CN111913161B - Method for improving NLFM waveform radar target angle measurement precision - Google Patents
Method for improving NLFM waveform radar target angle measurement precision Download PDFInfo
- Publication number
- CN111913161B CN111913161B CN202010575170.8A CN202010575170A CN111913161B CN 111913161 B CN111913161 B CN 111913161B CN 202010575170 A CN202010575170 A CN 202010575170A CN 111913161 B CN111913161 B CN 111913161B
- Authority
- CN
- China
- Prior art keywords
- pulse
- echo signal
- radar target
- radar
- doppler
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 238000005259 measurement Methods 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 38
- 230000006835 compression Effects 0.000 claims abstract description 61
- 238000007906 compression Methods 0.000 claims abstract description 61
- 230000035485 pulse pressure Effects 0.000 claims abstract description 56
- 238000012545 processing Methods 0.000 claims abstract description 32
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 22
- 238000003786 synthesis reaction Methods 0.000 claims abstract description 22
- 238000009825 accumulation Methods 0.000 claims description 22
- 238000005070 sampling Methods 0.000 claims description 7
- 238000001514 detection method Methods 0.000 claims description 6
- 238000013461 design Methods 0.000 abstract description 2
- 238000000691 measurement method Methods 0.000 description 9
- 238000010586 diagram Methods 0.000 description 5
- 238000004088 simulation Methods 0.000 description 4
- 230000000694 effects Effects 0.000 description 2
- 238000000342 Monte Carlo simulation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005094 computer simulation Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 230000003595 spectral effect Effects 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Images
Classifications
-
- 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
- G01S7/414—Discriminating targets with respect to background clutter
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
Landscapes
- 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 method for improving the angle measurement precision of an NLFM waveform radar target, which comprises the following steps: performing first pulse compression processing on the radar target echo signal to obtain a first pulse pressure echo signal; carrying out beam synthesis processing on the first pulse pressure echo signal to obtain a beam synthesis result; doppler frequency shift processing is carried out on the beam synthesis result by adopting a Doppler filter to obtain a Doppler frequency estimated value; performing second pulse compression processing on the radar target echo signal according to the Doppler estimated value to obtain a second pulse pressure echo signal; and carrying out sum-difference beam phase comparison single pulse angle measurement on the second pulse pressure echo signal to obtain a radar target angle measurement. According to the method for improving the angle measurement precision of the NLFM waveform radar target, the Doppler frequency estimation of the radar target echo signal is utilized to design a completely matched impulse response filter, and the impulse compression processing of the radar target echo signal is carried out, so that the signal-to-noise ratio loss of angle estimation data is reduced, and therefore the angle measurement precision is improved and the performance is stable.
Description
Technical Field
The invention belongs to the technical field of radar signal processing, and particularly relates to a method for improving the angle measurement precision of an NLFM waveform radar target.
Background
Non-linear frequency modulation (Non-Linear Frequency Modulation, NLFM) signals can be directly matched filtered without windowing, so that main lobe broadening and signal-to-noise ratio loss caused by windowing are avoided, and the Non-linear frequency modulation (NLFM) signals are widely paid attention to the radar field in recent years.
The target angular accuracy of the radar is also inseparable from the target signal-to-noise ratio, in addition to being affected by the parameters of the system itself, the estimation method and the antenna aperture. Therefore, the method can be used for improving the angle measurement accuracy by improving the signal to noise ratio. Zhao Yongbo et al, "a multipulse angle measurement method under multiple objectives [ A ]. Western An university of electronics science and technology report, 2005,32 (3): the conventional angle measurement method proposed in the 383-386 article is to measure the angle of target data after signal processing (including pulse compression, beam forming, doppler filtering, etc.) of a detection channel by a contrast method, and finally estimate the angle of the target.
