target based on whether the intensity and / or edge shape characteristics of the target signals are consistent.
[0010] Preferably, in the signal processing method, the time sequence of the target signal appearing in each returned signal is as follows:
[0011] A time series consisting of the time difference between the time when the target signal appears and the time when sampling of the returned signal in each returned signal.
[0012] Preferably, in the signal processing method, the correlation between the time series of the target signal appearing in each returned signal and the transmission jitter sequence is determined by calculating the Pearson correlation coefficient R between the time series of the target signal appearing in each returned signal and the transmission jitter sequence.
[0013] Preferably, in the signal processing method, the correlation is a negative correlation reaching a predetermined level, and determining whether the time sequence of the target signal identified as the same target appearing in each returned signal and the transmission jitter sequence are negatively correlated to a predetermined level includes:
[0014] The Pearson correlation coefficient R between the time series of the target signal appearing in each returned signal and the transmitted jitter sequence is calculated using the following formula:
[0015]
[0016]
[0017] Where N is the length of the sequence, δ is the mean of the time series; i This refers to the i-th time in the time series. PI is the mean of the transmitted jitter sequence. i The interval time of the i-th pulse in the transmit jitter sequence;
[0018] Determine whether the proximity between R and -1 meets a preset proximity condition; if so, determine that the time series and the transmission jitter sequence are negatively correlated to a predetermined degree.
[0019] Preferably, the signal processing method further includes, after determining that the target signal is an interference signal from the previous pulse:
[0020] Eliminate the interference signal.
[0021] On the other hand, a signal processing apparatus for a monopulse radar is provided, including a memory and a processor, wherein the memory stores at least one program, which is executed by the processor to implement the signal processing method as described above.
[0022] In another aspect, a computer-readable storage medium is provided, wherein at least one program is stored therein, the at least one program being executed by the processor to implement the signal processing method as described in any of the above descriptions.
[0023] The above technical solution has the following technical effects:
[0024] The technical solution of this invention provides a novel signal transmission and reception processing method for monopulse radar. Instead of using an equally spaced pulse transmission method, it introduces a variation in the repetition frequency of each transmission. This variation is usually small, forming a transmission jitter sequence. Then, by performing target identification on each returned signal, the interference signal caused by the return signal of the previous pulse is identified in the pulse return signal by utilizing the correlation between the time of occurrence of the interference signal caused by the return signal of the previous pulse in the time sequence of multiple returns and the transmission jitter sequence. This achieves target identification and differentiation in the echo signal.
[0025] Furthermore, it can accurately eliminate the interference signals from the previous pulse echo signal to the target of the current pulse echo signal, avoid the radar's misjudgment of false targets and the measurement error of distance, and improve the performance of the radar system. Attached Figure Description
[0026] Figure 1 This is a schematic flowchart of a signal processing method for a monopulse radar according to an embodiment of the present invention;
[0027] Figure 2 This is a schematic diagram of the pulse repetition interval sequence used in one embodiment of the present invention;
[0028] Figure 3 This is a schematic diagram of the sampling of five echo signals received in one embodiment of the present invention;
[0029] Figure 4 for Figure 3 The diagram shows a target grouping analysis of the echo signal.
[0030] Figure 5 This is a schematic diagram of the signal processing device for a monopulse radar according to an embodiment of the present invention. Detailed Implementation
[0031] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.
[0032] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.
[0033] Example 1:
[0034] Figure 1 This is a schematic flowchart illustrating a signal processing method for a monopulse radar according to an embodiment of the present invention. In this embodiment, the signal processing method for the monopulse radar includes the following steps:
[0035] Pulses are transmitted using a predetermined transmit pulse interval time sequence, wherein the transmit pulse interval time sequence is a transmit jitter sequence with non-equal intervals;
[0036] Target identification is performed on the signal returned from each pulse transmission. When the time sequence of the target signal identified as the same target in each returned signal is related to the transmission jitter sequence, the target signal is determined to be an interference signal from the previous pulse.
