CN107271955B - Time difference and scale difference estimation method for broadband linear frequency modulation signal - Google Patents
Time difference and scale difference estimation method for broadband linear frequency modulation signal Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S5/00—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations
- G01S5/02—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves
- G01S5/0273—Position-fixing by co-ordinating two or more direction or position line determinations; Position-fixing by co-ordinating two or more distance determinations using radio waves using multipath or indirect path propagation signals in position determination
Abstract
The invention discloses a time difference and scale difference estimation method of broadband linear frequency modulation signals, which mainly comprises the following steps: determining a radar radiation source, first particleThe system comprises a satellite and a second satellite, wherein the first satellite and the second satellite are respectively in the detection range of a radar radiation source, and the radar radiation source transmits broadband linear frequency modulation signals to the first satellite and the second satellite; the radar radiation source emits broadband chirp signals to the first satellite and the second satellite as
The first satellite receives a wideband chirp of
The second satellite receives a wideband chirp of
Respectively calculating the broadband chirp signals received by the first satellite
To estimate the optimum angle
And a second satellite receiving a broadband chirp signal
To estimate the optimum angle
And calculating the difference between the two satellite received broadband chirp signals
And further calculating to obtain the time difference estimation of the broadband linear frequency modulation signals received by the two satellites
Description
Technical Field
The invention belongs to the technical field of radars, and particularly relates to a time difference and scale difference estimation method for broadband Linear Frequency modulation signals, which is suitable for positioning unknown radar radiation sources for transmitting broadband Linear Frequency Modulation (LFM) signals on the surface of the earth by two satellites.
Background
The double-satellite passive positioning technology is that two satellites are used for receiving signals radiated by a radar radiation source and then parameters between the two satellite receiving signals are estimated to position an unknown radiation source; the radar is used as an important detection tool and plays a key role in modern war, so that a radar radiation source of an opposite side needs to be quickly and accurately positioned; in modern radars, a wideband Linear Frequency Modulation (LFM) signal is one of the most common wideband radar transmission signals, because the LFM signal can ensure good detection capability and higher range and speed resolution of the radar.
The method is mainly characterized in that the time difference and the scale difference between two-satellite receiving signals are estimated by searching a Wideband Cross Ambiguity Function (WBCAF) peak value, the WBCAF performs scale expansion of one path of receiving signals and then performs time domain correlation with the other path of receiving signals, and when the scale expansion scale is the same as the scale difference between two paths of receiving signals, the time domain correlation at the time forms a Wideband Cross Ambiguity Function peak value. According to the position of the peak value of the broadband mutual fuzzy function, the time difference and the scale difference can be estimated. However, the method based on the wideband mutual fuzzy function WBCAF mainly has two problems: when the wideband mutual ambiguity function WBCAF is calculated, the received discrete signal needs to be stretched, however, the analytic expression of the received discrete signal is unknown, and the operation amount in the stretching process is overlarge; secondly, in order to obtain the peak position of the wideband mutual fuzzy function WBCAF, the fuzzy function value at each point on the whole fuzzy plane needs to be calculated, and the operation amount is large. Although the learner quickly implements the scaling of the discrete signals through the interpolation of the Sinc function, when the method is used for calculating the wideband mutual fuzzy function WBCAF, all possible scales need to be traversed, and the received discrete signals are scaled on each scale, which is not beneficial to real-time processing.
Disclosure of Invention
In view of the above-mentioned deficiencies of the prior art, the present invention provides a method for estimating time difference and scale difference of wideband chirp signals, which first estimates the scale difference between two-satellite received signals and then estimates the time difference by using the characteristics of wideband chirp LFM signals.
The main ideas of the invention are as follows: the time when the broadband linear frequency modulation signal radiated by the radar radiation source reaches two satellites is different, and the time difference exists between the two satellite receiving signals; meanwhile, the radial speeds of the double satellites relative to the radar radiation source are different, the waveform of a received signal of one satellite is compressed or broadened relative to the waveform of a received signal of another satellite, and the scale difference is defined as the ratio of the waveform expansion of a received signal of a second satellite relative to the waveform expansion of a received signal of a first satellite; when the signal radiated by the radar radiation source is a broadband linear frequency modulation signal LFM signal, the ratio of the modulation frequencies between the signals received by the two stars is equal to the square of the scale difference, which can be known from the Wigner-Ville Distribution (WVD) of the broadband linear frequency modulation LFM signal; according to this feature, the frequency modulation rates of the two-star received signals can be estimated separately to obtain an estimate of the scale difference.
