CN118534431A - Improved algorithm and device for Doppler frequency shift of multi-target radar signal - Google Patents
Improved algorithm and device for Doppler frequency shift of multi-target radar signal Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
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- G01S7/4052—Means for monitoring or calibrating by simulation of echoes
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Abstract
The invention relates to the technical field of radar signal processing, and discloses an improved algorithm and device for Doppler frequency shift of a multi-target radar signal, wherein the algorithm comprises the following steps: generating multiple paths of different analog signals according to the acquired analog distances of different radar signals; the energy detection and the signal fusion are carried out on the analog signals, and the signals after the energy detection are also subjected to the signal fusion and are fused into a composite signal; digital down-conversion is carried out on the fused composite signal to obtain a relatively low-frequency signal; low-pass filtering is carried out on the lower-frequency signals to obtain purer signals; and carrying out digital up-conversion on the purer signal and the signal after energy detection and then outputting the signal. The device applies the algorithm. The invention adds the energy detection module and the signal fusion module, improves the digital up-conversion module, fuses the simulated multipath signals into one path of signals according to the energy detection result, and finally completes the Doppler frequency shift function of the multipath signals.
Description
Technical Field
The invention relates to the technical field of radar signal processing, in particular to an improved algorithm and device for Doppler frequency shift of a multi-target radar signal.
Background
The radar signal simulator is important testing equipment for detecting functions of the radar, the multi-target radar signal simulation is an important function of the simulator, and parameters such as speed, distance and movement direction of each signal generated by the simulator can be independently set.
According to the operation change rule of electromagnetic waves, a Doppler frequency shift effect is generated by radar echo signals relative to the emitted electromagnetic waves of the radar, so that a radar simulator is required to simulate a plurality of radar signals with different speeds, and frequency point movement is required to be carried out on the sampled signals.
The current implementation mode is to design multiple paths of DDSs in the FPGA aiming at different signals, and each path of DDS respectively and independently modulates the Doppler frequency of each target echo signal; however, since DDS requires a large amount of RAM resources and logic resources of FPGA, designing multiple DDS has a great limitation in some complex engineering designs.
The limitations are embodied as:
Firstly, a plurality of analog signals are required to be processed in parallel, each path of signals is required to be designed with independent digital down-conversion, low-pass filtering, digital up-conversion and other modules, and a large amount of design resources inside the FPGA are occupied;
Secondly, expansibility is poor, internal resources of the FPGA are limited, and when one more signal is needed, a large number of designs are needed to be added, so that the whole design is changed, and design failure is likely to be caused due to performance bottleneck of the FPGA.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides an improved algorithm for Doppler shift of a multi-target radar signal, which comprises the following steps:
S1: generating multiple paths of different analog signals according to the acquired different analog distances of the radar signals;
S2: respectively carrying out energy detection and signal fusion on the analog signals, and carrying out signal fusion on the signals after energy detection, so as to integrate multiple paths of signals into one path of composite signal;
s3: digital down-conversion is carried out on the fused composite signal to obtain a relatively low-frequency signal;
s4: performing low-pass filtering on the lower-frequency signal to obtain a purer signal;
s5: and carrying out digital up-conversion on the purer signal and the energy detected signal and then outputting the signals to finish the Doppler frequency shift function of the multipath signals.
On the basis of the technical scheme, the invention can be improved as follows.
Preferably, step S2 includes: and switching the channel of the effective signal to the output channel according to the result of energy detection, so as to realize the signal fusion function of multiple input and one output.
Preferably, step S5 includes: and (2) setting different frequency points according to the result of energy detection in the step (S2) aiming at signals of different channels, and refreshing the DDS frequency points in real time.
Based on the algorithm, the invention also provides an improved device for Doppler frequency shift of the multi-target radar signal, the device applies the algorithm, and the device comprises: the system comprises a signal storage forwarding module, an energy detection module, a signal fusion module, a digital down-conversion module, a low-pass filtering module and a digital up-conversion module.
Preferably, the signal store-and-forward module is used for generating multiple paths of different analog signals according to the acquired different analog distances of the radar signals; the input end of the signal storage forwarding module is used for inputting different radar signals acquired from outside, and the output end of the signal storage forwarding module is electrically connected to the input ends of the energy detection module and the signal fusion module respectively.
Preferably, the energy detection module is used for energy detection of the analog signal; the output end of the energy detection module is also electrically connected to the input end of the signal fusion module.
Preferably, the signal fusion module is used for carrying out signal fusion on the analog signal and the signal after energy detection; the output end of the signal fusion module is electrically connected to the input end of the digital down-conversion module.
