CN109756968A - The precise synchronization timing method and precise synchronization timing means of single carrier spread spectrum system - Google Patents
The precise synchronization timing method and precise synchronization timing means of single carrier spread spectrum system Download PDFInfo
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Abstract
The present invention relates to field of communication technology more particularly to the precise synchronization timing methods and precise synchronization timing means of a kind of single carrier spread spectrum system.Method includes the following steps: matched filtering and interpolation are carried out to base band sample data using root raised cosine filter, the data after obtaining matched filtering；Data after matched filtering are scanned for the interval of half symbol, and are extracted using multiphase filter, slippage correlation acquisition algorithm carries out fast Acquisition to the data after matched filtering；When correlation upon acquisition is more than pre-determined threshold, with near current catch position correlation peak point for basic point, search for more accurate synchronous point, after the synchronous search of completion, cubic spline interpolation algorithm is continued to use on this basis or 3 peak-peaks calculate more accurate optimum sampling point, the present invention can promote timing accuracy to higher precision, meet the needs of precision distance measurement equipment, provide complete algorithm support for high-precision flyer ranging.
Description
Technical field
The present invention relates to the precise synchronization timing method of field of communication technology more particularly to a kind of single carrier spread spectrum system and
Precise synchronization timing means.
Background technique
Clock synchronization system collectivity Scheme Design such as Fig. 1, whole system are made of 4 synchronizing stations, 1 Reference BTS (
Face station or main website, referred to as A), 3 target BS (rover station or slave station, be briefly referred to as B1, B2, B3).4 base stations
Generate pulse per second (PPS) simultaneously, main website generates 100MHz clock signal, it is desirable that main website and slave station not less than 10km apart from when punctual essence
Degree is not less than 4ns, and as shown in figure 1, the distance between main website and slave station are 50km to example.Mature Time synchronization technique has unidirectionally at present
Timing technology, Two-way Time technology, positioning Service of Timing and two-way time correlation technique etc., wherein two-way time correlation technique has
There is the features such as real-time is good, initialization time is short, good environmental adaptability, the punctual precision of especially two-way time correlation technique is higher,
Technically it is more conform with actual needs.
The cardinal principle of two-way time correlation technique is as shown in Figure 2.With the clock of 1 Reference BTS and 1 target BS
Synchronizing process briefly describes the working principle of two-way time correlation technique.Reference BTS and target BS are produced by crystal oscillator clock
Raw respective time standard, and the time service generated under independent time standard.Assuming that the time difference of A and B1 crystal oscillator clock
For Δ t, comparing signal by the time can be realized A and B1 if can accurately measure Δ t and correct the crystal oscillator clock of itself
Between time synchronization.
Assuming that A is t in oneself time0Moment sending time contrast signal, B1 are t in oneself time1Reception is to main website
Time compare signal, measuring the poor time difference is Δ t1=t1-t0.Assuming that propagation delay time from A to B1 is τ, then Δ t1=t1-t0
=τ+Δ t.Similarly, B1 is in oneself timeMoment sending time contrast signal, B1 are in oneself timeReception
To the time comparison signal of main website, the measurement poor time difference isAssuming that the propagation delay time from A to B1 is τ,When choosing same transmission frequency and suitable signal system, it may be considered that transmission
Time is just the same in the transmission process that the two-way time compares signal, then two time differences, which subtracted each other, to obtainThe time synchronization error between A and B1 is found out, thus correction time respective crystal oscillator clock,
Reach relatively high synchronization accuracy.
Two-way link between main website and slave station all includes three transmitter, transmission channel and receiver links.Entire
Many time delay error links are contained in propagation path.(1) transmitter time delay error: transmitter time delay is that an average drifting is slow
Normal state nonstationary random process.Its Change in Mean curve and variance can detect to obtain by null detection and process, at present
The supplier of profession can announce the performance indicator data of its product.Due to being large signal operation, change curve is substantially normal
Number, and variance is generally within 0.1ns.(2) propagation delay time error: signal propagation path usually contains the media such as atmosphere, has
More complicated delay character, depends primarily on transmission frequency and transmission time.Forward and backward frequency and pass through atmosphere
The time of layer, forward direction and reversed propagation delay time were substantially identical, and difference generally can determine in 0.5ns very close in the case where
Within.(3) receiver time delay error: the time delay for receiving channel is also the slow normal state nonstationary random process of an average drifting.
Its Change in Mean curve and variance can be obtained by unidirectional null detection, and value depends primarily on signal-to-noise ratio when demodulation,
Under the conditions of the signal-to-noise ratio of 20db or so, its variance can generally be made to be less than 0.5ns by smoothing processing.
Therefore, the synchronous error that the two-way time compares depends on two station of principal and subordinate to the measurement of time difference and the biography of two-way link
Defeated consistent row.Time difference measurements precision is made of systematic error and random error, and systematic error, which can be indicated and be corrected, to be measured
In mean value, random error is the principal element of influence time difference measurements, and in addition the consistency of two-way link time delay also directly affects
To synchronous error estimated accuracy.
