CN115396269A - Carrier parameter estimation method and system suitable for burst communication - Google Patents
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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 and 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 instantaneous autocorrelation processing to obtain a third sequence; splitting the third sequence into a first subsequence and a second subsequence, and then respectively carrying out 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, thereby saving the carrier estimation time and reducing the carrier estimation complexity. And the carrier parameters are estimated with high precision by adopting segmented Fourier transform, so that the parameter estimation error is effectively reduced.
Description
Technical Field
The present disclosure relates generally to the field of burst communication and signal parameter estimation, and in particular, to a method and system for estimating carrier parameters for burst communication.
Background
Currently, aircrafts gradually develop towards the direction of high maneuverability and hypersonic motion. Under a high dynamic environment, a received signal necessarily contains a larger Doppler frequency and a change rate thereof caused by high-speed and high-acceleration motion; if the parameters of the aircraft are not estimated, 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 transmitting and receiving cooperative party performs data transmission according to a predetermined time slot. The signal is not continuously transmitted in the time domain, and the non-cooperative party cannot effectively interfere and affect the burst communication because the communication time slot cannot be known.
Under the environment of large frequency deviation and high dynamic communication, the traditional carrier estimation method for continuous wave communication is mainly a loop tracking method, and the carrier estimation method for burst communication is mainly a fixed stepping search method. The two methods have respective defects, the loop tracking is only suitable for continuous waves, and the estimation effect is very poor due to the fact that the loop convergence cannot be realized for burst communication due to time discontinuity; the fixed step search method needs to ensure the estimation accuracy, generally, the search step needs to be set to a small value, the search range is extremely large for a large frequency offset and high dynamic environment, the fast search cannot be realized, and the real-time performance and the realization complexity of the parameter estimation cannot meet the requirements.
Disclosure of Invention
In view of the above-mentioned drawbacks and deficiencies of the prior art, it is desirable to provide a method and system for estimating carrier parameters suitable for burst communication.
The present application provides an aspect of a carrier parameter estimation method suitable for burst communication, including:
acquiring an initial signal, wherein the initial signal is obtained by multiplying an original signal by a periodic pseudo code sequence;
carrying out down-conversion on the initial signal, and then sampling the signal obtained by the down-conversion 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 respectively carrying out segmented discrete Fourier transform on the first subsequence and the second subsequence 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 frequency spectrum and the peak position k m Corresponding first phase, determining the second frequency spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating a frequency rate of change estimate according to equation (one)
Wherein, tau is the time delay of the instantaneous autocorrelation processing, T is the period of the first subsequence or the 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 sample point, t n ＝nt s Represents a sampling time;
C(nt s -τ 0 ) For periodic pseudo-code sequences, τ 0 Is the initial phase of a periodic pseudo-code 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 ξ = v/c represents the ratio of the speed of motion of the aircraft relative to the satellite to the speed of light for the radio frequency carrier frequency;
mu represents the rate of change of frequency due to acceleration, exp represents a power series with e as the base, j represents an imaginary unit,
is the radio frequency carrier initial phase.
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 the pseudo codes is sliding correlation processing; calculating the second sequence generated after the sliding correlation processing and pseudo code stripping through a formula (IV);
wherein the content of the first and second substances,
representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase;
estimating phase, N, for periodic pseudo-code sequences c ＝T c f s Number of samples of periodic pseudo-code sequence, T c ＝LT cp Being the period of a periodic pseudo-code sequence, T cp ＝1/R cp Is 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 reducing the second sequence through instantaneous autocorrelation processing by taking the estimated phase of the periodic pseudo code sequence as delay specifically comprises the following steps:
delaying the second sequence by tau according to the formula (five) to obtain a delayed sequence r c (t n +τ)；
Calculating the third sequence according to formula (six);
wherein r is c * (t n ) Is represented by r c (t n ) I.e. the conjugate sequence of said second sequence, f μ = μ τ being the frequency of said second sequence after reduction, Φ 1 ＝2πf d τ is a 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 length, wherein the first subsequence and the second subsequence are calculated by formula (seven);
wherein r is 1 (n) is a first subsequence, r 2 (n) is the second subsequence.
According to the technical scheme provided by the embodiment of the application, the step of segmented discrete fourier transform further comprises:
respectively carrying out N/2-point Fourier transform on the first subsequence and the second subsequence to obtain a first frequency spectrum and a second frequency spectrum, wherein the first frequency spectrum and the second frequency spectrum are obtained by calculation of a formula (eight);
wherein A is k Is the amplitude of the first sub-sequence,
calculating the amplitude of the first subsequence and the phase of the first subsequence by using formula (nine), wherein the phase of the first subsequence is the phase of the first subsequence;
according to the technical scheme provided by the embodiment of the application, the first frequency spectrum and the second frequency spectrum are respectively subjected to peak detection to obtain two identical peak positions k m And then calculating the frequency estimation value; the frequency estimation value is calculated according to a formula (ten);
wherein the content of the first and second substances,
as a frequency estimate, F 0 Is the frequency resolution of the fourier transform.
Another aspect of the present application provides a carrier parameter estimation system suitable for burst communication, including:
the antenna module is arranged on the aircraft and used for acquiring initial signals transmitted by a satellite; the initial signal is obtained by multiplying an original signal by a periodic pseudo code sequence;
the processing module is installed 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:
carrying out down-conversion on the initial signal, and then sampling the signal obtained by the down-conversion 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 which are equal in length, and respectively carrying out segmented discrete Fourier transform on the first subsequence and the second subsequence to obtain a first frequency spectrum and a second frequency spectrum;
determining a peak position k of the first and second frequency spectra m ；
Determining the first frequency spectrum and the peak position k m Corresponding first phase, determining the second frequency spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating a frequency rate of change estimate according to equation (one)
Wherein, τ is the time delay of the instantaneous autocorrelation processing, T is the period of the first subsequence or the second subsequence, and π is the circumferential rate.
The beneficial effect of this application lies in:
by acquiring an initial signal; carrying out down-conversion on an initial signal, and then sampling a signal obtained by the down-conversion 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 instantaneous autocorrelation processing to obtain a third sequence; splitting the third sequence into a first subsequence and a second subsequence, and then respectively carrying out 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 signal, converting the continuous signal into a discrete sequence, and analyzing and calculating the discrete sequence without depending on continuous waves; the problem that the loop tracking method cannot realize loop convergence on discontinuous burst communication, so that the estimation effect is extremely poor is solved. The instantaneous autocorrelation processing is used for converting the frequency change rate into the frequency for estimation, the two-dimensional search is simplified into one-dimensional estimation, the search range is obviously reduced, the carrier estimation time is saved, the carrier estimation complexity is reduced, and the search speed is improved; and the real-time performance and the realization complexity of parameter estimation can be further met. The carrier parameters are estimated with high precision by adopting segmented Fourier transform, and meanwhile, the error of parameter estimation is effectively reduced by utilizing frequency and phase difference information.
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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:
fig. 1 is a schematic flowchart of a carrier parameter estimation method suitable for burst communication according to the present application;
fig. 2 is a schematic structural diagram of a carrier parameter estimation system suitable for burst communication according to the present application;
the method comprises the following steps of 1, an antenna module; 2. a processing module; 3. and a pseudo code generation module.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the relevant invention and not restrictive of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. 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 is shown, including:
s1: acquiring an initial signal, wherein the initial signal is obtained by multiplying an original signal by a periodic pseudo code sequence;
s2: carrying out down-conversion on the initial signal, and then sampling the signal obtained by the down-conversion 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 respectively carrying out segmented discrete Fourier transform on the first subsequence and the second subsequence to obtain a first frequency spectrum and a second frequency spectrum;
s6: determining a peak position k of the first and second frequency spectra m ；
Determining the first frequency spectrum and the peak position k m Corresponding first phase, determining the second frequency spectrum and the peak position k m A corresponding second phase;
calculating the first phase and the second phasePhase difference of two phases
S7: calculating a frequency rate of change estimate according to equation (one)
Wherein, τ is the time delay of the instantaneous autocorrelation processing, T is the period of the first subsequence or the second subsequence, and π is the circumferential rate.
The working process is as follows: the satellite multiplies the original signal by the periodic pseudo code sequence to generate an initial signal. The transmitting terminal of the satellite transmits the initial signal, and the antenna module 1 of the aircraft receives the initial signal and then inputs the initial signal into the processing module 2. The aircraft locally generates a periodic pseudo code sequence which is the same as that of the satellite and inputs the periodic pseudo code sequence into the processing module 2, and the processing module 2 calculates to obtain a frequency change estimated value.
In some embodiments, the periodic pseudo code sequence is generated by the pseudo code generation module 3, and the satellite-generated periodic pseudo code sequence is the same as the periodic pseudo code sequence generated by the on-board pseudo code generation module 3.
In some embodiments, the down-conversion is implemented by a down-conversion unit, and the output is a complex signal with data modulation; the sampling is realized by an AD sampling unit, and the set frequency of the 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 off the pseudo code to obtain a second sequence.
In some embodiments, the processing module 2 reduces the second sequence by instantaneous autocorrelation processing with the estimated phase of the periodic pseudo code sequence as a delay;
and firstly delaying the second sequence to obtain a delayed sequence, and multiplying the conjugate sequence of the second sequence by the delayed 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 again.
In some embodiments, the processing module 2 determines the peak position 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 subsequence and a second subsequence with equal length, and performs N/2-point segmented discrete fourier transform on the first subsequence and the second subsequence respectively to obtain a first spectrum and a second spectrum.
Further according to the peak position k m And calculating to obtain a first phase of the first frequency spectrum corresponding to the peak position, and determining a second phase of the second frequency spectrum corresponding to the peak position.
In some embodiments, equation (one) is derived from equation (eleven);
wherein the content of the first and second substances,
is the first phase of the first phase,
as a second phase of the first phase,
in order to be the phase difference between the two,
in order to be the result of the frequency estimation,
is a frequency rate of change estimate.
The working principle is as follows: sampling the signal, converting the continuous signal into a discrete sequence, and analyzing and calculating the discrete sequence without depending on continuous waves; the problem that the loop convergence cannot be realized on discontinuous burst communication by a loop tracking method, so that the estimation effect is extremely poor is solved. The instantaneous autocorrelation processing is used for converting the frequency change rate into the frequency for estimation, the two-dimensional search is simplified into one-dimensional estimation, the search range is obviously reduced, the carrier estimation time is saved, the carrier estimation complexity is reduced, and the search speed is improved; and the real-time performance and the realization complexity of parameter estimation can be further met. The carrier parameters are estimated with high precision by adopting segmented Fourier transform, and meanwhile, the error of parameter estimation is effectively reduced by utilizing frequency and phase difference information.
Further, the baseband sampling sequence is calculated according to a formula (two);
wherein N is the total sampling point number; t is t s ＝1/f s Is a time domain sampling interval, n represents the nth sample point, t n ＝nt s Represents a sampling time;
C(nt s -τ 0 ) For periodic pseudo-code sequences, τ 0 Is the initial phase of a periodic pseudo-code 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 ξ = v/c represents the ratio of the speed of motion of the aircraft relative to the satellite to the speed of light for the radio frequency carrier frequency;
mu represents the rate of change of frequency due to acceleration, exp represents a power series with e as the base, j represents an imaginary unit,
is the radio frequency carrier initial phase.
In some embodiments, the sampling frequency is greater than or equal to twice the signal frequency, so that the nyquist theorem is satisfied, and the signal before sampling can be restored after sampling.
Further, the first sequence is calculated according to formula (three);
stripping pseudo codes from the first sequence according to the baseband sampling sequence, wherein the method for stripping the pseudo codes is sliding correlation processing; the second sequence generated after the sliding correlation processing and the pseudo code stripping is calculated by a formula (IV);
wherein, the first and the second end of the pipe are connected with each other,
representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase;
estimating phase, N, for periodic pseudo-code sequences c ＝T c f s Is the number of sampling points, T, of the periodic pseudo-code sequence c ＝LT cp Being the period of a periodic pseudo-code sequence, T cp ＝1/R cp Is the chip duration, R cp Is the code rate.