[0037] The interference signal from the previous pulse is the interference signal generated by the return signal of the previous pulse. Typically, this interference signal is generated by the signal reflected back from an object outside the measurement range after the previous pulse has been emitted.
[0038] Preferably, in the above-mentioned transmit jitter sequence, the intervals between transmit pulses are all different, or at least the intervals between adjacent transmit pulses are different. In specific implementations, the intervals between transmit pulses in the transmit jitter sequence are generated in ascending, descending, or random order according to the transmit sequence.
[0039] In practice, a transmission jitter sequence is formed by introducing a small change in the repetition frequency of each pulse transmission.
[0040] Preferably, the target signals are determined to be the same target based on the consistency of the target signal intensity and / or edge shape characteristics.
[0041] Preferably, the time sequence of the target signal appearing in each returned signal refers to a time sequence composed of the time difference between the time of appearance of the target signal and the sampling start time of the returned signal in each returned signal. The order of each returned signal corresponds to the order of pulse transmission, and this time sequence corresponds to the return order of the pulse return signals.
[0042] In one possible implementation, the correlation between the time series of target signals identified as the same target appearing in each returned signal and the transmission jitter sequence is approximate. A predetermined correlation is considered to exist between the time series of target signals identified as the same target appearing in each returned signal and the transmission jitter sequence. This predetermined correlation includes a predetermined negative correlation.
[0043] Preferably, the correlation between the time series of target signals identified as the same target appearing in each returned signal and the transmission jitter sequence is measured by the Pearson correlation coefficient R, which is used to measure the linear correlation between the two sets of variables.
[0044] Example 2:
[0045] The signal processing method for a monopulse radar according to another embodiment of the present invention will now be described. This signal processing method for a monopulse radar, i.e., a signal transmission and reception method, includes the following steps:
[0046] Step 1: Set the pulse repetition interval jitter sequence, i.e., the transmit jitter sequence;
[0047] By controlling the pulse repetition interval jitter of the transmitter, pulse transmission is achieved according to the set pulse repetition interval jitter sequence, so that the interval time between pulses is jittered; preferably, the jitter sequence includes a series of tiny pulse interval changes, thereby creating a tiny difference in the interval time between transmitted pulses.
[0048] Figure 2 This is a schematic diagram of the pulse repetition interval sequence used in this example. In this example, the pulse repetition interval sequence is set as follows, with 5 pulses per group: {PI1,PI2,PI3,PI4}. Five pulses are emitted sequentially according to the intervals in this pulse repetition interval sequence. Figure 2 The numbers ①-⑤ represent the pulses transmitted at time t0, t1, t2, t4, and t5, respectively. The transmission time interval (time difference) between t1 and t0 is PI1, between t2 and t1 is PI2, between t3 and t2 is PI3, and between t4 and t3 is PI4.
[0049] Step 2: Record and analyze the return signals, i.e., echo signals, of each received pulse;
[0050] Figure 3 This is a sampling diagram of the five echo signals received in this embodiment. Figure 3 The signals returned from the first five transmissions were sampled to form five echo curves with time and intensity information, namely echo 1 to echo 5, which were then recorded for subsequent analysis. Figure 3 The signal with protruding parts in the echo is the signal reflected back from the detected target, i.e., the target signal. Its height in the curve is related to the distance and size of the target.
[0051] Step 3: Target jitter identification;
[0052] Detect all targets in the echo curve. Figure 3 In this context, one protrusion is considered one target, i.e., one target signal or target pulse. For example... Figure 3 In this example, there are 14 targets in total from the 5 echo signals. These 14 targets are labeled TG1 to TG14 according to the order of their appearance. Figure 4 These 14 targets specifically include TG1 and TG2 in echo 1, TG3, TG4, and TG5 in echo 2, TG6, TG7, and TG8 in echo 3, TG9, TG10, and TG11 in echo 4, and TG12, TG13, and TG14 in echo 5. By analyzing these 14 targets (target signals) according to their intensity and / or edge shape characteristics, targets whose signal intensity and / or edge shape characteristics meet predetermined similarity conditions are identified as the same target. In this example, TG{1,3,6,9,12}, TG{4,7,10,13}, and TG{2,5,8,11,14} are considered the same target and grouped into three groups: A, B, and C. Figure 4 For targets in groups A and C, the time difference between the moment they appear in each echo signal and the initial sampling point (initial sampling time) of that echo signal remains almost constant. Each target in groups A and C can be considered as the same target received within the range after each pulse transmission. In other words, for targets in groups A and C, the times in the time series composed of the time difference between their appearance in each echo signal and the initial sampling point (initial sampling time) of that echo signal are essentially equal; that is, this time series is unaffected by the preceding pulse repetition interval jitter sequence (i.e., the transmission jitter sequence) and is unrelated to the transmission jitter sequence.