To sum up, two-way time comparison technology realizes that remote time synchronization theoretical error can control within 2ns, considers
Various uncertainties during engineering practice can determine that the technical solution can control time synchronization error in 3ns substantially
Hereinafter, complying fully with the requirement of technical indicator.The technology and have, skill small by the relative motion dynamic effects between two individuals
Art realization is easier to, the good feature of time synchronization real-time, and can be very good satisfaction design applies needs.
The determination of split-second precision difference is the key that realize two-way time comparison technology and basis.Only it has been determined that other side sends out
Sending the time difference at moment and local reception moment just can determine that the time synchronization error of two places, and the precision that the time difference determines
The synchronous error precision of final two places is directly affected, needs to improve the measurement accuracy of time difference in design as far as possible.Engineering
On generally using time-interval counter time of measuring it is poor, due to used pseudo noise code as the time comparison signal starting arteries and veins
Punching, is greatly improved the measurement accuracy of time difference.
If system requirements meets the synchronous error of 3ns when designing, time difference measurements need to combine essence synchronous by slightly synchronous
Two links are completed.According to design requirement, Reference BTS generates the local crystal oscillator clock of 100MHz, by capturing received ratio
The theoretical error of time difference measurements can only will be controlled within 10ns to signal, it is contemplated that the uncompensable errors of engineering practice, only
Comparison signal by capturing local reception cannot complete the time synchronized measurement of demand.Therefore, it is necessary to design smart synchronism link,
Complete the amendment slightly synchronized to the time.The synchronous realization approach of essence is as follows: target BS is synchronous to produce according to itself crystal oscillator clock
Raw one with Reference BTS pseudorandom catch code is duplicate compares code, using measured pulse and reference pulse as comparison, together
Shi Kaiqi high-frequency count pulse is counted, and pulse value is equal to the synchronous amendment difference of essence multiplied by the period is counted, and is synchronized and is repaired with essence
Positive difference completes slightly synchronous time complexity curve, promotes time difference measurements precision.
Time difference of the precision within 10ns can be calculated due to slightly synchronous, using the high frequency of 1000MHz
Pulse counter, the every 2ns of count value complete primary zero, can ensure necessary timing tracking accuracy and save resource.But
It is to use so high high-frequency impulse counter, and there are at high cost, the big problems of realization difficulty.
Therefore, it is badly in need of the precise synchronization timing method and precise synchronization timing means of a kind of single carrier spread spectrum system.
Summary of the invention
The present invention provides a kind of precise synchronization timing method of single carrier spread spectrum system and precise synchronization timing means, with
Convenient for obtaining the net synchronization capability of high-precision and high-stability using the smallest resource.
One aspect of the present invention provides a kind of precise synchronization timing method of single carrier spread spectrum system, including following
Step:
Matched filtering and interpolation are carried out to base band sample data, the data after obtaining matched filtering；
Data after matched filtering are captured；
When correlation upon acquisition is more than pre-determined threshold, optimum sampling point is calculated using current catch position as basic point；
Channel synchronization is carried out using the optimum sampling point as timing point, receives user data.
Further, matched filtering and interpolation are carried out to base band sample data using root raised cosine filter.
Further, it in the step of being captured to the data after matched filtering, is scanned for the interval of half symbol.
Further, the data after matched filtering are captured using slippage correlation acquisition algorithm.
Further, in the step of being captured to the data after matched filtering, using have limit for length's unit impulse response filter
Wave device is related to the progress of known synchronous head by the data after the matched filtering received, while the precision in order to guarantee timing, is
Chip synchronization needs to reach 1/8CHIP precision, is inserted into 8 times of spreading rate, i.e. 4 times of interpolations in sample rate, and when interpolation uses
Multiphase filter structure, the coefficient of filter are the 4 groups of coefficients extracted from matched filter coefficient with interval 4, data after interpolation is complete
Become 4 tunnels, after 4 times of interpolation, become 8 times of spreading rate, reach the precision of 1/8 chip, 4 road multiphase filterings export 4 times of interpolations
Output signal afterwards, wherein output is related to local synchronizing sequence all the way for any selection, and operand is made to be reduced to 1/4.
Further, it when correlation upon acquisition is more than pre-determined threshold, is calculated most using current catch position as basic point
The mode of optimum sampling point is calculated in the step of good sampled point are as follows: calculate current catch position and its forward and backward each 1/2 chip totally 9
The correlation of a sampled point chooses the point of wherein maximum value as optimum sampling point.
Further, when completion polyphase interpolating algorithm progress related synchronization reaches 1/8CHIP precision, relevant peaks are being obtained
Value nearby continues to use cubic spline interpolation algorithm or 3 peak-peak computing devices, further promotes correlation peak point
Precision reaches the Timing Synchronization of 1/32CHIP or more.
Further, 3 peak-peak computing devices are calculated by the following formula 3 highest correlations before and after correlation peak
Peak point P1, P2, P3 corresponding amplitude R1, R2, R3 calculate optimum sampling point:
As R1≤R3,
As R1 > R3,
Wherein, T is chip period, TsFor the sampling period, τ is that actual optimum sampling point is most preferably adopted with what is obtained when capture
The time difference of sampling point, P1, P2, P3 are respectively 3 highest correlation peak points before and after correlation peak, R1, R2, R3 be respectively P1, P2,
The corresponding correlation of P3.