Preferably, the digital down-conversion module is configured to digitally down-convert the fused signal, and an output end of the digital down-conversion module is electrically connected to an input end of the low-pass filtering module.
Preferably, the low-pass filtering module is used for performing low-pass filtering; the output end of the low-pass filtering module is electrically connected to the input end of the digital up-conversion module.
Preferably, the digital up-conversion module is used for performing digital up-conversion; the output end of the energy detection module is also electrically connected to the input end of the digital up-conversion module; the digital up-conversion module has a frequency point real-time frequency conversion function, and the DDS frequency points are refreshed in real time aiming at different signals.
Compared with the prior art, the invention adds an energy detection module and a signal fusion module aiming at the current algorithm, improves a digital up-conversion module, and can generate the following beneficial technical effects:
1. The invention can know which signal is the current main signal in the simulated multipath signals by adding the energy detection function aiming at each signal;
2. According to the energy detection result, different input signals are switched to an output channel in real time, and the simulated multipath signals are fused into one path of signals, so that the data flow control of the multipath signals is carried out;
3. because the fused signals contain multiple paths of analog signals, the speeds of the signals are different, different frequency points are required to be set in the DDS according to different signals, and the signals are updated in real time according to the energy detection result; the invention has the advantages that the DDS real-time frequency conversion function is added, so that the DDS frequency point can be changed in real time aiming at different signals, and the Doppler frequency shift function of a single DDS for realizing multiple signals is realized.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of steps of a modified algorithm for Doppler shift of a multi-target radar signal according to the present invention;
fig. 2 is a schematic structural diagram of an improved device for doppler shift of a multi-target radar signal according to the present invention.
In the drawings, the list of component names indicated by the respective reference numerals is as follows:
100: signal store-and-forward module, 201: energy detection module, 202: signal fusion module, 300: digital down conversion module, 400: low pass filter module, 500: and a digital up-conversion module.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, a flowchart of steps of an improved algorithm for doppler shift of a multi-target radar signal according to the present invention is shown; the method comprises the following steps:
S1: generating multiple paths of different analog signals according to the acquired different analog distances of the radar signals;
S2: respectively carrying out energy detection and signal fusion on the analog signals, carrying out signal fusion on the signals after energy detection, and finally, fusing multiple paths of signals into a composite signal; preferably, according to the result of energy detection, the channel of the effective signal is switched to the output channel, so as to realize the signal fusion function of multiple inputs and one output;
The energy detection method is a relatively simple signal detection method, belongs to incoherent detection means, is very similar to spectrum analysis, and is realized through judgment. The method detects the signal according to the difference of the power of the received signal under the condition that the sensor has two hypotheses of the signal. This method is an effective method for deterministic signal of unknown parameters and its presence detection. No a priori information of the grant signal is needed, since the energy detection does not limit the signal type. Signal energy detection is a technique known in the art and is not described in detail herein.
S3: digital down-conversion is carried out on the composite signal after fusion (English: digital Down Converter or DDC means a frequency mixing mode that the intermediate frequency signal obtained after frequency mixing in the superheterodyne receiver is lower than the frequency of the original signal) to obtain a signal with lower frequency; specifically, the high-frequency signal is subjected to frequency spectrum shifting, so that the signal rate is reduced, and the high-speed signal is conveniently processed;
s4: the low-pass filtering is carried out on the lower-frequency signals to filter clutter signals, so that purer signals are obtained;
S5: performing digital up-conversion (English: digital Up Converter or DUC means that a baseband signal is modulated to medium-high frequency in a digital mode, then converted into an analog signal through a D/A conversion module, finally transmitted through an antenna) on the purer signal and the signal after energy detection, and then outputting the signal to finally finish the Doppler frequency shift function of multiple paths of signals; preferably, DDS frequency points are adjusted/refreshed in real time for different signals, i.e. different frequency points are set for signals of different channels according to the result of energy detection in step S2.