In order to achieve the technical purpose, the invention is realized by adopting the following technical scheme.
A time difference and scale difference estimation method for broadband linear frequency modulation signals comprises the following steps:
Step 2, respectively calculating the broadband linear frequency modulation signals received by the first satellite
To estimate the optimum angle
And a second satellite receiving a broadband chirp signal
To estimate the optimum angle
Further calculating to obtain the scale difference estimation between the broadband linear frequency modulation signals received by the two satellites
Step 3, estimating the scale difference between the broadband linear frequency modulation signals received by two satellites
Obtaining the time difference estimation of the broadband linear frequency modulation signals received by two satellites
Compared with the prior art, the invention has the advantages that:
compared with the traditional wideband mutual ambiguity function WBCAF method, the method has the core that the optimal angle corresponding to the linear frequency modulation LFM signals received by the two stars is searched in a grading mode to obtain the estimation of the scale difference, only the linear frequency modulation LFM signals received by the two stars need to be stretched once, the peak value of the wideband mutual ambiguity function WBCAF does not need to be searched in a two-dimensional mode, and therefore the calculation amount is small and the method is easy to achieve.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
FIG. 1 is a flow chart of a method of time difference and scale difference estimation for a wideband chirp signal in accordance with the present invention;
FIG. 2 is a schematic diagram of a Wigner-Ville distribution (WVD) of a broadband chirp LFM signal received by two stars;
FIG. 3a is a graph of fractional Fourier transforms (FRFTs) of a wideband chirp LFM signal received by a first satellite at different angles;
FIG. 3b is a plot of fractional Fourier transforms (FRFTs) of a broadband chirp LFM signal received by a second satellite at different angles;
FIG. 4 is a graph of the signal received by a first satellite over a scale
The time domain correlation graph of the signals received by the second satellite after the expansion and contraction;
FIG. 5a is a plot comparing the time difference estimation RMS error curve of the present invention to the RMS error curve of the conventional method;
FIG. 5b is a plot comparing the scale deviation estimation RMS error curve of the method of the present invention with the RMS error curve of the conventional method;
fig. 6 is a graph of the CPU time required to estimate the time/scale difference for wideband chirped LFM signals of different lengths using the method of the present invention and the conventional method.
Detailed Description
Referring to fig. 1, it is a flowchart of a time difference and scale difference estimation method for wideband chirp signals of the present invention; the time difference and scale difference estimation method of the broadband linear frequency modulation signal comprises the following steps:
Determining a radar radiation source, a first satellite and a second satellite, wherein the first satellite and the second satellite are respectively in the detection range of the radar radiation source, and the radar radiation source transmits broadband Linear Frequency Modulation (LFM) signals to the first satellite and the second satellite; the broadband chirp LFM signal emitted by the radar radiation source to the first satellite and the second satellite is
The first satellite receives a wideband chirp LFM signal of
The second satellite receives a wideband chirp LFM signal of
The expressions are respectively:
wherein the first satellite receives a wideband chirp LFM signal
And a second satellite receiving a broadband chirp LFM signal
Recording the signals as broadband linear frequency modulation LFM signals received by two satellites;
a time variable is represented by a time variable,
m represents the broadband emitted by the radar radiation source to the first satellite and the second satelliteLinear frequency modulated LFM signal
M is B/T, and m>0, B is a broadband chirp LFM signal transmitted by a radar radiation source to a first satellite and a second satellite
T is a broadband chirp LFM signal transmitted by a radar radiation source to a first satellite and a second satellite
