CN108287335A - A method of ranging and range rate being carried out to multiple target using the frequency modulated signal of LFMCW radars - Google Patents

A method of ranging and range rate being carried out to multiple target using the frequency modulated signal of LFMCW radars Download PDF

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Publication number
CN108287335A
CN108287335A CN201810356508.3A CN201810356508A CN108287335A CN 108287335 A CN108287335 A CN 108287335A CN 201810356508 A CN201810356508 A CN 201810356508A CN 108287335 A CN108287335 A CN 108287335A
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frequency
target
modulation
lfmcw
echo
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张轶
梁卫祖
叶常青
刘培育
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Guangzhou Wisdom Ruida Technology Co Ltd
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Guangzhou Wisdom Ruida Technology Co Ltd
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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
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

The invention discloses a kind of frequency modulated signals using LFMCW radars come the method for carrying out ranging and range rate to multiple target, and to existing triangle frequency modulation LFMCW radar FM signals, it is T to increase a lengthm2Modulation period, which is T including 2 lengthm2/ 2 and frequency be respectively fs1And fs2Simple signal；To being solved after two simple signal echo FFT transform | fd|, further according to the phase difference of two simple signal echo spectrum main lobe peak pointsSolve target range R and fR, to obtain | fR±fd| result；By the result and Tm1Result in modulation period after echo FFT transform is matched, and determines the echo spectrum component of moving target；Remaining Tm1Echo spectrum component main lobe is corresponding in modulation period is all | fR|, the corresponding f of static target is directly obtained between positive slope regionR, to obtain the distance R of static target.The present invention simplifies the solution procedure of the multiple target distance of single channel down coversion LFMCW radars, while improving the measurement accuracy of moving target distance.