The second aspect of the invention provides a kind of precise synchronization for realizing the single carrier spread spectrum system described among the above
The precise synchronization timing means of the single carrier spread spectrum system of timing method, comprising:
Base band sample data processing module obtains matching filter for carrying out matched filtering and interpolation to base band sample data
Data after wave；
Trapping module, for being captured to the data after matched filtering；
Optimum sampling point computing module, when being more than pre-determined threshold for correlation upon acquisition, with current catch position
Optimum sampling point is calculated for basic point；
Data reception module carries out channel synchronization using the optimum sampling point as timing point, receives user data.
Further, base band sample data processing module matches base band sample data using root raised cosine filter
Filtering and interpolation.
The precise synchronization timing method and precise synchronization timing means of single carrier spread spectrum system provided by the invention, and it is existing
Technology, which is compared, has following progress: the present invention carries out channel synchronization using calculated optimum sampling point as timing point, receives and uses
User data, can effectively resistance multi-path jamming, it is synchronous to complete accurate system under seldom resource situation, meets
The demand of precision distance measurement equipment.
The above description is only an overview of the technical scheme of the present invention, in order to better understand the technical means of the present invention,
And it can be implemented in accordance with the contents of the specification, and in order to allow above and other objects of the present invention, feature and advantage can
It is clearer and more comprehensible, the followings are specific embodiments of the present invention.
Detailed description of the invention
By reading the following detailed description of the preferred embodiment, various other advantages and benefits are common for this field
Technical staff will become clear.The drawings are only for the purpose of illustrating a preferred embodiment, and is not considered as to the present invention
Limitation.And throughout the drawings, the same reference numbers will be used to refer to the same parts.In the accompanying drawings:
Fig. 1 is clock system general frame figure；
Fig. 2 is the cardinal principle figure for the two-way time comparing scheme；
The step of Fig. 3 is the precise synchronization timing method of single carrier spread spectrum system in the embodiment of the present invention is schemed；
Fig. 4 is that the device of the precise synchronization timing means of single carrier spread spectrum system in the embodiment of the present invention connects block diagram；
Fig. 5 is multiple signals input, only selects to export polyphase interpolating filtering schematic diagram all the way；
Fig. 6 is the system structure diagram of the synchronous code capture method of sliding correlation method；
Fig. 7 is optimum sampling point and its both sides totally 3 points of schematic diagrames in time domain waveform；
Fig. 8 is using the correlation peak power points after spline3 interpolation；
Fig. 9 is that (true peak point is left in original peaks points for point after spline3 interpolation and original correlation peak point corresponding diagram
Side)；
Figure 10 be spline3 interpolation after point and original correlation peak point corresponding diagram (true peak point is in original peaks point
The right)；
Figure 11 is the flow chart for reaching high-precise synchronization；
Figure 12 is the structural schematic diagram of repetition training sequence；
Figure 13 is single carrier spread spectrum system frequency domain equalization block diagram.
Specific embodiment
Exemplary embodiments of the present disclosure are described in more detail below with reference to accompanying drawings.Although showing the disclosure in attached drawing
Exemplary embodiment, it being understood, however, that may be realized in various forms the disclosure without should be by embodiments set forth here
It is limited.On the contrary, these embodiments are provided to facilitate a more thoroughly understanding of the present invention, and can be by the scope of the present disclosure
It is fully disclosed to those skilled in the art.
Those skilled in the art of the present technique are appreciated that unless otherwise defined, all terms used herein (including technology art
Language and scientific term), there is meaning identical with the general understanding of those of ordinary skill in fields of the present invention.Should also
Understand, those terms such as defined in the general dictionary, it should be understood that have in the context of the prior art
The consistent meaning of meaning, and unless otherwise will not be explained in an idealized or overly formal meaning by specific definitions.
Present embodiments provide the precise synchronization timing method and precise synchronization timing means of a kind of single carrier spread spectrum system.
Such as Fig. 3, the precise synchronization timing method of the single carrier spread spectrum system of the present embodiment, comprising the following steps:
S1, matched filtering and interpolation are carried out to base band sample data, the data after obtaining matched filtering；
S2, the data after matched filtering are captured；
When S3, correlation upon acquisition are more than pre-determined threshold, optimum sampling is calculated using current catch position as basic point
Point；
S4, channel synchronization is carried out using the optimum sampling point as timing point, receive user data.
The precise synchronization timing method of the single carrier spread spectrum system of the present embodiment, using calculated optimum sampling point as calmly
Time point carry out channel synchronization, receive user data, can effectively resistance multi-path jamming, can under seldom resource situation
It is synchronous to complete accurate system, meets the needs of precision distance measurement equipment.
