CN105301592B - Using the multi-targets recognition algorithm of automobile anti-collision radar system - Google Patents

Using the multi-targets recognition algorithm of automobile anti-collision radar system Download PDF

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CN105301592B
CN105301592B CN201510654175.9A CN201510654175A CN105301592B CN 105301592 B CN105301592 B CN 105301592B CN 201510654175 A CN201510654175 A CN 201510654175A CN 105301592 B CN105301592 B CN 105301592B
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radar
signal
fmcw
modulation
fsk
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CN105301592A (en
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张鉴
童睿
戚昊琛
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Hefei University of Technology
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Hefei University of Technology
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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01SRADIO 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
    • G01S13/00Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88Radar or analogous systems specially adapted for specific applications
    • G01S13/93Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles

Abstract

The invention discloses a kind of automobile anti-collision radar system and its multi-targets recognition algorithm, the automobile anti-collision radar system includes modulation circuit, modulating mode controller, FMCW/FSK dual-role radars, radar system switch, radio-frequency front-end, IF process module, data processing module;The multi-targets recognition algorithm includes 6 steps.Beneficial technique effect:The present invention is not in the case where increasing amount of calculation and hardware cost, compared with the system singly modulated using frequency modulated continuous wave radar, multi-target detection matching can be made clear and definite, compared with the system singly modulated using frequency shift keying radar, static and motion state target component can be measured simultaneously, make radar system can be while effectively recognizing and detecting static and motion state single or multiple targets.

Description

Using the multi-targets recognition algorithm of automobile anti-collision radar system
Technical field
The present invention relates to automobile collision avoidance radar technical field, more particularly to a kind of automobile anti-collision radar system and using its Multi-targets recognition algorithm.
Background technology
In domestic and international existing car radar measuring system, front-end detection is used as frequently with CW with frequency modulation (FMCW) radar Sensor.Fmcw radar has the advantages that high sensitivity and High Range Resolution, but it is fuzzy, difficult to there is easily generation difference frequency matching To detect the shortcoming of multiple targets simultaneously.
Now conventional software settling mode is:Frequency spectrum is carried out to the intermediate-freuqncy signal of acquisition by computational methods in receiving terminal With processing.Or in transmitting terminal by setting the modulating mode of regular variable period or random variable period, then calculated by the later stage Eliminate the empty target that multi-targets recognition is produced.But these method difficult, modulation because frequency spectrum is matched being improved for fmcw radar Signal period is long or the excessively reason such as complexity, all operand can be increased severely so that execution cycle is long, influence system operating Speed, can also decline accuracy of detection.High-performance hardware is needed to realize, so as to increase hardware cost.
Now conventional hardware solutions are:Made simultaneously with system or different radar using multi-section in same investigative range Mode, this mode will certainly be significantly increased hardware cost, and can produce interference problem.
Frequency shift keying (FSK) though radar can measure multiple moving targets simultaneously, when geo-stationary between multiple target then not It can detect, and its accuracy of detection is not high, and later stage signal transacting need to be relied on during exclusive use.
Recently as the development of Radar Technology, though many radars have two kinds of modulating modes of FSK and FMCW simultaneously, together A kind of modulating mode is only used in one time.
The content of the invention
The invention aims to solve shortcoming present in prior art, and a kind of automobile collision avoidance radar system proposed System and use its multi-targets recognition algorithm, this radar arrangement and algorithm can not only detect single goal apart from speed, also may be used Identification and detection multiple target apart from speed.
The technical solution adopted by the present invention is:
A kind of automobile anti-collision radar system, including modulation circuit 11, modulating mode controller 17, CW with frequency modulation FMCW/ Frequency shift keying fsk dual-role radar 12, radar system switch 16, radio-frequency front-end 13, IF process module 14, data processing mould Block 15.Wherein,
Modulation circuit 11 is responsible for producing the modulation waveform wave band and the modulating wave suitable for FSK radars suitable for fmcw radar Shape wave band.
Modulating mode controller 17 is responsible for control modulation circuit 11.Modulating mode controller 17 is by the time command received Make the output signal of modulation circuit 11 within a cycle, both including the modulation waveform wave band one section suitable for fmcw radar, wrap again One section of modulation waveform wave band for being applied to FSK radars is included, in other words, it is adaptable to the modulation waveform wave band of fmcw radar and be applied to The modulation waveform band combination of FSK radars is the repetition modulation waveform of a cycle.
Radar system switch 16 is responsible for synchronous with modulating mode controller 17, and radar system switch 16 is by receiving The working system of time command switching FMCW/FSK dual-role radars 12.
FMCW/FSK dual-role radars 12 are responsible for difunctional with fmcw radar and FSK radars, produce modulated signal.
The modulated signal that radio-frequency front-end 13 is responsible for exporting FMCW/FSK dual-role radars 12 is exported by voltage controlled oscillator The echo-signal obtained after transmission signal, with discovery target is mixed in frequency mixer, exports the intermediate-freuqncy signal containing interference.
The intermediate-freuqncy signal containing interference that IF process module 14 is responsible for exporting radio-frequency front-end is amplified the processing such as filtering, Export effective intermediate-freuqncy signal.