[0053] The target in group B did not appear in the first echo, but began to appear in the second echo, and its position in the subsequent echoes changed. The time difference δ between the time when the target in group B appeared in the echo and the time when the echo sampling began was recorded sequentially. iδ1 is the time difference between the appearance time of target TG4 in echo 2 and the start time of sampling of echo 2; δ2 is the time difference between the appearance time of target TG7 in echo 3 and the start time of sampling of echo 3; δ3 is the time difference between the appearance time of target TG10 in echo 4 and the start time of sampling of echo 4; δ4 is the time difference between the appearance time of target TG13 in echo 5 and the start time of sampling of echo 5.
[0054] like Figure 4 It can be seen that the time difference between the time of the target in group B in each echo and the start time of the corresponding echo sampling is jittered, and the time series formed by them is also a jittered sequence, which is referred to here as the receiving jittered sequence.
[0055] Step 3: Calculate the correlation between the received jitter sequence and the transmitted jitter sequence.
[0056] In this embodiment, the Pearson correlation coefficient R is used to represent the correlation between the received jitter sequence and the transmitted jitter sequence. The formula for calculating R is as follows:
[0057]
[0058]
[0059] Where R is the Pearson correlation coefficient between the received jitter sequence and the transmitted jitter sequence, used to measure the linear correlation between the two sets of variables; N is the length of the sequence, i.e., the number of elements in the sequence. The mean of the received jitter sequence mentioned above; δ i To receive the i-th time difference in the jitter sequence; PI is the mean of the transmitted pulse jitter sequence. i is the interval time of the i-th pulse in the transmitted pulse jitter sequence.
[0060] Step 5: Echo signal matching and interference cancellation
[0061] After calculating the correlation coefficient R, its value is used to determine the degree of correlation between the time interval sequence and the jitter sequence. If R is close to -1, it can be considered that the time interval between the appearance of the B group target in each echo and the initial sampling time of that echo is highly negatively correlated with the transmitted jitter sequence. That is, it is assumed that the target signal appearing in each echo of the B group target comes from the return of the previous pulse, i.e., it is an interference signal caused by the return of the previous pulse. In this case, it is eliminated to avoid misjudging false targets.
[0062] In practical implementation, proximity conditions can be preset. By judging whether the proximity between R and -1 reaches the preset proximity conditions, it can be determined whether the two jitter sequences being compared reach a predetermined degree of negative correlation. When the two jitter sequences being compared reach a predetermined degree of negative correlation, the corresponding target signal is determined to be an interference signal, which can be eliminated.
[0063] Preferably, when R = -0.8, the two jitter sequences being compared are determined to have a predetermined degree of negative correlation. In other embodiments, other thresholds or threshold ranges close to -1 besides -0.8 can be set, which will not be elaborated here.
[0064] In this embodiment, for example, the transmit jitter sequence includes four pulse transmission time intervals for five pulse transmissions; in other embodiments, the transmit jitter sequence may include other numbers of pulse transmission time intervals depending on specific requirements, and the present invention does not limit this.
[0065] Example 3:
[0066] The present invention also provides a signal processing device for monopulse radar, such as... Figure 5 As shown, the device includes a processor 501, a memory 502, a bus 503, and a computer program stored in the memory 502 and executable on the processor 501. The processor 501 includes one or more processing cores. The memory 502 is connected to the processor 501 via the bus 503. The memory 502 is used to store program instructions. When the processor executes the computer program, it implements the steps in the above-described method embodiment of Embodiment 1 of the present invention.