The precise synchronization timing method of the single carrier spread spectrum system of the present embodiment uses root raised cosine in the specific implementation
Filter carries out matched filtering and interpolation to base band sample data.The precise synchronization timing of the single carrier spread spectrum system of the present embodiment
Method uses Synchronization Design, and working clock frequency and ADC (A/D converter) sample rate are all 2 times of character rate in method
(such as 61.44MHz), baseband I, Q sampled data first pass around matched filtering and interpolation, and matched filter is root raised cosine filter
RRC, interpolation are also to be realized simultaneously with the filter, and the corresponding sampling rate of this filter is very high, it should be to consider
Rate 61.44*4=245.76MHZ after interpolation, filter order is long at this time, and signal processing rate is high, it usually needs consumption
Take more FPGA (field programmable gate array) resource.Simultaneously in order to guarantee the precision of timing, chip synchronization under normal circumstances
Need to reach 1/8CHIP precision, thus sample rate need in be inserted into 8 times of spreading rate, i.e. 4 times of interpolations, using more when interpolation
Phase filter structure, the coefficient of filter are the 4 groups of coefficients extracted from matched filter coefficient with interval 4, number after such interpolation is complete
According to becoming 4 tunnels.
The precise synchronization timing method of the single carrier spread spectrum system of the present embodiment, in the specific implementation, after matched filtering
Data the step of being captured in, scanned for the interval of half symbol.Be conducive to improve the accuracy and subsequent when capture
Synchronous accuracy.
The precise synchronization timing method of the single carrier spread spectrum system of the present embodiment is in the specific implementation, related using sliding
Acquisition algorithm captures the data after matched filtering.Burst capture is carried out using the synchronous code in preceding top guide, preceding top guide
Modulation system is BPSK (Binary Phase Shift Keying, binary phase shift keying)/QPSK (Quadrature
Phase Shift Keying is a kind of digital modulation mode), burst capture is caught using commonly sliding correlation in acquiring pseudo code
Algorithm is obtained, this is a kind of serial searching method.The system structure diagram of sliding correlation method method for acquiring pseudo code is as shown in Figure 6.
The precise synchronization timing method of the single carrier spread spectrum system of the present embodiment, in the specific implementation, step S1 is to matching
In the step of filtered data are captured, using there is limit for length's unit impulse response filter will be after the matched filtering that received
Data it is related to the progress of known synchronous head.I.e. every half-chip carries out related with reception data to known synchronous head.Due to being
Correlation is carried out according to the interval of half symbols, correlation can use FIR filter (having limit for length's unit impulse response filter) Lai Shixian,
Locally associated sequence is exactly m-sequence, and the filter coefficient of m-sequence only has 1 and -1 two kind of value, related at this time there was only addition and subtraction fortune
It calculates, without multiplying.Half-chip synchronisation stage at this time is actually the signal rate of ADC sampling back, interpolation int_
After hb=4 times, become int_all=8 times of spreading rate, reaches the precision of 1/8 chip.The road int_hb=4 multiphase filtering is defeated
Output signal after 4 times of interpolations out, any choose wherein export, such operand reduction related to local synchronizing sequence all the way
To 1/4.The input data rate of every group of filter is int_rrc=2 times of spreading rate, under the clock of 2 times of spreading rates
Work, this hardware implementing architecture for reducing rate are as shown in Figure 5.
The precise synchronization timing method of the single carrier spread spectrum system of the present embodiment, in the specific implementation, step S3 is when capture
When correlation when being more than pre-determined threshold, calculated most preferably in the step of calculating optimum sampling point as basic point using current catch position
The mode of sampled point are as follows: calculate the correlation of current catch position and its forward and backward each 1/2 chip totally 9 sampled points, choose wherein
The point of maximum value is as optimum sampling point.Preceding 1/2 chip (corresponding 8 sampled points of 1 chip, corresponding 4 sampled points of 1/2 chip)
Totally 9 sampled points in the range of to rear 1/2 chip (4 sampled points).Optimum sampling point and its both sides totally 3 points in time domain waveform
On schematic diagram it is as shown in Figure 7.In Fig. 7, T is chip period, TsFor the sampling period, τ is actual optimum sampling point and capture
When obtained time difference of optimum sampling point, if before the optimum sampling point that actual optimum sampling point is obtained in capture, τ
It is negative, otherwise τ is positive.τ is the amount for needing to estimate.
If reception signal is r (n), pseudo-code is p (n), then the expression formula of correlated process are as follows:
When correlation is more than thresholding upon acquisition, illustrates to have captured pseudo-code, reach the thick synchronous calibration point of the first order
Point1_pos, since the precision of half chip is relatively low, it is therefore desirable to 1/2 chip (4 samplings before current catch position
Point) to (totally 9 sampled points) in the range of rear 1/2 chip (4 sampled points) using the point as starting point 9 correlations of calculating, it looks for
The point of maximum value is used as second level essence synchronous point point2_pos as optimum sampling point at this time out.Subsequent demodulation process is pressed
+ synchronous method acquisition signal optimum sampling point the best_point of essence is slightly synchronized according to following formula:
Best_point=point1_pos*4+point2_pos-int_all/2；
It is extracted using the best_point point as benchmark starting point, obtains benchmark pacemaker, while also obtaining in 4 phases
Which phase output, such as point1_pos=171, int_hb=4, point2_pos=3, int_all=8.