In some embodiments, the pseudo code is stripped by performing sliding correlation processing on the first sequence according to the baseband sampling sequence, so that the two sequences can be kept aligned, and the pseudo code is successfully stripped, so that the signal sequence can be identified.
Further, taking the estimated phase of the periodic pseudo code sequence as a delay, and performing order reduction on the second sequence through instantaneous autocorrelation processing to obtain a third sequence specifically includes:
according to the formula (V)The second sequence is delayed by tau to obtain a delayed sequence r c (t n +τ)；
Calculating the third sequence according to formula (six);
wherein r is c * (t n ) Is represented by r c (t n ) I.e. the conjugate sequence of said second sequence, f μ = μ τ being the frequency of said second sequence after reduction, Φ 1 ＝2πf d τ is the phase constant term.
In some embodiments, the second sequence is delayed to obtain a delayed sequence through transient autocorrelation processing, and then a conjugate sequence of the second sequence is multiplied by the delayed sequence to realize order reduction of the second sequence; the frequency change rate is converted into the frequency for estimation, and the two-dimensional search is simplified into one-dimensional estimation, so that the carrier estimation time is saved, and the carrier estimation complexity is reduced.
Further, the step of piecewise discrete fourier transform comprises:
dividing the third sequence into the first subsequence and the second subsequence with equal length, wherein the first subsequence and the second subsequence are calculated by formula (seven);
wherein r is 1 (n) is a first subsequence, r 2 (n) is the second subsequence.
Further, the step of piecewise discrete fourier transform further comprises:
respectively carrying out N/2-point Fourier transform on the first subsequence and the second subsequence to obtain a first frequency spectrum and a second frequency spectrum, wherein the first frequency spectrum and the second frequency spectrum are obtained by calculation of a formula (eight);
wherein A is k Is the amplitude of the first sub-sequence,
calculating the amplitude of the first subsequence and the phase of the first subsequence by formula (nine), wherein the phase of the first subsequence is the phase of the first subsequence;
in some embodiments, a segmented discrete fourier transform is used to estimate the carrier parameters with high accuracy. And splitting the third sequence into a first subsequence and a second subsequence, and respectively carrying out N/2-point Fourier transform on the first subsequence and the second subsequence to obtain a first frequency spectrum and a second frequency spectrum, so that the frequency and the phase can be conveniently calculated.
Further, performing peak detection on the first spectrum and the second spectrum respectively to obtain two identical peak positions k m And then calculating the frequency estimation value; the frequency estimation value is calculated according to a formula (ten);
wherein, the first and the second end of the pipe are connected with each other,
as a frequency estimate, F 0 Is the frequency resolution of the fourier transform.
In some embodiments, the first subsequence and the second subsequence are equally split from the third sequence, and the first subsequence and the second subsequence have 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 estimation result is calculated by using the frequency and phase difference information simultaneously, so as to calculate the frequency change rate estimation value, thereby effectively reducing the error of parameter estimation.
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 mounted on an aircraft and used for acquiring initial signals transmitted by satellites; the initial signal is obtained by multiplying an original signal by a periodic pseudo code sequence;
the processing module 2 is installed 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 configured to:
carrying out down-conversion on the initial signal, and then sampling the signal obtained by the down-conversion 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 respectively carrying out segmented discrete Fourier transform on the first subsequence and the second subsequence to obtain a first frequency spectrum and a second frequency spectrum;
determining peak positions of the first spectrum and the second spectrumSet k m ；
Determining the first frequency spectrum and the peak position k m Corresponding first phase, determining the second frequency spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating a frequency rate of change estimate according to equation (one)
Wherein, τ is the time delay of the instantaneous autocorrelation processing, T is the period of the first subsequence or the second subsequence, and π is the circumferential rate.
In some embodiments, the periodic pseudo code sequence is generated by pseudo code generation module 3, and the periodic pseudo code sequence generated by the satellite is the same as the periodic pseudo code sequence generated by pseudo code generation module 3 on the aircraft.
In some embodiments, the satellite multiplies the original signal by a periodic pseudo code sequence to generate an initial signal. The transmitting terminal of the satellite transmits the initial signal, and the antenna module 1 of the aircraft receives the initial signal and then inputs the initial signal into the processing module 2. The pseudo code generating module 3 on the aircraft generates a periodic pseudo code sequence which is the same as that of the satellite and inputs the periodic pseudo code sequence into the processing module 2, and the processing module 2 calculates to obtain a frequency change estimated value.
In some embodiments, the down-conversion is implemented by a down-conversion unit, and the output is a complex signal with data modulation; the sampling is realized by an AD sampling unit, and the set frequency of the 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 off the pseudo code to obtain a second sequence.
In some embodiments, the processing module 2 reduces the second sequence by instantaneous autocorrelation processing with the estimated phase of the periodic pseudo code sequence as a delay;
and firstly delaying the second sequence to obtain a delayed sequence, and multiplying the conjugate sequence of the second sequence by the delayed sequence to obtain a third sequence.
The estimated phase of the periodic pseudo code sequence is obtained by 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 position 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 subsequence and a second subsequence with equal length, and performs N/2-point segmented discrete fourier transform on the first subsequence and the second subsequence respectively to obtain a first spectrum and a second spectrum.
Further according to the peak position k m And calculating to obtain a first phase of the first frequency spectrum corresponding to the peak position, and determining a second phase of the second frequency spectrum corresponding to the peak position.
In some embodiments, equation (one) is derived from equation (eleven);
wherein, the first and the second end of the pipe are connected with each other,
is a first phase of the electromagnetic wave and a second phase of the electromagnetic wave,
in the second phase, the first phase is the first phase,
in order to be the phase difference,
in order to be the result of the frequency estimation,
is a frequency rate of change estimate.
The working principle is as follows: sampling the signal, converting the continuous signal into a discrete sequence, and analyzing and calculating the discrete sequence without depending on continuous waves; the problem that the loop convergence cannot be realized on discontinuous burst communication by a loop tracking method, so that the estimation effect is extremely poor is solved. The instantaneous autocorrelation processing is used for converting the frequency change rate into the frequency for estimation, the two-dimensional search is simplified into the one-dimensional estimation, the search range is obviously reduced, the carrier estimation time is saved, the carrier estimation complexity is reduced, and the search speed is improved; and the real-time performance and the realization complexity of parameter estimation can be further met. The carrier parameters are estimated with high precision by adopting segmented Fourier transform, and the error of parameter estimation is effectively reduced by using frequency and phase difference information.
The foregoing description is only exemplary of the preferred embodiments of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.
Claims (8)
1. A method for estimating carrier parameters for burst communication, comprising:
acquiring an initial signal, wherein the initial signal is obtained by multiplying an original signal by a periodic pseudo code sequence;
carrying out down-conversion on the initial signal, and then sampling the signal obtained by the down-conversion 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 respectively carrying out segmented discrete Fourier transform on the first subsequence and the second subsequence 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 frequency spectrum and the peak position k m Corresponding first phase, determining the second frequency spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating a frequency rate of change estimate according to equation (one)
Wherein, τ is the time delay of the instantaneous autocorrelation processing, T is the period of the first subsequence or the second subsequence, and π is the circumferential rate.
2. The method according to claim 1, wherein the baseband sampling sequence is calculated according to formula (two);
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 sample point, t n ＝nt s Represents a sampling time;
C(nt s -τ 0 ) For periodic pseudo-code sequences, tau 0 Is the initial phase of a periodic pseudo-code 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 ξ = v/c represents the ratio of the speed of motion of the aircraft relative to the satellite to the speed of light for the radio frequency carrier frequency;
mu represents the rate of change of frequency due to acceleration, exp represents a power series with e as the base, j represents an imaginary unit,
is the radio frequency carrier initial phase.
3. The method according to claim 2, wherein 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 the pseudo codes is sliding correlation processing; the second sequence generated after the sliding correlation processing and the pseudo code stripping is calculated by a formula (IV);
wherein the content of the first and second substances,
representing a sequence obtained by sampling a periodic pseudo code sequence with an estimated phase;
for estimating the phase of a periodic pseudo-code sequence, N c ＝T c f s Number of samples of periodic pseudo-code sequence, T c ＝LT cp Being the period of a periodic pseudo-code sequence, T cp ＝1/R cp Is the chip duration, R cp Is the code rate.
4. The method according to claim 3, wherein the step of reducing the second sequence by instantaneous autocorrelation processing with the estimated phase of the periodic pseudo code sequence as a delay to obtain a third sequence specifically comprises:
delaying the second sequence by tau according to the formula (five) to obtain a delayed sequence r c (t n +τ)；
Calculating the third sequence according to formula (six);
wherein r is c * (t n ) Is represented by r c (t n ) I.e. the conjugate sequence of said second sequence, f μ = μ τ being the frequency of said second sequence after reduction, Φ 1 ＝2πf d τ is a phase constant term.
5. The method according to claim 4, wherein the step of segmented discrete Fourier transforming comprises:
dividing the third sequence into the first subsequence and the second subsequence with equal length, wherein the first subsequence and the second subsequence are calculated by formula (seven);
wherein r is 1 (n) is a first subsequence, r 2 (n) is the second subsequence.
6. The method of claim 5, wherein the step of piecewise discrete Fourier transform further comprises:
respectively carrying out N/2-point Fourier transform on the first subsequence and the second subsequence to obtain a first frequency spectrum and a second frequency spectrum, wherein the first frequency spectrum and the second frequency spectrum are obtained by calculation of a formula (eight);
wherein, A k Is the amplitude of the first sub-sequence,
calculating the amplitude of the first subsequence and the phase of the first subsequence by formula (nine), wherein the phase of the first subsequence is the phase of the first subsequence;
7. the method according to claim 6, wherein the peak detection is performed on the first spectrum and the second spectrum to obtain two identical peak positions k m And then calculating the frequency estimation value; the frequency estimation value is calculated according to a formula (ten);
wherein, the first and the second end of the pipe are connected with each other,
as a frequency estimate, F 0 Is the frequency resolution of the fourier transform.
8. A carrier parameter estimation system adapted for burst communications, comprising:
the antenna module is arranged on the aircraft and used for acquiring initial signals transmitted by a satellite; the initial signal is obtained by multiplying an original signal by a periodic pseudo code sequence;
the processing module is installed 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:
carrying out down-conversion on the initial signal, and then sampling the signal obtained by the down-conversion 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 which are equal in length, and respectively carrying out segmented discrete Fourier transform on the first subsequence and the second subsequence 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 frequency spectrum and the peak position k m Corresponding first phase, determining the second frequency spectrum and the peak position k m A corresponding second phase;
calculating the phase difference between the first phase and the second phase
Calculating a frequency rate of change estimate according to equation (one)
Wherein, τ is the time delay of the instantaneous autocorrelation processing, T is the period of the first subsequence or the second subsequence, and π is the circumferential rate.
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Citations (7)
| 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 |
| US20030021237A1 (en) * | 2001-06-08 | 2003-01-30 | Min Jonathan S. | Receiver having integrated spectral analysis capability |
| US20110200074A1 (en) * | 2008-10-29 | 2011-08-18 | Thales Alenia Space Italia S.P.A. | Method and system for spread spectrum signal acquisition |
| 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 |
-
2022
- 2022-08-26 CN CN202211031461.6A patent/CN115396269B/en active Active
Patent Citations (7)
| 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 |
| US20030021237A1 (en) * | 2001-06-08 | 2003-01-30 | Min Jonathan S. | Receiver having integrated spectral analysis capability |
| US20110200074A1 (en) * | 2008-10-29 | 2011-08-18 | Thales Alenia Space Italia S.P.A. | Method and system for spread spectrum signal acquisition |
| 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 |
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