Data processing module 15 is responsible for instructing to modulating mode controller 17 and radar system by modulating mode output time Switch 16.Effective intermediate-freuqncy signal is subjected to time-domain and frequency-domain etc. and calculates analysis, the target range velocity information needed for obtaining.Will meter Feedback of the information is calculated to IF process module 14, the gain amplifier of the intermediate-freuqncy signal containing interference is controlled.
The input of modulation circuit 11 is connected with the output end of modulating mode controller 17.
The output end of modulation circuit 11, the output end of radar system switch 16 respectively with FMCW/FSK dual-role radars 12 Input is connected.
The output end of FMCW/FSK dual-role radars 12 is connected through radio-frequency front-end 13 with the input of IF process module 14 Connect.
IF process module 14 is connected with data processing module 15, and two-way communication.
The input of the output end of data processing module 15 respectively with radar system switch 16 and modulating mode controller 17 End is connected.Modulating mode controller 17 is connected with radar system switch 16, and two-way communication.
Using the multi-targets recognition algorithm of automobile anti-collision radar system of the present invention, carry out as follows:
Step 1:By the modulating mode manually set, set by data processing module 15 to the input of modulating mode controller 17 Fix time instruction.Modulation circuit 11 is controlled by modulating mode controller 17, the time received by modulating mode controller 17 refers to Order makes the output signal of modulation circuit 11 within a cycle, and the output signal includes one section of modulating wave for being applied to fmcw radar Shape wave band, and one section of modulation waveform wave band suitable for FSK radars, in other words, it is adaptable to the modulation waveform wave band of fmcw radar With the repetition modulation waveform that the modulation waveform band combination suitable for FSK radars is a cycle.
Step 2:By the modulating mode manually set, set by data processing module 15 to the input of radar system switch 16 Fix time instruction, make radar system switch 16 synchronous with modulating mode controller 17, switch by the time command received
The working system of FMCW/FSK dual-role radars 12.
Step 3:In step 1, the double work(of FMCW/FSK after the control of modulation waveform input step 2 that modulation circuit 11 is produced The sensor of energy radar 12, obtains modulated signal.
Step 4:Modulated signal as obtained by radio-frequency front-end 13 by step 3 is converted into the intermediate-freuqncy signal containing interference.It is described Intermediate-freuqncy signal containing interference is the information such as target range speed containing needed for, but simultaneously containing high frequency spurs and dry by noise Disturb and intermediate-freuqncy signal that amplitude is small.
Step 5:As IF process module 14 to the IF signal processing obtained by step 4, effective intermediate-freuqncy signal is obtained.Institute It is by filtering out high frequency spurs, noise jamming and after amplification, can be used for the intermediate frequency letter calculated to state effective intermediate-freuqncy signal Number.
Step 6:As data processing module, 15 pairs are analyzed and processed as effective intermediate-freuqncy signal obtained by step 5, needed for obtaining The single or multiple targets of geo-stationary and/or relative motion state apart from velocity information.By 15 pairs of data processing module Intermediate-freuqncy signal containing interference obtained by step 4 is amplified the calculating of parameter, and by this parameter feedback to IF signal processing module 14。
It is preferred that, in a kind of automobile anti-collision radar system of the present invention:
Radio-frequency front-end 13 includes voltage controlled oscillator and frequency mixer.
IF process module 14 includes filter circuit, variable gain amplifier, peak-detector circuit, adc circuit.
Data processing module 15 includes DAC-circuit, fifo circuit, by data processor circuits of the DSP or FPGA for core. It is preferred that, using the modulated signal in the multi-targets recognition algorithm of automobile anti-collision radar system of the present invention, in step 1, The modulating mode manually set is while has the modulation feature of fmcw radar and FSK radars.Wherein, it is adaptable to fmcw radar Modulation waveform is the composite wave of sawtooth waveforms, triangular wave or sawtooth waveforms and triangular wave, it is adaptable to which the modulation waveform of FSK radars is rank Jump waveform.
In step 3, it is applied to FSK radars containing one section of wave band for being applied to fmcw radar modulation waveform and one section to modulate The formula of the modulated signal of the wave band of waveform is:
Wherein, f0For the centre frequency of signal, Δ f is the bandwidth of radar, and T is the modulated signal cycle, and a=2 Δs f/T is suitable The slope that audio range frequency for fmcw radar modulation waveform changes.
In step 4, the transmission signal exported through voltage controlled oscillator in radio-frequency front-end 13 is:
Above-mentioned transmission signal meets the echo-signal obtained after target:
Wherein ArIt is that signal launches affected amplitude, n after antenna propagation from oscillatorr(t) it is noise signal.
It is preferred that, in the multi-targets recognition algorithm using automobile anti-collision radar system of the present invention, in step 6, Analyze and process effective intermediate-freuqncy signal can obtain geo-stationary and relative motion state single or multiple targets apart from speed letter Breath, detailed process is as follows:
(a) when single or multiple targets and radar geo-stationary, radar system is by being applied to FMCW in modulated signal The intermediate-freuqncy signal that radar modulation waveform wave band is obtained, after being calculated by IF process and Fast Fourier Transform (FFT), obtains the wave band Each peak value f of intermediate-freuqncy signal spectrogrammi, wherein i=1,2..... is the quantity for finding target.So as to obtain single or multiple quiet The only distance of target
I=1,2......Wherein Δ f is the bandwidth of radar, and T is the modulated signal cycle, and c is the light velocity.
B passes through the Doppler's frequency obtained in any wave band of modulated signal when single target and radar generation relative motion Move, obtain target relative velocity v=fdλ/2, wherein fdFor Doppler frequency shift, λ is radar wavelength.
C is when with radar relative motion occurs for multiple targets, and radar system is by being applied to FSK radars in modulated signal Modulation waveform wave band occur Doppler frequency shift, can recognize that each moving target, by filtering, Fast Fourier Transform (FFT) calculate and The distance of each target is can obtain after modulation /demodulationWherein i=1,2..... Δs φiFor the phase of each echo signal Difference, B is radar bandwidth.
It is preferred that, in a kind of automobile anti-collision radar system of the present invention and its multi-targets recognition algorithm of use, In step 6, amplifying parameters feedback procedure is:Intermediate-freuqncy signal containing interference is put through the adjustable gain in IF signal processing module 14 Big device carries out pre-amplification, and input peak-detector circuit detection signal amplitude, input adc circuit obtains numeral after carrying out analog-to-digital conversion The calculating of parameter is amplified in the signal amplitude of amount, input data processing module 15, passes through the DAC in data processing module 15 Circuit carries out digital-to-analogue conversion into the control signal of analog quantity, feeds back to the variable gain amplifier in IF signal processing module 14 Complete the enhanced processing of the intermediate-freuqncy signal containing interference.
It is preferred that, the finding range of automobile anti-collision radar system detection target of the present invention is 0-150m, and test the speed scope For 0-220km/h, error allowed band is ± 10%;The centre frequency of FMCW/FSK dual-role radars 12 is 10-90GHz, ripple A length of 3-30mm, carrier bandwidths are 5-200MHz, and tuning sensitivity is 100-400MHz/V.The modulation period of modulated signal is 4- 400us。
Beneficial effect
The present invention is directed to the demand for effectively recognizing and detecting simultaneously static and/or motion state single or multiple targets, On the basis of hardware cost and amount of calculation is not increased, with reference to fmcw radar and the respective advantage of FSK radars, it is proposed that a kind of vapour Car anti-collision radar system and its multi-targets recognition algorithm is used, can meet and detect the static single or multiple mesh with motion state Target precision and efficiency requirements.
The present invention be directed to current anti-collision system for automobile in commonly use fmcw radar effectively recognize and detect at the same time it is static with Deficiency in terms of the multiple target of motion state, based on the synergy of FSK radars, proposes a kind of radar system structure and its calculation Method.The algorithm was used within a modulation period, was applicable by one section of waveform wave band modulated suitable for fmcw radar and another section The modulation system for the waveform band combination modulated in FSK radars is right respectively using the cyclically-varying feature of frequency modulating signal The single goal or multiple target of inactive state and/or motion state realize effective distance and velocity measuring, and do not increase hardware into Sheet and amount of calculation.The present invention combines the modulation feature of fmcw radar and FSK radars, when target occurs, and radar system is by adjusting The first half cycle of signal processed and later half cycle can effectively recognize geo-stationary and/or the single or multiple mesh of relative motion state Mark, carries out after corresponding filtering process and data processing, can obtain required apart from velocity information.Meanwhile, the present invention is not increasing Plus in the case of amount of calculation and hardware cost, compared with the system singly modulated using frequency modulated continuous wave radar, multiple target can be examined Survey matching is clear and definite, compared with the system singly modulated using frequency shift keying radar, and static and motion state target can be measured simultaneously Parameter, makes radar system can be while effectively recognizing and detecting static and motion state single or multiple targets.
The present invention is emulated and verified to the algorithm proposed using Matlab, shows that the algorithm can not only accurately be caught Detected target is caught, and has higher precision in the measurements, it is adaptable to the measurement of automobile collision avoidance radar under steam.
Brief description of the drawings
Fig. 1 is the theory diagram of structure of the present invention.
Fig. 2 is radar modulated signal figure of the invention.
Fig. 3 is the simulated spectrum that radar system of the present invention finds to obtain after 30m and the targets of 90m bis- under inactive state Figure.As seen from Figure 3, there is peak value in Fourier transformation at 9.766KHz and 29.88KHz, can be in the hope of distance now 29.298m and 89.64m, the error with actual range is respectively 2.3% and 4.4%, in error allowed band.
Fig. 4 is that radar system of the present invention is found under motion state, apart from 10m, speed 18.5m/s and apart from 100m, speed What is obtained after the targets of 36m/s bis- does not demodulate simulated spectrum figure.
Fig. 5 is the signal waveforms that will be obtained after 10m, speed 18.5m/s target demodulation under motion state in Fig. 4.
Fig. 6 is the signal waveforms that will be obtained after 100m, speed 36m/s target demodulation under motion state in Fig. 4.
Fig. 7 is amplifying parameters process of feedback figure of the present invention.
Embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete Site preparation is described, it is clear that described embodiment is only a part of embodiment of the invention, rather than whole embodiments.It is based on Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under the premise of creative work is not made Embodiment, belongs to the scope of protection of the invention.
Referring to Fig. 1, a kind of automobile anti-collision radar system, including modulation circuit 11, modulating mode controller 17, frequency modulation are continuous Ripple FMCW/ frequency shift keying fsks dual-role radar 12, radar system switch 16, radio-frequency front-end 13, IF process module 14, number According to processing module 15.Wherein,
Modulation circuit 11 is responsible for producing the modulation waveform wave band and the modulating wave suitable for FSK radars suitable for fmcw radar Shape wave band.
Modulating mode controller 17 is responsible for control modulation circuit 11.Modulating mode controller 17 is by the time command received Make the output signal of modulation circuit 11 within a cycle, both including the modulation waveform wave band one section suitable for fmcw radar, wrap again One section of modulation waveform wave band for being applied to FSK radars is included, in other words, it is adaptable to the modulation waveform wave band of fmcw radar and be applied to The modulation waveform band combination of FSK radars is the repetition modulation waveform of a cycle.
Radar system switch 16 is responsible for synchronous with modulating mode controller 17, and radar system switch 16 is by receiving The working system of time command switching FMCW/FSK dual-role radars 12.
FMCW/FSK dual-role radars 12 are responsible for difunctional with fmcw radar and FSK radars, produce modulated signal.
The modulated signal that radio-frequency front-end 13 is responsible for exporting FMCW/FSK dual-role radars 12 is exported by voltage controlled oscillator The echo-signal obtained after transmission signal, with discovery target is mixed in frequency mixer, exports the intermediate-freuqncy signal containing interference.
The intermediate-freuqncy signal containing interference that IF process module 14 is responsible for exporting radio-frequency front-end is amplified the processing such as filtering, Export effective intermediate-freuqncy signal.
Data processing module 15 is responsible for instructing to modulating mode controller 17 and radar system by modulating mode output time Switch 16.Effective intermediate-freuqncy signal is subjected to time-domain and frequency-domain etc. and calculates analysis, the target range velocity information needed for obtaining.Will meter Feedback of the information is calculated to IF process module 14, the gain amplifier of the intermediate-freuqncy signal containing interference is controlled.
The input of modulation circuit 11 is connected with the output end of modulating mode controller 17.
The output end of modulation circuit 11, the output end of radar system switch 16 respectively with FMCW/FSK dual-role radars 12 Input is connected.
The output end of FMCW/FSK dual-role radars 12 is connected through radio-frequency front-end 13 with the input of IF process module 14 Connect.
IF process module 14 is connected with data processing module 15, and two-way communication.
The input of the output end of data processing module 15 respectively with radar system switch 16 and modulating mode controller 17 End is connected.Modulating mode controller 17 is connected with radar system switch 16, and two-way communication.
Furtherly, radio-frequency front-end 13 includes voltage controlled oscillator and frequency mixer.
IF process module 14 includes filter circuit, variable gain amplifier, peak-detector circuit, adc circuit.
Data processing module 15 includes DAC-circuit, fifo circuit, by data processor circuits of the DSP or FPGA for core. Using the multi-targets recognition algorithm of automobile anti-collision radar system of the present invention, carry out as follows:
Step 1:By the modulating mode manually set, set by data processing module 15 to the input of modulating mode controller 17 Fix time instruction.Modulation circuit 11 is controlled by modulating mode controller 17, the time received by modulating mode controller 17 refers to Order makes the output signal of modulation circuit 11 within a cycle, and the output signal includes one section of modulating wave for being applied to fmcw radar Shape wave band, and one section of modulation waveform wave band suitable for FSK radars, in other words, it is adaptable to the modulation waveform wave band of fmcw radar With the repetition modulation waveform that the modulation waveform band combination suitable for FSK radars is a cycle.
Step 2:By the modulating mode manually set, set by data processing module 15 to the input of radar system switch 16 Fix time instruction, make radar system switch 16 synchronous with modulating mode controller 17, switch by the time command received
The working system of FMCW/FSK dual-role radars 12.
Step 3:In step 1, the double work(of FMCW/FSK after the control of modulation waveform input step 2 that modulation circuit 11 is produced The sensor of energy radar 12, obtains modulated signal.
Step 4:Modulated signal as obtained by radio-frequency front-end 13 by step 3 is converted into the intermediate-freuqncy signal containing interference.It is described Intermediate-freuqncy signal containing interference is the information such as target range speed containing needed for, but simultaneously containing high frequency spurs and dry by noise Disturb and intermediate-freuqncy signal that amplitude is small.
Step 5:As IF process module 14 to the IF signal processing obtained by step 4, effective intermediate-freuqncy signal is obtained.Institute It is by filtering out high frequency spurs, noise jamming and after amplification, can be used for the intermediate frequency letter calculated to state effective intermediate-freuqncy signal Number.
Step 6:As data processing module, 15 pairs are analyzed and processed as effective intermediate-freuqncy signal obtained by step 5, needed for obtaining The single or multiple targets of geo-stationary and relative motion state apart from velocity information.By data processing module 15 to step The amplifying parameters of 4 intermediate-freuqncy signals of the gained containing interference are calculated, and by this parameter feedback to IF signal processing module 14.
Furtherly, in step 1, the modulating mode manually set is while has the tune of fmcw radar and FSK radars Feature processed.Wherein, it is adaptable to which the modulation waveform of fmcw radar is the composite wave of sawtooth waveforms, triangular wave or sawtooth waveforms and triangular wave, Modulation waveform suitable for FSK radars is step waveform.
In step 3, it is applied to FSK radars containing one section of wave band for being applied to fmcw radar modulation waveform and one section to modulate The formula of the modulated signal of the wave band of waveform is:
Wherein, f0For the centre frequency of signal, Δ f is the bandwidth of radar, and T is the modulated signal cycle, and a=2 Δs f/T is suitable The slope that audio range frequency for fmcw radar modulation waveform changes.
In step 4, the transmission signal exported through voltage controlled oscillator in radio-frequency front-end 13 is:
Above-mentioned transmission signal meets the echo-signal obtained after target:
Wherein ArIt is that signal launches affected amplitude, n after antenna propagation from oscillatorr(t) it is noise signal.
Furtherly, in step 6, analyze and process effective intermediate-freuqncy signal and can obtain geo-stationary and relative motion state Single or multiple targets apart from velocity information, detailed process is as follows:
(a) when single or multiple targets and radar geo-stationary, radar system is by being applied to FMCW in modulated signal The intermediate-freuqncy signal that radar modulation waveform wave band is obtained, after being calculated by IF process and Fast Fourier Transform (FFT), obtains the wave band Each peak value f of intermediate-freuqncy signal spectrogrammi, wherein i=1,2..... is the quantity for finding target.So as to obtain single or multiple quiet The only distance of target
I=1,2......Wherein Δ f is the bandwidth of radar, and T is the modulated signal cycle, and c is the light velocity.
B passes through the Doppler's frequency obtained in any wave band of modulated signal when single target and radar generation relative motion Move, obtain target relative velocity v=fdλ/2, wherein fdFor Doppler frequency shift, λ is radar wavelength.
C is when with radar relative motion occurs for multiple targets, and radar system is by being applied to FSK radars in modulated signal Modulation waveform wave band occur Doppler frequency shift, can recognize that each moving target, by filtering, Fast Fourier Transform (FFT) calculate and The distance of each target is can obtain after modulation /demodulationWherein i=1,2..... Δs φiFor the phase of each echo signal Difference, B is radar bandwidth.
From fig. 4, it can be seen that Doppler frequency shift is respectively 3.047KHz and 5.977KHz, can be calculated target velocity is respectively 18.1m/s, 35.7m/s, relative error are respectively 4% and 3%, in error allowed band.
It is 9.62m that phase difference, which can calculate distance, in Fig. 5, and error is 3.8%, in error allowed band.
It is 91.4m that phase difference, which can calculate distance, in Fig. 6, and error is 9.6%, in error allowed band.
Referring to Fig. 7, furtherly, in step 6, amplifying parameters feedback procedure is:Intermediate-freuqncy signal containing interference is through intermediate frequency Variable gain amplifier in signal processing module 14 carries out pre-amplification, input peak-detector circuit detection signal amplitude, input Adc circuit obtain after analog-to-digital conversion being amplified parameter in the signal amplitude of digital quantity, input data processing module 15 Calculate, digital-to-analogue conversion is carried out into the control signal of analog quantity by the DAC-circuit in data processing module 15, feed back to intermediate frequency letter Variable gain amplifier in number processing module 14 completes the enhanced processing of the intermediate-freuqncy signal containing interference.
Furtherly, the finding range of automobile anti-collision radar system detection target is 0-150m, and the scope that tests the speed is 0- 220km/h, error allowed band is ± 10%.The centre frequency of FMCW/FSK dual-role radars 12 is 10-90GHz, and wavelength is 3-30mm, carrier bandwidths are 5-200MHz, and tuning sensitivity is 100-400MHz/V.The modulation period of modulated signal is 4- 400us。
Hardware, method characteristic in conjunction with the present invention are further described below:Fig. 1 is the radar arrangement that the present invention is used, Including modulation circuit 11, modulating mode controller 17, CW with frequency modulation/frequency shift keying dual-role radar 12, radar system switching Device 16, radio-frequency front-end 13, IF process module 14 and data processing module 15.
Modulation module controller 17 controls modulation circuit 11, and the temporal regularity set by modulating mode makes modulation circuit 11 defeated Go out modulation waveform.Radar system switch 16 is synchronous with modulation module controller 17, and the temporal regularity set by modulating mode is cut Change the working system of CW with frequency modulation/frequency shift keying dual-role radar 12.The modulation waveform input that modulation circuit 11 is exported is controlled CW with frequency modulation/frequency shift keying dual-role radar sensor 12, make its export modulated signal.Modulated signal is through radio-frequency front-end 13 The transmission signal of output is mixed with the echo-signal for finding to obtain after target, obtains the intermediate-freuqncy signal containing interference.Through intermediate frequency Effective intermediate-freuqncy signal is obtained after the processing of signal processing module 14.After effective intermediate-freuqncy signal is analyzed and processed through data processing module 15, The single or multiple targets of geo-stationary and relative motion state needed for obtaining apart from velocity information, while exporting feedback letter Number give IF signal processing module 14, to ensure counting accuracy.