[0067] Furthermore, as an executable solution, the signal processing device of the monopulse radar can be a computer unit, which can be a desktop computer, laptop, handheld computer, or cloud server, etc. The computer unit may include, but is not limited to, a processor and memory. Those skilled in the art will understand that the above-described structure of the computer unit is merely an example and does not constitute a limitation on the computer unit. It may include more or fewer components, or combine certain components, or use different components. For example, the computer unit may also include input / output devices, network access devices, buses, etc., and this embodiment of the invention does not limit this.
[0068] Furthermore, as an executable solution, the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor, etc. The processor is the control center of the computer unit, connecting various parts of the entire computer unit via various interfaces and lines.
[0069] The memory can be used to store the computer programs and / or modules. The processor implements various functions of the computer unit by running or executing the computer programs and / or modules stored in the memory and by calling data stored in the memory. The memory may mainly include a program storage area and a data storage area. The program storage area may store the operating system and at least one application program required for a function; the data storage area may store data created based on the use of the mobile phone, etc. In addition, the memory may include high-speed random access memory and may also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.
[0070] Example 4:
[0071] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the method described in the embodiments of the present invention.
[0072] If the modules / units integrated in the computer unit are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), and software distribution media, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.
[0073] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.
Claims
1. A signal processing method for a monopulse radar, characterized in that, include: Pulses are transmitted using a predetermined transmit pulse interval time sequence, wherein the transmit pulse interval time sequence is a transmit jitter sequence with non-equal intervals; Target identification is performed on the signal returned from each pulse transmission. When the time sequence of the target signal identified as the same target in each returned signal is related to the transmission jitter sequence, the target signal is determined to be an interference signal from the previous pulse.
2. The signal processing method according to claim 1, characterized in that, In the transmit jitter sequence, the intervals between transmit pulses are all different or at least the intervals between adjacent transmit pulses are different.
3. The signal processing method according to claim 2, characterized in that, In the transmission jitter sequence, the transmission pulse interval time increases, decreases, or is randomly generated according to the transmission sequence.
4. The signal processing method according to claim 1, characterized in that, Whether the targets corresponding to the target signals are the same target is determined by whether the intensity and / or edge shape characteristics of the target signals are consistent.
5. The signal processing method according to claim 1, characterized in that, The time sequence of the target signal appearing in each returned signal is as follows: A time series consisting of the time difference between the time when the target signal appears and the time when sampling of the returned signal in each returned signal.
6. The signal processing method according to claim 5, characterized in that, The correlation coefficient R between the time series of the target signal appearing in each returned signal and the transmission jitter sequence is calculated to determine whether the time series of the target signal identified as the same target appearing in each returned signal is correlated with the transmission jitter sequence.
7. The signal processing method according to claim 6, characterized in that, The correlation is a negative correlation that reaches a predetermined level. Determining whether the time series of target signals identified as the same target appearing in each returned signal and the transmission jitter sequence have a negative correlation that reaches a predetermined level includes: The Pearson correlation coefficient R between the time series of the target signal appearing in each returned signal and the transmitted jitter sequence is calculated using the following formula: Where N is the length of the sequence, δ is the mean of the time series; i This refers to the i-th time in the time series. PI is the mean of the transmitted jitter sequence. i The interval time of the i-th pulse in the transmit jitter sequence; Determine whether the proximity between R and -1 meets a preset proximity condition; if so, determine that the time series and the transmission jitter sequence are negatively correlated to a predetermined degree.
8. The signal processing method according to claim 1, characterized in that, After determining that the target signal is an interference signal from the previous pulse, the method further includes: Eliminate the interference signal.
9. A signal processing device for a monopulse radar, characterized in that, The system includes a memory and a processor, the memory storing at least one program, which is executed by the processor to implement the signal processing method as described in any one of claims 1 to 8.
10. A computer-readable storage medium, characterized in that, The storage medium stores at least one program, which is executed by the processor to implement the signal processing method as described in any one of claims 1 to 8.