Illustrate mphase=point2_pos-int_all/2=-1, illustrate be exactly the isolation of current phase mphase phase
That phase of position.
Such as Fig. 9, Figure 10 and Figure 11, the precise synchronization timing method of the single carrier spread spectrum system of the present embodiment, specific real
Shi Shi calculates optimum sampling point using any in cubic spline interpolation algorithm or 3 peak-peak computing devices.Afterwards
Continuous despreading, demodulation process are carried out by benchmark starting point of optimum sampling point, but this precision is inadequate for ranging.Therefore, to phase
It closes peak value R and does the synchronization that further fine processing reaches more accurate.The first scheme is using spline3 interpolation algorithm
(cubic spline interpolation algorithm, spline interpolation be in a kind of industrial design it is common, obtain a kind of interpolation method of smoothed curve,
Cubic spline is relatively broad one kind wherein again), the decimal that can reach more accurate is synchronous, that is, in relevant peaks
Value nearby carries out further interpolation processing.Carry out correlation peak power points as can be seen from Figure 8 and differs 2 apart from optimum sampling point
Sampled point then differs 1/4Ts if it is 8 times of over-samplings, and Ts at this time has been the precision of 1/8CHIP, so reaching 1/ at this time
The precision of 32CHIP, so can achieve very high precision at this time, is less than if Tchip=1/10MHZ=100ns
100ns/32 < 4ns.
Second scheme is calculating that can be simple and quick by following formula by 3 neighbouring points of correlation peak
Out.Such as 3 highests correlation peak point P1, P2, P3 in Fig. 7 near correlation peak, if practical optimum sampling point is not
This point of P2, but be A, then P in Fig. 7 with the peak value of P2 distance τ2Point value be1 and -1 in chip
When even distribution, having half in N number of sampled value is the value, and having half is A, then P2The correlation of point
P in above formulaNFor the power of noise.Similarly, P can be obtained1With P3The correlation of point is respectively as follows:
τ, specific practice can be solved according to above-mentioned 3 equations are as follows:
As R1≤R3, obtained according to the solution of equation of above-mentioned 3 peak points:
As R1 > R3, obtained according to above-mentioned 3 peak point solution of equations:
In the present system, Ts=T/10, that is, the duration of a symbol is T, if 10 times of mistakes of a symbol are adopted
Sample, then a sampled point is Ts=T/10, then integer interpolation multiple INT_IPOINT=10 at this time；Then if a symbol continues
Time is 100ns, then the duration of a sampled point is 10ns.
As R1≤R3, the normalization time difference is
As R1 > R3, the normalization time difference is
τ is obtained by calculation, so that it is determined that the absolute time from optimum sampling point, passes throughObtain decimal interpolation multiple
Relationship.
Such as in Fig. 9,3 points and original correlation peak point corresponding diagram after spline3 interpolation are calculated, P1 by formula
Point R1=1.36E+5, P2 point R2=1.56E+5, P3 point R3=1.15E+5, has R1 > R3, then utilizes as R1 > R3 according to upper
State the location matches that the formula that 3 solution of equations obtain calculates τ=- 0.27Ts and calculates below by 3 spline interpolation, maximum peak
Value point and the second largest peak point are after spline3 interpolation between (10 times of interpolation FRAC_IPOINT=10 of decimal) in 10 points
For corresponding point substantially between the 8th and the 7th point, true peak point is then negative on the correlation peak maximal peak point left side.
The integer interpolation multiple INT_IPOINT=10 of one symbol, that is, a symbol are interpolated and sample as 10
Point, and spline3 is on this basis, and it is then small to carry out 10 times of decimal interpolation FRAC_IPOINT=10. again to each sampled point
Precision after number interpolation reaches the measurement accuracy of 1ns.
Such as Calling MATLAB function yi=spline (x, y, xi).This is according to known x, y data, with batten letter
Number interpolation calculation goes out the value at xi.I.e. by x, the value of y calculates the corresponding functional value of xi.
Y=78657 102,996 140,116 157,855 117,692 92,208 65149
XI=1:1:7, Y=0:1/10:7-1/10 then obtain the signal after interpolation:
YI=88035 84,983 82,457 80,435 78,898 77,823 77,189 76,977 77,165 77,732 78657
79919 81497 83370 85518 87920 90554 93399 96435 99641 102996 106478 110067
113742 117482 121266 125074 128883 132674 136425 140116 143713 147141 150311
153134 155523 157388 158642 159197 158964 157855 155819 152963 149427 145356
140893 136180 131360 126577 121973 117692 113843 110412 107350 104609 102140
99897 97830 95891 94033 92208 90366 88461 86444 84266 81881 79239 76293 72995
69296
If Fig. 9 illustrates, y above is exactly correlation peak power points in Fig. 9, and YI is exactly correlation peak after spline3 interpolation
Power points.In Fig. 9 and Figure 10, decimal interpolation multiple FRACE_IPOINT=10.