Description

A kind of frequency modulated signal using LFMCW radars is come to multiple target progress ranging survey The method of speed
Technical field
The invention belongs to radar system technical fields, and in particular to a kind of frequency modulated signal using LFMCW radars come The method that ranging and range rate is carried out to multiple target.
Background technology
LFMCW (linear frequency modulation continuous wave) radar generates and processing broadband signal, can obtain very high range measurement essence Degree, and fuzzy distance will not be introduced, thus be often applied in target distance measurement.The frequency of LFMCW radar emission signals with Linearly variation, is changed generally according to triangle or zigzag rule.The target echo signal and local oscillation signal received It is directly mixed, since frequency modulation(PFM) rule is linear rule, the time difference for receiving signal and emitting between signal can bring Frequency difference, thus the Beat Signal of gained will be frequency and target range linearly related signal after mixing, then can utilize The frequency of Beat Signal carries out ranging to target.
Since Moving Target Return signal frequency has coupled Doppler frequency shift so that only use single-slope segment signal can not be accurate The distance of target is measured, this utilizes the Beat Signal obtained by triangular modulation negative slope section often, with beat obtained by positive slope section Combined signal solves, to solve target range and speed.And in the LFMCW radars using single channel down coversion, positive and negative frequency Rate information is fuzzy, if measured to multiple target, only leaning on positive negative slope section to carry out range-rate measurement can introduce again Miscellaneous frequency spectrum matching and decoupling computational problem.
Invention content
It is a kind of using LFMCW radars present invention aims at providing in order to solve the above problem of the existing technology Frequency modulated signal carrys out the method for carrying out ranging and range rate to multiple target.
The technical solution adopted in the present invention is：
A method of ranging and range rate, including step being carried out to multiple target using the frequency modulated signal of LFMCW radars：
S1, positive slope region is divided between the frequency modulation(PFM) period between negative slope region, frequency fm1, modulation period Tm1 Single channel down coversion structure triangle frequency modulation LFMCW radar FM signals, in every adjacent 2 modulation periods of Tm1Between increase It is T to add a lengthm2Modulation period form new frequency modulation(PFM) combination signal, which is including 2 length Tm2/ 2 and frequency be respectively fs1And fs2Simple signal, the frequency intervals of the two simple signals is Δ f；
S2, to being solved after two simple signal echo FFT transform | fd|, further according to two simple signal echo spectrums The phase difference of main lobe peak pointTarget range R is solved, the f of moving target is then obtainedR, to obtain | fR±fd| knot Fruit；
S3, by the obtained results of S2 and Tm1Result in modulation period after echo FFT transform is matched, and then determines fortune The echo spectrum component of moving-target；
S4, remaining Tm1Echo spectrum component main lobe is corresponding in modulation period is all | fR|, between positive slope region directly Obtain the corresponding f of static targetR, to obtain the distance R of static target.
Specifically, signal such as formula (2) is combined in the new frequency modulation(PFM)：
Wherein fs1=fs2+ Δ f, K=2fm1/Tm1。
Further, in the step S2, | fd| solution procedure be：
First, FFT changes formula such as formula (3)：
WhereinX [k] is discrete digital frequency spectrum, if spectrum peak is in k points, then corresponding Then have
F in formulasampleIt is system sampling frequency, λ is system carrier frequency f0Corresponding wavelength.
Further, in the step S2, the f of target range R and moving targetRSolution procedure is：
First, according to the phase difference of two simple signal echo spectrum main lobe peak pointsTarget range R is found out, is solved Formula such as formula (5)：
C in formula is the light velocity；
Then the f of moving target is obtainedR=KR/2C.
Still further, in the step S5, the distance R=f of static targetR2C/K。
Beneficial effects of the present invention are：
The present invention can simplify the solution procedure of the multiple target distance of single channel down coversion LFMCW radars, to reduce original adjust Waveform processed is in the complexity solved in spectral pair, due in Tm2It is to be moved by phase difference to measure target in modulation period Distance also can improve the precision of range measurement under conditions of not increasing system bandwidth of operation.
Description of the drawings
Fig. 1 is the system construction drawing of existing triangle frequency modulation LFMCW radars.
Fig. 2 is existing triangle frequency modulation LFMCW radar frequency modulation law curves figure (time-frequency curve).
Fig. 3 is the triangle frequency modulation LFMCW radar frequency modulation law curve figures (time-frequency curve) of the present invention.
Specific implementation mode
Below in conjunction with the accompanying drawings and specific embodiment does further explaination to the present invention.
Embodiment 1：
For the triangle frequency modulation LFMCW radars of single channel down coversion structure, the frequency modulation(PFM) period is divided into positive slope region Between between negative slope region, frequency fm1, modulation period Tm1, wherein Fig. 1 is the system structure of triangle frequency modulation LFMCW radars Figure, Fig. 2 are triangle frequency modulation LFMCW radar frequency modulation law curve figures.The triangle frequency modulation LFMCW radars FM signal can indicate For formula (1).
K=2f in formulam1/Tm1。
Radar digital signal processing machine is in each Tm1Beat Signal is carried out between negative slope region between the positive slope region in period FFT transform, since Beat Signal is real signal, the frequency obtained after transformation is Symmetrical, can be only to positive frequency Component f+=| fR±fd| it is analyzed, wherein fRAnd fdCaused by indicating the frequency deviation caused by apart from time delay and movement respectively Doppler shift, it can be seen that due to the f obtained after FFT transform+It is absolute value, in the f for solving multiple targetsRAnd fdWhen need Repeatedly pairing is attempted, and increases solution difficulty.
The side of ranging and range rate is carried out to multiple target the present embodiment provides a kind of frequency modulated signal using LFMCW radars Method includes the following steps：
The first step：Positive slope region being divided between the frequency modulation(PFM) period between negative slope region, frequency fm1, modulation period is Tm1Single channel down coversion structure triangle frequency modulation LFMCW radar FM signals, in every adjacent 2 modulation periods of Tm1It Between to increase length be Tm2Modulation period form new frequency modulation(PFM) combination signal, such as formula (2), which includes 2 A length is Tm2/ 2 and frequency be respectively fs1And fs2Simple signal, the frequency intervals of the two simple signals is Δ f, such as Shown in Fig. 3, Fig. 3 is improved triangle frequency modulation LFMCW radars frequency modulation law curve figure.
Signal such as formula (2) is combined in new frequency modulation(PFM)：
Wherein fs1=fs2+ Δ f, K=2fm1/Tm1
Within the increased modulation period, due to being simple signal, all exist after beat is handled after static target echo Zero-frequency position, can not solve the distance of multiple static targets, but can be used for solving the distance and velocity information of moving target.Tool The solution procedure of body is as follows：
Second step：To being solved after two simple signal echo FFT transform | fd|, FFT transform formula is as follows.
WhereinX [k] is discrete digital frequency spectrum, if spectrum peak is in k points, then corresponding
Then have
F in formulasampleIt is system sampling frequency, λ is system carrier frequency f0Corresponding wavelength.
Further according to the phase difference of two simple signal echo spectrum main lobe peak pointsFind out target range R, solution formula Such as formula (5).
C in formula is the light velocity.
So as to obtain the f of moving targetR=KR/2C
Further can be obtained | fR±fd| result.
Third walks：The result and T that second step is obtainedm1Result in modulation period after echo FFT transform is matched, can To determine the echo spectrum component of moving target.
4th step：Remaining Tm1Echo spectrum component main lobe is corresponding in modulation period is all | fR|, between positive slope region Directly obtain the corresponding f of static targetR, to obtain the R=f of static targetR2C/K
The method of the present invention can reduce original modulation waveform in the complexity solved in spectral pair, and due in Tm2It adjusts Be in period processed by phase difference come measure target movement distance, also can under conditions of not increasing system bandwidth of operation, Improve the precision of range measurement.
It is not limited to above-mentioned optional embodiment, anyone can obtain other various forms under the inspiration of the present invention Product.Above-mentioned specific implementation mode should not be understood the limitation of pairs of protection scope of the present invention, and protection scope of the present invention is answered It is defined in claims when being subject to, and specification can be used for interpreting the claims.

