Passive remote sensing and reconnaissance integrated detection method based on conical scanning system

Abstract

A passive remote sensing and reconnaissance integrated detection method based on a conical scanning system belongs to the technical field of space microwave remote sensing, and comprises the following steps: carrying out AD acquisition on an intermediate frequency signal output by a multi-band radiometer receiver; carrying out FFT (Fast Fourier Transform) change on the data acquired by the AD to divide the data into a plurality of channels, and carrying out RFI (Radio Frequency Identification) detection on each channel; if the RFI exists in the channel, IFFT and SFFT are sequentially carried out on a channel result with the RFI to obtain channel time-frequency information, parameterized measurement is carried out on the channel time-frequency information to obtain target pulse description word information, and then the target pulse description word information and channel data without RFI detection are packaged and output together. According to the invention, joint detection of satellite-borne microwave radiation detection and electronic reconnaissance is realized, the signal-to-noise ratio of satellite-borne electronic reconnaissance detection is improved, the detection capability is improved, the influence of RFI on the satellite-borne microwave radiometer is reduced, and the high-precision detection capability of a radiometer system is ensured.

Description

Technical Field

[0001] This invention relates to an integrated passive remote sensing reconnaissance detection method based on a conical scanning system, belonging to the field of space microwave remote sensing technology. Background Technology

[0002] Spaceborne microwave radiometers are a type of passive remote sensing technology. They do not emit electromagnetic waves themselves, but passively receive microwave radiation energy from the observed scene and targets. Through inversion, they can then determine the characteristics of the observed scene and targets, typically used for atmospheric, oceanic, and land remote sensing. Spaceborne electronic reconnaissance is also a passive detection technology, primarily receiving electromagnetic signals emitted by ground-based radiation sources (communication, radar, telemetry, and control, etc.) to obtain intelligence information such as the electromagnetic signal characteristic parameters, location, and trajectory of relevant targets. These two types of spaceborne passive detection technologies have become core technologies for Earth observation after decades of development.

[0003] Spaceborne conical scanning radiometers, as the mainstream atmospheric and oceanographic detection equipment, generally employ a large-aperture antenna combined with conical scanning to achieve high-resolution, wide-swath, and high-sensitivity Earth observations. However, current spaceborne electronic reconnaissance payloads utilize interferometers or time-frequency difference techniques, resulting in small antenna equivalent apertures, low signal-to-noise ratios, and limited target detection capabilities, failing to meet the future application requirements for detecting "low-zero-power" radiation sources. Adding electronic reconnaissance capabilities to spaceborne conical scanning radiometers would improve antenna gain, significantly enhancing the performance of electronic reconnaissance methods, enabling the detection of weak targets, and solving the challenge of detecting "low-zero-power" radiation sources. Furthermore, with the development of 5G and 6G communications, spaceborne microwave radiometers face increasing and narrower frequencies of ground-based RFI (radio frequency interference), posing extremely serious challenges. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a passive remote sensing reconnaissance integrated detection method based on conical scanning system, so as to realize the joint detection of spaceborne microwave radiation detection and electronic reconnaissance, improve the signal-to-noise ratio of spaceborne electronic reconnaissance detection, enhance the detection capability, and at the same time reduce the impact of RFI on the spaceborne microwave radiometer, ensuring the high-precision detection capability of the radiometer system.

[0005] The technical solution of this invention is: Firstly, a passive remote sensing reconnaissance integrated detection method based on a conical scanning system, comprising:

[0006] The intermediate frequency signal output from the multi-band radiometer receiver is acquired by analog-to-digital converter (ADC).

[0007] The data acquired by the AD converter is divided into several channels by FFT transformation, and RFI detection is performed on each channel. If RFI interference exists in the channel, the results of the channel with RFI interference are sequentially transformed by IFFT and SFFT to obtain the channel time-frequency information. The channel time-frequency information is then parametrically measured to obtain the target pulse descriptor information. Finally, it is packaged and output together with the channel data without RFI detection.

[0008] Furthermore, the data collected by the AD is S k ={s i}; s i S represents the intermediate frequency signal AD sampling data at the i-th sampling point, where S is s i The k-th sampled data segment sequence, where k is a positive integer, k = 0, 1, 2, ..., M-1, N is the sequence length, and M is the number of data segment sequences.

[0009] Furthermore, the RFI detection method is the angularity method.

[0010] Furthermore, the sharpness value calculated using the aforementioned sharpness method is J = <(SF k,l - <SF k,l >) 4 > / <(SF k,l - <SF k,l >) 2 > 2 Where, <·> represents the expected value of the data, SF k,l For SF k The power spectrum of the detection results in the l-th channel, SF k =FFT(S) k FFT stands for Fourier Transform.

