CN115396269B - Carrier parameter estimation method and system suitable for burst communication - Google Patents

Carrier parameter estimation method and system suitable for burst communication Download PDF

Info

Publication number
CN115396269B
CN115396269B CN202211031461.6A CN202211031461A CN115396269B CN 115396269 B CN115396269 B CN 115396269B CN 202211031461 A CN202211031461 A CN 202211031461A CN 115396269 B CN115396269 B CN 115396269B
Authority
CN
China
Prior art keywords
sequence
frequency
phase
subsequence
spectrum
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
Application number
CN202211031461.6A
Other languages
Chinese (zh)
Other versions
CN115396269A (en
Inventor
郭一超
张涛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Tianjin Jinhang Computing Technology Research Institute
Original Assignee
Tianjin Jinhang Computing Technology Research Institute
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Tianjin Jinhang Computing Technology Research Institute filed Critical Tianjin Jinhang Computing Technology Research Institute
Priority to CN202211031461.6A priority Critical patent/CN115396269B/en
Publication of CN115396269A publication Critical patent/CN115396269A/en
Application granted granted Critical
Publication of CN115396269B publication Critical patent/CN115396269B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/0014—Carrier regulation
    • H04L2027/0024—Carrier regulation at the receiver end
    • 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
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Radio Relay Systems (AREA)

Abstract

The application provides a carrier parameter estimation method and a carrier parameter estimation system suitable for burst communication, wherein the method comprises the following steps: acquiring an initial signal; performing down-conversion resampling on the initial signal to obtain a baseband sampling sequence; sampling the periodic pseudo code sequence to obtain a first sequence; stripping pseudo codes from the first sequence to obtain a second sequence; reducing the order of the second sequence through transient autocorrelation processing to obtain a third sequence; splitting the third sequence into a first subsequence and a second subsequence, and performing segmented discrete Fourier transform to obtain a first frequency spectrum and a second frequency spectrum; determining a phase difference of the first spectrum and the second spectrum; and finally, calculating a frequency change rate estimation value according to a formula. The instantaneous autocorrelation processing can convert the frequency change rate into frequency for estimation, so that the carrier estimation time is saved, and the carrier estimation complexity is reduced. And the carrier parameters are estimated with high precision by adopting the segmented Fourier transform, so that the parameter estimation error is effectively reduced.