Fig. 2 is the period of change of frequency modulating signal of the present invention, in diagram linear relationship.It is within a modulation period, knot Unify wave band and another section of wave band suitable for FSK radar modulation waveforms that section is applied to fmcw radar modulation waveform, with two Person modulates feature.The formula of modulated signal is:
Wherein, f0For the centre frequency of signal, Δ f is the bandwidth of radar, and a=2 Δs f/T is first half cycle sawtooth waveforms wave band The slope of frequency change
The transmission signal that above-mentioned modulated signal is exported by the voltage controlled oscillator of automobile collision avoidance radar radio-frequency front-end can be with table It is shown as:
It was found that the echo-signal after target can be expressed as:
Wherein ArIt is that signal launches affected amplitude, n after antenna propagation from oscillatorr(t) it is noise signal.
For the single or multiple targets of geo-stationary, how general do not occur in the later half cycle step wave wave band of modulation waveform Frequency displacement is strangled, but radar system can obtain target information using the intermediate-freuqncy signal obtained in first half cycle sawtooth waveforms wave band.It is sent out Penetrate signal S11It is represented by:
Echo-signal S21For:
The intermediate-freuqncy signal S obtained after filtering after mixing1' be:
Make f0td-Δftd/2-Δftd2/T=φ1,AtAr=Am, then intermediate-freuqncy signal S1' be represented by:
From formula 6, the t of target range information is includeddJust in expression formula.Fast Fourier is carried out to intermediate-freuqncy signal Convert FFT to calculate, it is possible to the frequency information of signal is drawn, in certain fm=Δ ftdMaximum is obtained at/T, what each target was obtained Peak value is fmi, wherein i=1,2....., to find the quantity of target, now the distance of each target is represented by:
Δ f is the bandwidth of radar, and T is the modulated signal cycle, and c is the light velocity.
Therefore, the range information of target can be obtained at the peak value of the intermediate-freuqncy signal spectrogram of this wave band.
When relative motion occurs for single target and radar, pass through the Doppler frequency shift obtained in any wave band of modulated signal It is identical, target relative velocity v=f can be tried to achievedλ/2, wherein fdFor Doppler frequency shift, λ is radar wavelength.
When target and radar have relative motion, although can also capture target information by first half cycle, but when multiple False target occurs when target occurs, obvious target information now can be captured by later half cycle step wave wave band.
Now the transmission signal of radar can be expressed as:
Wherein f2=f0+B/2,f1=f0- B/2, n=0,1,2 ...
When detecting objects ahead, echo-signal is:
Wherein n=0,1,2 ... .., fd1,fd2For the Doppler frequency shift under same target different-waveband
Signal after mixing:
Waveform after mixing removes high frequency and DC terms, and the intermediate-freuqncy signal that noise signal is obtained after bandpass filtering For:
Wherein n=0,1,2 ... ..,The phase of two sections of intermediate-freuqncy signals.
BecauseIt can obtain
From above formula, the velocity information v of target can pass through Doppler frequency shift fd1、fd2To obtain.Wherein λ1、λ2 , can be by the frequency f of radar tuning signal for wavelength1、f2Calculate and obtain.The conventional tuning signal of millimeter-wave automotive anti-collision radar Frequency is between 10GHz-90GHz, and radar modulating bandwidth Δ f of the invention is megahertz rank, therefore, corresponding to a target The intermediate-freuqncy signal obtained, decompositing the signal come has identical Doppler frequency shift.
When there are multiple different motion objects in front, the different object of speed then has different Doppler frequency shifts, can lead to The frequency spectrum for crossing analysis unlike signal comes multiple target identifications of friction speed.
By (12) formula S '2Understand, intermediate-freuqncy signal can be demodulated to two signals that phase is different, frequency is almost identical again, It is possible thereby to the range information of target be obtained by analyzing the phase difference and difference on the frequency of the two signals, as shown in (15) formula.
The distance of multiple targetsWherein i=1,2..... Δs φiFor the phase difference of each echo signal, B is thunder Up to bandwidth.
So far, the identification and measuring and calculating of the multiple target under motion state can be completed.
In order to prove the algorithm feasibility of the present invention, matlab emulation experiments are carried out, experiment is to geo-stationary and phase The measurement that multiple target to motion is carried out.
By selected each relevant parameter:It is set to 400us modulation periods, carrier bandwidths Δ f is set to 10MB, and centre frequency is set to 24GHz, fundamental wavelength is set to 12mm or so.Tuning sensitivity is set to Kv=200MHz/V, substitutes into the journey that matlab is integrally emulated In sequence, to transmission signal, echo-signal and respectively to the intermediate-freuqncy signal obtained by the target under different motion state and different distance Analog simulation is carried out, final simulation result can be obtained.
First the multiple target to inactive state is detected, the tested distance respectively 30m and 90m of target, now from preceding half cycle The frequency spectrum for the intermediate-freuqncy signal that phase obtains is as shown in Figure 3, it is seen that peak value occurs in Fourier transformation at 9.766KHz and 29.88KHz, Can be 29.298m and 89.64m in the hope of the distance measured now, error is respectively 2.3% and 4.4%, is existed by formula 8 In error allowed band.