However, this method suffers from a loss of signal-to-noise ratio due to its detection channel signal processing, for example, when the radar transmits an NLFM waveform, the impulse response filter for pulse compression does not take into account the doppler information of the target, and there is some loss of signal-to-noise ratio in its output, thereby affecting the angular accuracy of the target.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for improving the target angle measurement precision of an NLFM waveform radar, which comprises the following steps:
step 1, performing first pulse compression processing on a radar target echo signal to obtain a first pulse pressure echo signal;
step 3, doppler processing is carried out on the beam synthesis result by adopting a Doppler filter to obtain a Doppler frequency estimated value;
and step 5, performing sum-difference beam phase-contrast single-pulse angle measurement on the second pulse pressure echo signal to obtain a radar target angle measurement.
In one embodiment of the present invention, the step 1 specifically includes:
step 1.1, radar target echo signals received by N array elements are obtained, wherein the radar target echo signals are expressed as follows:
S＝[S 1 ,S 2 ,...,S N ] T ；
wherein S represents radar target echo signals, S i Represents the radar target echo signal received by the ith array element, i=1, 2,3, N, radar purpose of each array elementTarget echo signal S i ＝[S qr ] M×R, wherein ,Sqr Representing radar target echo signal S i The (R) sampling point of the (q) th pulse, M is the number of received pulses of each array element, R is the number of sampling points in the pulse width of the radar transmitting signal, [] T Representing the vector transpose;
step 1.2, obtaining a pulse compression weight coefficient according to a radar transmitting NLFM waveform, wherein the pulse compression weight coefficient is expressed as:
Y＝[F 1 ,F 2 ，...,F R ] H ；
wherein Y represents a pulse compression weight coefficient, F r An R-th value representing a pulse compression weight coefficient, r=1, 2,3..] H Representing a vector conjugate transpose;
step 1.3, obtaining a first pulse pressure echo signal according to a radar target echo signal and a pulse compression weight coefficient, wherein the first pulse pressure echo signal is expressed as:
X＝[X 1 ,X 2 ,..,X N ] T ；
wherein X represents a first pulse pressure echo signal, X i ＝S i Y represents the first pulse pressure echo signal on the ith element.
In one embodiment of the present invention, the beam synthesis result in the step 2 is expressed as:
P＝a H (θ 0 )X；
where P represents the beam forming result, a (θ 0 )＝[1,exp(j2πdsinθ 0 /λ),...,exp(j2πd(N-1)sinθ 0 /λ)] T Represents a weight vector, exp represents an exponent power based on e, j represents an imaginary unit, d represents an array element pitch, θ 0 Indicating the detection beam direction.
In one embodiment of the present invention, the step 3 specifically includes:
step 3.1, doppler processing is carried out on the beam synthesis result by adopting a Doppler filter to obtain a plurality of amplitude response results;
and 3.2, finding out a frequency point with the maximum corresponding amplitude from the amplitude response results, and correspondingly obtaining the Doppler estimated value according to the frequency point.
In one embodiment of the present invention, the step 4 specifically includes:
step 4.1, pulse accumulation is carried out on the radar target echo signals according to the Doppler estimated value to obtain pulse accumulation results, wherein the pulse accumulation results are expressed as:
G＝[G 1 ,G 2 ,...,G N ] T ；
wherein G represents the pulse accumulation result, G i ＝b(f′ d )S i Representing the pulse accumulation result of the ith element, b (f' d )＝[1,exp(j2πf′ d t r ),...,exp(j2πf′ d ((M-1)t r )]Pilot vector representing target, f d ' represents Doppler frequency estimation value, t r Representing a pulse repetition period;
and 4.2, updating the pulse compression weight coefficient according to the Doppler estimated value to obtain a new pulse compression coefficient, wherein the new pulse compression coefficient is expressed as:
Q＝Y⊙c(f′ d )；
wherein Q represents a new pulse compression coefficient, c (f' d )＝[1,exp(-j2πf′ d t s ),...,exp(-j2πf′ d ((R-1)t s )] T Representing Doppler shift function, t s Indicating the time interval between adjacent samples, +.;
step 4.3, obtaining a second pulse pressure echo signal according to the pulse accumulation result and the new pulse compression coefficient, wherein the second pulse pressure echo signal is expressed as:
Z＝[Z 1 ,Z 2 ,...,Z N ] T ；
wherein Z represents the second pulse pressure echo signal, Z i ＝G i Q represents the second pulse pressure echo signal at the ith element.