Description

Carrier parameter estimation method and system suitable for burst communication
Technical Field
The present disclosure relates generally to the field of burst communication and signal parameter estimation technologies, and in particular, to a carrier parameter estimation method and system suitable for burst communication.
Background
Currently, aircraft are gradually moving towards high maneuver and hypersonic motion. In a high dynamic environment, the received signal necessarily contains a large Doppler frequency and a change rate thereof caused by high-speed and high-acceleration motion; if the parameter estimation is not performed, the data cannot be effectively demodulated, and the wireless communication between the aircraft and the platform cannot be effectively interconnected. Meanwhile, in order to ensure the anti-interception and anti-interference capabilities of communication, burst communication is mostly adopted, and a receiving and transmitting cooperative party performs data transmission according to a time slot appointed in advance. The signal is not continuously transmitted in the time domain, but the communication time slot cannot be known by the non-cooperators, so that effective interference and influence on burst communication cannot be formed.
Under the large frequency deviation and high dynamic communication environment, the traditional carrier wave estimation method aiming at continuous wave communication is mainly a loop tracking method, and the carrier wave estimation method aiming at burst communication is mainly a fixed step search method. Both methods have respective defects, loop tracking is only applicable to continuous waves, and loop convergence cannot be realized due to time discontinuity for burst communication, so that the estimation effect is extremely poor; the fixed step search method needs to ensure the estimation precision, so that the search step needs to be set to be smaller, the search range is extremely large aiming at the environment with large frequency deviation and high dynamic, the quick search cannot be realized, and the real-time performance and the realization complexity of parameter estimation cannot meet the requirements.
Disclosure of Invention
In view of the foregoing drawbacks or shortcomings of the prior art, it is desirable to provide a carrier parameter estimation method and system suitable for burst communication.
The application provides a carrier parameter estimation method suitable for burst communication, which comprises the following steps:
obtaining an initial signal, wherein the initial signal is obtained by multiplying a periodic pseudo code sequence by an original signal;
down-converting the initial signal, and sampling the down-converted signal at a set frequency to obtain a baseband sampling sequence;
sampling the periodic pseudo code sequence at a set frequency to obtain a first sequence;
stripping pseudo codes from the first sequence according to the baseband sampling sequence to obtain a second sequence;
taking the estimated phase of the periodic pseudo code sequence as delay, and reducing the order of the second sequence through instantaneous autocorrelation processing to obtain a third sequence; the estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm;
splitting the third sequence into a first subsequence and a second subsequence with equal length, and performing segmented discrete Fourier transform on the first subsequence and the second subsequence respectively to obtain a first frequency spectrum and a second frequency spectrum;
determining peak positions k of the first spectrum and the second spectrum m ；
Determining the first spectrum and the peak position k m Corresponding first phase, determining the second spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating the frequency change rate estimation value according to the formula (I)
Where τ is the delay of the transient autocorrelation process, T is the period of the first or second subsequence, and pi is the circumference ratio.
According to the technical scheme provided by the embodiment of the application, the baseband sampling sequence is calculated according to a formula (II);
wherein N is the total sampling point number; t is t s ＝1/f s For the time domain sampling interval, n represents the nth sampling point, t n ＝nt s Representing a sampling time;
C(nt s -τ 0 ) For periodic pseudo-code sequences, τ 0 For initial phase of periodic pseudocode sequence, f d ＝(v/c)·f RF ＝ξF RF Is the carrier Doppler frequency;
c is the speed of light, v is the speed of movement of the aircraft relative to the satellite, f RF For radio frequency carrier frequency, ζ=v/c represents the ratio of the speed of motion of the aircraft relative to the satellite to the speed of light;
μ represents a rate of change in frequency due to acceleration, exp represents a power series based on e, j represents an imaginary unit,is the initial phase of the radio frequency carrier.
According to the technical scheme provided by the embodiment of the application, the first sequence is calculated according to a formula (III);
stripping pseudo codes from the first sequence according to the baseband sampling sequence, wherein the method for stripping pseudo codes is sliding correlation processing; the second sequence generated after the pseudo code is stripped by sliding correlation processing is calculated by a formula (IV);
wherein,representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase; />For estimating phase of periodic pseudo-code sequence, N c ＝T c f s Is the number of sampling points, T, of the periodic pseudo-code sequence c ＝LT cp For the period of the periodic pseudo-code sequence, T cp ＝1/R cp For chip duration, R cp Is the code rate.
According to the technical scheme provided by the embodiment of the application, the method for obtaining the third sequence by taking the estimated phase of the periodic pseudo code sequence as delay and reducing the order of the second sequence through instantaneous autocorrelation processing specifically comprises the following steps:
the second sequence is delayed by tau to obtain a delayed sequence r according to the formula (five) c (t n +τ)；
Calculating the third sequence according to formula (six);
wherein r is c * (t n ) R represents c (t n ) I.e. the conjugated sequence of said second sequence, f μ Mu tau is the frequency of the second sequence after the reduction, phi 1 ＝2πf d τ is the phase constant term.
According to the technical scheme provided by the embodiment of the application, the step of segmented discrete fourier transform comprises the following steps:
dividing the third sequence into the first subsequence and the second subsequence with equal lengths, wherein the first subsequence and the second subsequence are calculated by a formula (seventh);
wherein r is 1 (n) is the first subsequence, r 2 (n) is a second subsequence.
According to the technical scheme provided by the embodiment of the application, the step of segmented discrete fourier transform further comprises:
performing N/2 point Fourier transform on the first subsequence and the second subsequence respectively to obtain the first frequency spectrum and the second frequency spectrum, wherein the first frequency spectrum and the second frequency spectrum are calculated through a formula (eight);
wherein A is k For the amplitude of the first sub-sequence,for the phase of the first sub-sequence, the amplitude of the first sub-sequence and the phase of the first sub-sequence are calculated by the formula (nine);
according to the technical solution provided in the embodiments of the present application, for the first frequencies respectivelyPeak detection is carried out on the spectrum and the second spectrum to obtain two identical peak positions k m Further calculating the frequency estimation value; the frequency estimation value is calculated according to a formula (ten);
wherein,for frequency estimation, F 0 Is the frequency resolution of the fourier transform.
Another aspect of the present application provides a carrier parameter estimation system adapted for burst communication, including:
the antenna module is arranged on the aircraft and is used for acquiring initial signals transmitted by satellites; the initial signal is obtained by multiplying the original signal by a periodic pseudo code sequence;
the processing module is arranged on the aircraft, and the output end of the antenna module is connected with the input end of the processing module;
the processing module is used for:
down-converting the initial signal, and sampling the down-converted signal at a set frequency to obtain a baseband sampling sequence;
sampling the periodic pseudo code sequence at a set frequency to obtain a first sequence;
stripping pseudo codes from the first sequence according to the baseband sampling sequence to obtain a second sequence;
taking the estimated phase of the periodic pseudo code sequence as delay, and reducing the order of the second sequence through instantaneous autocorrelation processing to obtain a third sequence; the estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm;
splitting the third sequence into a first subsequence and a second subsequence with equal length, and performing segmented discrete Fourier transform on the first subsequence and the second subsequence respectively to obtain a first frequency spectrum and a second frequency spectrum;
determining peak positions k of the first spectrum and the second spectrum m ；
Determining the first spectrum and the peak position k m Corresponding first phase, determining the second spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating the frequency change rate estimation value according to the formula (I)
Where τ is the delay of the transient autocorrelation process, T is the period of the first or second subsequence, and pi is the circumference ratio.
The beneficial effects of this application lie in:
by acquiring an initial signal; firstly, down-converting an initial signal, and then sampling the down-converted signal to obtain a baseband sampling sequence; sampling the periodic pseudo code sequence to obtain a first sequence; stripping pseudo codes from the first sequence to obtain a second sequence; reducing the order of the second sequence through transient autocorrelation processing to obtain a third sequence; splitting the third sequence into a first subsequence and a second subsequence, and performing segmented discrete Fourier transform to obtain a first frequency spectrum and a second frequency spectrum; determining a phase difference of the first spectrum and the second spectrum; and finally, calculating a frequency change rate estimation value according to a formula. Sampling the signals, converting the continuous signals into discrete sequences, and analyzing and calculating the discrete sequences without depending on continuous waves; the problem that the loop tracking method cannot achieve loop convergence on discontinuous burst communication, so that the estimation effect is extremely poor is avoided. The instantaneous autocorrelation processing can be used for converting the frequency change rate into frequency for estimation, two-dimensional search is simplified into one-dimensional estimation, the search range is obviously shortened, the carrier estimation time is saved, the carrier estimation complexity is reduced, and the search speed is improved; and further, the real-time performance and the implementation complexity of parameter estimation can be met. The carrier parameter is estimated with high precision by adopting the segmented Fourier transform, and meanwhile, the error of parameter estimation is effectively reduced by utilizing the frequency and phase difference information.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the detailed description of non-limiting embodiments, made with reference to the following drawings, in which:
fig. 1 is a flow chart of a carrier parameter estimation method suitable for burst communication provided in the present application;
fig. 2 is a schematic structural diagram of a carrier parameter estimation system suitable for burst communication provided in the present application;
1, an antenna module; 2. a processing module; 3. and a pseudo code generation module.
Detailed Description
The present application is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be noted that, for convenience of description, only the portions related to the invention are shown in the drawings.
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
Example 1
Referring to fig. 1, a schematic diagram of a carrier parameter estimation method suitable for burst communication according to this embodiment includes:
s1: obtaining an initial signal, wherein the initial signal is obtained by multiplying a periodic pseudo code sequence by an original signal;
s2: down-converting the initial signal, and sampling the down-converted signal at a set frequency to obtain a baseband sampling sequence;
s3: sampling the periodic pseudo code sequence at a set frequency to obtain a first sequence;
stripping pseudo codes from the first sequence according to the baseband sampling sequence to obtain a second sequence;
s4: taking the estimated phase of the periodic pseudo code sequence as delay, and reducing the order of the second sequence through instantaneous autocorrelation processing to obtain a third sequence; the estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm;
s5: splitting the third sequence into a first subsequence and a second subsequence with equal length, and performing segmented discrete Fourier transform on the first subsequence and the second subsequence respectively to obtain a first frequency spectrum and a second frequency spectrum;
s6: determining peak positions k of the first spectrum and the second spectrum m ；
Determining the first spectrum and the peak position k m Corresponding first phase, determining the second spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
S7: calculating the frequency change rate estimation value according to the formula (I)
Where τ is the delay of the transient autocorrelation process, T is the period of the first or second subsequence, and pi is the circumference ratio.
The working process comprises the following steps: the satellite multiplies the original signal by the periodic pseudocode sequence to generate an initial signal. The transmitting end of the satellite transmits an initial signal, and the antenna module 1 of the aircraft inputs the initial signal to the processing module 2 after receiving the initial signal. The aircraft locally generates a periodic pseudo code sequence identical to the satellite and inputs the periodic pseudo code sequence into the processing module 2, and the processing module 2 calculates a frequency change estimated value.
In some embodiments, the periodic pseudocode sequence is generated by a pseudocode generation module 3, and the satellite generated periodic pseudocode sequence is identical to the periodic pseudocode sequence generated by the pseudocode generation module 3 on board the aircraft.
In some embodiments, the down-conversion is achieved by a down-conversion unit, outputting as a complex signal with data modulation; sampling is realized by an AD sampling unit, and the set frequency of sampling is f s 。
In some embodiments, the processing module 2 performs sliding correlation processing on the first sequence according to the baseband sampling sequence, and strips pseudo codes to obtain a second sequence.
In some embodiments, the processing module 2 steps down the second sequence by transient autocorrelation processing with the estimated phase of the periodic pseudocode sequence as a delay;
and firstly delaying the second sequence to obtain a delay sequence, and multiplying the conjugate sequence of the second sequence by the delay sequence to obtain a third sequence.
The estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm, which belongs to the prior art and is not described herein.
In some embodiments, the processing module 2 determines the peak positions k of the first spectrum and the second spectrum by peak detection m 。
In some embodiments, the processing module 2 splits the third sequence into a first sub-sequence and a second sub-sequence with equal lengths, and performs N/2-point discrete fourier transform on the first sub-sequence and the second sub-sequence to obtain a first spectrum and a second spectrum.
And then according to the peak position k m Calculating the first spectrum and the peakAnd determining a second phase corresponding to the peak position of the second frequency spectrum according to the first phase corresponding to the value position.
In some embodiments, equation (one) is derived from equation (eleven);
wherein,for the first phase, +>For the second phase>For the phase difference->For the frequency estimation result, +.>Is an estimate of the rate of change of frequency.
Working principle: sampling the signals, converting the continuous signals into discrete sequences, and analyzing and calculating the discrete sequences without depending on continuous waves; the problem that the loop tracking method cannot achieve loop convergence on discontinuous burst communication, so that the estimation effect is extremely poor is avoided. The instantaneous autocorrelation processing can be used for converting the frequency change rate into frequency for estimation, two-dimensional search is simplified into one-dimensional estimation, the search range is obviously shortened, the carrier estimation time is saved, the carrier estimation complexity is reduced, and the search speed is improved; and further, the real-time performance and the implementation complexity of parameter estimation can be met. The carrier parameter is estimated with high precision by adopting the segmented Fourier transform, and meanwhile, the error of parameter estimation is effectively reduced by utilizing the frequency and phase difference information.
Further, the baseband sampling sequence is calculated according to a formula (II);
wherein N is the total sampling point number; t is t s ＝1/f s For the time domain sampling interval, n represents the nth sampling point, t n ＝nt s Representing a sampling time;
C(nt s -τ 0 ) For periodic pseudo-code sequences, τ 0 For initial phase of periodic pseudocode sequence, f d ＝(v/c)·f RF ＝ξF RF Is the carrier Doppler frequency;
c is the speed of light, v is the speed of movement of the aircraft relative to the satellite, f RF For radio frequency carrier frequency, ζ=v/c represents the ratio of the speed of motion of the aircraft relative to the satellite to the speed of light;
μ represents a rate of change in frequency due to acceleration, exp represents a power series based on e, j represents an imaginary unit,is the initial phase of the radio frequency carrier.
In some embodiments, the sampling frequency is greater than or equal to two times of the signal frequency, so as to satisfy the nyquist theorem and ensure that the signal before sampling can be restored after sampling.
Further, the first sequence is calculated according to formula (III);
stripping pseudo codes from the first sequence according to the baseband sampling sequence, wherein the method for stripping pseudo codes is sliding correlation processing; the second sequence generated after the pseudo code is stripped by sliding correlation processing is calculated by a formula (IV);
wherein,representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase; />For estimating phase of periodic pseudo-code sequence, N c ＝T c f s Is the number of sampling points, T, of the periodic pseudo-code sequence c ＝LT cp For the period of the periodic pseudo-code sequence, T cp ＝1/R cp For chip duration, R cp Is the code rate.
In some embodiments, the pseudo code is stripped by performing sliding correlation on the first sequence according to the baseband sampling sequence, so that the two sequences can be aligned, the successful stripping of the pseudo code is ensured, and the signal sequence can be identified.
Further, the method for obtaining the third sequence by taking the estimated phase of the periodic pseudo code sequence as delay and reducing the order of the second sequence through instantaneous autocorrelation processing specifically comprises the following steps:
the second sequence is delayed by tau to obtain a delayed sequence r according to the formula (five) c (t n +τ)；
Calculating the third sequence according to formula (six);
wherein r is c * (t n ) R represents c (t n ) I.e. the conjugated sequence of said second sequence, f μ Mu tau is the frequency of the second sequence after the reduction, phi 1 ＝2πf d τ is the phase constant term.
In some embodiments, the step of reducing the second sequence is implemented by delaying the second sequence to obtain a delay sequence and multiplying the conjugate sequence of the second sequence by the delay sequence through transient autocorrelation; the frequency change rate is converted into frequency for estimation, the two-dimensional search is simplified into one-dimensional estimation, the carrier estimation time is saved, and the carrier estimation complexity is reduced.
Further, the step of segmented discrete fourier transform comprises:
dividing the third sequence into the first subsequence and the second subsequence with equal lengths, wherein the first subsequence and the second subsequence are calculated by a formula (seventh);
wherein r is 1 (n) is the first subsequence, r 2 (n) is a second subsequence.
Further, the step of segmented discrete fourier transform further comprises:
performing N/2 point Fourier transform on the first subsequence and the second subsequence respectively to obtain the first frequency spectrum and the second frequency spectrum, wherein the first frequency spectrum and the second frequency spectrum are calculated through a formula (eight);
wherein A is k For the amplitude of the first sub-sequence,for the phase of the first sub-sequence, the amplitude of the first sub-sequence and the phase of the first sub-sequence are calculated by the formula (nine);
in some embodiments, a segmented discrete fourier transform is employed to make a high-precision estimate of the carrier parameters. And splitting the third sequence into a first subsequence and a second subsequence, and performing N/2 point Fourier transform on the first subsequence and the second subsequence respectively to obtain the first frequency spectrum and the second frequency spectrum, so that frequency and phase are convenient to calculate.
Further, peak detection is performed on the first frequency spectrum and the second frequency spectrum respectively to obtain two identical peak positions k m Further calculating the frequency estimation value; the frequency estimation value is calculated according to a formula (ten);
wherein,for frequency estimation, F 0 Is the frequency resolution of the fourier transform.
In some embodiments, the first and second subsequences are averaged and split from the third sequence, the first and second subsequences having the same peak position and frequency estimate; the first sub-sequence and the second sub-sequence have different phases due to being in different segments of the third sequence.
In some embodiments, the frequency and phase difference information are used to calculate the frequency estimation result and further calculate the frequency change rate estimation value, so that the error of parameter estimation is effectively reduced.
Example 2
Referring to fig. 2, the present application further provides a carrier parameter estimation system suitable for burst communication, including:
the antenna module 1 is installed on an aircraft and is used for acquiring initial signals transmitted by satellites; the initial signal is obtained by multiplying the original signal by a periodic pseudo code sequence;
the processing module 2 is arranged on the aircraft, and the output end of the antenna module 1 is connected with the input end of the processing module 2;
the processing module 2 is used for:
down-converting the initial signal, and sampling the down-converted signal at a set frequency to obtain a baseband sampling sequence;
sampling the periodic pseudo code sequence at a set frequency to obtain a first sequence;
stripping pseudo codes from the first sequence according to the baseband sampling sequence to obtain a second sequence;
taking the estimated phase of the periodic pseudo code sequence as delay, and reducing the order of the second sequence through instantaneous autocorrelation processing to obtain a third sequence; the estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm;
splitting the third sequence into a first subsequence and a second subsequence with equal length, and performing segmented discrete Fourier transform on the first subsequence and the second subsequence respectively to obtain a first frequency spectrum and a second frequency spectrum;
determining peak positions k of the first spectrum and the second spectrum m ；
Determining the first spectrum and the peak position k m Corresponding first phase, determining the second spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating the frequency change rate estimation value according to the formula (I)
Where τ is the delay of the transient autocorrelation process, T is the period of the first or second subsequence, and pi is the circumference ratio.
In some embodiments, the periodic pseudocode sequence is generated by a pseudocode generation module 3, and the satellite generated periodic pseudocode sequence is identical to the periodic pseudocode sequence generated by the pseudocode generation module 3 on board the aircraft.
In some embodiments, the satellite multiplies the original signal with a periodic pseudocode sequence to generate an initial signal. The transmitting end of the satellite transmits an initial signal, and the antenna module 1 of the aircraft inputs the initial signal to the processing module 2 after receiving the initial signal. The pseudo code generation module 3 on the aircraft generates a periodic pseudo code sequence identical to the satellite and inputs the periodic pseudo code sequence into the processing module 2, and the processing module 2 calculates a frequency change estimated value.
In some embodiments, the down-conversion is achieved by a down-conversion unit, outputting as a complex signal with data modulation; sampling is realized by an AD sampling unit, and the set frequency of sampling is f s 。
In some embodiments, the processing module 2 performs sliding correlation processing on the first sequence according to the baseband sampling sequence, and strips pseudo codes to obtain a second sequence.
In some embodiments, the processing module 2 steps down the second sequence by transient autocorrelation processing with the estimated phase of the periodic pseudocode sequence as a delay;
and firstly delaying the second sequence to obtain a delay sequence, and multiplying the conjugate sequence of the second sequence by the delay sequence to obtain a third sequence.
The estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm, which belongs to the prior art and is not described herein.
In some embodiments, the processing module 2 determines the peak positions k of the first spectrum and the second spectrum by peak detection m 。
In some embodiments, the processing module 2 splits the third sequence into a first sub-sequence and a second sub-sequence with equal lengths, and performs N/2-point discrete fourier transform on the first sub-sequence and the second sub-sequence to obtain a first spectrum and a second spectrum.
And then according to the peak position k m And calculating a first phase corresponding to the peak position of the first frequency spectrum, and determining a second phase corresponding to the peak position of the second frequency spectrum.
In some embodiments, equation (one) is derived from equation (eleven);
wherein,for the first phase, +>For the second phase>For the phase difference->For the frequency estimation result, +.>Is an estimate of the rate of change of frequency.
Working principle: sampling the signals, converting the continuous signals into discrete sequences, and analyzing and calculating the discrete sequences without depending on continuous waves; the problem that the loop tracking method cannot achieve loop convergence on discontinuous burst communication, so that the estimation effect is extremely poor is avoided. The instantaneous autocorrelation processing can be used for converting the frequency change rate into frequency for estimation, two-dimensional search is simplified into one-dimensional estimation, the search range is obviously shortened, the carrier estimation time is saved, the carrier estimation complexity is reduced, and the search speed is improved; and further, the real-time performance and the implementation complexity of parameter estimation can be met. The carrier parameter is estimated with high precision by adopting the segmented Fourier transform, and meanwhile, the error of parameter estimation is effectively reduced by utilizing the frequency and phase difference information.
The foregoing description is only of the preferred embodiments of the present application and is presented as a description of the principles of the technology being utilized. It will be appreciated by persons skilled in the art that the scope of the invention referred to in this application is not limited to the specific combinations of features described above, but it is intended to cover other embodiments in which any combination of features described above or equivalents thereof is possible without departing from the spirit of the invention. Such as the above-described features and technical features having similar functions (but not limited to) disclosed in the present application are replaced with each other.

Claims (8)

1. A carrier parameter estimation method suitable for burst communication, comprising:
obtaining an initial signal, wherein the initial signal is obtained by multiplying a periodic pseudo code sequence by an original signal;
down-converting the initial signal, and sampling the down-converted signal at a set frequency to obtain a baseband sampling sequence;
sampling the periodic pseudo code sequence at a set frequency to obtain a first sequence;
stripping pseudo codes from the first sequence according to the baseband sampling sequence to obtain a second sequence;
taking the estimated phase of the periodic pseudo code sequence as delay, and reducing the order of the second sequence through instantaneous autocorrelation processing to obtain a third sequence; the estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm;
splitting the third sequence into a first subsequence and a second subsequence with equal length, and performing segmented discrete Fourier transform on the first subsequence and the second subsequence respectively to obtain a first frequency spectrum and a second frequency spectrum;
determining the first spectrum and the first spectrumPeak position of the second spectrum；
Determining the first spectrum and the peak positionCorresponding first phase, determining the second spectrum and the peak position +.>A corresponding second phase;
calculating the phase difference between the first phase and the second phase；
Calculating the frequency change rate estimation value according to the formula (I)，
(one);
wherein,delay for transient autocorrelation processing, +.>For the period of the first sub-sequence or the second sub-sequence, -/-, for the period of the first sub-sequence or the second sub-sequence>Is the circumference ratio;
the first sequence is stripped according to the baseband sampling sequence, and the method for stripping the pseudo code is sliding correlation processing; the second sequence generated after the pseudo code is stripped by sliding correlation processing is calculated by a formula (IV);
(IV);
wherein,representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase; />For the estimated phase of the periodic pseudo-code sequence, +.>Is the number of samples of the periodic pseudo-code sequence, +.>For the period of the periodic pseudo-code sequence, +.>For chip duration, +.>Is the code rate.
2. The method for estimating carrier parameters suitable for burst communication according to claim 1, wherein said baseband sampling sequence is calculated according to formula (two);
(II) the second step;
wherein,counting the total sampling points; />For the time domain sampling interval, +.>Represents->Sampling points->Representing a sampling time;
for periodic pseudo-code sequences, +.>For the initial phase of the periodic pseudo-code sequence, +.>Is the carrier Doppler frequency;
for the speed of light->For the speed of movement of the aircraft relative to the satellites, +.>Is a radio frequency carrier frequency->Representing the ratio of the speed of movement of the aircraft relative to the satellite to the speed of light;
representing the rate of change of frequency due to acceleration, +.>Representative is->Power series as base>Representing the units of an imaginary number,is the initial phase of the radio frequency carrier.
3. The method for estimating carrier parameters suitable for burst communication according to claim 2, wherein said first sequence is calculated according to formula (iii);
(III);
stripping pseudo codes from the first sequence according to the baseband sampling sequence, wherein the method for stripping pseudo codes is sliding correlation processing; the second sequence generated after the pseudo code is stripped by sliding correlation processing is calculated by a formula (IV);
(IV);
wherein,representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase; />For the estimated phase of the periodic pseudo-code sequence, +.>Is the number of samples of the periodic pseudo-code sequence, +.>For the period of the periodic pseudo-code sequence, +.>For chip duration, +.>Is the code rate.
4. A carrier parameter estimation method suitable for burst communication according to claim 3, wherein the method for obtaining the third sequence by reducing the order of the second sequence by transient autocorrelation processing with the estimated phase of the periodic pseudo code sequence as a delay time specifically comprises:
the second sequence will be delayed according to equation (five)Obtaining a delay sequence->；
(V) a fifth step;
calculating the third sequence according to formula (six);
(six);
wherein,representation->Is the conjugated sequence of said second sequence,/->For the frequency of said second sequence after reduction, < >>Is a phase constant term.
5. The method for estimating carrier parameters suitable for burst communication as recited in claim 4, wherein said step of piecewise discrete fourier transform comprises:
dividing the third sequence into the first subsequence and the second subsequence with equal lengths, wherein the first subsequence and the second subsequence are calculated by a formula (seventh);
(seventh);
wherein,for the first subsequence, < >>Is the second subsequence.
6. The method for estimating carrier parameters for burst communication as recited in claim 5, wherein said step of piecewise discrete fourier transforming further comprises:
respectively performing the first subsequence and the second subsequencePerforming point Fourier transform to obtain the first frequency spectrum and the second frequency spectrum, wherein the first frequency spectrum and the second frequency spectrum are calculated through a formula (eight);
(eighth);
wherein,for the magnitude of said first sub-sequence, < >>For the phase of the first sub-sequence, the amplitude of the first sub-sequence and the phase of the first sub-sequence are calculated by the formula (nine);
and (nine).
7. The method for estimating carrier parameters for burst communication as recited in claim 6 wherein peak detection is performed on said first spectrum and said second spectrum respectively to obtain two identical peak positionsFurther calculating a frequency estimation value; the frequency estimation value is calculated according to a formula (ten);
(ten);
wherein,for the frequency estimation value, +.>Is the frequency resolution of the fourier transform.
8. A carrier parameter estimation system adapted for burst communication, comprising:
the antenna module is arranged on the aircraft and is used for acquiring initial signals transmitted by satellites; the initial signal is obtained by multiplying the original signal by a periodic pseudo code sequence;
the processing module is arranged on the aircraft, and the output end of the antenna module is connected with the input end of the processing module;
the processing module is used for:
down-converting the initial signal, and sampling the down-converted signal at a set frequency to obtain a baseband sampling sequence;
sampling the periodic pseudo code sequence at a set frequency to obtain a first sequence;
stripping pseudo codes from the first sequence according to the baseband sampling sequence to obtain a second sequence;
taking the estimated phase of the periodic pseudo code sequence as delay, and reducing the order of the second sequence through instantaneous autocorrelation processing to obtain a third sequence; the estimated phase of the periodic pseudo code sequence is obtained through a phase estimation algorithm;
splitting the third sequence into a first subsequence and a second subsequence with equal length, and performing segmented discrete Fourier transform on the first subsequence and the second subsequence respectively to obtain a first frequency spectrum and a second frequency spectrum;
determining peak positions of the first spectrum and the second spectrum；
Determining the first spectrum and the peak positionCorresponding first phase, determining the second spectrum and the peak position +.>A corresponding second phase;
calculating the phase difference between the first phase and the second phase；
Calculating the frequency change rate estimate according to equation (one)Metering value，
(one);
wherein,delay for transient autocorrelation processing, +.>For the period of the first sub-sequence or the second sub-sequence, -/-, for the period of the first sub-sequence or the second sub-sequence>Is the circumference ratio;
the first sequence is stripped according to the baseband sampling sequence, and the method for stripping the pseudo code is sliding correlation processing; the second sequence generated after the pseudo code is stripped by sliding correlation processing is calculated by a formula (IV);
(IV);
wherein,representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase; />For the estimated phase of the periodic pseudo-code sequence, +.>Is the number of samples of the periodic pseudo-code sequence, +.>For the period of the periodic pseudo-code sequence, +.>For chip duration, +.>Is the code rate.
CN202211031461.6A 2022-08-26 2022-08-26 Carrier parameter estimation method and system suitable for burst communication Active CN115396269B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202211031461.6A CN115396269B (en) 2022-08-26 2022-08-26 Carrier parameter estimation method and system suitable for burst communication