Time width of (d), exp denotes an exponential function, τ1Wideband chirp LFM signal received for a first satellite
Time delay, σ, relative to the emission of a broadband chirp LFM signal by a radar radiation source1Wideband chirp LFM signal received for a first satellite
Scaling, τ, of a wideband chirp LFM signal emitted relative to a radar radiation source2Broadband chirp LFM signal received for a second satellite
Time delay, σ, relative to the emission of a broadband chirp LFM signal by a radar radiation source2Broadband chirp LFM signal received for a second satellite
Relative to the scale of the extension of the wideband chirp LFM signal emitted by a radar radiation source, △ tau is the time difference between the wideband chirp LFM signals received by two satellites, △ tau is tau2-τ1△ sigma is the difference in scale between the wideband chirped LFM signals received by two satellites,
when the signal transmitted by the radar radiation source is a narrow-band signal, the stretching effect can be approximately considered that the signal received by the satellite has a Doppler frequency shift relative to the signal transmitted by the radar radiation source, and at the moment, the radar radiation source can be accurately positioned by respectively estimating the time difference and the Doppler frequency difference between the signals transmitted by the radar radiation source and received by the first satellite and the second satellite; however, when the signal emitted by the radar radiation source is a broadband signal, the stretching effect continues to be approximated by doppler shift, which causes a large error in positioning. Therefore, in the double-satellite positioning, in order to accurately position the radar radiation source, the time difference and the scale difference between the received signals of the first satellite and the second satellite need to be estimated; wherein the satellite is a first satellite or a second satellite, and the signal is a wideband chirp LFM signal.
Step 2, referring to fig. 2, a schematic diagram of a Wigner-Ville Distribution (WVD) of a broadband chirp LFM signal received by two stars is shown; where x (t) represents a broadband chirp LFM signal having a bandwidth B, where B is a broadband chirp LFM signal transmitted by a radar radiation source to a first satellite and a second satellite
The bandwidth of (a) is determined,
a time variable is represented by a time variable,
t is a broadband chirp LFM signal transmitted by a radar radiation source to a first satellite and a second satellite
Time-width broadband linear frequency modulation LFM signal with bandwidth of B
Has an initial frequency of kappa and a bandwidth of B
Broadband linear frequency modulation LFM signal with modulation frequency of B/T and bandwidth of B
Has a spectral range of [ kappa, kappa + B]。
For broadband linear frequency modulation LFM signal with bandwidth of B
Performing scale sigma expansion to obtain scale-expanded broadband linear frequency modulation LFM signal
σ>1; due to sigma>1, wide band linear frequency modulation LFM signal after scale expansion
Broadband chirp LFM signal with respect to bandwidth B
Stretched in the time domain, and thus scaled, wideband chirped LFM signal
Has a time domain range of [0, σ T](ii) a According to the property of Fourier transform, the broadband linear frequency modulation LFM signal after scale expansion
When the time domain is stretched, the whole frequency spectrum of the time domain is compressed, so that the broadband linear frequency modulation LFM signal after scale expansion is obtained
Has a spectral range of [ kappa/sigma, (kappa + B)/sigma]. Therefore, the broadband linear frequency modulation LFM signal with the scale being expanded and contracted is obtained
Has a modulation frequency of B/sigma2T, can see the broadband linear frequency modulation LFM signal after the scale expansion
The frequency modulation is a broadband linear frequency modulation LFM signal before expansion, namely a broadband linear frequency modulation LFM signal with a bandwidth of B
1/sigma of the modulation frequency of2。
Wideband chirp LFM signal due to reception by a second satellite
Wideband chirp LFM signal received relative to a first satellite
By scaling, the scale difference △ σ exists between the wideband chirp LFM signals received by two satellites, so that the tuning frequencies of the wideband chirp LFM signals received by two satellites can be estimated respectively to obtain an estimate of the scale difference of the wideband chirp LFM signals received by two satellites.
Step 3, when the fractional Fourier transform (FRFT) is used for estimating the frequency modulation of LFM signals received by two satellites, the step length △α is firstly used for traversing the whole angle range [ -pi/2, pi/2]，0<△α<Pi; obtaining the current optimal angle by fractional Fourier transform (FRFT) peak values, and respectively calculating to obtain broadband linear frequency modulation signals received by the first satellite
To estimate the optimum angle
And a second satellite receiving a broadband chirp signal
To estimate the optimum angle
Further calculating to obtain the scale difference estimation between the broadband linear frequency modulation signals received by the two satellites
In particular, Fractional Fourier Transform (FRFT) is a common tool for estimating the tuning frequency of a chirped LFM signal. For a linear frequency modulation LFM signal, an angle can be found, the fractional Fourier transform (FRFT) of the linear frequency modulation LFM signal at the angle is made to obtain the maximum value, and the angle is recorded as the optimal angle corresponding to the linear frequency modulation LFM signal; at the same time, the optimum angle is only related to the frequency modulation rate of the chirped LFM signal. Therefore, the process of estimating the frequency modulation of the linear frequency modulation LFM signal by using the FRFT is to calculate fractional Fourier transform (FRFT) of the linear frequency modulation LFM signal at different angles, search the peak value of the fractional Fourier transform (FRFT), and calculate the frequency modulation according to the angle corresponding to the peak value; obviously, in order to obtain the estimation of the optimal angle, the whole angle range needs to be traversed, and the fractional order fourier transform FRFT at each angle is calculated; when the angle estimation precision is high, the number of the angles to be searched is large, and the calculation amount is large; the fractional fourier transform FRFT of the chirp LFM signal at an angle is larger as the angle of the fractional fourier transform FRFT is closer to the optimum angle. According to the characteristic, in order to reduce the operation amount, the optimal angle can be gradually searched through a hierarchical searching structure, and the scale difference estimation is obtained.
After the estimation of the scale difference is carried out, one path of receiving signals is stretched by the scale difference estimation, the stretched signals and the other path of receiving signals are subjected to time domain correlation, and the position of a signal peak value obtained after the time domain correlation is the estimation of the time difference; wherein, one path of receiving signal and the other path of receiving signal are any two paths of signals in the signals received by the double stars.
3.1 initialization: the angle range of the h-th traversal is
Step size of the h-th traversal is △αh，
△α denotes the set step size, and 0<△α<Pi; the number of the h-th traversal angles is QhH belongs to {1,2, …, H }, wherein H is the set total number of traversal times, and H is a positive integer greater than 0; in this embodiment, H takes the value of 3;
3.2 broadband chirp LFM signals received for the first satellite
Is made to rotate by an angle deltatThe fractional Fourier transform FRFT of (1) to obtain a rotation angle of deltatFractional fourier transform of (d) result peak pt。
3.3 let t take 1 to Q, respectivelyhAnd repeating the step 3.2 to respectively obtain the rotation angles delta1Fractional fourier transform of (d) result peak p1To a rotation angle of
Fractional order fourier transform ofPeak value of result
Is recorded as QhA peak value, and QhThe angle corresponding to the maximum peak value in the peak values is used as the optimal angle after the h-th traversal
3.4 adding 1 to H, setting t to 1, returning to the substep 3.1 until the optimal angle after the H-th traversal is obtained
And the optimal angle after the H-th traversal is obtained
Wideband chirp LFM signal received as a first satellite
To estimate the optimum angle
3.5 initialization: the h' th traversal has an angular range of
Step size of h' th traversal △αh'，
△α denotes the set step size, and 0<△α<Pi; the number of the h' th traversal angle is Qh'H 'belongs to {1,2, …, H' }, H 'is the set total number of traversal times, and H' is a positive integer greater than 0; in this example, H' takes the value of 3;
Let t' be e {1,2, …, Qh'Instruction of
The t' th angle is shown as,
the initial values of t 'and h' are 1, respectively.
3.6 broadband chirp LFM signal received to second satellite
Is rotated by an angle of
The fractional Fourier transform (FRFT) of (1) to obtain a rotation angle of
Fractional fourier transform result peak of
3.7 let t' take 1 to Q, respectivelyh'Repeating the execution for 3.6, and obtaining the rotation angles of
Fractional fourier transform result peak of
To a rotation angle of
Fractional fourier transform ofPeak value of conversion result
Is recorded as Qh'A peak value, and Qh'The angle corresponding to the maximum peak value in the peak values is used as the optimal angle after h' th traversal
3.8 adding 1 to H ', setting t ' to 1, returning to the substep 3.5 until the optimal angle after the H ' th traversal is obtained
And the optimal angle after the H' th traversal is obtained
Broadband chirp LFM signal received as a second satellite
To estimate the optimum angle
According to the broadband chirp LFM signal received by the first satellite
To estimate the optimum angle
And a second satellite receiving a broadband chirp LFM signal
To estimate the optimum angle
Then the broadband linear frequency modulation LFM signals received by the first satellite are respectively calculated
Frequency modulation rate estimation of
And a second satellite receiving a broadband chirp LFM signal
Frequency modulation rate estimation of
Further calculating to obtain the scale difference estimation between the broadband linear frequency modulation LFM signals received by the two satellites
cot denotes a resection operation.
Step 4, estimating the scale difference between the broadband linear frequency modulation LFM signals received by two satellites
Wideband chirp LFM signal received for a first satellite
Performing expansion and contraction to obtain an expanded signal
Signal after expansion and contraction
Broadband chirp LFM signal received with a second satellite
Performing correlation processing on time domain to obtain correlation processed dataThe broadband chirp signal C (τ) of (a), τ represents the time difference of the broadband chirp signal after the correlation processing; further obtaining the time difference estimation of the broadband linear frequency modulation LFM signals received by two satellites
argmax represents the time difference of the wideband chirp signal when the signal C (τ) after correlation processing is maximized.
The effect of the present invention is further illustrated by simulation below.
Simulation parameters:
the radar radiation source transmits signals which are broadband linear frequency modulation LFM signals, B is 250MHz, T is 5 mus, and sampling frequency fsThe scale difference △ σ is 1.01 at 1GHz, the time difference △ τ is 0.5 μ s, and the noise is additive complex gaussian zero mean white noise.
(II) simulation content and analysis:
FIG. 3a is a plot of fractional Fourier transforms (FRFT) of a wideband chirp LFM signal received by a first satellite at different angles; wherein the horizontal axis is the angle and the vertical axis is the normalized amplitude.
FIG. 3b is a plot of fractional Fourier transforms (FRFT) of a broadband chirp LFM signal received by a second satellite at different angles; wherein the horizontal axis is the angle and the vertical axis is the normalized amplitude.
As can be seen from fig. 3a and 3b, the FRFTs searched hierarchically can respectively search the optimal angles of the LFM signals received by the first satellite and the second satellite, and the estimation of the scale difference can be calculated according to the angles corresponding to the peaks in fig. 3a and 3b
FIG. 4 shows signals received from a first satelliteOver-scale
The time domain correlation graph of the signals received by the second satellite after the expansion and contraction; wherein the horizontal axis is the time delay and the vertical axis is the normalized amplitude.
As can be seen from fig. 4, the time-domain correlation forms a peak, from the position of which an estimate of the time difference can be obtained
Therefore, the method can accurately estimate the time difference and the scale difference under the condition of lower signal-to-noise ratio.
Simulation 2, under different signal-to-noise ratios, the root mean square error curve of the time difference and the scale difference estimated by the invention is compared with the root mean square error curve of the traditional method for simulation, and the result is shown in fig. 5a and 5b, wherein:
FIG. 5a is a graph comparing the time difference estimation RMS error curve of the present invention with the RMS error curve of the conventional method; wherein the horizontal axis is the signal-to-noise ratio and the vertical axis is the root mean square error.
FIG. 5b is a comparison of the scale deviation estimation RMS error curve of the present invention and the RMS error curve of the conventional method; wherein the horizontal axis is the signal-to-noise ratio and the vertical axis is the root mean square error.
As can be seen from fig. 5a and 5b, the root mean square error curve estimated by the method of the present invention is substantially consistent with that estimated by the conventional method. As the signal-to-noise ratio is improved, the root mean square error of the time difference and the scale difference estimated by the two methods is obviously reduced and gradually approaches the lower boundary of the Cramer-Rao.
Simulation 3, the present invention simulates the CPU time needed by the LFM signals with different lengths to estimate the time difference and the scale difference with the traditional method, the result is shown in FIG. 6, FIG. 6 is the CPU time graph needed by the LFM signals with different lengths to estimate the time/scale difference by using the method of the present invention and the traditional method; wherein, the horizontal axis is the signal time width, and the vertical axis is the CPU time.
As can be seen from fig. 6, the estimation time required by the present invention is significantly less than that of the conventional method. Particularly when long signals are processed, the invention can better meet the requirement of real-time processing.
In conclusion, the simulation experiment verifies the correctness, the effectiveness and the reliability of the method.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention; thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (3)
1. A time difference and scale difference estimation method of a broadband linear frequency modulation signal is characterized by comprising the following steps:
step 1, determining a radar radiation source, a first satellite and a second satellite, wherein the first satellite and the second satellite are respectively in the detection range of the radar radiation source, and the radar radiation source transmits broadband linear frequency modulation signals to the first satellite and the second satellite; the radar radiation source emits broadband chirp signals to the first satellite and the second satellite as
The first satellite receives a wideband chirp of
The second satellite receives a wideband chirp of
Step 2, respectively calculating the broadband linear frequency modulation signals received by the first satellite
To estimate the optimum angle
And a second satellite receiving a broadband chirp signal
To estimate the optimum angle
Further calculating to obtain the scale difference estimation between the broadband linear frequency modulation signals received by the two satellites
The specific obtaining process comprises the following steps:
according to the broadband chirp signal received by the first satellite
To estimate the optimum angle
And a second satellite receiving a broadband chirp signal
To estimate the optimum angle
Then respectively calculating to obtain the broadband linear frequency modulation signal received by the first satellite
Frequency modulation rate estimation of
And a second satellite receiving a broadband chirp signal
Frequency modulation rate estimation of
Further calculating to obtain the scale difference estimation between the broadband linear frequency modulation signals received by the two satellites
cot represents a cut-after operation;
step 3, estimating the scale difference between the broadband linear frequency modulation signals received by two satellites
Obtaining the time difference estimation of the broadband linear frequency modulation signals received by two satellites
The specific obtaining process comprises the following steps:
estimation of the difference in scale between broadband chirp signals received using two satellites
Wideband chirp signal received for a first satellite
Performing expansion and contraction to obtain an expanded signal
Signal after expansion and contraction
Broadband chirp signal received with a second satellite
Performing correlation processing on a time domain to obtain a broadband linear frequency modulation signal C (tau) after correlation processing, wherein tau represents the time difference of the broadband linear frequency modulation signal after correlation processing; to further obtainWideband chirp time difference estimation to two satellite receptions
argmax represents the time difference of the wideband chirp signal when the signal C (τ) after correlation processing is maximized.
2. The method of claim 1, wherein in step 1, the radar radiation source transmits broadband chirp signals to the first satellite and the second satellite as
The first satellite receives a wideband chirp of
The second satellite receives a wideband chirp of
The expressions are respectively:
wherein the broadband chirp signal received by the first satellite is transmitted
And a second satellite receiving a broadband chirp signal
Recording the signals as broadband linear frequency modulation signals received by two satellites;
a time variable is represented by a time variable,
m represents a broadband chirp signal transmitted by a radar radiation source to a first satellite and a second satellite
M is B/T, and m is greater than 0, B is a broadband chirp signal transmitted by a radar radiation source to a first satellite and a second satellite
T is a broadband chirp signal transmitted by a radar radiation source to a first satellite and a second satellite
Time width of (d), exp denotes an exponential function, τ1Wideband chirp signal received for a first satellite
Time delay, sigma, relative to the emission of a broadband chirp signal by a radar radiation source1Wideband chirp signal received for a first satellite
Scale of extension, tau, relative to the radar radiation source emitting a broadband chirp signal2Broadband chirp signal received for a second satellite
Time delay, sigma, relative to the emission of a broadband chirp signal by a radar radiation source2Broadband chirp signal received for a second satellite