In one embodiment of the present invention, the step 5 specifically includes:
step 5.1, carrying out sum-difference beam phase-contrast single-pulse angle measurement on the second pulse pressure echo signal to obtain measurement data, wherein the measurement data are expressed as:
wherein K represents measurement data, w 2 ＝[1,exp(j2πdsinθ 0 /λ),...,exp(j2πd(N-1)sinθ 0 /λ)] T Weight vector representing sum beam, w 1 ＝[w 2 (1:N/2),-w 2 (N/2+1:N)]A weight vector representing the difference beam;
step 5.2, estimating the radar target angle according to the measurement data, wherein the radar target angle is expressed as:
wherein ,
represents radar target angle measurement, || represents modulo, a (θ) = [1, exp (j 2 pi dsin θ/λ),..exp (j 2 pi d (N-1) sin θ/λ)] T The steering vector of the antenna element is shown, and θ represents the angular range.
Compared with the prior art, the invention has the beneficial effects that:
according to the method for improving the angle measurement precision of the NLFM waveform radar target, the Doppler frequency estimation of the radar target echo signal is utilized to design a completely matched impulse response filter, and the impulse compression processing of the radar target echo signal is carried out, so that the signal-to-noise ratio loss of angle estimation data is reduced, and therefore the angle measurement precision is improved and the performance is stable.
Drawings
Fig. 1 is a schematic flow chart of a method for improving the accuracy of measuring the angle of an NLFM waveform radar target according to an embodiment of the present invention;
FIG. 2 is a diagram showing the comparison result of the angle root mean square error of the angle measurement when the target angle is changed by the conventional angle measurement method and the method provided by the embodiment of the invention;
FIG. 3 is a graph showing the comparison of the pulse pressure results of the conventional method and the pulse pressure results of the method according to the embodiment of the present invention;
fig. 4 is a partially enlarged schematic illustration of the comparison of the conventional pulse pressure results with the pulse pressure results of the method provided in the examples of the present invention.
Detailed Description
The present invention will be described in further detail with reference to specific examples, but embodiments of the present invention are not limited thereto.
Example 1
Since NLFM radar waveforms are sensitive to Doppler frequency, signal-to-noise ratio loss exists in the output of pulse compression, and target detection and angle measurement performance of the radar are affected. Therefore, referring to fig. 1, fig. 1 is a flowchart of a method for improving the accuracy of the target angle measurement of the NLFM waveform radar according to an embodiment of the present invention, and the method for improving the accuracy of the target angle measurement of the NLFM waveform radar according to the embodiment of the present invention includes the following steps:
and step 1, performing first pulse compression processing on the radar target echo signal to obtain a first pulse pressure echo signal.
Specifically, in this embodiment, a uniform linear array including N array elements is used to receive a radar target echo signal, and pulse compression processing is performed on the radar target echo signal, where step 1 specifically includes steps 1.1, 1.2, and 1.3:
and step 1.1, acquiring radar target echo signals S received by N array elements.
Specifically, the embodiment receives radar target echo signals for N array elements, and specifically, the radar target echo signals are expressed as:
S＝[S 1 ,S 2 ,...,S N ] T ；
wherein S represents radar target echo signals, S i Represents the radar target echo signal received by the ith array element, i=1, 2,3, N, radar target echo signal S for each array element i ＝[S qr ] M×R, wherein ,Sqr Representing radar target echoesSignal S i The (R) sampling point of the (q) th pulse, M is the number of received pulses of each array element, R is the number of sampling points in the pulse width of the radar transmitting signal, [] T Representing the vector transpose.
And 1.2, obtaining a pulse compression weight coefficient according to the NLFM waveform transmitted by the radar.
Specifically, the present embodiment considers that the NLFM radar waveform is sensitive to doppler frequency, and thus constructs a pulse compression weight coefficient from the radar-transmitted NLFM waveform, specifically expressed as:
Y＝[F 1 ,F 2 ，...,F R ] H ；
wherein Y represents a pulse compression weight coefficient, F r An R-th value representing a pulse compression weight coefficient, r=1, 2,3..] H Representing the vector conjugate transpose.