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202211031461.6A CN115396269B (en) 2022-08-26 2022-08-26 Carrier parameter estimation method and system suitable for burst communication

Publications (2)

Publication Number Publication Date
CN115396269A CN115396269A (en) 2022-11-25
CN115396269B true CN115396269B (en) 2024-01-16

Family

ID=84121717

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202211031461.6A Active CN115396269B (en) 2022-08-26 2022-08-26 Carrier parameter estimation method and system suitable for burst communication

Country Status (1)

Country Link
CN (1) CN115396269B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0966111A2 (en) * 1998-06-15 1999-12-22 Kuroyanagi, Noriyoshi Matched filter output analysis for interference control in a CDMA communications system
CN103929215A (en) * 2014-05-06 2014-07-16 许昌学院 Efficient MSK direct spread communication detecting method
CN106054204A (en) * 2016-07-26 2016-10-26 北京邮电大学 Long distance and high accuracy oriented compound laser range finding method and system
CN106230475A (en) * 2016-07-06 2016-12-14 北京理工大学 A kind of based on Tong detector pseudo-code Doppler effect correction catching method and device
CN111007476A (en) * 2019-12-17 2020-04-14 北京理工大学 High-dynamic pseudo code continuous wave radar long-time accumulation method

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7403578B2 (en) * 2001-06-08 2008-07-22 Broadcom Corporation Robust burst detection and acquisition system and method
EP2182645B1 (en) * 2008-10-29 2014-07-02 Thales Alenia Space Italia S.p.A. Method and system for spread spectrum signal acquisition

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0966111A2 (en) * 1998-06-15 1999-12-22 Kuroyanagi, Noriyoshi Matched filter output analysis for interference control in a CDMA communications system
CN103929215A (en) * 2014-05-06 2014-07-16 许昌学院 Efficient MSK direct spread communication detecting method
CN106230475A (en) * 2016-07-06 2016-12-14 北京理工大学 A kind of based on Tong detector pseudo-code Doppler effect correction catching method and device
CN106054204A (en) * 2016-07-26 2016-10-26 北京邮电大学 Long distance and high accuracy oriented compound laser range finding method and system
CN111007476A (en) * 2019-12-17 2020-04-14 北京理工大学 High-dynamic pseudo code continuous wave radar long-time accumulation method

Also Published As

Publication number Publication date
CN115396269A (en) 2022-11-25

Similar Documents

Publication Publication Date Title
JP5247056B2 (en) Propagation delay time measuring apparatus and radar apparatus
WO2012046419A1 (en) Radar device
EP2280491B1 (en) Apparatus and method for estimating a frequency shift and a time shift
US10921434B2 (en) Radar system
JP5089460B2 (en) Propagation delay time measuring apparatus and radar apparatus
WO2012140859A1 (en) Radar device
CN112910499B (en) Spread spectrum signal accurate acquisition system
JP3600459B2 (en) Method and apparatus for estimating direction of arrival of radio wave
CN107872419B (en) Pseudo code auxiliary bit timing synchronization implementation method for terahertz communication
CN109088838B (en) Pseudo code-Doppler fast capturing method of direct sequence spread spectrum DPSK signal under high dynamic condition
CN105842713A (en) INS (Inertial Navigation System) assisted fast acquisition method for BDS (Beidou Navigation System) signals based on SFT (Sparse Fourier Transform)
CN110764067A (en) Fourier transform LFM-BPSK composite modulation radar signal parameter estimation method
CN112187316A (en) Signal processing method, signal processing device, receiver and storage medium
CN104765052B (en) GEO navigation satellite high-sensitivity carrier tracking method
CN107272026B (en) A kind of navigation signal component phase test bias method
JP2006261985A (en) Receiver for spread spectrum communications
CN115396269B (en) Carrier parameter estimation method and system suitable for burst communication
CN114217329A (en) Short code capturing method based on serial search
CN102508265A (en) Signal separation estimation theory-based satellite navigation signal multipath interference suppression method
JPH08297162A (en) Bi-static radar equipment
CN110958035A (en) Frequency secondary capturing device and method based on triangular envelope fitting
JP3950242B2 (en) Offset QPSK modulation analysis method
CN115469341A (en) Rapid acquisition method for CL code of GPS L2C signal
CN112764063A (en) Method for realizing capture processing and receiver
CN108833320B (en) Keystone transformation-based broadband DS/FH signal parameter estimation method and system

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