Claims (5)

1. a kind of frequency modulated signal using LFMCW radars is come the method to multiple target progress ranging and range rate, it is characterised in that： Including step：
S1, positive slope region is divided between the frequency modulation(PFM) period between negative slope region, frequency fm1, modulation period Tm1Single-pass The triangle frequency modulation LFMCW radar FM signals of road down coversion structure, in every adjacent 2 modulation periods of Tm1Between increase by one Length is Tm2Modulation period form new frequency modulation(PFM) combination signal, which is T including 2 lengthm2/ 2 and frequency Rate is respectively fs1And fs2Simple signal, the frequency intervals of the two simple signals is Δ f；
S2, to being solved after two simple signal echo FFT transform | fd|, further according to two simple signal echo spectrum main lobes The phase difference of peak pointTarget range R is solved, the f of moving target is then obtainedR, to obtain | fR±fd| result；
S3, by the obtained results of S2 and Tm1Result in modulation period after echo FFT transform is matched, and then determines movement mesh Target echo spectrum component；
S4, remaining Tm1Echo spectrum component main lobe is corresponding in modulation period is all | fR|, it is directly obtained between positive slope region The corresponding f of static targetR, to obtain the distance R of static target.
2. a kind of frequency modulated signal using LFMCW radars according to claim 1 is come to multiple target progress ranging survey The method of speed, it is characterised in that：Signal such as formula (2) is combined in the new frequency modulation(PFM)：
Wherein fs1=fs2+Δf。
3. a kind of frequency modulated signal using LFMCW radars according to claim 2 is come to multiple target progress ranging survey The method of speed, it is characterised in that：In the step S2, | fd| solution procedure be：
First, FFT changes formula such as formula (3)：
WhereinX [k] is discrete digital frequency spectrum, if spectrum peak is in k points, then correspondingThen have
F in formulasampleIt is system sampling frequency, λ is system carrier frequency f0Corresponding wavelength.
4. a kind of frequency modulated signal using LFMCW radars according to claim 3 is come to multiple target progress ranging survey The method of speed, it is characterised in that：In the step S2, the f of target range R and moving targetRSolution procedure is：
First, according to the phase difference of two simple signal echo spectrum main lobe peak pointsTarget range R is found out, solution formula is such as Formula (5)：
C in formula is the light velocity；
Then the f of moving target is obtainedR=KR/2C.
5. a kind of frequency modulated signal using LFMCW radars according to claim 4 is come to multiple target progress ranging survey The method of speed, it is characterised in that：In the step S5, the distance R=f of static targetR2C/K。
CN201810356508.3A 2018-04-19 2018-04-19 A method of ranging and range rate being carried out to multiple target using the frequency modulated signal of LFMCW radars Pending CN108287335A (en)

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CN109932710A (en) * 2018-08-08 2019-06-25 中国航空工业集团公司雷华电子技术研究所 Distant object speed modification method based on sawtooth LFMCW waveform system velocity radar
CN110596671A (en) * 2019-10-16 2019-12-20 云南大学 Optimization processing method and system for LFMCW speed and distance measuring radar
CN110865350A (en) * 2019-11-21 2020-03-06 清华大学 Multi-target distance and speed measuring method and system based on dual-band triangular LFMW radar
CN111650576A (en) * 2020-05-11 2020-09-11 安徽百诚慧通科技有限公司 Speed and distance measuring method and device of FMCW radar system and storage medium
CN112805591A (en) * 2019-06-20 2021-05-14 华为技术有限公司 Radar system
WO2022088314A1 (en) * 2020-10-30 2022-05-05 苏州镭智传感科技有限公司 Target measurement method and apparatus, measurement device and storage medium

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CN105301592A (en) * 2015-10-12 2016-02-03 合肥工业大学 Automotive anti-collision radar system and multi-target identification algorithm utilizing same
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CN112805591A (en) * 2019-06-20 2021-05-14 华为技术有限公司 Radar system
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WO2022088314A1 (en) * 2020-10-30 2022-05-05 苏州镭智传感科技有限公司 Target measurement method and apparatus, measurement device and storage medium

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