Such as Figure 10, when R1 < R3, then the location matches for τ=0.28Ts being calculated by formula above and being calculated by interpolation,
Maximal peak point and the second largest peak point are after spline3 interpolation 10 between (10 times of interpolation FRACE_IPOINT=10 of decimal)
Corresponding point is substantially between the 8th and the 7th point in a point, and true peak point is on the right of correlation peak maximal peak point, then
For positive number.
It is connect using the calculated result of second scheme and using the result of the spline3 interpolation algorithm of the first scheme
Closely, reach measurement target.
Therefore, the present embodiment can accurately calculate the position of actual peak power point by 3 points.
A kind of precise synchronization for realizing single carrier spread spectrum system described in above-described embodiment such as Fig. 4, the present embodiment is fixed
The precise synchronization timing means of the single carrier spread spectrum system of Shi Fangfa, comprising:
Base band sample data processing module obtains matching filter for carrying out matched filtering and interpolation to base band sample data
Data after wave；
Trapping module, for being captured to the data after matched filtering；
Optimum sampling point computing module, when being more than pre-determined threshold for correlation upon acquisition, with current catch position
Optimum sampling point is calculated for basic point；
Data reception module carries out channel synchronization using the optimum sampling point as timing point, receives user data.
The precise synchronization timing means of the single carrier spread spectrum system of the present embodiment, using calculated optimum sampling point as calmly
Time point carry out channel synchronization, receive user data, can effectively resistance multi-path jamming, can under seldom resource situation
It is synchronous to complete accurate system, meets the needs of precision distance measurement equipment.
The precise synchronization timing means of the single carrier spread spectrum system of the present embodiment, in the specific implementation, base band sample data
Processing module carries out matched filtering and interpolation to base band sample data using root raised cosine filter.
The precise synchronization timing means of the single carrier spread spectrum system of the present embodiment, in the specific implementation, trapping module is with half
The interval of symbol scans for.
Chip equalizer carries out equilibrium in chip-level, it is a kind of special equilibrium for improving single carrier spread spectrum system performance
Device can only use linear equalization.The principle of this method is that chip-level is carried out before descrambling/despreading to receiving Chip Waveform
Adaptive equalization, so, balanced due to completing, the channel after equilibrium is flat, in the time domain the signal reason after equilibrium
As soon as there is only paths on, a paths are only existed before despreading, i.e., have restored to be broken by multipath channel to a certain extent
Bad vector signal planisphere, namely inhibit multi-path jamming.Under mobile communication environment, the tap coefficient of pilot tone training is utilized
Balanced, signal despreading after equilibrium, so that it may more matched completion spreading gain is carried out to subscriber signal.
Such as Figure 12 and Figure 13, precise synchronization timing method and the precise synchronization timing of the single carrier spread spectrum system of the present embodiment
Device when in use, firstly, transmitter emit one known to, the training sequence of fixed length, so that the balanced device at receiver can
To make correct setting.What is transmitted after training sequence is user data.When receiving user data, with equilibrium
Judgement obtains required data after device compensation channel.It is repeated periodically trained balanced device with adaptive algorithm, is constantly become with tracking
The channel of change.
Doppler in the present embodiment adds the magnitude about 2ppm (2*10-6) of clock deviation, under the carrier frequency of 1.7GHz, produces
Raw frequency deviation value is about 1.7GHz*2*10-6=3.4kHz, it is assumed that is Doppler frequency shift caused by high-speed mobile signal is added
1.6kHz, offset Af=5KHz total in this way, the maximum phase rotation amount that when capture generates under 510 chips are
2 π * 3.4kHz*255/61.44MHz=pi*2*5*10^3*512/ (61.44*10^6)=0.083pi are small in this way
Phase error to capture caused by loss it is very small, can ignore.
In the precise synchronization timing method and precise synchronization timing means of the single carrier spread spectrum system of the present embodiment, training sequence
Column are applied not only to channel equalization, but also are used for channel synchronization, frequency deviation measurement etc..In order to realize the code of spreading channel 1/8CHIP
Synchronous, using polyphase interpolating filtering algorithm, polyphase interpolating processing only needs to realize filtering processing all the way.Low speed signal is found greatly
It after causing sync bit, selectes the INT_ALL/2 data in front and back and does primary correlation relatively, just obtain most accurate 1/8CHIP and synchronize,
2 grades of synchronized algorithms are namely used, the net synchronization capability of high-precision and high-stability is obtained using the smallest resource.
The precise synchronization timing method and precise synchronization timing means of the single carrier spread spectrum system of the present embodiment, can have very much
The resistance multi-path jamming of effect filters single-pathway algorithm using polyphase interpolating, can complete under seldom resource situation accurate
1/8 chip of system synchronization, on this basis using in cubic spline interpolation algorithm or 3 peak-peak computing devices
It is any calculate optimum sampling point, can timing accuracy promoted to 1/32CHIP precision, meet precision distance measurement equipment
Demand, provide the support of complete algorithm for high-precision flyer ranging.