[0011] Furthermore, the IFFT transformation includes: SF for channels with RFI interference. k IFFT analysis was performed to obtain the time-domain sequence ST of the electronic reconnaissance target. k =IFFT(SF k As the data pipeline is processed, the data segments k = 0, 1, 2, ..., M-1 are concatenated end-to-end to obtain the RFI signal pipeline sequence S = {ST}. k}; where SF k Let M be the target time-domain sequence, and M be the total length of the data segment.

[0012] Furthermore, the parameterized measurement includes:

[0013] Set a pulse detection threshold δ, and detect the start time o and end time p of the RFI signal pipeline sequence S that are greater than the threshold δ. Then, the arrival time TOA of the j-th RFI signal is determined. j =o / F S The corresponding pulse width PW j =(po) / F S , where F S Let be the sampling rate of the AD converter; perform FFT spectral analysis on the pipeline sequence S of the RFI signal, and find the index r = index(max(FFT(S))) corresponding to the maximum value of its spectral amplitude, then the carrier CF j =(r-1) / F S RFI signal amplitude PA j =mean(S), obtain the pulse description word (PDW) of the RFI signal. j ={TOA j PW j ,CF j PA j}; j is a natural number, index(·) is the sequence number corresponding to the maximum value in the search sequence ·, r is the sequence number value corresponding to the maximum value, and mean(·) is the mean of the sequence ·.

[0014] Secondly, a passive remote sensing reconnaissance integrated detection system based on a conical scanning system is characterized by comprising:

[0015] The first module is used to perform AD acquisition on the intermediate frequency signal output by the multi-band radiometer receiver and send the AD-acquired data to the second module;

[0016] The second module is used to receive the data collected by the AD converter and divide it into several channels by performing FFT transformation. RFI detection is performed on each channel. If RFI interference exists in the channel, IFFT transformation and SFFT transformation are performed on the channel results with RFI interference in sequence to obtain the channel time-frequency information. The channel time-frequency information is then parametrically measured to obtain the target pulse descriptor information. Finally, it is packaged and output together with the channel data without RFI detection.

[0017] Furthermore, the data collected by the AD is S k ={s i}; s i S represents the intermediate frequency signal AD sampling data at the i-th sampling point, where S is s i The k-th sampled data segment sequence, where k is a positive integer, k = 0, 1, 2, ..., M-1, N is the sequence length, and M is the number of data segment sequences;

[0018] The RFI detection method is the angularity method;

[0019] The sharpness value calculated using the sharpness method is J = <(SF) k,l - <SF k,l >) 4 > / <(SF k,l - <SF k,l >) 2 > 2 Where, <·> represents the expected value of the data, SF k,l For SF k The power spectrum of the detection results in the l-th channel, SF k =FFT(S) k FFT stands for Fourier Transform;

[0020] The IFFT change includes: the SF of the channel where RFI interference is detected. k IFFT analysis was performed to obtain the time-domain sequence ST of the electronic reconnaissance target. k =IFFT(SF k As the data pipeline is processed, the data segments k = 0, 1, 2, ..., M-1 are concatenated end-to-end to obtain the RFI signal pipeline sequence S = {ST}. k}; where SF k Let M be the target time-domain sequence, and M be the total length of the data segment;

[0021] The parametric measurements include:

[0022] Set a pulse detection threshold δ, and detect the start time o and end time p of the RFI signal pipeline sequence S that are greater than the threshold δ. Then, the arrival time TOA of the j-th RFI signal is determined. j =o / F S The corresponding pulse width PW j =(po) / F S , where F S Let be the sampling rate of the AD converter; perform FFT spectral analysis on the pipeline sequence S of the RFI signal, and find the index r = index(max(FFT(S))) corresponding to the maximum value of its spectral amplitude, then the carrier CF j =(r-1) / F S RFI signal amplitude PA j =mean(S), obtain the pulse description word (PDW) of the RFI signal. j ={TOA j PW j ,CF j PA j}; j is a natural number, index(·) is the sequence number corresponding to the maximum value in the search sequence ·, r is the sequence number value corresponding to the maximum value, and mean(·) is the mean of the sequence ·.

[0023] Thirdly, a computer-readable storage medium storing a computer program, characterized in that, when the computer program is executed by a processor, it implements the steps of the passive remote sensing reconnaissance integrated detection method based on a conical scanning system.