Relative to the scale of the extension of the broadband chirp signals transmitted by a radar radiation source, delta tau is the time difference between the broadband chirp signals received by two satellites, and delta tau is tau2-τ1Delta sigma is the scale difference between the broadband chirp signals received by two satellites,
3. a method of time difference and scale difference estimation of a wideband chirp signal as claimed in claim 2, wherein in step 2, the wideband chirp signal received by the first satellite
To estimate the optimum angle
And a second satellite receiving a broadband chirp signal
To estimate the optimum angle
The obtaining process comprises the following steps:
3.1 initialization: the angle range of the h-th traversal is
Step size of h-th traversal is Δ αh，
Δ α represents the step size set, and 0 < Δ α < π, and the number of angles in the h-th traversal is QhH belongs to {1,2, …, H }, wherein H is the set total number of traversal times, and H is a positive integer greater than 0;
3.2 broadband chirp received for the first satellite
Is made to rotate by an angle deltatTo obtain a rotation angle delta by fractional Fourier transformtFractional fourier transform of (d) result peak pt；
3.3 let t take 1 to Q, respectivelyhAnd repeating the step 3.2 to respectively obtain the rotation angles delta1Fractional fourier transform of (d) result peak p1To a rotation angle of
Fractional fourier transform result peak of
Is recorded as QhA peak value, and QhThe angle corresponding to the maximum peak value in the peak values is used as the optimal angle after the h-th traversal
3.4 let h add1, setting t as 1, and returning to the substep 3.1 until the optimal angle after the H-th traversal is obtained
And the optimal angle after the H-th traversal is obtained
Wideband chirp signal received as a first satellite
Is estimated at the optimum angle
3.5 initialization: the h' th traversal has an angular range of
Step size of h' th traversal is Δ αh′，
Δ α represents the step size set, and 0 < Δ α < π, and the number of angles in the h' th traversal is Qh′H 'belongs to {1,2, …, H' }, H 'is the set total number of traversal times, and H' is a positive integer greater than 0;
Let t' be e {1,2, …, Qh′Instruction of
The t' th angle is shown as,
the initial values of t 'and h' are 1 respectively;
3.6 broadband chirp received to the second satellite
Is rotated by an angle of
The fractional Fourier transform (FRFT) of (1) to obtain a rotation angle of
Fractional fourier transform result peak of
3.7 let t' take 1 to Q, respectivelyh′Repeating the execution for 3.6, and obtaining the rotation angles of
Fractional fourier transform result peak of
To a rotation angle of
Fractional fourier transform result peak of
Is recorded as Qh′A peak value, and Qh′The angle corresponding to the maximum peak value in the peak values is used as the optimal angle after h' th traversal
3.8 adding 1 to H ', setting t ' to 1, returning to the substep 3.5 until the optimal angle after the H ' th traversal is obtained
And the optimal angle after the H' th traversal is obtained
Broadband chirp signal received as a second satellite
To estimate the optimum angle
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| CN109901107A (en) * | 2019-03-07 | 2019-06-18 | 西安电子科技大学 | A kind of time difference positioning method, device, computer equipment and readable storage medium storing program for executing |
| CN112346010B (en) * | 2020-09-28 | 2022-06-10 | 中国人民解放军海军航空大学 | Dual-computer passive positioning method based on scale difference and time difference |
| CN112710984B (en) * | 2020-12-11 | 2023-01-31 | 中国人民解放军海军航空大学 | Passive positioning method and system based on homotopy continuation |
| CN113514798A (en) * | 2021-07-12 | 2021-10-19 | 中国人民解放军海军航空大学 | Fourier Mellin transform-based method for estimating time difference/scale difference of broadband nonlinear frequency modulation signal |
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| US5351056A (en) * | 1993-06-21 | 1994-09-27 | International Business Machines Corp. | Target tracking in clutter degraded scenes using central level stereo processing |
| US5570096A (en) * | 1995-03-24 | 1996-10-29 | Interferometrics, Inc. | Method and system for tracking satellites to locate unknown transmitting accurately |
| CN102608621A (en) * | 2012-03-23 | 2012-07-25 | 桂林电子科技大学 | High-precision low-track double star seamless passive positioning method and system |
| CN103149571B (en) * | 2013-02-18 | 2014-12-10 | 桂林电子科技大学 | GNSS (Global Navigation Satellite System)-based signal aided time frequency difference comprehensive correction method |
| CN103645485B (en) * | 2013-10-28 | 2016-01-20 | 中国科学院国家授时中心 | A kind of pseudorange differential method based on the frequency difference passive location of the double star time difference |
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