It should be noted that, pulse compression weight coefficients correspondingly set by different radar emission waveforms are different, specifically, according to actual radar emission waveform setting, the radar emission waveform in this embodiment is an NLFM waveform.
And 1.3, obtaining a first pulse pressure echo signal according to the radar target echo signal and the pulse compression weight coefficient.
Specifically, the first pulse pressure echo signal is calculated according to the radar target echo signal obtained in the step 1.1 and the pulse compression weight coefficient obtained in the step 1.2, and specifically the first pulse pressure echo signal is expressed as:
X＝[X 1 ,X 2 ,..,X N ] T ；
wherein X represents a first pulse pressure echo signal, X i ＝S i Y represents the first pulse pressure echo signal on the i-th element, i=1, 2,3,..n.
In this embodiment, the effect of doppler shift is not considered when calculating the first pulse pressure echo signal in step 1.3, which is the same as the conventional goniometric method.
And step 2, carrying out beam synthesis processing on the first pulse pressure echo signal to obtain a beam synthesis result.
Specifically, in this embodiment, beam synthesis processing is performed on the first pulse pressure echo signal through a preset weight vector, and a beam synthesis result is obtained, where the beam synthesis result is specifically expressed as:
P＝a H (θ 0 )X；
where P represents the beam forming result, a (θ 0 )＝[1,exp(j2πdsinθ 0 /λ),...,exp(j2πd(N-1)sinθ 0 /λ)] T Representing a preset weight vector, exp represents an exponent power based on e, j represents an imaginary unit, d represents an array element spacing, θ 0 Indicating the detection beam direction.
And step 3, doppler processing is carried out on the beam synthesis result by adopting a Doppler filter to obtain a Doppler frequency estimated value.
Specifically, in the conventional angle measurement method, since the pulse response filter of pulse compression does not consider the Doppler information of the target, a certain signal-to-noise ratio loss exists in the output of the pulse response filter, so that the angle measurement precision of the target is affected. Therefore, the embodiment proposes to further perform radar target angle measurement based on consideration of doppler information, and step 3 specifically includes steps 3.1 and 3.2:
and 3.1, doppler processing is carried out on the beam synthesis result by adopting a Doppler filter to obtain a plurality of amplitude response results.
Specifically, in the case of doppler processing, since the doppler frequency is unknown, a plurality of doppler filters are required, the frequencies of the doppler filters corresponding to different doppler filters are different, and the doppler processing is performed on the beam synthesis result by using the plurality of doppler filters to obtain a plurality of amplitude response results.
And 3.2, finding out a frequency point with the maximum corresponding amplitude from a plurality of amplitude response results, and correspondingly obtaining a Doppler estimated value according to the frequency point.
Specifically, after the several amplitude response results are obtained in step 3.1, the larger the amplitude is, the more the doppler filter is matched with the doppler frequency, so that the embodiment finds the frequency point with the largest corresponding amplitude from the several amplitude response results, and determines the doppler estimated value according to the frequency point, where the pre-estimated value is the doppler estimated value that will be used to determine the perfectly matched impulse response filter in the embodiment.
And 4, performing second pulse compression processing on the radar target echo signal according to the Doppler estimated value to obtain a second pulse pressure echo signal.
Specifically, after determining the doppler estimation value according to step 3, a perfectly matched impulse response filter is generated by using the doppler estimation value, and step 4 specifically includes steps 4.1, 4.2, and 4.3:
and 4.1, pulse accumulation is carried out on the radar target echo signals according to the Doppler estimated value to obtain a pulse accumulation result.
Specifically, the present embodiment firstly performs pulse accumulation on the radar target echo signal by using the doppler estimation value to obtain a pulse accumulation result, and specifically the pulse accumulation result is expressed as:
G＝[G 1 ,G 2 ,...,G N ] T ；
wherein G represents the pulse accumulation result, G i ＝b(f′ d )S i Representing the pulse accumulation result of the ith element, b (f' d )＝[1,exp(j2πf′ d t r ),...,exp(j2πf′ d ((M-1)t r )]Pilot vector representing target, f d ' represents Doppler frequency estimation value, t r Representing the pulse repetition period.