When relative motion occurs for target and radar, analyzed by the later half cycle, one of target is tested distance 10m, tested speed 18.5m/s, when another target is tested apart from 100m, tested speed 36m/s, the intermediate-freuqncy signal not demodulated Frequency spectrum is as shown in Figure 4.Understand that Doppler frequency shift is respectively 3.047KHz and 5.977KHz, can calculate target velocity is respectively 18.1m/s, 35.7m/s, relative error are respectively 4% and 3%.Two signals and its phase difference such as Fig. 5, Fig. 6 institute after demodulation Show, it is respectively 9.62m and 91.4m that can calculate two distances, error is respectively 3.8% and 9.6%, allows model in error In enclosing.
Simulation result shows, set forth herein this multi-targets recognition algorithm, its performance reaches set design object, can Accurately identify and detect simultaneously the speed and range information of single or multiple targets.
The foregoing is only a preferred embodiment of the present invention, but protection scope of the present invention be not limited thereto, Any one skilled in the art the invention discloses technical scope in, technique according to the invention scheme and its Inventive concept is subject to equivalent substitution or change, should all be included within the scope of the present invention.

Claims (5)

1. using the multi-targets recognition algorithm of automobile anti-collision radar system, the automobile anti-collision radar system includes modulation circuit (11), modulating mode controller (17), FMCW/FSK dual-role radars (12), radar system switch (16), radio-frequency front-end (13), IF process module (14), data processing module (15);Wherein,
Modulation circuit (11) is responsible for producing the modulation waveform wave band and the modulation waveform suitable for FSK radars suitable for fmcw radar Wave band;Wherein, it is adaptable to which the modulation waveform of fmcw radar is the composite wave of sawtooth waveforms, triangular wave or sawtooth waveforms and triangular wave, is fitted Modulation waveform for FSK radars is step waveform;The modulation waveform of generation is that fmcw radar is applicable waveform in a cycle The combined waveform that modulation waveform respectively accounts for certain wave band is applicable with FSK radars;
Modulating mode controller (17) is responsible for control modulation circuit (11);Modulating mode controller (17) is referred to by the time received Order makes the output signal of modulation circuit (11) within a cycle, both including the modulation waveform wave band one section suitable for fmcw radar, Include one section of modulation waveform wave band for being applied to FSK radars again, in other words, it is adaptable to the modulation waveform wave band of fmcw radar and suitable Modulation waveform band combination for FSK radars is the repetition modulation waveform of a cycle;
Radar system switch (16) is responsible for synchronous with modulating mode controller (17), and radar system switch (16) is by receiving Time command switching FMCW/FSK dual-role radars (12) working system;
FMCW/FSK dual-role radars (12) are responsible for difunctional with fmcw radar and FSK radars, produce modulated signal;
Radio-frequency front-end (13) is responsible for exporting the modulated signal that FMCW/FSK dual-role radars (12) are exported by voltage controlled oscillator The echo-signal obtained after transmission signal, with discovery target is mixed in frequency mixer, exports the intermediate-freuqncy signal containing interference;
The intermediate-freuqncy signal containing interference that IF process module (14) is responsible for exporting radio-frequency front-end is amplified filtering process, exports Effective intermediate-freuqncy signal;
Data processing module (15) is responsible for instructing to modulating mode controller (17) and radar system by modulating mode output time Switch (16);Effective intermediate-freuqncy signal is subjected to time-domain and frequency-domain and calculates analysis, the target range velocity information needed for obtaining;Will meter Calculate feedback of the information and give IF process module (14), control the gain amplifier of the intermediate-freuqncy signal containing interference;
The input of modulation circuit (11) is connected with the output end of modulating mode controller (17);
Modulation circuit (11) output end, the output end of radar system switch (16) respectively with FMCW/FSK dual-role radars (12) Input be connected;
Input phase of the output end of FMCW/FSK dual-role radars (12) through radio-frequency front-end (13) with IF process module (14) Connection;
IF process module (14) is connected with data processing module (15), and two-way communication;
The output end of data processing module (15) is defeated with radar system switch (16) and modulating mode controller (17) respectively Enter end to be connected;
Modulating mode controller (17) is connected with radar system switch (16), and two-way communication;
Radio-frequency front-end (13) includes voltage controlled oscillator and frequency mixer;
IF process module (14) includes filter circuit, variable gain amplifier, peak-detector circuit, adc circuit;
Data processing module (15) includes DAC-circuit, fifo circuit, by data processor circuits of the DSP or FPGA for core;
It is characterized in that:Carry out as follows:
Step 1:By the modulating mode manually set, set by data processing module (15) to modulating mode controller (17) input Fix time instruction;By modulating mode controller (17) control modulation circuit (11), received by modulating mode controller (17) Time command makes the output signal of modulation circuit (11) within a cycle, and the output signal includes one section and is applied to fmcw radar Modulation waveform wave band, and one section be applied to FSK radars modulation waveform wave band, in other words, it is adaptable to the modulation of fmcw radar Waveform wave band and suitable for FSK radars modulation waveform band combination be a cycle repetition modulation waveform;
Step 2:By the modulating mode manually set, set by data processing module (15) to radar system switch (16) input Fix time instruction, make radar system switch (16) synchronous with modulating mode controller (17), cut by the time command received Change the working system of FMCW/FSK dual-role radars (12);
Step 3:In step 1, the FMCW/FSK after the modulation waveform input step 2 that modulation circuit (11) is produced is controlled is difunctional The sensor of radar (12), obtains modulated signal;
Step 4:Modulated signal as obtained by radio-frequency front-end (13) by step 3 is converted into the intermediate-freuqncy signal containing interference;It is described to contain The intermediate-freuqncy signal of interference for the target range speed containing needed for information, but simultaneously containing high frequency spurs and by noise jamming and The small intermediate-freuqncy signal of amplitude;
Step 5:As IF process module (14) to the IF signal processing obtained by step 4, effective intermediate-freuqncy signal is obtained;It is described Effective intermediate-freuqncy signal is by filtering out high frequency spurs, noise jamming and after amplification, can be used for the intermediate-freuqncy signal calculated;
Step 6:As data processing module (15) to being analyzed and processed as effective intermediate-freuqncy signal obtained by step 5, required phase is obtained To static and/or relative motion state target apart from velocity information;As data processing module (15) to containing obtained by step 4 The intermediate-freuqncy signal of interference is amplified the calculating of parameter, and by this parameter feedback to IF process module (14).
2. the multi-targets recognition algorithm of automobile anti-collision radar system is used according to claim 1, it is characterised in that:
In step 1, the modulating mode manually set is while has the modulation feature of fmcw radar and FSK radars;Wherein, fit Modulation waveform for fmcw radar is sawtooth waveforms, triangular wave or sawtooth waveforms and the composite wave of triangular wave, it is adaptable to FSK radars Modulation waveform be step waveform;
In step 3, it is applied to FSK radar modulation waveforms containing one section of wave band for being applied to fmcw radar modulation waveform and one section The formula of modulated signal of wave band be:
Wherein, f0For the centre frequency of signal, Δ f is the bandwidth of radar, and T is the modulated signal cycle, a=2 Δs f/T be suitable for The slope of the audio range frequency change of fmcw radar modulation waveform;
In step 4, the transmission signal exported through voltage controlled oscillator in radio-frequency front-end (13) is:
Above-mentioned transmission signal meets the echo-signal obtained after target:
Wherein ArIt is that signal launches affected amplitude, n after antenna propagation from oscillatorr(t) it is noise signal.
3. the multi-targets recognition algorithm of automobile anti-collision radar system is used according to claim 1, it is characterised in that:
In step 6, analyze and process effective intermediate-freuqncy signal and can obtain geo-stationary and the single or multiple mesh of relative motion state Target is apart from velocity information, and detailed process is as follows:
(a) when single or multiple targets and radar geo-stationary, radar system is by being applied to fmcw radar in modulated signal The intermediate-freuqncy signal that modulation waveform wave band is obtained, after being calculated by IF process and Fast Fourier Transform (FFT), is obtained in the wave band Each peak value f of frequency signal spectrum figuremi, wherein i=1,2 ... to find the quantity of target;So as to obtain single or multiple static mesh Target distanceWherein Δ f is the bandwidth of radar, and T is the modulated signal cycle, and c is the light velocity;
(b) when relative motion occurs for single target and radar, by the Doppler frequency shift obtained in any wave band of modulated signal, Obtain target relative velocity v=fdλ/2, wherein fdFor Doppler frequency shift, λ is radar wavelength;
(c) when relative motion occurs for multiple targets and radar, radar system is adjusted by being applied to FSK radars in modulated signal The Doppler frequency shift that waveform wave band processed occurs, can recognize that each moving target, calculates and adjusts by filtering, Fast Fourier Transform (FFT) The distance of each target is can obtain after system demodulationWherein i=1,2 ...;ΔφiFor the phase difference of each echo signal, B For radar bandwidth.
4. the multi-targets recognition algorithm of automobile anti-collision radar system is used according to claim 1, it is characterised in that:
In step 6, amplifying parameters feedback procedure is:Intermediate-freuqncy signal containing interference is through the adjustable increasing in IF process module (14) Beneficial amplifier carries out pre-amplification, and input peak-detector circuit detection signal amplitude, input adc circuit is obtained after carrying out analog-to-digital conversion The calculating of parameter is amplified in the signal amplitude of digital quantity, input data processing module (15), passes through data processing module (15) DAC-circuit in carries out digital-to-analogue conversion into the control signal of analog quantity, feeds back to adjustable in IF process module (14) Gain amplifier completes the enhanced processing of the intermediate-freuqncy signal containing interference.
5. the multi-targets recognition algorithm of automobile anti-collision radar system is used according to claim 1, it is characterised in that:Automobile is prevented Hit radar system detection target finding range be 0-150m, the scope that tests the speed be 0-220km/h, error allowed band for ± 10%;The centre frequency of FMCW/FSK dual-role radars (12) is 10-90GHz, and wavelength is 3-30mm, and carrier bandwidths are 5- 200MHz, tuning sensitivity is 100-400MHz/V;The modulation period of modulated signal is 4-400us.
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