For embodiment of the method, for simple description, therefore, it is stated as a series of action combinations, but this field
Technical staff should be aware of, and embodiment of that present invention are not limited by the describe sequence of actions, because implementing according to the present invention
Example, some steps may be performed in other sequences or simultaneously.Secondly, those skilled in the art should also know that, specification
Described in embodiment belong to preferred embodiment, the actions involved are not necessarily necessary for embodiments of the present invention.
Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, rather than its limitations；Although
Present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that: it still may be used
To modify the technical solutions described in the foregoing embodiments or equivalent replacement of some of the technical features；
And these are modified or replaceed, technical solution of various embodiments of the present invention that it does not separate the essence of the corresponding technical solution spirit and
Range.
Claims (10)
1. a kind of precise synchronization timing method of single carrier spread spectrum system, which comprises the following steps:
Matched filtering and interpolation are carried out to base band sample data, the data after obtaining matched filtering；
Data after matched filtering are captured；
When correlation upon acquisition is more than pre-determined threshold, optimum sampling point is calculated using current catch position as basic point；
Channel synchronization is carried out using the optimum sampling point as timing point, receives user data.
2. the precise synchronization timing method of single carrier spread spectrum system according to claim 1, which is characterized in that use root liter
Cosine filter carries out matched filtering and interpolation to base band sample data.
3. the precise synchronization timing method of single carrier spread spectrum system according to claim 2, which is characterized in that filtered to matching
In the step of data after wave are captured, scanned for the interval of half symbol.
4. the precise synchronization timing method of single carrier spread spectrum system according to claim 3, which is characterized in that using sliding
Correlation Acquisition Algorithm captures the data after matched filtering.
5. the precise synchronization timing method of single carrier spread spectrum system according to claim 4, which is characterized in that filtered to matching
In the step of data after wave are captured, using there is limit for length's unit impulse response filter will be after the matched filtering that received
Data are related to the progress of known synchronous head, while the precision in order to guarantee timing, in order to which chip synchronization needs to reach 1/8CHIP essence
Degree, is inserted into 8 times of spreading rate in sample rate, i.e. 4 times of interpolations, and when interpolation uses multiphase filter structure, and the coefficient of filter is
The 4 groups of coefficients extracted from matched filter coefficient with interval 4, data become 4 tunnels after interpolation is complete, after 4 times of interpolation, become 8 times
Spreading rate, reaches the precision of 1/8 chip, and 4 road multiphase filterings export the output signal after 4 times of interpolations, any to choose wherein one
Road output is related to local synchronizing sequence, and operand is made to be reduced to 1/4.
6. the precise synchronization timing method of single carrier spread spectrum system according to claim 5, which is characterized in that upon acquisition
Correlation when being more than pre-determined threshold, calculate in the step of calculating optimum sampling point as basic point using current catch position and most preferably adopt
The mode of sampling point are as follows: calculate the correlation of current catch position and its forward and backward each 1/2 chip totally 9 sampled points, choose wherein most
The point being worth greatly is as optimum sampling point.
7. the precise synchronization timing method of single carrier spread spectrum system according to claim 5, which is characterized in that more in completion
Phase interpolation algorithm carries out related synchronization when reaching 1/8CHIP precision, inserts obtaining continuing to use cubic spline near correlation peak
Value-based algorithm or 3 peak-peak computing devices further promote the precision of correlation peak point, reach 1/32CHIP's or more
Timing Synchronization.
8. the precise synchronization timing method of single carrier spread spectrum system according to claim 7, which is characterized in that 3 points maximum
Peak computational device is calculated by the following formula the corresponding amplitude of 3 highest correlation peak points P1, P2, P3 before and after correlation peak
R1, R2, R3 calculate optimum sampling point:
As R1≤R3,
As R1 > R3,
Wherein, T is chip period, TsFor the sampling period, τ is the optimum sampling point obtained when actual optimum sampling point and capture
Time difference, P1, P2, P3 are respectively 3 highest correlation peak points before and after correlation peak, and R1, R2, R3 are respectively P1, P2, P3 couple
The correlation answered.
9. a kind of single carrier spread spectrum system for the precise synchronization timing method for realizing single carrier spread spectrum system according to any one of claims 8
Precise synchronization timing means characterized by comprising
Base band sample data processing module, for carrying out matched filtering and interpolation to base band sample data, after obtaining matched filtering
Data；
Trapping module, for being captured to the data after matched filtering；
Optimum sampling point computing module, when being more than pre-determined threshold for correlation upon acquisition, using current catch position as base
Point calculates optimum sampling point；
Data reception module carries out channel synchronization using the optimum sampling point as timing point, receives user data.
10. the precise synchronization timing means of single carrier spread spectrum system according to claim 9, which is characterized in that base band is adopted
Sample data processing module carries out matched filtering and interpolation to base band sample data using root raised cosine filter.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110149197A (en) * | 2019-05-22 | 2019-08-20 | 熊军 | A kind of high-precise synchronization method and synchronization system for clock system |
| CN110726901A (en) * | 2019-10-28 | 2020-01-24 | 深圳市国电科技通信有限公司 | Ranging method based on high-speed carrier zero-crossing synchronization and signal-to-noise ratio |
| CN110958196A (en) * | 2019-07-11 | 2020-04-03 | 北京中科晶上科技股份有限公司 | Optimal sampling point acquisition method for burst system timing synchronization algorithm |
| CN112272069A (en) * | 2020-08-31 | 2021-01-26 | 北京航天控制仪器研究所 | Satellite-to-ground time synchronization method and system based on GNSS satellite time service and feature code matching |
| CN114884536A (en) * | 2022-05-06 | 2022-08-09 | 中国人民解放军国防科技大学 | Anti-interference time-frequency synchronization method, device, equipment and medium |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102065043A (en) * | 2010-12-09 | 2011-05-18 | 北京理工大学 | Frequency domain parallel demodulation method in high-speed communication system |
| CN104125052A (en) * | 2014-07-24 | 2014-10-29 | 清华大学 | Parallel timing synchronization system and method |
| CN104619004A (en) * | 2014-12-19 | 2015-05-13 | 中国航空无线电电子研究所 | Method and system for achieving timed synchronization of aircraft wireless communication system |
| CN104821927A (en) * | 2015-04-27 | 2015-08-05 | 西安空间无线电技术研究所 | Multiplied-sampling-based parallel burst signal detection system in burst demodulation |
| CN105337915A (en) * | 2015-09-30 | 2016-02-17 | 电信科学技术第一研究所 | Pi/4-QPSK demodulator base-band sampling data optimal sampling point acquisition method |
| US20170237483A1 (en) * | 2009-12-08 | 2017-08-17 | Treq Labs, Inc. | Subchannel Photonic Routing, Switching and Protection with Simplified Upgrades of WDM Optical Networks |
-
2019
- 2019-01-25 CN CN201910071532.7A patent/CN109756968B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20170237483A1 (en) * | 2009-12-08 | 2017-08-17 | Treq Labs, Inc. | Subchannel Photonic Routing, Switching and Protection with Simplified Upgrades of WDM Optical Networks |
| CN102065043A (en) * | 2010-12-09 | 2011-05-18 | 北京理工大学 | Frequency domain parallel demodulation method in high-speed communication system |
| CN104125052A (en) * | 2014-07-24 | 2014-10-29 | 清华大学 | Parallel timing synchronization system and method |
| CN104619004A (en) * | 2014-12-19 | 2015-05-13 | 中国航空无线电电子研究所 | Method and system for achieving timed synchronization of aircraft wireless communication system |
| CN104821927A (en) * | 2015-04-27 | 2015-08-05 | 西安空间无线电技术研究所 | Multiplied-sampling-based parallel burst signal detection system in burst demodulation |
| CN105337915A (en) * | 2015-09-30 | 2016-02-17 | 电信科学技术第一研究所 | Pi/4-QPSK demodulator base-band sampling data optimal sampling point acquisition method |
Non-Patent Citations (3)
| Title |
|---|
| PANASONIC: "The impact of the inaccurate measurement due to LBT failure", 《3GPP TSG-RAN WG2 #104 R2-1816711》 * |
| 秦瑶: "扩频通信***及其同步技术的研究与实现", 《中国优秀硕士论文电子期刊网》 * |
| 肖磊: "并行高速通信解调***中同步技术的研究与实现", 《中国优秀硕士论文电子期刊网》 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110149197A (en) * | 2019-05-22 | 2019-08-20 | 熊军 | A kind of high-precise synchronization method and synchronization system for clock system |
| CN110149197B (en) * | 2019-05-22 | 2021-12-07 | 北京睿信丰科技有限公司 | High-precision synchronization method and system for clock synchronization system |
| CN110958196A (en) * | 2019-07-11 | 2020-04-03 | 北京中科晶上科技股份有限公司 | Optimal sampling point acquisition method for burst system timing synchronization algorithm |
| CN110958196B (en) * | 2019-07-11 | 2022-07-29 | 北京中科晶上科技股份有限公司 | Optimal sampling point acquisition method for burst system timing synchronization algorithm |
| CN110726901A (en) * | 2019-10-28 | 2020-01-24 | 深圳市国电科技通信有限公司 | Ranging method based on high-speed carrier zero-crossing synchronization and signal-to-noise ratio |
| CN110726901B (en) * | 2019-10-28 | 2022-01-07 | 深圳市国电科技通信有限公司 | Ranging method based on high-speed carrier zero-crossing synchronization and signal-to-noise ratio |
| CN112272069A (en) * | 2020-08-31 | 2021-01-26 | 北京航天控制仪器研究所 | Satellite-to-ground time synchronization method and system based on GNSS satellite time service and feature code matching |
| CN112272069B (en) * | 2020-08-31 | 2023-11-10 | 北京航天控制仪器研究所 | Satellite-to-ground time synchronization method and system based on GNSS satellite time service and feature code matching |
| CN114884536A (en) * | 2022-05-06 | 2022-08-09 | 中国人民解放军国防科技大学 | Anti-interference time-frequency synchronization method, device, equipment and medium |
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