And 4.2, updating the pulse compression weight coefficient according to the Doppler estimated value to obtain a new pulse compression coefficient.
Specifically, in this embodiment, the pulse compression weight coefficient in step 1.2 is updated according to the doppler estimation value to obtain a new pulse compression coefficient, and specifically, the new pulse compression coefficient is expressed as:
Q＝Y⊙c(f′ d )；
wherein Q represents a new pulse compression coefficient, c (f' d )＝[1,exp(-j2πf′ d t s ),...,exp(-j2πf′ d ((R-1)t s )] T Representing Doppler shift function, t s Indicates the time interval between adjacent samples, +..
And 4.3, obtaining a second pulse pressure echo signal according to the pulse accumulation result and the new pulse compression coefficient.
Specifically, the radar target echo signal and the pulse compression coefficient of the embodiment are respectively subjected to doppler frequency consideration to obtain a pulse accumulation result and a new pulse compression coefficient after the doppler frequency consideration, and a second pulse pressure echo signal is obtained according to the pulse accumulation result and the new pulse compression coefficient, and specifically, the second pulse pressure echo signal is expressed as:
Z＝[Z 1 ,Z 2 ,...,Z N ] T ；
wherein Z represents the second pulse pressure echo signal, Z i ＝G i Q represents the second pulse pressure echo signal on the i-th element, i=1, 2,3,..n.
And step 5, performing sum-difference beam phase-contrast single-pulse angle measurement on the second pulse pressure echo signal to obtain a radar target angle measurement.
Specifically, in the embodiment, step 4 obtains a second pulse pressure echo signal Z through second pulse compression, and performs sum-difference beam phase-comparison monopulse angle measurement on the second pulse pressure echo signal, and step 5 specifically includes steps 5.1 and 5.2:
and 5.1, carrying out sum-difference beam phase-contrast single-pulse angle measurement on the second pulse pressure echo signal to obtain measurement data.
Specifically, in this embodiment, a sum-difference beam phase-contrast single pulse angle measurement method is adopted to obtain measurement data corresponding to an angle measurement, and specifically, the measurement data is expressed as:
wherein K represents measurement data, w 2 ＝[1,exp(j2πdsinθ 0 /λ),...,exp(j2πd(N-1)sinθ 0 /λ)] T Weight vector representing sum beam, w 1 ＝[w 2 (1:N/2),-w 2 (N/2+1:N)]Representing the weight vector of the difference beam.
And 5.2, estimating and obtaining a radar target angle according to the measurement data.
Specifically, a radar target angle of measurement is estimated from the above measurement data K, specifically expressed as:
wherein ,
represents radar target angle measurement, || represents modulo, a (θ) = [1, exp (j 2 pi dsin θ/λ),..exp (j 2 pi d (N-1) sin θ/λ)] T The steering vector of the antenna element is shown, and θ represents the angular range.
According to the method for improving the angle measurement precision of the NLFM waveform radar target, the Doppler frequency of the radar target echo signal is estimated to obtain a Doppler frequency estimated value by utilizing output results of pulse compression processing (without considering Doppler information) and beam synthesis processing in sequence, then a pulse response filter which is completely matched with the Doppler frequency estimated value is generated by utilizing the Doppler frequency estimated value, the pulse compression processing is carried out on the original radar target echo signal by adopting the completely matched pulse response filter, and finally the radar target angle is measured by carrying out sum-difference beam comparison monopulse angle measurement on data after the pulse compression processing.
In order to illustrate the effectiveness of the method for improving the target angle measurement accuracy of the NLFM waveform radar, the method is verified through the following computer simulation:
1. simulation conditions
In simulation, the bandwidth of radar transmitting signals is B=2MHz, and the pulse transmitting time width is T p =300 μs, target doppler frequency f d The radar antenna array element number n=10, the wavelength lambda=0.05 m, the array element distance d=0.025 m, the sum and difference beam phase-contrast single pulse angle measurement method is adopted, the sum beam is directed to 0 degree, the single array element signal-to-noise ratio SNR=10 dB, and the sampling frequency f s Doppler frequency estimate f 'for target =10 MHz' d Monte carlo experiments 1000 times =10.01 kHz.