[0024] Fourthly, a passive remote sensing reconnaissance integrated detection device based on a conical scanning system includes a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: when the processor executes the computer program, it implements the steps of the passive remote sensing reconnaissance integrated detection method based on a conical scanning system.

[0025] The advantages of this invention compared to the prior art are:

[0026] (1) Based on the spaceborne scanning radiometer, electronic reconnaissance and RFI detection and suppression functions are simultaneously realized, improving the anti-interference capability of the spaceborne microwave radiometer. The conical scanning system spaceborne passive remote sensing reconnaissance integrated detection device consists of an antenna, scanning mechanism, servo controller, feed array, multi-band receiver, integrated acquisition and signal processor, and integrated processor.

[0027] (2) The large-aperture antenna capability of the spaceborne scanning radiometer is utilized to improve the signal-to-noise ratio of electronic reconnaissance and detection, and enhance detection performance. Attached Figure Description

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0029] Figure 1 This is a block diagram illustrating the system principle of the present invention;

[0030] Figure 2 This is a block diagram illustrating the integrated acquisition and signal processor principle of the present invention.

[0031] Figure 3 This is a schematic diagram of the processing flow of the method of the present invention. Detailed Implementation

[0032] To better understand the above technical solutions, the technical solutions of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present invention, rather than limitations on the technical solutions of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0033] The following description, in conjunction with the accompanying drawings, provides a more detailed explanation of the passive remote sensing reconnaissance integrated detection method based on a conical scanning system provided by the embodiments of the present invention. Figure 3 Specific implementation methods may include:

[0034] The intermediate frequency signal output from the multi-band radiometer receiver is acquired by analog-to-digital converter (ADC).

[0035] The data acquired by the AD converter is divided into several channels by FFT transformation, and RFI detection is performed on each channel. If RFI interference exists in the channel, the results of the channel with RFI interference are sequentially transformed by IFFT and SFFT to obtain the channel time-frequency information. The channel time-frequency information is then parametrically measured to obtain the target pulse descriptor information. Finally, it is packaged and output together with the channel data without RFI detection.

[0036] In the solution provided in the embodiments of the present invention, the conical scanning system spaceborne passive remote sensing reconnaissance integrated detection device consists of an antenna, a scanning mechanism, a servo controller, a feed array, a multi-band receiver, an integrated acquisition and signal processor, and a comprehensive processor.

[0037] The servo controller and scanning mechanism enable the antenna and feed array to perform uniform conical scanning.

[0038] The feed array includes C-band (6.9GHz), X-band (10.7GHz), K1-band (18.7GHz), K2-band (23.8GHz), Ka-band (37GHz), and W-band (89GHz);

[0039] The receivers include C-band (6.9GHz), X-band (10.7GHz), K1-band (18.7GHz), K2-band (23.8GHz), Ka-band (37GHz), and W-band (89GHz). All receivers use superheterodyne reception and output intermediate frequency signals.

[0040] like Figure 2 The integrated acquisition and signal processor can acquire and process the intermediate frequency signal output by each receiver, and then send it to the integrated processor.

[0041] The integrated processor can receive the output signals from the integrated acquisition and signal processor, and then organize, package, and send them to the satellite data transmission subsystem.

[0042] The specific implementation method of the conical scanning system spaceborne passive remote sensing integrated detection method is as follows:

[0043] S1. A high-speed AD converter is used to digitize the signal output from the receiver at each frequency of the multi-band radiometer. The acquired signal is S.k ={s i}, where i is

[0044]

[0045] The signal consists of M segment sequences, each segment having a length of N (N is typically 1024), for a total length of M×N.

[0046] S2, for the k-th segment S k ={s i Perform an N-point FFT analysis to obtain SF. k =FFT(S) k ), divided into N channels.

[0047] S3. Perform RFI detection on each channel using the ridge method;

[0048] The preferred solution is as follows:

[0049] Microwave thermal radiation signals from natural scenes are Gaussian white noise, with amplitude values ​​flat in both the time and frequency domains, and both following a Gaussian distribution. For a Gaussian-distributed signal, its kurtosis value should be equal to 3. If radio frequency interference (RFI) is present, its kurtosis value will deviate from 3. Therefore, based on this characteristic, kurtosis values ​​can be calculated in both the time and frequency domains for the intermediate frequency (IF) signal and sub-band segmentation signal from a high-resolution sea surface temperature microwave imager to detect data contaminated by RFI.

[0050] The sharpness value is calculated as follows:

[0051]

[0052] Where <> represents the expected value (mean) of the data, and x is the power spectrum of the detection result in the nth channel.

[0053] Ideally, without radio frequency interference (RF interference), the sharpness value should be 3. When RF interference is present, the sharpness value will deviate from 3. Therefore, data with a sharpness value deviating from 3 by a certain margin are identified as RFI-contaminated data.

[0054] |KK nom |>β K σ K (2)

[0055] Where K is the measured rutance value, K nom This is a preset value, which can be derived from ground testing or internal calibration values ​​(ideally 3), σ K It is the receiver sensitivity, β K It is a scaling factor used to control the false alarm rate of the algorithm.

[0056] S4. If RFI interference exists in the channel, for microwave radiometer signal processing, discard the channel results, retain the channel data for which no RFI was detected, and output them in a package.

[0057] S5. For channels where RFI is detected, the frequency domain will be restored to the time domain sequence via IFFT.

[0058] The preferred solution is as follows:

[0059] SF for discovering RFI channel k IFFT analysis yields a more refined time-domain sequence of electronic reconnaissance targets: ST k =IFFT(SF k As the data pipeline is processed, the pipeline segments k = 1, 2, ..., M are spliced ​​together to obtain the RFI signal pipeline sequence S = {ST}. k}

[0060] S6. Perform parameterized measurement on S to obtain the target pulse descriptor word information (PDW) and output it in a package.

[0061] The preferred solution is as follows:

[0062] Set a pulse detection threshold δ, and detect the start time m and end time n of the RFI signal pipeline sequence S that are greater than the threshold δ. Then, the arrival time TOA of the j-th RFI signal (j is a natural number) is calculated. j =m / F S The corresponding pulse width PW j = (nm) / F S , where F S Let be the sampling rate of the AD converter. For the pipelined RFI signal S, perform FFT spectral analysis. The index r corresponding to the maximum spectral amplitude is r = index(max(FFT(S))). Then the carrier CF... j =(r-1) / F S RFI signal amplitude PA j =mean(S), thus completing the pulse description word (PDW) for the RFI signal. j ={TOA j PW j ,CF j PA j}

[0063] like Figure 1 Based on and Figure 3 With the same inventive concept, the present invention also provides a passive remote sensing reconnaissance integrated detection system based on a conical scanning system, characterized in that it comprises:

[0064] The first module is used to perform AD acquisition on the intermediate frequency signal output by the multi-band radiometer receiver and send the AD-acquired data to the second module;

[0065] The second module is used to receive the data collected by the AD converter and divide it into several channels by performing FFT transformation. RFI detection is performed on each channel. If RFI interference exists in the channel, IFFT transformation and SFFT transformation are performed on the channel results with RFI interference in sequence to obtain the channel time-frequency information. The channel time-frequency information is then parametrically measured to obtain the target pulse descriptor information. Finally, it is packaged and output together with the channel data without RFI detection.

[0066] This invention provides a computer-readable storage medium storing computer instructions that, when executed on a computer, cause the computer to perform... Figure 1 The method described.

[0067] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0068] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0069] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0070] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0071] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0072] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A passive remote sensing reconnaissance integrated detection method based on a conical scanning system, characterized in that, The method comprises the following steps: AD collecting intermediate frequency signals output by a multi-band radiometer receiver; performing FFT change on the AD collected data to divide the data into a plurality of channels, performing RFI detection on each channel, if there is RFI interference in the channel, performing IFFT change and SFFT change on the channel results in which RFI interference exists in sequence to obtain channel time-frequency information, performing parameterized measurement on the channel time-frequency information to obtain target pulse description word information, and then packing the target pulse description word information and channel data in which no RFI is detected and outputting the packed data.

2. The integrated passive remote sensing reconnaissance detection method based on the conical scanning system according to claim 1, characterized in that, The data collected by the AD is S k = {s i}; s i is the intermediate frequency signal AD sampling data at the i th sampling point, S is the s i k th sampling data segment sequence, k is a positive integer, k = 0, 1, 2,..., M-1, N is the sequence length, and M is the number of data segment sequences.

3. The integrated detection method of passive remote sensing reconnaissance based on conical scanning system according to claim 1, characterized in that, The RFI detection method is a sharpness method.

