Radio telescope radio frequency interference suppression method and system

Abstract

The present invention relates to a radio telescope radio frequency interference suppression method and system, the method comprising: obtaining a radio astronomy signal received by a radio telescope and at least one baseband interference signal received by a reference antenna; wherein the radio astronomy signal and the at least one baseband interference signal are obtained by synchronous sampling; performing phase correction on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal with the same phase and each corrected baseband interference signal; performing radio frequency interference suppression on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain a radio astronomy signal after radio frequency interference suppression. The radio telescope radio frequency interference suppression method and system of the present invention firstly performs phase correction on the baseband interference signal to make it have the same phase as the radio astronomy signal, and then performs RFI suppression to improve the suppression effect.

Description

Technical Field

[0001] The present invention relates to the field of radio astronomy, and more particularly to a method and system for suppressing radio frequency interference of a radio telescope. Background Art

[0002] Radio Frequency Interference (RFI) refers to other signals other than the expected astronomical signals during radio telescope observations, which may come from communication base stations, artificial satellites, TV broadcast antennas, etc. RFI seriously affects the efficiency of observations. In the process of scientific observations, avoiding RFI is the most direct way to improve the signal-to-noise ratio. The Least Mean Square (LMS) algorithm is one of the most commonly used adaptive filtering algorithms. The tap coefficients of the iterative filter minimize the mean square value of the cost function.

[0003] In order to suppress RFI, the commonly used method is to first measure the baseband interference signal through a reference antenna, and then input the observed radio astronomy signal and the baseband interference signal into the LMS filter to suppress RFI using the LMS algorithm and output the astronomical signal after RFI suppression.

[0004] However, the existing method is to adjust the phase difference between the baseband interference signal and the radio astronomy signal through an LMS filter, and the RFI suppression effect is poor. Summary of the invention

[0005] The object of the present invention is to provide a method and system for suppressing radio frequency interference of a radio telescope, firstly performing phase correction on a baseband interference signal to make it have the same phase as a radio astronomy signal, and then performing RFI suppression to improve the suppression effect.

[0006] Based on the above purpose, the present invention provides a radio telescope radio frequency interference suppression method on one hand, comprising: obtaining a radio astronomy signal received by a radio telescope and at least one baseband interference signal received by a reference antenna; wherein the radio astronomy signal and the at least one baseband interference signal are obtained by synchronous sampling;

[0007] Performing phase correction on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal and each corrected baseband interference signal with the same phase;

[0008] The radio frequency interference suppression is performed on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain the radio astronomy signal after the radio frequency interference suppression.

[0009] Further, phase correction is performed on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal and each corrected baseband interference signal with the same phase, specifically including:

[0010] For each baseband interference signal, obtain a phase offset between the baseband interference signal and the radio astronomy signal;

[0011] The corrected radio astronomy signal and each corrected baseband interference signal are obtained according to the radio astronomy signal, each baseband interference signal and the phase offset between each baseband interference signal and the radio astronomy signal.

[0012] Furthermore, the lengths of the radio astronomy signal and the baseband interference signal are both N;

[0013] The phase offset between the roadbed interference signal and the radio astronomy signal is obtained, specifically including:

[0014] N-1 zeros are filled after N sampling data of the radio astronomy signal, and FFT is performed on the filled radio astronomy signal to obtain the radio astronomy signal after FFT;

[0015] Rearrange the N sampling data of the roadbed band interference signal in reverse order and fill them with N-1 zeros, perform FFT on the filled roadbed band interference signal to obtain a baseband interference signal after FFT;

[0016] The radio astronomy signal after FFT and the roadbed interference signal after FFT are multiplied to obtain a correlation signal;

[0017] Perform IFFT on the relevant signal to obtain 2N-1 time domain data;

[0018] The phase offset between the roadbed band interference signal and the radio astronomy signal is obtained according to 2N-1 time domain data.

[0019] Further, when the at least one baseband interference signal includes only one baseband interference signal, obtaining the corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal, and a phase offset between each baseband interference signal and the radio astronomy signal specifically includes:

[0020] Arrange N sampling data of the radio astronomy signal and the baseband interference signal in sequence according to the sampling time sequence;

[0021] When the phase offset between the baseband interference signal and the radio astronomy signal is positive, outputting sampling data with a sequence number of the phase offset from the N sampling data of the radio astronomy signal as the sampling data of the corrected radio astronomy signal, and outputting the first sampling data from the N sampling data of the baseband interference signal as the sampling data of the corrected baseband interference signal;

[0022] When the phase offset between the baseband interference signal and the radio astronomy signal is negative, the first sampling data is output from the N sampling data of the radio astronomy signal as the sampling data of the corrected radio astronomy signal, and the sampling data whose sequence number is the absolute value of the phase offset is output from the N sampling data of the baseband interference signal as the sampling data of the corrected baseband interference signal.

[0023] Further, when the at least one baseband interference signal includes multiple baseband interference signals, obtaining the corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal, and a phase offset between each baseband interference signal and the radio astronomy signal specifically includes:

[0024] Delaying N sampling data of the radio astronomy signal by N time points, and outputting one data in sequence as the sampling data of the radio astronomy signal after correction;

[0025] According to the phase offset between each baseband interference signal and the radio astronomy signal, sampling data with the same phase as the sampling data of the corrected radio astronomy signal are output from 2N-1 continuous sampling data of each baseband interference signal as the sampling data of each baseband signal after correction.

[0026] Further, when the at least one baseband interference signal includes only one baseband interference signal, performing radio frequency interference suppression on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain the radio astronomy signal after radio frequency interference suppression specifically includes:

[0027] Rearranging the corrected baseband interference signal into a block so that the rearranged baseband interference signal includes a preset number of sampling data;

[0028] According to the rearranged baseband interference signal, a preset filtering algorithm is used to suppress radio frequency interference on the radio astronomy signal to obtain a radio astronomy signal after radio frequency interference suppression;

[0029] When the at least one baseband interference signal includes multiple baseband interference signals, performing radio frequency interference suppression on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain the radio astronomy signal after radio frequency interference suppression specifically includes:

[0030] The corrected baseband interference signals are combined into one to obtain a combined interference signal;

[0031] Rearranging the synthetic interference signal into a block so that the rearranged synthetic interference signal includes a preset number of sampling data;

[0032] According to the rearranged synthetic interference signal, a preset filtering algorithm is used to suppress radio frequency interference on the corrected radio astronomy signal to obtain a radio astronomy signal after radio frequency interference suppression.

[0033] Another aspect of the present invention provides a radio telescope radio frequency interference suppression system, comprising:

[0034] An acquisition module, used to acquire a radio astronomy signal received by a radio telescope and at least one baseband interference signal received by a reference antenna; wherein the radio astronomy signal and the at least one baseband interference signal are obtained by synchronous sampling;

[0035] A phase correction module is used to perform phase correction on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal and each corrected baseband interference signal with the same phase;

[0036] The radio frequency interference suppression module is used to suppress the radio frequency interference of the corrected radio astronomy signal according to each corrected baseband interference signal to obtain the radio astronomy signal after the radio frequency interference is suppressed.

[0037] Furthermore, the phase correction module comprises:

[0038] A phase offset calculation circuit is used to obtain the phase offset between each roadbed band interference signal and the radio astronomy signal;

[0039] The correction circuit is used for obtaining the corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal and the phase offset between each baseband interference signal and the radio astronomy signal.

[0040] Furthermore, the lengths of the radio astronomy signal and the baseband interference signal are both N;

[0041] The phase offset calculation circuit includes at least one calculation unit corresponding to the at least one baseband interference signal, each calculation unit includes a first zero-adding circuit, a first FFT circuit, a reverse order rearrangement circuit, a second zero-adding circuit, a second FFT circuit, a multiplication circuit, an IFFT circuit and an offset circuit, the first zero-adding circuit is used to fill N-1 zeros after N sampling data of the radio astronomy signal, the first FFT circuit is used to perform FFT on the filled radio astronomy signal to obtain the radio astronomy signal after FFT; the reverse order rearrangement circuit is used to add N sampling data of the baseband interference signal corresponding to the calculation unit to the multiplication circuit, and the first FFT circuit is used to perform FFT on the filled radio astronomy signal to obtain the radio astronomy signal after FFT; the reverse order rearrangement circuit is used to add N sampling data of the baseband interference signal corresponding to the calculation unit to the multiplication circuit. The data is rearranged in reverse order, the second zero-adding circuit is used to fill N-1 zeros after the N sampling data after the reverse order is rearranged, the second FFT circuit is used to perform FFT on the filled roadbed band interference signal to obtain the roadbed band interference signal after FFT; the multiplication circuit is used to multiply the radio astronomy signal after FFT and the roadbed band interference signal after FFT to obtain a related signal, the IFFT circuit is used to perform IFFT on the related signal to obtain 2N-1 time domain data, and the offset circuit is used to obtain a phase offset between the roadbed band interference signal and the radio astronomy signal according to the 2N-1 time domain data.

[0042] Further, the correction circuit includes a first N-way selector, a first N-bit shift register, a second N-way selector and a second N-bit shift register, the N bits of the first N-bit shift register respectively store N sampling data of the baseband interference signal, the N bits of the second N-bit shift register respectively store N sampling data of the radio astronomy signal, the N input ends of the first N-way selector are respectively connected to the N bits of the first N-bit shift register, the N input ends of the second N-way selector are respectively connected to the N bits of the second N-bit shift register, the control end of the first N-way selector and the control end of the second N-way selector are both connected to the output end of the offset circuit to receive the phase offset, and the output ends of the first N-way selector and the second N-way selector are respectively connected to the radio frequency interference suppression module; the first N-way selector and the second N-way selector are used to output the corrected baseband interference signal and the corrected radio astronomy signal with the same phase according to the phase offset.

[0043] Further, when the at least one baseband interference signal includes multiple baseband interference signals, the correction circuit includes a third N-bit shift register and multiple third selectors, the multiple third selectors correspond one to one to the multiple baseband interference signals, each third selector includes 2N-1 input terminals, which are respectively connected to the 2N-1 bits of the 2N-1 shift register, the first N-1 bits in the 2N-1 shift register store 0, and the last N bits in the 2N-1 shift register respectively store N sampling data of the baseband interference signal corresponding to the third selector, the control terminal of each third selector is used to receive the phase offset between the baseband interference signal corresponding to the third selector and the radio astronomy signal, and the output terminal of the third selector is connected to the radio frequency interference suppression module to output the corrected sampling data of the baseband interference signal; the N bits of the third N-bit shift register respectively store the N sampling data of the radio astronomy signal, and the radio astronomy signal is fixedly delayed by N time points to be output as the corrected sampling data of the radio astronomy signal.

[0044] Further, when the at least one baseband interference signal includes a baseband interference signal, the radio frequency interference suppression module specifically includes:

[0045] A first rearrangement circuit is used to rearrange the corrected baseband interference signal into one block, so that the rearranged baseband interference signal includes a preset number of sample data;

[0046] A first filter is used to suppress radio frequency interference on the radio astronomy signal by using a preset filtering algorithm according to the rearranged baseband interference signal to obtain a radio astronomy signal after radio frequency interference suppression;

[0047] When the at least one baseband interference signal includes multiple baseband interference signals, the radio frequency interference suppression module specifically includes:

[0048] A synthesis circuit, used for synthesizing the corrected baseband interference signals into one to obtain a synthesized interference signal;

[0049] A second rearrangement circuit is used to rearrange the synthetic interference signal into one block, so that the rearranged synthetic interference signal includes a preset number of sampling data;

[0050] The second filter is used to suppress radio frequency interference on the corrected radio astronomy signal according to the rearranged synthetic interference signal by using a preset filtering algorithm to obtain the radio astronomy signal after radio frequency interference suppression.

[0051] The radio telescope radio frequency interference suppression method and system of the present invention firstly performs phase correction on the baseband interference signal to make it have the same phase as the radio astronomy signal, and then performs RFI suppression on the radio astronomy signal according to the corrected baseband interference signal to improve the suppression effect; after respectively correcting multi-path interference signals in different directions, they are synthesized into one baseband interference signal to obtain a high-quality baseband interference signal, thereby further improving the suppression effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is a flow chart of a radio telescope radio frequency interference suppression method according to an embodiment of the present invention;

[0053] Figure 2 A schematic diagram of a structure for collecting radio astronomy signals and baseband interference signals according to an embodiment of the present invention;

[0054] Figure 3 is a structural block diagram of a radio telescope radio frequency interference suppression system according to another embodiment of the present invention;

[0055] Figure 4 is a schematic diagram of the structure of a phase offset calculation circuit according to an embodiment of the present invention;

[0056] Figure 5 is a schematic structural diagram of an offset circuit according to an embodiment of the present invention;

[0057] Figure 6 is a structural schematic diagram of a correction circuit when there is one baseband interference signal according to an embodiment of the present invention;

[0058] Figure 7 is a schematic diagram of the structure of a correction circuit when the baseband interference signal is multi-path according to an embodiment of the present invention;

[0059] Figure 8 is a structural schematic diagram of a radio frequency interference suppression module when there is one baseband interference according to an embodiment of the present invention;

[0060] Fig. 9 4 is a schematic diagram of the structure of a radio frequency interference suppression module when the baseband interference signal is multi-path according to an embodiment of the present invention. DETAILED DESCRIPTION

[0061] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings and described in detail.

[0062] like Figure 1 As shown, an embodiment of the present invention provides a method for suppressing radio frequency interference of a radio telescope, comprising the following steps:

[0063] S100: Acquire a radio astronomy signal received by a radio telescope and at least one baseband interference signal received by a reference antenna; wherein the radio astronomy signal and the at least one baseband interference signal are obtained by synchronous sampling.

[0064] like Figure 2 As shown, in some embodiments, the radio telescope 10 and the reference antenna 20 are connected to the first ADC sampling circuit 31 and the second ADC sampling circuit 32 respectively, so as to respectively collect the radio astronomy signal and the baseband interference signal through the first ADC sampling circuit 31 and the second ADC sampling circuit 32. The sampling frequencies of the two ADC sampling circuits are the same and are controlled by the same clock signal CLK, so as to obtain synchronized radio astronomy signals and baseband interference signals. The highest frequency f of the radio telescope 10 and the reference antenna 20 is H , minimum frequency f L And the observation bandwidth B are the same.

[0065] According to Nyquist's bandpass sampling theorem, the bandpass signal can be reconstructed with less data after decimation. The number of decimation points M needs to be selected according to the specific frequency parameters. For example, f H =1420MHz, f L When B=1400 MHz and B=20 MHz, M can be 75. That is, one sampling point is extracted from every 75 sampling points, and the signal is reconstructed through the extracted sampling points.

[0066] In some embodiments, the reference antenna 20 can only receive interference signals from one direction, the baseband interference signal includes only one path, and there is only one second ADC sampling circuit 32. In other embodiments, the reference antenna 20 can receive interference signals from multiple different directions, the baseband interference signal includes multiple paths, and there are multiple second ADC sampling circuits 32 to respectively collect the multiple paths of baseband interference signals.

[0067] S200: performing phase correction on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal and each corrected baseband interference signal having the same phase.

[0068] In some embodiments, step S200 specifically includes:

[0069] S210: For each roadbed band interference signal, obtain a phase offset between the roadbed band interference signal and the radio astronomy signal.

[0070] In some embodiments, the length of the radio astronomy signal and each baseband interference signal is N (i.e., includes N time domain sampling data). In order to obtain a true phase offset, the lower bound of N satisfies the following relationship:

[0071]

[0072] Among them, N L Indicates the lower bound of N, S T&R represents the distance between the radio telescope and the reference antenna, c represents the propagation speed of electromagnetic waves in the medium, and f s represents the sampling rate, Indicates rounding up.

[0073] When the baseband interference signal includes only one path, it is only necessary to perform phase offset calculation on the one path of the baseband interference signal; when the baseband interference signal includes multiple paths, it is necessary to perform phase offset calculation on the radio astronomy signal and each path of the baseband interference signal to obtain the phase offset between each path of the baseband interference signal and the radio astronomy signal. In some embodiments, step S210 specifically includes:

[0074] S211: filling N-1 zeros after N sampling data of the radio astronomy signal, and performing FFT (Fast Fourier Transform) on the filled radio astronomy signal to obtain a radio astronomy signal after FFT;

[0075] S212: Rearrange the N sampling data of the roadbed interference signal in reverse order and fill them with N-1 zeros, perform FFT on the filled roadbed interference signal to obtain the roadbed interference signal after FFT;

[0076] S213: multiplying the radio astronomy signal after FFT and the roadbed interference signal after FFT to obtain a correlation signal;

[0077] S214: performing IFFT (i.e., inverse fast Fourier transform) on the correlation signal to obtain 2N-1 time domain data;

[0078] S215: Obtain a phase offset between the roadbed band interference signal and the radio astronomy signal according to the 2N-1 time domain data.

[0079] Specifically, 2N-1 time domain data can be stored in 2N-1 registers respectively, and then any two adjacent time domain data are input into a comparator, and the larger value between the two is output to the next layer for further pairwise comparison, and so on. The comparator at the highest layer can output the largest time domain data, and its corresponding address p can be obtained at the same time. The phase offset offset can be calculated by the following formula:

[0080] offset = N + 1 - p

[0081] In order to obtain the address corresponding to the largest time domain data, a register can be established for each comparator. When the time domain data of the low address bit is larger than the time domain data of the high address bit, the register of the comparator is recorded as 0, otherwise it is recorded as 1. When the highest level comparator obtains the output result, it is indexed from high to low. If the highest level register value is 0, the register value of the second highest level low address bit comparator is read. If the highest level register value is 1, the register value of the second highest level high address bit comparator is read. Then, according to the second highest level register value, the register value of the upper level comparator is read according to the above rules. And so on. The final register value is composed of the register value of the highest level comparator to the register value of the lowest level comparator. The binary number is the address corresponding to the largest time domain data.

[0082] S220: Obtain a corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal, and a phase offset between each baseband interference signal and the radio astronomy signal.

[0083] In some embodiments, when the baseband interference signal includes only one path, step S220 specifically includes:

[0084] S221: Arrange N sampling data of the radio astronomy signal and the baseband interference signal in sequence according to the sampling time sequence;

[0085] S222: when the phase offset between the baseband interference signal and the radio astronomy signal is positive, outputting the sampling data with the sequence number being the phase offset from the N sampling data of the radio astronomy signal as the sampling data of the corrected radio astronomy signal, and outputting the first sampling data from the N sampling data of the baseband interference signal as the sampling data of the corrected baseband interference signal;

[0086] When the phase offset between the baseband interference signal and the radio astronomy signal is negative, the first sampling data is output from the N sampling data of the radio astronomy signal as the sampling data of the corrected radio astronomy signal, and the sampling data whose sequence number is the absolute value of the phase offset is output from the N sampling data of the baseband interference signal as the sampling data of the corrected baseband interference signal.

[0087] When the phase offset is positive, it means that the baseband interference signal is ahead of the radio astronomy signal in phase, and at this time, the first sampling data of the baseband interference signal is the same as the sampling data of the radio astronomy signal whose serial number is the phase offset. When the phase offset is negative, it means that the baseband interference signal is behind the radio astronomy signal in phase, and at this time, the first sampling data of the radio astronomy signal is the same as the sampling data of the baseband interference signal whose serial number is the absolute value of the phase offset. Thus, for every N sampling data, a sampling data of a radio astronomy signal and a sampling data of a baseband interference signal with the same phase can be obtained, and after multiple acquisitions, multiple sampling data with the same phase can be obtained, thereby obtaining a corrected radio astronomy signal and a corrected baseband interference signal including multiple sampling data with the same phase.

[0088] When the baseband interference signal is multi-path, step S220 specifically includes:

[0089] S223: delaying N sampling data of the radio astronomy signal by N time points and outputting one data in sequence as the sampling data of the radio astronomy signal after correction;

[0090] S224: Outputting sampling data having the same phase as the sampling data of the corrected radio astronomy signal from 2N-1 consecutive sampling data of each baseband interference signal according to the phase offset between each baseband interference signal and the radio astronomy signal as the sampling data of each baseband signal after correction.

[0091] S300: performing radio frequency interference suppression on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain a radio astronomy signal after radio frequency interference suppression.

[0092] When the baseband interference signal includes only one path, step S300 specifically includes:

[0093] S310: rearrange the corrected baseband interference signal into a block, so that the rearranged baseband interference signal includes a preset number of sample data;

[0094] S320: According to the rearranged baseband interference signal, a preset filtering algorithm is used to suppress radio frequency interference on the radio astronomy signal to obtain a radio astronomy signal after radio frequency interference suppression.

[0095] In some embodiments, the preset filtering algorithm is a fast block LSM algorithm, which can be implemented by a fast block LSM filter. Specifically, the rearranged baseband interference signal and the radio astronomy signal can be input into the fast block LSM filter so that it outputs the radio astronomy signal after radio frequency interference suppression. The preset number is L+M, where L is the length of the block and M is the order of the fast block LSM filter. The fast block LMS algorithm uses Fourier transform instead of matrix multiplication on the basis of the LMS algorithm, which effectively reduces the amount of multiplication operations. For example, when L and M are both 512, the amount of calculation using the fast block LMS algorithm is about 9 times less than that of the traditional LSM algorithm. When filtering with the fast block LMS algorithm, the input is L+M sampling data of the baseband interference signal and L sampling data of the radio astronomy signal, wherein the first L sampling data of the baseband interference signal and the L sampling data of the radio astronomy signal have the same phase, and the other M sampling data are the M sampling data immediately following the L sampling data, which will be used as part of the L sampling data in the next calculation to suppress radio frequency interference of the corrected radio astronomy signal of the next period again; the L+M sampling data of the baseband interference signal will obtain L data after a series of processing, and then the L sampling data of the radio astronomy signal obtained after the processing are subtracted from the L data of the baseband interference signal to obtain the radio astronomy signal after radio frequency interference suppression.

[0096] When the baseband interference signal includes multiple paths, step S300 specifically includes:

[0097] S330: Combining the corrected baseband interference signals into one to obtain a composite interference signal;

[0098] S340: rearrange the synthetic interference signal into a block, so that the rearranged synthetic interference signal includes a preset number of sample data;

[0099] S350: According to the rearranged synthetic interference signal, a preset filtering algorithm is used to suppress radio frequency interference on the corrected radio astronomy signal to obtain a radio astronomy signal after radio frequency interference suppression.

[0100] Since the corrected synthetic interference signal is synthesized by multiple interference signals from different directions, the interference signals from different directions can be suppressed, and the RFI suppression effect is better.

[0101] In some embodiments, the radio telescope RF interference suppression method of the present invention can be applied to FPGA (field programmable gate array) to avoid applying it to GPU, thereby avoiding transmitting baseband interference signals to GPU and reducing the amount of data transmission.

[0102] The radio telescope radio frequency interference suppression method of the embodiment of the present invention first performs phase correction on the baseband interference signal to make it the same phase as the radio astronomy signal, and then suppresses the RFI of the radio astronomy signal according to the corrected baseband interference signal to improve the suppression effect; after correcting multiple interference signals in different directions respectively, they are synthesized into one synthetic interference signal to obtain a high-quality interference signal, thereby further improving the suppression effect.

[0103] like Figure 3 As shown, another embodiment of the present invention provides a radio telescope radio frequency interference suppression system, including an acquisition module 410, a phase correction module 420 and a radio frequency interference suppression module 430.

[0104] The acquisition module 410 is used to acquire the radio astronomy signal received by the radio telescope and at least one baseband interference signal received by the reference antenna; wherein the radio astronomy signal and the at least one baseband interference signal are obtained by synchronous sampling.

[0105] The phase correction module 420 is used to perform phase correction on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal and each corrected baseband interference signal with the same phase.

[0106] The radio frequency interference suppression module 430 is used to suppress radio frequency interference on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain the radio astronomy signal after radio frequency interference suppression.

[0107] The phase correction module 420 includes a phase offset calculation circuit 421 and a correction circuit 422. The phase offset calculation circuit 421 is used to obtain the phase offset between each baseband interference signal and the radio astronomy signal. The correction circuit 422 is used to obtain the corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal, and the phase offset between each baseband interference signal and the radio astronomy signal.

[0108] Since the radio astronomy signal and the baseband interference signal are used for both the phase shift calculation circuit 421 and the correction circuit 422, a plurality of beam splitters can be used to divide the same radio astronomy signal into a plurality of identical radio astronomy signals, and each baseband interference signal can be divided into a plurality of identical baseband interference signals of the same path, so as to be input into the phase shift calculation circuit 421 and the correction circuit 422 respectively.

[0109] like Figure 4As shown, the phase offset calculation circuit 421 includes at least one calculation unit corresponding to at least one baseband interference signal, and each calculation unit includes a first zero-adding circuit 4211, a first FFT circuit 4212, a reverse order rearrangement circuit 4213, a second zero-adding circuit 4214, a second FFT circuit 4215, a multiplication circuit 4216, an IFFT circuit 4217 and an offset circuit 4218. The first zero-adding circuit 4211 is used to fill N-1 zeros after N sampling data of the radio astronomical signal, and the first FFT circuit 4212 is used to perform FFT on the filled radio astronomical signal to obtain the radio astronomical signal after FFT; the reverse order rearrangement circuit 4213 is used to add the zeros corresponding to the calculation unit The N sampling data of the corresponding baseband interference signal are rearranged in reverse order, the second zero-adding circuit 4214 is used to fill N-1 zeros after the N sampling data after the reverse order is rearranged, and the second FFT circuit 4215 is used to perform FFT on the filled baseband interference signal to obtain the baseband interference signal after FFT; the multiplication circuit 4216 is used to multiply the radio astronomy signal after FFT and the baseband interference signal after FFT to obtain a related signal, the IFFT circuit 4217 is used to perform IFFT on the related signal to obtain 2N-1 time domain data, and the offset circuit 4218 is used to obtain the phase offset between the baseband interference signal and the radio astronomy signal according to the 2N-1 time domain data.

[0110] like Figure 5 As shown, in some embodiments, the offset circuit 4218 may include 2N-1 registers, each register storing a time domain data, for example, the first register stores the time domain data r 0 , the Nth register stores the time domain data r N-1 , the N+1th register stores the time domain data r N , the 2N-1th register stores the time domain data r 2N-2 Any two adjacent registers are connected to a comparator MAX, and any two adjacent time domain data are input into a comparator MAX. The larger value between the two is output to multiple comparators of the next layer for pairwise comparison, and so on. The comparator MAX of the highest layer can output the largest time domain data, and its corresponding address p can be obtained at the same time. The phase offset offset can be calculated from p.

[0111] In order to obtain the address corresponding to the maximum time domain data, a register can be established for each comparator MAX. When the time domain data of the low address bit is larger than the time domain data of the high address bit, the register of the comparator MAX is recorded as 0, otherwise it is recorded as 1. When the highest-level comparator obtains the output result, it is indexed from high to low. If the highest-level register value is 0, the register value of the second-highest-level low-address comparator is read. If the highest-level register value is 1, the register value of the second-highest-level high-address comparator is read. Then, according to the second-highest-level register value, the register value of the upper-level comparator is read according to the above rules, and so on (for example, according to Figure 5 The red arrow in the middle) is finally composed of the register value of the highest level comparator to the register value of the lowest level comparator. The binary number is the address corresponding to the largest time domain data.

[0112] like Figure 6 As shown, when the baseband interference signal includes only one path, the correction circuit 422 may include a first N-path selector 4221, a first N-bit shift register 4222, a second N-path selector 4223 and a second N-bit shift register 4224, the N bits of the first N-bit shift register 4222 respectively store N sampling data of the baseband interference signal, the N bits of the second N-bit shift register 4224 respectively store N sampling data of the radio telescope signal, the N input ends of the first N-path selector 4221 are respectively connected to the N bits of the first N-bit shift register 4222, the N input ends of the second N-path selector 4223 are respectively connected to the N bits of the second N-bit shift register 4224, the control end of the first N-path selector 4221 and the control end of the second N-path selector 4223 are both connected to the output end of the offset circuit 4218 to receive the phase offset, and when the phase offset offset is positive, the first N-path selector 4221 outputs the bit numbered 0000 in the first N-bit shift register 4222. The first N-way selector 4221 outputs the sampling data of the bit numbered as the phase offset in the second N-bit shift register 4224 as the corrected radio astronomy signal. When the phase offset is negative, the first N-way selector 4221 outputs the sampling data of the bit numbered as the phase offset in the first N-bit shift register 4222 as the corrected baseband interference signal, and the second N-way selector 4223 outputs the sampling data of the bit numbered as 0000 in the second shift register 4224 as the corrected radio astronomy signal. The corrected baseband interference signal and the corrected radio astronomy signal have the same phase. The output end of the first N-way selector 4221 and the output end of the second N-way selector 4223 are both connected to the radio frequency interference suppression module 430, so that the radio frequency interference suppression module 430 performs RFI suppression on the corrected radio astronomy signal according to the corrected baseband interference signal to obtain the radio astronomy signal after RFI suppression.

[0113] like Figure 7 As shown, when the baseband interference signal includes multiple channels, the correction circuit 422 includes a third N-bit shift register 4225 and a plurality of third selectors 4226. The plurality of third selectors 4226 correspond to the multiple baseband interference signals one by one. Each third selector 4226 includes 2N-1 input terminals, which are respectively connected to the 2N-1 shift register 4227. The first N-1 bits (numbered 0001 to N-1) in the 2N-1 shift register 4227 store 0, and the last N bits in the 2N-1 shift register 4227 store 0. The bits (numbered -N+1 to 0000) respectively store N sampling data of a baseband interference signal corresponding to the third selector 4226, and the control end of each third selector 4226 is used to receive the phase offset between the baseband interference signal corresponding to the third selector 4226 and the radio astronomy signal; the third N-bit shift register 4225 respectively stores N sampling data of the radio astronomy signal, and makes the radio astronomy signal output after a fixed delay of N moments as the sampling data of the corrected radio astronomy signal. When the phase offset offset is a negative number, the baseband interference signal lags behind the radio astronomy signal, and the third selector 4226 outputs the sampling data of the bit numbered as the phase offset offset in the 2N-1 bit shift register 4227; when the phase offset offset is a positive number, the baseband interference signal lags behind the radio astronomy signal, and the third selector 4226 outputs the sampling data of the bit numbered as the phase offset offset in the 2N-1 bit shift register 4227 as the sampling data of the corrected baseband interference signal.

[0114] like Figure 8 As shown, when the baseband interference signal includes only one path, the radio frequency interference suppression module 430 includes a first rearrangement circuit 431 and a first filter 432. The first rearrangement circuit 431 is used to rearrange the corrected baseband interference signal into one block, so that the rearranged baseband interference signal includes a preset number of sampling data. The first filter 432 is used to suppress radio frequency interference on the radio astronomy signal according to the rearranged baseband interference signal using a preset filtering algorithm to obtain the radio astronomy signal after radio frequency interference suppression.

[0115] like Fig. 9As shown, when the baseband interference signal includes multiple channels, the radio frequency interference suppression module 430 includes a synthesis circuit 433, a second rearrangement circuit 434 and a second filter 435. The synthesis circuit 433 is used to synthesize the corrected baseband interference signals into one channel to obtain a synthesized interference signal. The second rearrangement circuit 434 is used to rearrange the synthesized interference signal into one block so that the rearranged synthesized interference signal includes a preset number of sampling data. The second filter 435 is used to suppress radio frequency interference on the corrected radio astronomy signal according to the rearranged synthesized interference signal using a preset filtering algorithm to obtain a radio astronomy signal after radio frequency interference suppression.

[0116] In some embodiments, both the first filter 432 and the second filter 436 may be fast block LSM filters.

[0117] In some embodiments, the radio telescope RF interference suppression system of the present invention can be applied to FPGA.

[0118] The radio telescope radio frequency interference suppression system of the embodiment of the present invention first performs phase correction on the baseband interference signal to make it the same phase as the radio astronomy signal, and then suppresses the RFI of the radio astronomy signal according to the corrected baseband interference signal to improve the suppression effect; after correcting multiple interference signals in different directions respectively, they are synthesized into one baseband interference signal to obtain a high-quality baseband interference signal, thereby further improving the suppression effect.

[0119] Each embodiment of the present invention is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0120] The above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. The above embodiment of the present invention can also be modified in various ways. That is, all simple, equivalent changes and modifications made according to the claims and the description of the present invention fall within the scope of protection of the claims of the present invention. The contents not described in detail in the present invention are all conventional technical contents.

Claims

1. A radio telescope radio frequency interference suppression method, characterized in that: include: Acquire a radio astronomy signal received by a radio telescope and at least one baseband interference signal received by a reference antenna; wherein the radio astronomy signal and the at least one baseband interference signal are obtained by synchronous sampling; Performing phase correction on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal and each corrected baseband interference signal with the same phase; Performing radio frequency interference suppression on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain a radio astronomy signal after radio frequency interference suppression; Phase correction is performed on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal with the same phase and each corrected baseband interference signal, specifically including: For each baseband interference signal, obtain a phase offset between the baseband interference signal and the radio astronomy signal; Obtaining a corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal, and a phase offset between each baseband interference signal and the radio astronomy signal; The lengths of the radio astronomy signal and the baseband interference signal are both N; The phase offset between the roadbed interference signal and the radio astronomy signal is obtained, specifically including: N-1 zeros are filled after N sampling data of the radio astronomy signal, and FFT is performed on the filled radio astronomy signal to obtain the radio astronomy signal after FFT; Rearrange the N sampling data of the roadbed band interference signal in reverse order and fill them with N-1 zeros, perform FFT on the filled roadbed band interference signal to obtain a baseband interference signal after FFT; The radio astronomy signal after FFT and the roadbed interference signal after FFT are multiplied to obtain a correlation signal; Perform IFFT on the relevant signal to obtain 2N-1 time domain data; Obtaining the phase offset between the roadbed band interference signal and the radio astronomy signal according to 2N-1 time domain data; When the at least one baseband interference signal includes only one baseband interference signal, obtaining the corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal, and a phase offset between each baseband interference signal and the radio astronomy signal specifically includes: Arrange N sampling data of the radio astronomy signal and the baseband interference signal in sequence according to the sampling time sequence; When the phase offset between the baseband interference signal and the radio astronomy signal is positive, outputting sampling data with a sequence number of the phase offset from the N sampling data of the radio astronomy signal as the sampling data of the corrected radio astronomy signal, and outputting the first sampling data from the N sampling data of the baseband interference signal as the sampling data of the corrected baseband interference signal; When the phase offset between the baseband interference signal and the radio astronomy signal is negative, outputting the first sampled data from the N sampled data of the radio astronomy signal as the sampled data of the corrected radio astronomy signal, and outputting the sampled data whose serial number is the absolute value of the phase offset from the N sampled data of the baseband interference signal as the sampled data of the corrected baseband interference signal; When the at least one baseband interference signal includes multiple baseband interference signals, obtaining a corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal, and a phase offset between each baseband interference signal and the radio astronomy signal specifically includes: Delaying N sampling data of the radio astronomy signal by N time points, and outputting one data in sequence as the sampling data of the radio astronomy signal after correction; Outputting sampling data having the same phase as the sampling data of the radio astronomy signal after correction from 2N-1 consecutive sampling data of each baseband interference signal according to the phase offset between each baseband interference signal and the radio astronomy signal as the sampling data of each baseband signal after correction; When the at least one baseband interference signal includes only one baseband interference signal, performing radio frequency interference suppression on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain the radio astronomy signal after radio frequency interference suppression specifically includes: Rearranging the corrected baseband interference signal into a block so that the rearranged baseband interference signal includes a preset number of sampling data; According to the rearranged baseband interference signal, a preset filtering algorithm is used to suppress radio frequency interference on the radio astronomy signal to obtain a radio astronomy signal after radio frequency interference suppression; When the at least one baseband interference signal includes multiple baseband interference signals, performing radio frequency interference suppression on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain the radio astronomy signal after radio frequency interference suppression specifically includes: The corrected baseband interference signals are combined into one to obtain a combined interference signal; Rearranging the synthetic interference signal into a block so that the rearranged synthetic interference signal includes a preset number of sampling data; According to the rearranged synthetic interference signal, a preset filtering algorithm is used to suppress radio frequency interference on the corrected radio astronomy signal to obtain a radio astronomy signal after radio frequency interference suppression.

2. A radio telescope radio frequency interference suppression system, characterized in that: include: An acquisition module, used to acquire a radio astronomy signal received by a radio telescope and at least one baseband interference signal received by a reference antenna; wherein the radio astronomy signal and the at least one baseband interference signal are obtained by synchronous sampling; A phase correction module is used to perform phase correction on each baseband interference signal according to the radio astronomy signal to obtain a corrected radio astronomy signal and each corrected baseband interference signal with the same phase; A radio frequency interference suppression module is used to suppress radio frequency interference on the corrected radio astronomy signal according to each corrected baseband interference signal to obtain a radio astronomy signal after radio frequency interference suppression; The phase correction module comprises: A phase offset calculation circuit is used to obtain the phase offset between each roadbed band interference signal and the radio astronomy signal; The correction circuit is used to obtain the corrected radio astronomy signal and each corrected baseband interference signal according to the radio astronomy signal, each baseband interference signal and the phase offset between each baseband interference signal and the radio astronomy signal; The lengths of the radio astronomy signal and the baseband interference signal are both N; The phase offset calculation circuit includes at least one calculation unit corresponding to the at least one baseband interference signal, each calculation unit includes a first zero-adding circuit, a first FFT circuit, a reverse order rearrangement circuit, a second zero-adding circuit, a second FFT circuit, a multiplication circuit, an IFFT circuit and an offset circuit, the first zero-adding circuit is used to fill N-1 zeros after N sampling data of the radio astronomy signal, the first FFT circuit is used to perform FFT on the filled radio astronomy signal to obtain the radio astronomy signal after FFT; the reverse order rearrangement circuit is used to add N sampling data of the baseband interference signal corresponding to the calculation unit to the multiplication circuit, and the first FFT circuit is used to perform FFT on the filled radio astronomy signal to obtain the radio astronomy signal after FFT; the reverse order rearrangement circuit is used to add N sampling data of the baseband interference signal corresponding to the calculation unit to the multiplication circuit. The data is rearranged in reverse order, the second zero-adding circuit is used to fill N-1 zeros after the N sampled data after the reverse order is rearranged, the second FFT circuit is used to perform FFT on the filled roadbed band interference signal to obtain the roadbed band interference signal after FFT; the multiplication circuit is used to multiply the radio astronomy signal after FFT and the roadbed band interference signal after FFT to obtain a related signal, the IFFT circuit is used to perform IFFT on the related signal to obtain 2N-1 time domain data, and the offset circuit is used to obtain the phase offset between the roadbed band interference signal and the radio astronomy signal according to the 2N-1 time domain data; The correction circuit includes a first N-way selector, a first N-bit shift register, a second N-way selector and a second N-bit shift register, the N bits of the first N-bit shift register respectively store N sampling data of the baseband interference signal, the N bits of the second N-bit shift register respectively store N sampling data of the radio astronomy signal, the N input ends of the first N-way selector are respectively connected to the N bits of the first N-bit shift register, the N input ends of the second N-way selector are respectively connected to the N bits of the second N-bit shift register, the control end of the first N-way selector and the control end of the second N-way selector are both connected to the output end of the offset circuit to receive the phase offset, and the output ends of the first N-way selector and the second N-way selector are respectively connected to the radio frequency interference suppression module; the first N-way selector and the second N-way selector are used to output the corrected baseband interference signal and the corrected radio astronomy signal with the same phase according to the phase offset; When the at least one baseband interference signal includes multiple baseband interference signals, the correction circuit includes a third N-bit shift register and multiple third selectors, the multiple third selectors correspond to the multiple baseband interference signals one by one, each third selector includes 2N-1 input terminals, which are respectively connected to the 2N-1 bits of the 2N-1 shift register, the first N-1 bits in the 2N-1 shift register store 0, and the last N bits in the 2N-1 shift register respectively store N sampling data of the baseband interference signal corresponding to the third selector, the control terminal of each third selector is used to receive the phase offset between the baseband interference signal corresponding to the third selector and the radio astronomy signal, and the output terminal of the third selector is connected to the radio frequency interference suppression module to output the corrected sampling data of the baseband interference signal; the N bits of the third N-bit shift register respectively store the N sampling data of the radio astronomy signal, and the radio astronomy signal is fixedly delayed by N time points to be output as the corrected sampling data of the radio astronomy signal; When the at least one baseband interference signal includes a baseband interference signal, the radio frequency interference suppression module specifically includes: A first rearrangement circuit is used to rearrange the corrected baseband interference signal into one block, so that the rearranged baseband interference signal includes a preset number of sample data; A first filter is used to suppress radio frequency interference on the radio astronomy signal by using a preset filtering algorithm according to the rearranged baseband interference signal to obtain a radio astronomy signal after radio frequency interference suppression; When the at least one baseband interference signal includes multiple baseband interference signals, the radio frequency interference suppression module specifically includes: A synthesis circuit, used for synthesizing the corrected baseband interference signals into one to obtain a synthesized interference signal; A second rearrangement circuit is used to rearrange the synthetic interference signal into one block, so that the rearranged synthetic interference signal includes a preset number of sampled data; The second filter is used to suppress radio frequency interference on the corrected radio astronomy signal according to the rearranged synthetic interference signal by using a preset filtering algorithm to obtain the radio astronomy signal after radio frequency interference suppression.

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