2. Emulation content
Referring to fig. 2, fig. 2 is a schematic diagram of comparison results of angle root mean square errors of angles measured by a conventional angle measuring method and the method provided by the embodiment of the invention when a target angle is changed, and by using the conditions, a change curve diagram of angle measurement precision of the conventional angle measuring method and the method of the invention when the target angle is changed is obtained through simulation, as shown in fig. 2, wherein an abscissa is the target angle, and an ordinate is the angle root mean square error. As can be seen from fig. 2, the root mean square error of the conventional angle measurement method and the angle measurement method of the present invention varies with the change of the target angle. But the target angle root mean square error of the present invention is smaller. Fig. 2 can fully illustrate that the method of the invention has higher angle measurement precision and more stable performance, and can indeed improve the angle measurement precision of NLFM waveform.
In summary, in the method for improving the angular accuracy of the NLFM waveform radar target provided in the embodiment, a perfectly matched impulse response filter is designed by using the doppler frequency estimation of the radar target echo signal, and the impulse compression processing of the radar target echo signal is performed, so that the signal-to-noise ratio loss for the angle estimation data is reduced, and therefore, the angular accuracy is improved and the performance is stable.
The foregoing is a further detailed description of the invention in connection with the preferred embodiments, and it is not intended that the invention be limited to the specific embodiments described. It will be apparent to those skilled in the art that several simple deductions or substitutions may be made without departing from the spirit of the invention, and these should be considered to be within the scope of the invention.
Claims (4)
1. The method for improving the target angle measurement precision of the NLFM waveform radar is characterized by comprising the following steps of:
step 1, performing first pulse compression processing on a radar target echo signal to obtain a first pulse pressure echo signal;
step 2, carrying out beam synthesis processing on the first pulse pressure echo signal to obtain a beam synthesis result;
step 3, doppler processing is carried out on the beam synthesis result by adopting a Doppler filter to obtain a Doppler frequency estimated value;
step 4.1, pulse accumulation is carried out on the radar target echo signal according to the Doppler frequency estimated value to obtain a pulse accumulation result, wherein the pulse accumulation result is expressed as:
G＝[G 1 ,G 2 ,...,G N ] T ；
wherein G represents the pulse accumulation result, G i ＝b(f′ d )S i Representing the pulse accumulation result of the ith array element, S i Representing radar target echo signals received by the i-th element, i=1, 2,3. d )＝[1,exp(j2πf′ d t r ),...,exp(j2πf′ d ((M-1)t r )]Pilot vector representing target, f d ' represents Doppler frequency estimation value, t r Representing a pulse repetition period;
step 4.2, updating a pulse compression weight coefficient according to the Doppler frequency estimation value to obtain a new pulse compression coefficient, wherein the pulse compression weight coefficient is obtained according to an NLFM waveform transmitted by a radar, and the new pulse compression coefficient is expressed as:
Q＝Y⊙c(f′ d )；
wherein Q represents a new pulse compression coefficient, Y represents a pulse compression weight coefficient, c (f' d )＝[1,exp(-j2πf′ d t s ),...,exp(-j2πf′ d ((R-1)t s )] T Representing Doppler shift function, t s Indicating the time interval between adjacent samples, +.;
step 4.3, obtaining a second pulse pressure echo signal according to the pulse accumulation result and the new pulse compression coefficient, wherein the second pulse pressure echo signal is expressed as:
Z＝[Z 1 ,Z 2 ,...,Z N ] T ；
wherein Z represents the second pulse pressure echo signal, Z i ＝G i Q represents a second pulse pressure echo signal on the ith array element;
step 5.1, performing sum-difference beam phase-contrast single-pulse angle measurement on the second pulse pressure echo signal to obtain measurement data, wherein the measurement data are expressed as:
wherein K represents measurement data, w 2 ＝[1,exp(j2πdsinθ 0 /λ),...,exp(j2πd(N-1)sinθ 0 /λ)] T Weight vector representing sum beam, w 1 ＝[w 2 (1:N/2),-w 2 (N/2+1:N)]A weight vector representing the difference beam;
step 5.2, estimating the radar target angle according to the measurement data, wherein the radar target angle is expressed as:
wherein ,
represents radar target angle measurement, || represents modulo, a (θ) = [1, exp (j 2 pi dsin θ/λ),..exp (j 2 pi d (N-1) sin θ/λ)] T The steering vector of the antenna element is shown, and θ represents the angular range.