4. The integrated passive remote sensing reconnaissance detection method based on the conical scanning system according to claim 3, characterized in that, The calculated sharpness value using the sharpness method is J = <(SF k,l - <SF k,l >) / <(SF 4 + <SF k,l >); wherein <·> denotes the expected value of the data, SF k,l is the power spectrum of the detection result in the lth channel, SF 2 = FFT(S 2 ), and FFT is the Fourier transform. k,l k k k ​​​​ 5. The integrated detection method of passive remote sensing reconnaissance based on conical scanning system according to claim 1, characterized in that, The IFFT change includes: SF k Performing IFFT analysis to obtain an electronic reconnaissance target time-domain sequence ST k = IFFT(SF k ), and performing head-to-tail splicing on data segments k = 0, 1, 2,..., M-1 to obtain an RFI signal stream sequence S = {ST k}; wherein SF k is the target time-domain sequence, and M is the total length of the data segments.

6. The integrated passive remote reconnaissance detection method based on conical scanning regime according to claim 1, characterized in that, The parameterized measurement comprises: A pulse detection threshold δ is set, and the start time index o and the end time index p of the RFI signal stream sequence S greater than the threshold δ are detected, then the arrival time TOA of the jth RFI signal j = o / F S , the corresponding pulse width PW j = (p-o) / F S , where F S is the sampling rate of the AD; for the RFI signal stream sequence S, FFT spectrum analysis is performed, and the maximum value of the spectrum amplitude corresponds to the index r = index(max(FFT(S))), then the carrier CF j = (r-1) / F S , the RFI signal amplitude PA j = mean(S), and the pulse description word PDW of the RFI signal is obtained j = {TOA j , PW j , CF j , PA j}; j is a natural number, index(·) is the sequence number corresponding to the maximum value in the sequence ·, r is the sequence number value corresponding to the maximum value, and mean(·) is the mean value of the sequence ·.

7. The integrated detection system of passive remote sensing reconnaissance based on conical scanning system, characterized in that, The method comprises the following steps: a first module for AD collecting intermediate frequency signals output by a multi-band radiometer receiver and sending AD collected data to a second module; a second module for receiving AD collected data and performing FFT change to divide the data into a plurality of channels, performing RFI detection on each channel, if there is RFI interference in the channel, performing IFFT change and SFFT change on the channel results in which RFI interference exists in sequence to obtain channel time-frequency information, performing parameterized measurement on the channel time-frequency information to obtain target pulse description word information, and then packing the target pulse description word information and channel data in which no RFI is detected and outputting the packed data.

8. The passive remote sensing reconnaissance integrated detection system based on conical scanning regime according to claim 7, characterized in that, The data collected by the AD is S k = {s i}; s i is the intermediate frequency signal AD sampling data at the i-th sampling point, S is the intermediate frequency signal AD sampling data at the sampling point, s i is the k-th sampling data segment sequence, k is a positive integer, k = 0, 1, 2, …, M-1, N is the sequence length, and M is the number of data segment sequences. The RFI detection method is a sharpness method; The calculated sharpness value using the sharpness method is J = <(SF k,l - <SF k,l ) 4 > / <(SF k,l - <SF k,l ) 2 > 2 ; wherein <·> represents the expected value of the data, SF k,l is the power spectrum of the detection result in the lth channel, SF k = FFT(S k ), and FFT is the Fourier transform. k ​ The IFFT change includes: SF of the channel where the RFI interference is found k An IFFT analysis is performed to obtain an electronic reconnaissance target time-domain sequence ST k k , and with data stream processing, the data segments k=0, 1, 2,...M-1 are spliced at the beginning and the end to obtain an RFI signal stream sequence S={ST k}; wherein SF k is the target time-domain sequence, and M is the total length of the data segments.​ The parameterized measurement comprises: A pulse detection threshold δ is set, and the start time index o and the end time index p of the RFI signal stream sequence S greater than the threshold δ are detected, then the arrival time TOA of the jth RFI signal j = o / F S , the corresponding pulse width PW j = (p-o) / F S , where F S is the sampling rate of the AD; for the RFI signal stream sequence S, FFT spectrum analysis is performed, and the maximum value of the spectrum amplitude corresponds to the index r = index(max(FFT(S))), then the carrier CF j = (r-1) / F S , the RFI signal amplitude PA j = mean(S), and the pulse description word PDW of the RFI signal is obtained j = {TOA j , PW j , CF j , PA j}; j is a natural number, index(·) is the sequence number corresponding to the maximum value in the sequence ·, r is the sequence number value corresponding to the maximum value, and mean(·) is the mean value of the sequence ·.

9. A computer-readable storage medium storing a computer program, the computer program comprising instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1-8. The computer program is executed by the processor to realize the steps of the method according to any one of claims 1-6.

10. An integrated detection device for passive remote sensing reconnaissance based on a conical scanning regime, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, characterized in that: The processor executes the computer program to realize the steps of the method according to any one of claims 1-6.

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