Fig. 2 is a schematic structural diagram of an improved device for doppler shift of a multi-target radar signal according to the present invention; in the present invention, the device applies the algorithm, which includes: a signal store-and-forward module 100, an energy detection module 201, a signal fusion module 202, a digital down-conversion module 300, a low-pass filtering module 400, and a digital up-conversion module 500; wherein,
The signal store-and-forward module 100 is configured to generate multiple paths of different analog signals according to the acquired different analog distances of the radar signals; the input end of the signal store-and-forward module 100 is used for inputting different externally collected radar signals, and the output ends are respectively and electrically connected to the input ends of the energy detection module 201 and the signal fusion module 202;
The energy detection module 201 is configured to perform energy detection on the analog signal; the output end of the energy detection module 201 is also electrically connected to the input end of the signal fusion module 202;
The signal fusion module 202 is configured to perform signal fusion on the analog signal and the signal after energy detection; the output end of the signal fusion module 202 is electrically connected to the input end of the digital down-conversion module 300;
The digital down-conversion module 300 is configured to perform digital down-conversion on the fused signal, and an output end of the digital down-conversion module 300 is electrically connected to an input end of the low-pass filtering module 400;
The low-pass filtering module 400 is configured to perform low-pass filtering; the output end of the low-pass filtering module 400 is electrically connected to the input end of the digital up-conversion module 500;
The digital up-conversion module 500 is configured to perform digital up-conversion; in addition, the output end of the energy detection module 201 is also electrically connected to the input end of the digital up-conversion module 500; in the present invention, the digital up-conversion module 500 has a frequency point real-time frequency conversion function, and can adjust DDS frequency points in real time for different signals, so as to realize multiple paths of signal doppler shift.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.
Claims (10)
1. An improved algorithm for doppler shift of a multi-target radar signal, comprising the steps of:
S1: generating multiple paths of different analog signals according to the acquired different analog distances of the radar signals;
S2: respectively carrying out energy detection and signal fusion on the analog signals, and carrying out signal fusion on the signals after energy detection, so as to integrate multiple paths of signals into one path of composite signal;
s3: digital down-conversion is carried out on the fused composite signal to obtain a relatively low-frequency signal;
s4: performing low-pass filtering on the lower-frequency signal to obtain a purer signal;
s5: and carrying out digital up-conversion on the purer signal and the energy detected signal and then outputting the signals to finish the Doppler frequency shift function of the multipath signals.
2. The improved algorithm for doppler shift of a multi-target radar signal according to claim 1, wherein step S2 comprises: and switching the channel of the effective signal to the output channel according to the result of energy detection, so as to realize the signal fusion function of multiple input and one output.
3. An improved algorithm for doppler shift of a multi-target radar signal according to claim 1 or 2, wherein step S5 comprises: and (2) setting different frequency points according to the result of energy detection in the step (S2) aiming at signals of different channels, and refreshing the DDS frequency points in real time.
4. An improved apparatus for doppler shifting of a multi-target radar signal, the apparatus applying the algorithm of any one of claims 1 to 3, the apparatus comprising: the system comprises a signal storage forwarding module, an energy detection module, a signal fusion module, a digital down-conversion module, a low-pass filtering module and a digital up-conversion module.
5. The improved apparatus for doppler shift of multi-target radar signals according to claim 4, wherein said signal store-and-forward module is configured to generate multiple different analog signals according to the acquired analog distances of the different radar signals; the input end of the signal storage forwarding module is used for inputting different radar signals acquired from outside, and the output end of the signal storage forwarding module is electrically connected to the input ends of the energy detection module and the signal fusion module respectively.
6. The improved apparatus for doppler shift of a multi-target radar signal of claim 5, wherein the energy detection module is configured to perform energy detection on the analog signal; the output end of the energy detection module is also electrically connected to the input end of the signal fusion module.
7. The improved apparatus for doppler shift of multi-target radar signals according to claim 6, wherein said signal fusion module is configured to perform signal fusion on said analog signal and said energy detected signal; the output end of the signal fusion module is electrically connected to the input end of the digital down-conversion module.
8. The improved apparatus for doppler shifting of multi-target radar signals of claim 7, wherein the digital down conversion module is configured to digitally down convert the fused signal, and wherein an output of the digital down conversion module is electrically connected to an input of the low pass filter module.
9. The improved apparatus for doppler shift of a multi-target radar signal of claim 8, wherein the low pass filtering module is configured to perform low pass filtering; the output end of the low-pass filtering module is electrically connected to the input end of the digital up-conversion module.
10. The improved apparatus for doppler shifting of multi-target radar signals of claim 9, wherein the digital up-conversion module is configured to perform digital up-conversion; the output end of the energy detection module is also electrically connected to the input end of the digital up-conversion module; the digital up-conversion module has a frequency point real-time frequency conversion function, and the DDS frequency points are refreshed in real time aiming at different signals.
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| CN202410992834.9A CN118534431B (en) | 2024-07-24 | Improved algorithm and device for Doppler frequency shift of multi-target radar signal |
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| CN202410992834.9A CN118534431B (en) | 2024-07-24 | Improved algorithm and device for Doppler frequency shift of multi-target radar signal |
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