2. The method for improving the target angle measurement precision of the NLFM waveform radar according to claim 1, wherein the step 1 specifically comprises:
step 1.1, radar target echo signals received by N array elements are obtained, wherein the radar target echo signals are expressed as follows:
S＝[S 1 ,S 2 ,...,S N ] T ；
wherein S represents radar target echo signals, and the radar target echo signals S of each array element i ＝[S qr ] M×R, wherein ,Sqr Representing radar target echo signal S i The (R) sampling point of the (q) th pulse, M is the number of received pulses of each array element, R is the number of sampling points in the pulse width of the radar transmitting signal, [] T Representing the vector transpose;
step 1.2, obtaining a pulse compression weight coefficient according to a radar transmitting NLFM waveform, wherein the pulse compression weight coefficient is expressed as:
Y＝[F 1 ,F 2 ，...,F R ] H ；
wherein ,Fr An R-th value representing a pulse compression weight coefficient, r=1, 2,3..] H Representing a vector conjugate transpose;
step 1.3, obtaining a first pulse pressure echo signal according to a radar target echo signal and a pulse compression weight coefficient, wherein the first pulse pressure echo signal is expressed as:
X＝[X 1 ,X 2 ,..,X N ] T ；
wherein X represents a first pulse pressure echo signal, X i ＝S i Y represents the first pulse pressure echo signal on the ith element.
3. The method for improving the target angle measurement accuracy of the NLFM waveform radar according to claim 2, wherein the beam synthesis result in step 2 is expressed as:
P＝a H (θ 0 )X；
where P represents the beam forming result, a (θ 0 )＝[1,exp(j2πdsinθ 0 /λ),...,exp(j2πd(N-1)sinθ 0 /λ)] T Represents a weight vector, exp represents an exponent power based on e, j represents an imaginary unit, d represents an array element pitch, θ 0 Indicating the detection beam direction.
4. A method for improving the accuracy of the target angle measurement of the NLFM waveform radar according to claim 3, wherein the step 3 specifically comprises:
step 3.1, doppler processing is carried out on the beam synthesis result by adopting a Doppler filter to obtain a plurality of amplitude response results;
and 3.2, finding out a frequency point with the maximum corresponding amplitude from the amplitude response results, and correspondingly obtaining the Doppler frequency estimated value according to the frequency point.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010575170.8A CN111913161B (en) | 2020-06-22 | 2020-06-22 | Method for improving NLFM waveform radar target angle measurement precision |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010575170.8A CN111913161B (en) | 2020-06-22 | 2020-06-22 | Method for improving NLFM waveform radar target angle measurement precision |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111913161A CN111913161A (en) | 2020-11-10 |
| CN111913161B true CN111913161B (en) | 2023-05-26 |
Family
ID=73226961
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010575170.8A Active CN111913161B (en) | 2020-06-22 | 2020-06-22 | Method for improving NLFM waveform radar target angle measurement precision |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111913161B (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103412301A (en) * | 2013-08-23 | 2013-11-27 | 西安电子科技大学 | Metrewave radar angle measurement method |
| CN103616679A (en) * | 2013-11-19 | 2014-03-05 | 北京航空航天大学 | PD radar ranging and angle measuring method based on difference beam modulation and waveform analysis |
| CN105974390A (en) * | 2016-06-30 | 2016-09-28 | 西安电子科技大学 | Mechanic scan meter-wave radar mass center angle measuring method based on Doppler information |
| CN106646451A (en) * | 2017-01-24 | 2017-05-10 | 成都泰格微电子研究所有限责任公司 | Angle tracking subsystem based on radar signal processing system |
