CN117572354A - Radar pulse description word measuring method and system of broadband radar detection receiver - Google Patents
Radar pulse description word measuring method and system of broadband radar detection receiver Download PDFInfo
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Abstract
The invention relates to the field of radar detection, in particular to a radar pulse description word measuring method and system of a broadband radar detection receiver. The method comprises the following steps: step 1), converting an original sampling radar signal received by a broadband radar detection receiver into an intermediate frequency signal; dividing M sub-channels of the intermediate frequency signal, carrying out multi-phase filtering, and then carrying out calculation of radar pulse description words in each sub-channel in parallel to obtain a radar pulse description word result of each sub-channel; step 2) cross-channel signal combination is carried out on the radar pulse description word results of the M sub-channels, and the combined radar pulse description word results are output as total combined radar pulse description word measurement results. The invention has built-in cross-channel processing capability, effectively solves the problems of detection errors and out-of-tolerance radar pulse description word measurement caused by the fact that broadband signals fall on a plurality of channels, and meets the application requirements of complex electromagnetic environment and effective detection of ultra-broadband signals.
Description
Technical Field
The invention relates to the technical field of radar detection, in particular to a radar pulse description word measuring method and system of a broadband radar detection receiver.
Background
With the development of modern radar technology, the requirements on the technical performance and technical indexes of a broadband detection receiver with the instantaneous bandwidth of more than 2GHz are higher, and the broadband detection receiver is required to be capable of coping with and processing radars with various frequency bands, various systems and various waveforms, and has the functions of signal sorting, target selection and the like in a complex electromagnetic environment. At present, how to extract radar target parameters rapidly and accurately is still a worth exploring problem.
Means and methods for processing and analysing signals of an intercepted target are mainly to extract inter-pulse modulation information of the target, which is mainly referred to as pulse repetition frequency, and intra-pulse signal characteristics, which are mainly represented by pulse descriptors (Pulse Description Word, PDW), including pulse amplitude (a P ) Pulse arrival time (t) TOA ) Pulse width (τ) PW ) Carrier frequency (f) RF ) Sum bandwidth (B) W ). By effectively extracting pulse information and combining the information such as the direction and the polarization measured by the antenna array, the radiation source is sorted, identified and positioned. Fig. 1 shows the basic components of a conventional digital detection receiver. Traditional radar detection receivers often aim at radar pulse signals of single carrier waves, and the instantaneous bandwidth is limited; however, radar signals nowadays have the characteristics of large bandwidth, narrow pulse and low signal to noise ratio, and the traditional method is difficult to realize high-precision real-time measurement of the radar pulses.
The measurement of radar pulse descriptors has been developed over the years in the academy, and a set of complete computing systems is provided, and fig. 2 is a technical roadmap of the existing pulse descriptor measurement system. For Lei Dafu signals obtained through orthogonal transformation, firstly, quick amplitude and phase measurement is carried out by utilizing a CORDIC algorithm to obtain instantaneous envelope and phase information of the signals, then, the signal envelope is detected, if the signals are detected to exist, an intra-pulse parameter measurement algorithm is executed, and the measurement results are packed and arranged into pulse description words and are sent to a radiation source identification unit. The signal detection is usually performed by comparing a predefined or adaptively adjusted threshold value with an instantaneous envelope of the signal, and if the envelope of the signal exceeds the threshold value at a plurality of continuous sampling points, the target signal is considered to exist.
The radar time-domain parameters mainly include pulse amplitude (a P ) Pulse arrival time (t) TOA ) And pulse width (τ) PW ) The waveform of the radar signal pulse front is shown in fig. 3. The pulse top of the actual signal is uneven, and even after filtering and shaping, the pulse top has certain fluctuation.
So pulse amplitude (A) P ) The video samples of the top maximum portion of the pulse may be averaged as a measure of the pulse amplitude. The determination of the maximum value at the top of the pulse can be achieved by detecting the maximum value in the envelope of the pulse (the overshoot sample), and when a sample is larger than the following N samples, it is considered to be the overshoot sample, and the value of N is determined by the possible width of the envelope overshoot.
Pulse arrival time (t) TOA ) When the measurement of the pulse is carried out, a leading edge measuring method is adopted, the envelope of the pulse is influenced by a filter, the leading edge of the pulse with a certain length, which is generally between 0.5 and 0.9 times of pulse amplitude, can be approximately linear, and the moment corresponding to the-3 dB threshold value is selected as the pulse arrival time of the signal. Because the method relies on calculation of pulse amplitude, when engineering is realized, buffering of data of the pulse front edge is needed, after the calculation of the pulse amplitude is completed, the data of the pulse front edge is compared with the calculated arrival time threshold value in a reverse order, and the moment corresponding to the point with the minimum absolute value of the difference value of the data of the pulse front edge and the arrival time of the pulse is taken as the arrival time of the pulse. The pulse trailing edge can be obtained by the same method due to the symmetry of the pulse shape, and the difference is the estimated pulse width (tau PW )。
The frequency domain parameters of the radar mainly include the carrier frequency (f RF ) Sum bandwidth (B) W ) In order to effectively acquire the two kinds of information, an instantaneous frequency difference of a radar signal needs to be calculated, and a phase difference method has the advantages of low calculation consumption, strong instantaneity and low implementation difficulty. The measured value of the complex signal can be easily estimated by adopting the CORDIC algorithmNamely:
wherein Q is k (m) and I k (m) representing the real and imaginary parts of the complex signal respectively, and solving the instantaneous frequency w by phase difference division based on the differential relationship between frequency and phase k (m)：
Wherein,for the current phase +.>For the phase at the previous time, the phase value is [ -pi, pi]In the range, therefore, the problem of phase ambiguity occurs, and the result of the phase difference needs to be subjected to phase unwrapping, and the formula is as follows:
the pulse descriptor measurement system is mature relative to a narrow-band signal, but has poor applicability and measurement accuracy for ultra-wideband signals.
Disclosure of Invention
The invention aims to overcome the defect that the conventional broadband detection receiver is difficult to realize high-precision real-time measurement of radar pulses with large bandwidth, narrow pulse and low signal to noise ratio, thereby providing a radar pulse description word measurement method and a radar pulse description word measurement system of the broadband radar detection receiver. The radar pulse description word measuring method and system of the broadband radar detection receiver break through the problem of limited detection bandwidth of the traditional method, can achieve 2GHz instantaneous processing bandwidth, simultaneously ensure the time-frequency measuring precision of radar signals, can reach 50ns, and has the frequency measuring resolution of 1MHz.
In order to solve the technical problems, the technical scheme of the invention provides a radar pulse description word measuring method and a radar pulse description word measuring system for a broadband radar detection receiver. The invention provides a radar pulse description word measuring method of a broadband radar detection receiver, which comprises the following steps: the method comprises the following steps:
step 1), converting an original sampling radar signal received by a broadband radar detection receiver into an intermediate frequency signal; dividing M sub-channels of the intermediate frequency signal, carrying out multi-phase filtering, and then carrying out calculation of radar pulse description words in each sub-channel in parallel to obtain a radar pulse description word result of each sub-channel;
step 2) cross-channel signal combination is carried out on the radar pulse description word results of the M sub-channels, and the combined radar pulse description word results are output as total combined radar pulse description word measurement results.
As an improvement of the above method, the radar pulse descriptor result comprises: pulse amplitude, pulse arrival time, pulse width, signal carrier frequency, and signal bandwidth.
As an improvement of the above method, the step 2) specifically includes:
step 2-1) combining the radar pulse description word measurement result of the rear sub-channel and the radar pulse description word measurement result of the front sub-channel in the two sub-channels meeting the preset combining condition to form a first combined radar pulse description word measurement result;
step 2-2) judging whether the next adjacent sub-channel of the back sub-channel meets the preset merging condition, if so, taking the first merging radar pulse description word measuring result as a radar pulse description word measuring result of the new front sub-channel, taking the next adjacent sub-channel as the new back sub-channel, merging the radar pulse description word measuring results of the two sub-channels until the next adjacent sub-channel meeting the preset merging condition does not exist in the M sub-channels, outputting the merging radar pulse description word measuring result recorded at the moment as a total merging radar pulse description word measuring result, and outputting.
As an improvement of the above method, the step 2-1) specifically includes:
step 2-1-1) obtaining a combined pulse amplitude A of the first combined radar pulse descriptor measurement P ：
A P1 Pulse amplitude, A, of the radar pulse descriptors measurement for the front subchannel P2 Pulse amplitude of the radar pulse descriptor measurement result for the rear subchannel;
step 2-1-2) obtaining a combined pulse arrival time t of the first combined radar pulse descriptor measurement TOA ：
t TOA ＝t TOA1 ；
t TOA1 Pulse arrival time for the radar pulse descriptor measurement of the preceding subchannel;
step 2-1-3) obtaining a combined pulse width τ of the first combined radar pulse descriptor measurement PW ：
τ PW ＝t TOD2 -t TOA1 ；
t TOA1 Pulse arrival time, t, for radar pulse descriptor measurement of a preceding subchannel TOD2 Pulse arrival time for the radar pulse descriptor measurement of the rear subchannel;
step 2-1-4) obtaining a combined signal carrier frequency f of the first combined radar pulse descriptor measurement result RF ：
f b1 The starting frequency, f, of the radar pulse descriptor measurement for the preceding subchannel e2 Cut-off frequency of the radar pulse descriptor measurement result for the rear subchannel;
step 2-1-5) obtaining a first merged radar pulse descriptorCombined signal bandwidth B of measurement results W ：
B W ＝f e2 -f b1 ；
f e2 Cut-off frequency, f, for radar pulse descriptor measurement of the rear subchannel b1 The starting frequency of the word measurement is described for the radar pulse of the preceding subchannel.
As an improvement of the above method, the preset combining condition is that the following conditions are all satisfied:
the two sub-channels are adjacent;
the absolute value of the difference between the pulse arrival time of the radar pulse descriptor measurement result of the rear sub-channel and the pulse departure time of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset time tolerance deltat;
the absolute value of the difference between the starting frequency of the radar pulse descriptor measurement result of the rear sub-channel and the cut-off frequency of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset frequency tolerance delta f;
the absolute value of the difference between the frequency modulation of the radar pulse descriptor measurement result of the rear sub-channel and the frequency modulation of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset frequency modulation tolerance deltak.
As an improvement of the above method, the preset time tolerance Δt is 1 to 500ns;
the preset frequency tolerance delta f is 1-100 MHz;
the preset frequency modulation tolerance delta k is 0.1-10 MHz/us.
As an improvement of the above method, the preset time tolerance Δt is 100ns;
the preset frequency tolerance deltaf is 10MHz;
the preset frequency tolerance ak is 0.5MHz/us.
In order to achieve another object of the present invention, the present invention further provides a radar pulse descriptor measurement system of a wideband radar detection receiver: comprising the following steps: a radar pulse descriptor measurement method for performing the above-described wideband radar detection receiver, the radar pulse descriptor measurement system comprising:
the conversion module is used for converting the original sampled radar signals received by the broadband radar detection receiver into intermediate frequency signals;
the digital channelizing module is used for dividing M sub-channels of the intermediate frequency signal and performing multiphase filtering;
the measuring module is used for carrying out calculation of radar pulse description words in each sub-channel in parallel so as to obtain a radar pulse description word result of each sub-channel; and
and the merging module is used for carrying out cross-channel signal merging on the radar pulse description word results of the M sub-channels, and outputting the merged radar pulse description word results as total merged radar pulse description word measurement results.
As an improvement of the above system, the measuring module comprises:
the signal detection unit is used for detecting whether a signal to be measured exists in the sub-channel;
the time domain parameter measurement unit is used for calculating the pulse amplitude, the pulse arrival time and the pulse width of the radar pulse description word result; and
the instantaneous frequency measuring unit is used for calculating the instantaneous frequency difference so as to obtain the signal carrier frequency and the signal bandwidth of the radar pulse description word result.
As an improvement of the above system, the conversion module adopts an ADC chip, and the sampling rate is: 5GSPS; the conversion module is used for converting the original sampled radar signals into intermediate frequency signals with the instantaneous bandwidth being more than 2 GHz; the digital channelizing module adopts: a digital channelization module based on a polyphase filter, a digital channelization module based on an STFT, or a digital channelization module based on a WOLA filter bank.
As an improvement of the system, the radar pulse descriptor measuring system is deployed on an FPGA development board.
The invention provides a radar pulse description word measuring method and a system of a broadband radar detection receiver, which comprise the following steps:
1. the invention is based on the design of a broadband radar receiver system, and processes radar signals with ultra-broadband, low signal-to-noise ratio and complex system and low interception probability, which are not traditional radar pulse signals;
2. the invention breaks through the index requirement of a radar receiver of 2GHz, can ensure the time domain parameter measurement precision of 50ns and the frequency resolution of 1MHz, and the index level is in the front of the domestic field;
3. the system provided by the invention is internally provided with the cross-channel processing capability, so that the problems of detection errors, ultra-poor radar Pulse Descriptor (PDW) measurement and the like caused by the fact that broadband signals fall on a plurality of channels can be effectively solved, and the application requirements of effective detection of complex electromagnetic environments and ultra-broadband signals are met.
Drawings
FIG. 1 is a basic composition of a conventional digital scout receiver;
FIG. 2 is a technical roadmap of a prior art pulse descriptor measurement system;
FIG. 3 is a radar signal pulse leading edge waveform;
FIG. 4 is a diagram of a wideband radar receiver architecture of the present invention;
FIG. 5 is a schematic block diagram of a polyphase filter of the present invention;
FIG. 6 is a flow chart of a method for measuring radar pulse descriptors of the wideband radar detection receiver of the present invention;
FIG. 7 is a diagram of an upper computer display control software interface;
fig. 8 is a flow chart of a signal cross-channel combining method of the present invention.
Detailed Description
The technical scheme provided by the invention is further described below by combining with the embodiment.
Example 1
The embodiment provides a radar pulse descriptor measuring method of a broadband radar detection receiver, which comprises the following steps:
step 1), converting an original sampling radar signal received by a broadband radar detection receiver into an intermediate frequency signal; dividing M sub-channels of the intermediate frequency signal, carrying out multi-phase filtering, and then carrying out calculation of radar pulse description words in each sub-channel in parallel to obtain a radar pulse description word result of each sub-channel;
step 2) cross-channel signal combination is carried out on the radar pulse description word results of the M sub-channels, and the combined radar pulse description word results are output as total combined radar pulse description word measurement results.
Preferably, the radar pulse descriptor result includes: pulse amplitude, pulse arrival time, pulse width, signal carrier frequency, and signal bandwidth.
Preferably, the step 2) specifically includes:
step 2-1) combining the radar pulse description word measurement result of the rear sub-channel and the radar pulse description word measurement result of the front sub-channel in the two sub-channels meeting the preset combining condition to form a first combined radar pulse description word measurement result;
step 2-2) judging whether the next adjacent sub-channel of the back sub-channel meets the preset merging condition, if so, taking the first merging radar pulse description word measuring result as a radar pulse description word measuring result of the new front sub-channel, taking the next adjacent sub-channel as the new back sub-channel, merging the radar pulse description word measuring results of the two sub-channels until the next adjacent sub-channel meeting the preset merging condition does not exist in the M sub-channels, outputting the merging radar pulse description word measuring result recorded at the moment as a total merging radar pulse description word measuring result, and outputting.
Preferably, the step 2-1) specifically includes:
step 2-1-1) obtaining a combined pulse amplitude A of the first combined radar pulse descriptor measurement P ：
A P1 Pulse amplitude, A, of the radar pulse descriptors measurement for the front subchannel P2 Pulse amplitude of the radar pulse descriptor measurement result for the rear subchannel;
step 2-1-2) obtaining a first combined radar pulse descriptor measurementIs the combined pulse arrival time t TOA ：
t TOA ＝t TOA1 ；
t TOA1 Pulse arrival time for the radar pulse descriptor measurement of the preceding subchannel;
step 2-1-3) obtaining a combined pulse width τ of the first combined radar pulse descriptor measurement PW ：
τ PW ＝t TOD2 -t TOA1 ；
t TOA1 Pulse arrival time, t, for radar pulse descriptor measurement of a preceding subchannel TOD2 Pulse arrival time for the radar pulse descriptor measurement of the rear subchannel;
step 2-1-4) obtaining a combined signal carrier frequency f of the first combined radar pulse descriptor measurement result RF ：
f b1 The starting frequency, f, of the radar pulse descriptor measurement for the preceding subchannel e2 Cut-off frequency of the radar pulse descriptor measurement result for the rear subchannel;
step 2-1-5) obtaining a combined signal bandwidth B of the first combined radar pulse descriptor measurement W ：
B W ＝f e2 -f b1 ；
f e2 Cut-off frequency, f, for radar pulse descriptor measurement of the rear subchannel b1 The starting frequency of the word measurement is described for the radar pulse of the preceding subchannel.
Preferably, the preset combining conditions are that the following conditions are all satisfied:
the two sub-channels are adjacent;
the absolute value of the difference between the pulse arrival time of the radar pulse descriptor measurement result of the rear sub-channel and the pulse departure time of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset time tolerance deltat;
the absolute value of the difference between the starting frequency of the radar pulse descriptor measurement result of the rear sub-channel and the cut-off frequency of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset frequency tolerance delta f;
the absolute value of the difference between the frequency modulation of the radar pulse descriptor measurement result of the rear sub-channel and the frequency modulation of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset frequency modulation tolerance deltak.
Preferably, the preset time tolerance Δt is 100ns;
the preset frequency tolerance deltaf is 10MHz;
the preset frequency tolerance ak is 0.5MHz/us.
Example 2
The embodiment is a radar pulse descriptor measuring system of a broadband radar detection receiver designed based on the broadband radar receiver, and the architecture of the broadband radar receiver is shown in fig. 4. The antenna receives radar signals in an electromagnetic space, converts the radar signals into intermediate frequency signals with the instantaneous bandwidth being more than 2GHz after radio frequency front end processing, then carries out analog-to-digital conversion through an analog-to-digital converter with the sampling rate being 5GSPS, namely an ADC chip, sends the digital signals obtained by sampling to a multifunctional digital module for measuring pulse description words, and then uploads the measurement results of the pulse description words to a host through optical fibers for signal sorting or spectrum event analysis and other operations.
According to the nyquist sampling theorem, to match the large bandwidth of radar signals, the high sampling rate of the ADC chip needs to be relied upon to achieve distortion-free reconstruction of the signal. As shown in fig. 4, the sampling rate of the ADC chip is 5GSPS, and the time interval of the sampling points is only 0.2ns, which is obviously helpful for improving the measurement accuracy of the time domain parameters of the system, but also significantly increases the processing difficulty of the FPGA, so that in order to adapt to the high-speed data stream, we choose to use the digital channelizing technology based on the polyphase filtering to perform the data deceleration, so as to change the time of the resources, and fully exert the characteristics of abundant FPGA resources and strong parallel computing capability. The multifunctional digital unit in fig. 4 represents a radar pulse descriptor measuring system, and interfaces for the multifunctional digital unit to communicate with a host computer, including but not limited to an ethernet interface or an LVDS interface. The radar pulse descriptor measuring system comprises: the conversion module is used for converting the original sampled radar signals received by the broadband radar detection receiver into intermediate frequency signals; the digital channelizing module is used for dividing M sub-channels of the intermediate frequency signal and performing multiphase filtering; the measuring module is used for carrying out calculation of radar pulse description words in each sub-channel in parallel so as to obtain a radar pulse description word result of each sub-channel; and the merging module is used for carrying out cross-channel signal merging on the radar pulse description word results of the M sub-channels, and outputting the merged radar pulse description word results as total merged radar pulse description word measurement results.
Digital channelization techniques for data rate conversion select polyphase filtering techniques, the remaining digital channelization methods (e.g., STFT or WOLA) can be used as alternatives to polyphase filter-based digital channelization modules;
the basic idea of the polyphase filter is that the original sampling bandwidth is divided into M sub-channels with equal bandwidth by the design of the prototype filter, and the data rate of each sub-channel is only 1/M of the original data rate due to the operation of time-lapse sampling, thereby achieving the purpose of data deceleration in the channel. After the polyphase filtering operation, the output y of the kth subchannel k (m) can be expressed as:
wherein p is the serial number of the sub-channel, j represents the imaginary part;
x p (m) and h p (M) represents the results of M times downsampling of the radar signal digital sequence and the impulse response of the prototype filter, respectively.
Assuming that 64 sub-channels are divided, after polyphase filtering, the data rate of each sub-channel is only 1/64 of the original data rate, namely 78.125MHz, then a calculation algorithm of pulse description words can be executed in each sub-channel respectively, and then the PDW results of the sub-channels are combined to output the final result of PDW. An algorithm flow chart of the whole wideband radar digital receiver pulse descriptor measurement system is shown in fig. 6.
Because the system aims at broadband signals, the problem of signal cross-channel cannot be avoided. If the signals are detected to exist in 2 or more adjacent sub-channels at the same time, the duration of the signals are overlapped, and the difference value of the amplitude of the signals is within a certain range, the signals in the sub-channels can be judged to belong to the same broadband radar signal, and pulse description word measurement results of the sub-channels are combined; if the three conditions are not satisfied, the radar pulse is determined to be different.
The system provided by the embodiment can realize two-way communication with the upper computer through the communication interface, send the calculated PDW result to the upper computer, and also receive the control instruction of the upper computer to execute the commands such as system soft reset or system start. The interface diagram of the upper computer display control software is shown in fig. 7.
For the sub-channels where signals are detected, the system will automatically perform a parameter estimation algorithm, outputting pulse descriptors of the signals within the sub-channels. When cross-subchannel signal combination is executed, the system divides pulse description words of two adjacent subchannels into a group to judge whether the requirement of signal combination is met. If the requirements are met, combining the two pulse descriptors into a new pulse descriptor, and comparing the new pulse descriptor with the next adjacent sub-channel; if the requirements are not met, the signals in the two sub-channels are considered to be divided into independent pulses, and the two pulse descriptors are respectively output.
Taking a fixed frequency chirped signal as an example, a cross-channel combining procedure of a wideband signal is illustrated as shown in fig. 8. The parameters for signal combining algorithm are mainly as follows: pulse arrival time t of radar pulse descriptor measurement of front subchannel TOA1 Pulse arrival time t of radar pulse descriptor measurement of a subsequent subchannel TOA2 Pulse arrival time t of radar pulse descriptor measurement of front sub-channel TOD1 Radar pulse descriptor measurement for post-subchannelResulting pulse arrival time t TOD2 Signal start frequency f of radar pulse descriptor measurement result of front sub-channel b1 Signal start frequency f of radar pulse descriptor measurement result of rear sub-channel b2 Signal cut-off frequency f of radar pulse descriptor measurement result of front sub-channel e1 Signal cut-off frequency f of radar pulse descriptor measurement result of rear sub-channel e2 Tone frequency k of radar pulse descriptor measurement result of front sub-channel 1 Tone frequency k of radar pulse descriptor measurement result of rear sub-channel 2 。
The flow of cross-channel signal combining can be expressed as:
judging whether the pulse descriptors originate from adjacent sub-channels, if the pulse descriptors originate from non-adjacent sub-channels, indicating that the spectrum of the signal in the two sub-channels has at least one interval of sub-band width, which does not conform to the characteristic of the spectrum continuity of the chirp signal, the two groups of pulse descriptors cannot be combined. If the pulse description word originates from the same sub-channel, the next stage of judgment is entered.
Judging the time interval of adjacent pulses, calculating the difference between the pulse arrival time of the second sub-channel, namely the rear sub-channel, and the pulse departure time of the first sub-channel, namely the front sub-channel, and if the absolute value of the difference is smaller than the time tolerance deltat (100 ns), considering that the two signals have time continuity and entering the next stage to continue judgment. Otherwise, the time intervals of the two signals are considered to have a larger gap, and the two signals belong to two mutually independent pulses.
Judging the start-stop frequency of the adjacent pulse, calculating the difference between the start frequency of the second sub-channel and the cut-off frequency of the first sub-channel, and if the absolute value of the difference is smaller than the frequency tolerance deltaf (10 MHz), considering that the two signals have continuity in frequency and entering the next stage of judgment. Otherwise, the start-stop frequency interval of the two signals is considered to be too large, the characteristic of continuous frequency spectrum of the linear frequency modulation signals is not met, and the two signals belong to two mutually independent pulses.
Judging the modulation frequency of the adjacent pulses, and because the signal aimed by the system is a linear frequency modulation signal with fixed modulation frequency, the modulation frequencies of the signals in the two sub-channels should not have great difference. And calculating the difference value of the modulation frequencies of the signals in the two sub-channels, and if the absolute value of the difference value is smaller than the modulation frequency tolerance delta k (0.5 MHz/us), considering that the modulation frequencies of the two signals are equal, belonging to the same linear modulation signal, and combining pulse description words of the two sub-channels. Otherwise, the two signals are considered to belong to the chirp signals of different modulation frequencies.
For two sub-channels satisfying the signal combining algorithm, we need to recombine the pulse descriptors output by the two sub-channels to form a new pulse descriptor, and the combined pulse descriptors are generated according to the following rule.
The pulse amplitude takes the average value of the original two signal pulse amplitudes:
pulse arrival time takes the pulse arrival time of the signal with the subchannel number preceding it:
t TOA ＝t TOA1
the pulse width takes the difference between the second sub-channel pulse departure time and the first sub-channel pulse arrival time:
τ PW ＝t TOD2 -t TOA1
the signal carrier frequency takes the average value of the cut-off frequency of the second sub-channel and the initial frequency of the first sub-channel:
the signal bandwidth takes the difference between the second sub-channel cut-off frequency and the first sub-channel start frequency:
B W ＝f e2 -f b1
after the new pulse descriptor is generated, the signal combination judgment is continued with the pulse descriptor generated by the next adjacent sub-channel until the sub-channel which can be combined is not existed, the pulse descriptor result recorded at the moment is output, and the pulse descriptor estimation of the next round is started.
Classical pulse descriptor measurement systems are poor in the ability to process wideband radar signals for simple single carrier pulses, and time-frequency measurement accuracy is limited. The pulse description word measuring system of the broadband radar digital receiver provided by the embodiment selects a high-speed ADC chip (the sampling rate is 6GSPS at the highest) and a high-performance FPGA development board, and the instantaneous bandwidth (more than 2 GHz) of the system is improved through the improvement of the sampling rate.
By combining the digital channelizing method and the multi-channel fusion method, the high-speed data stream can be processed at a low speed, a high-precision time-frequency measurement result can be obtained, and the frequency resolution under the ultra-wideband condition can reach 1MHz.
The results of the frequency resolution test record table in table 1 show that the digital unit can accurately distinguish the double-tone signals with the frequency difference of 1MHz, and the frequency resolution of the system is proved to be better than 1MHz.
Table 1 frequency resolution test record table
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the appended claims.
Claims (10)
1. A method of radar pulse descriptor measurement for a wideband radar detection receiver, the method comprising the steps of:
step 1), converting an original sampling radar signal received by a broadband radar detection receiver into an intermediate frequency signal; dividing M sub-channels of the intermediate frequency signal, carrying out multi-phase filtering, and then carrying out calculation of radar pulse description words in each sub-channel in parallel to obtain a radar pulse description word result of each sub-channel;
step 2) cross-channel signal combination is carried out on the radar pulse description word results of the M sub-channels, and the combined radar pulse description word results are output as total combined radar pulse description word measurement results.
2. The method of claim 1, wherein the radar pulse descriptor result comprises: pulse amplitude, pulse arrival time, pulse width, signal carrier frequency, and signal bandwidth.
3. The method for measuring radar pulse descriptors of a wideband radar detection receiver of claim 1, wherein said step 2) specifically comprises:
step 2-1) combining the radar pulse description word measurement result of the rear sub-channel and the radar pulse description word measurement result of the front sub-channel in the two sub-channels meeting the preset combining condition to form a first combined radar pulse description word measurement result;
step 2-2) judging whether the next adjacent sub-channel of the back sub-channel meets the preset merging condition, if so, taking the first merging radar pulse description word measuring result as a radar pulse description word measuring result of the new front sub-channel, taking the next adjacent sub-channel as the new back sub-channel, merging the radar pulse description word measuring results of the two sub-channels until the next adjacent sub-channel meeting the preset merging condition does not exist in the M sub-channels, outputting the merging radar pulse description word measuring result recorded at the moment as a total merging radar pulse description word measuring result, and outputting.
4. A method for measuring radar pulse descriptors of a wideband radar detection receiver according to claim 3, wherein said step 2-1) specifically comprises:
step 2-1-1) obtaining a combined pulse amplitude A of the first combined radar pulse descriptor measurement P ：
A P1 Pulse amplitude, A, of the radar pulse descriptors measurement for the front subchannel P2 Pulse amplitude of the radar pulse descriptor measurement result for the rear subchannel;
step 2-1-2) obtaining a combined pulse arrival time t of the first combined radar pulse descriptor measurement TOA ：
t TOA ＝t TOA1 ；
t TOA1 Pulse arrival time for the radar pulse descriptor measurement of the preceding subchannel;
step 2-1-3) obtaining a combined pulse width τ of the first combined radar pulse descriptor measurement PW ：
τ PW ＝t TOD2 -t TOA1 ；
t TOA1 Pulse arrival time, t, for radar pulse descriptor measurement of a preceding subchannel TOD2 Pulse arrival time for the radar pulse descriptor measurement of the rear subchannel;
step 2-1-4) obtaining a combined signal carrier frequency f of the first combined radar pulse descriptor measurement result RF ：
f b1 The starting frequency, f, of the radar pulse descriptor measurement for the preceding subchannel e2 Cut-off frequency of the radar pulse descriptor measurement result for the rear subchannel;
step 2-1-5) obtaining a combined signal bandwidth B of the first combined radar pulse descriptor measurement W ：
B W ＝f e2 -f b1 ；
f e2 Interception of radar pulse descriptor measurements for rear sub-channelsStop frequency f b1 The starting frequency of the word measurement is described for the radar pulse of the preceding subchannel.
5. A method for measuring radar pulse descriptors of a wideband radar detection receiver according to claim 3, wherein the predetermined combining condition is that:
the two sub-channels are adjacent;
the absolute value of the difference between the pulse arrival time of the radar pulse descriptor measurement result of the rear sub-channel and the pulse departure time of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset time tolerance deltat;
the absolute value of the difference between the starting frequency of the radar pulse descriptor measurement result of the rear sub-channel and the cut-off frequency of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset frequency tolerance delta f;
the absolute value of the difference between the frequency modulation of the radar pulse descriptor measurement result of the rear sub-channel and the frequency modulation of the radar pulse descriptor measurement result of the front sub-channel is smaller than a preset frequency modulation tolerance deltak.
6. The method for radar pulse descriptor measurement for a wideband radar detection receiver of claim 5,
the preset time tolerance delta t is 1-500 ns;
the preset frequency tolerance delta f is 1-100 MHz;
the preset frequency modulation tolerance delta k is 0.1-10 MHz/us.
7. A radar pulse profile measuring system for a wideband radar detection receiver for performing the radar pulse profile measuring method of the wideband radar detection receiver of claim 1, the radar pulse profile measuring system comprising:
the conversion module is used for converting the original sampled radar signals received by the broadband radar detection receiver into intermediate frequency signals;
the digital channelizing module is used for dividing M sub-channels of the intermediate frequency signal and performing multiphase filtering;
the measuring module is used for carrying out calculation of radar pulse description words in each sub-channel in parallel so as to obtain a radar pulse description word result of each sub-channel; and
and the merging module is used for carrying out cross-channel signal merging on the radar pulse description word results of the M sub-channels, and outputting the merged radar pulse description word results as total merged radar pulse description word measurement results.
8. The radar pulse descriptor measurement system of claim 7, wherein the measurement module comprises:
the signal detection unit is used for detecting whether a signal to be measured exists in the sub-channel;
the time domain parameter measurement unit is used for calculating the pulse amplitude, the pulse arrival time and the pulse width of the radar pulse description word result; and
the instantaneous frequency measuring unit is used for calculating the instantaneous frequency difference so as to obtain the signal carrier frequency and the signal bandwidth of the radar pulse description word result.
9. The radar pulse descriptor measurement system of claim 7, wherein the conversion module employs an ADC chip with a sampling rate of: 5GSPS; the conversion module is used for converting the original sampled radar signals into intermediate frequency signals with the instantaneous bandwidth being more than 2 GHz; the digital channelizing module adopts: a digital channelization module based on a polyphase filter, a digital channelization module based on an STFT, or a digital channelization module based on a WOLA filter bank.
10. The radar pulse profile measurement system of a wideband radar detection receiver of claim 7, wherein the radar pulse profile measurement system is deployed on an FPGA development board.
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| CN116819185A (en) * | 2023-08-29 | 2023-09-29 | 南京航天工业科技有限公司 | Digital phase discrimination method and system based on channelization in complex electromagnetic environment |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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| CN116819185A (en) * | 2023-08-29 | 2023-09-29 | 南京航天工业科技有限公司 | Digital phase discrimination method and system based on channelization in complex electromagnetic environment |
Non-Patent Citations (1)
| Title |
|---|
| 王思航: "宽带数字接收机脉冲信号提取实现", 哈尔滨商业大学学报(自然科学版), vol. 34, no. 04, 31 August 2018 (2018-08-31), pages 458 - 462 * |
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