| JP2019168255A (en) * | 2018-03-22 | 2019-10-03 | 株式会社東芝 | Pulse compression radar device and radar signal processing method therefor |
-
2020
- 2020-06-22 CN CN202010575170.8A patent/CN111913161B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103412301A (en) * | 2013-08-23 | 2013-11-27 | 西安电子科技大学 | Metrewave radar angle measurement method |
| CN103616679A (en) * | 2013-11-19 | 2014-03-05 | 北京航空航天大学 | PD radar ranging and angle measuring method based on difference beam modulation and waveform analysis |
| CN105974390A (en) * | 2016-06-30 | 2016-09-28 | 西安电子科技大学 | Mechanic scan meter-wave radar mass center angle measuring method based on Doppler information |
| CN106646451A (en) * | 2017-01-24 | 2017-05-10 | 成都泰格微电子研究所有限责任公司 | Angle tracking subsystem based on radar signal processing system |
| JP2019168255A (en) * | 2018-03-22 | 2019-10-03 | 株式会社東芝 | Pulse compression radar device and radar signal processing method therefor |
Non-Patent Citations (2)
| Title |
|---|
| Range and Angle Measurement in a Linear Pulsed Frequency Diverse Array Radar;Ramazan Cetiner等;《IEEE》;20171231;全文 * |
| 一种多目标情况下的单脉冲测角方法;赵永波等;《西安电子科技大学学报（自然科学版）》;20050630;第32卷(第3期);全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN111913161A (en) | 2020-11-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110850400B (en) | LFMCW radar multi-target detection method based on interferometer direction finding | |
| US7019686B2 (en) | RF channel calibration for non-linear FM waveforms | |
| CN104297740B (en) | Method for estimating Doppler spectrum of radar target on basis of phase analysis | |
| US6686874B2 (en) | Process for calibrating radar signals at subapertures of an antenna of two-channel SAR/MTI radar system | |
| JP2010535344A (en) | Ground reflected wave mitigation using parametric time-domain technique | |
| Li et al. | Software-defined calibration for FMCW phased-array radar | |
| US8358233B2 (en) | Radar target detection process | |
| CN112462356A (en) | Method for improving radar ranging precision based on Gaussian interpolation | |
| CN112698324A (en) | Sum-difference monopulse angle measurement method of frequency modulation stepping radar | |
| CN110045338A (en) | Amplitude phase error estimation and bearing calibration based on Hilbert transform | |
| US7339519B2 (en) | Methods and apparatus for target radial extent determination using deconvolution | |
| CN108828504A (en) | MIMO radar target direction method for quick estimating based on part waveform correlation | |
| CN112130138A (en) | Ionospheric phase pollution correction method for over-the-horizon radar | |
| CN111913161B (en) | Method for improving NLFM waveform radar target angle measurement precision | |
| JP2792338B2 (en) | Signal processing device | |
| CN115932824A (en) | FMCW radar ranging method and system based on multiple antennas | |
| CN114035149A (en) | Method for improving sensitivity of interferometer direction finding system | |
| CN111239719B (en) | Robust high-precision low-altitude target height measurement method based on composite reflection coefficient estimation | |
| US11585892B1 (en) | Calibration for multi-channel imaging systems | |
| CN115494485A (en) | Two-dimensional low-sidelobe constant-resolution forward-looking sonar imaging method and system | |
| CN103995262B (en) | MIMO sparse array ultrasonic measurement methods and system for fluctuation interface | |
| CN114114167A (en) | Non-inverse cross eye interference system with measurement and control subsystem and method | |
| CN110208778B (en) | Transducer broadband complex response measuring device and method based on logarithm variable window function | |
| CN112698263A (en) | Orthogonal propagation operator-based single-basis co-prime MIMO array DOA estimation algorithm | |
| CN116449304B (en) | SAR emission pulse arrival time measurement method based on frequency measurement |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |