CN107370705B - FFT optimization method in high-dynamic weak continuous phase modulation signal capture - Google Patents
FFT optimization method in high-dynamic weak continuous phase modulation signal capture Download PDFInfo
- Publication number
- CN107370705B CN107370705B CN201710494935.3A CN201710494935A CN107370705B CN 107370705 B CN107370705 B CN 107370705B CN 201710494935 A CN201710494935 A CN 201710494935A CN 107370705 B CN107370705 B CN 107370705B
- Authority
- CN
- China
- Prior art keywords
- signal
- data
- correlation function
- sampling
- code
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2689—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation
- H04L27/2695—Link with other circuits, i.e. special connections between synchronisation arrangements and other circuits for achieving synchronisation with channel estimation, e.g. determination of delay spread, derivative or peak tracking
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2657—Carrier synchronisation
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2668—Details of algorithms
- H04L27/2669—Details of algorithms characterised by the domain of operation
- H04L27/2672—Frequency domain
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
- H04L27/38—Demodulator circuits; Receiver circuits
- H04L27/3845—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier
- H04L27/3854—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
- H04L2027/0026—Correction of carrier offset
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Digital Transmission Methods That Use Modulated Carrier Waves (AREA)
Abstract
The invention discloses an FFT optimization method in high-dynamic weak continuous phase modulation signal capture, which mainly solves the problem that the capture time and sampling frequency are overhigh in the prior art. The implementation scheme is as follows: at a receiving end, filtering, down-conversion and digital sampling are sequentially carried out on a received signal to obtain a baseband complex signal and carry out frequency difference compensation on the baseband complex signal; performing FFT operation on the compensated signals and the local CA code modulation signals respectively, leaving the first 1/4 calculated data, and setting the rest 3/4 data to be zero to obtain two groups of sampling sequences; then, the two groups of sampling sequences are multiplied in a conjugate mode, and the result is subjected to IFFT operation to obtain a correlation function; and finally, accumulating and squaring the correlation function to obtain a decision quantity, and if the decision quantity has an obvious peak value, judging that the acquisition is successful, otherwise, judging that the acquisition is unsuccessful. The invention does not need to use overhigh sampling frequency, improves the capturing time, reduces the complexity and can be used for a CPM signal capturing system and satellite communication.
Description
Technical Field
The invention belongs to the technical field of space communication, and particularly relates to a Fast Fourier Transform (FFT) point number optimization method in signal capture, which can be used in the fields of a high-dynamic weak Continuous Phase Modulation (CPM) signal capture system based on a correlation function and satellite communication.
Background
The high dynamic weak CPM signal acquisition is a precondition for the system to normally perform subsequent work, and is widely applied to satellite communication, especially the field of deep space communication, but the power and the bandwidth are greatly limited. The spread spectrum technique is the most commonly used technique in the above communication field because of its characteristics of strong interference rejection, ability to communicate at a very low signal-to-noise ratio, and the like. The main indicators for measuring the acquisition performance of the spread spectrum signal are the complexity of the system, the acquisition time and the acquisition success rate, which are key points to be concerned.
In the research at home and abroad, the acquisition of the CPM weak signal subjected to spread spectrum processing mainly aims at the synchronization of a pseudo code phase and a carrier doppler frequency, and the traditional technology mainly comprises the following steps: the independent channel method, the sliding correlator method, the matched filter method, etc., which are simple to implement and have relatively low system complexity, but most of the acquisition time is long and cannot meet the actual requirements. In the end of the 20 th century and the 80 th era, with the development of the FFT technology and the DSP technology, the FFT-based capture algorithm gradually became a research hotspot in the field. The correlation operation in the time domain is converted into the conjugate multiplication operation in the frequency domain through the FFT and IFFT operation by utilizing the property of the FFT, so that the operation times of the whole acquisition process are greatly reduced, and the method is mainly used for a GPS receiver. Meanwhile, some scholars also propose related optimization algorithms.
Vandana Patel proposes an optimization algorithm For reducing the number of FFT points participating in Correlation operation in Reduced-Size FFT Correlation Techniques For GPS Signal Acquisition, and Evolution in Networks and Computer Communications. The basic capture model is shown in the attached figure 1, and the specific implementation steps are as follows: first, an initial assumed Doppler frequency estimate is preset locally using a complex carrier generatorWill have a frequency ofMultiplying the complex carrier signal by a received signal, and performing N-point FFT operation, wherein N is the number of sampling points of a CPM modulation signal in a spreading code period; secondly, performing CPM modulation on the local spread spectrum code, performing N-point FFT calculation, and solving complex conjugate of all points; thirdly, multiplying the results obtained in the first two steps, performing N-point IFFT calculation to obtain a group of cross-correlation function values, if an obvious peak value is obtained, indicating that the acquisition is successful, and obtaining the estimated value of the Doppler frequency assumed at the momentAnd code phase, if no obvious peak value is obtained, a new assumed Doppler frequency estimated value is setAnd the above process is repeated.
In the optimization algorithm, the sampling frequency for FFT and IFFT is 20MHz, the chip rate is 1.024MHz, 20000 sampling points exist in 1ms of one period of a spreading code, and if the sampling frequency is reduced to 1/4 originally, the number of sampling points is reduced to 5000 in one period of the spreading code, so that the calculation amount of 3/4 can be reduced. However, in practical applications, the sampling frequency is not set to be about 20 times of the chip rate, and the sampling frequency is reduced to meet the nyquist criterion even if the sampling frequency is reduced to 1/8, so that the requirement on system hardware is high, and a large amount of calculation data is wasted.
Disclosure of Invention
The present invention aims to provide an FFT optimization method in high dynamic weak continuous phase modulation signal acquisition, which can obtain higher acquisition probability and shorter acquisition time with lower sampling frequency and system complexity, in view of the above-mentioned deficiencies of the prior art.
The technical scheme for realizing the invention is that for each assumed Doppler frequency estimated value, FFT calculation is respectively carried out on a local spread spectrum code and a receiving end processing signal, points containing main information in a calculation result are intercepted, the size of the residual points is set to be zero, cross-correlation values corresponding to all local spread spectrum code phases are calculated at one time according to the good autocorrelation characteristic of the spread spectrum code, accumulation and envelope extraction processing are carried out, and whether acquisition is successful is judged finally. The method comprises the following implementation steps:
(1) at a sending end, a section of information sequence is subjected to CA code spread spectrum operation to form a group of spread spectrum sequences, and the sequences are subjected to shaping offset quadrature phase shift keying SOQPSK modulation and up-conversion in sequence to obtain a sent radio frequency signal;
(2) at a receiving end, filtering, down-conversion and digital sampling are sequentially carried out on the received radio frequency signal to obtain a baseband complex signal rn；
(3) For baseband complex signal rnAnd (3) frequency difference compensation is carried out:
(3a) calculating a hypothetical Doppler frequency estimateAnd obtaining complex carrier signal by using complex carrier generatorWherein t isnIs the nth sampling instant;
(3b) using complex carrier signalsFor baseband complex signal rnCompensating to obtain compensated signal
(4) For compensated signalPerforming N-point FFT calculation to obtain the first 1/4 calculated data, and setting the rest 3/4 data to zero to obtain frequency domain sampling sequence Y0,Y1...Yi...YN-1]N-1, where N is the compensated signalThe number of points for performing FFT calculation; if it isThen Y isiIs a compensated signalThe ith data calculated by N-point FFT, ifThen Y isiIs 0;
(5) SOQPSK modulation is carried out on the CA code used in the step (1), N-point FFT calculation is carried out on the modulated data, the first 1/4 calculated data are left, the rest 3/4 data are set to be zero, complex conjugates of all the data are calculated, and a frequency domain sampling sequence is obtainedIf it isThenIs the complex conjugate of the h data after the modulated data is processed by N-point FFT calculation, if soThenIs 0;
(6) will [ Y0,Y1...Yi...YN-1]Andmultiplying, and performing N-point IFFT calculation on the multiplication result to obtain all code phasesCorresponding correlation function
(7) Correlation function to adjacent spreading code periodsAccumulating to obtain processed correlation function
(8) For correlation functionPerforming a square operation to obtain a decision valueAnd then whether the capture is successful is confirmed according to the judgment value: if it isIf a distinct peak exists, the acquisition is considered successful, otherwise, the acquisition is considered failed.
Compared with the prior art, the invention has the following advantages:
first, the present invention does not need to use too high sampling frequency, and only needs to satisfy the nyquist sampling criterion, thereby reducing the complexity of the system and being easier to implement in hardware.
Secondly, the invention firstly intercepts the FFT calculation results of the received signal and the local spread spectrum code, and then sets the discarded point as zero, thus basically ensuring the autocorrelation characteristic of the sequence and saving the calculation time.
Drawings
FIG. 1 is a diagram illustrating a related function capturing method based on FFT
FIG. 2 is a schematic diagram of a high dynamic CPM weak signal acquisition system used in the present invention;
FIG. 3 is a schematic diagram of an implementation of the present invention;
FIG. 4 is a simulation diagram of the prior art FFT-based correlation function acquisition method for determining whether the acquisition of a signal is successful;
fig. 5 is a simulation diagram of the present invention for determining whether a signal acquisition was successful.
Detailed Description
The embodiments and effects of the present invention will be further described with reference to the accompanying drawings:
referring to fig. 2, the high dynamic weak CPM signal capturing system based on the correlation function applied in this embodiment includes a sending end and a receiving end, and a channel model adopts a white gaussian noise channel with additional carrier frequency offset and phase offset. The basic working principle is as follows:
the system comprises a transmitting end, a receiving end and a transmitting end, wherein the transmitting end carries out direct spread spectrum operation on a section of information sequence by using a spread spectrum code, then carries out Shaping Offset Quadrature Phase Shift Keying (SOQPSK) modulation on the information sequence to obtain a transmitted baseband complex signal, and obtains a transmitted radio frequency signal after up-conversion;
the receiving end sequentially filters, down-converts and digitally samples the received radio frequency signal to obtain a baseband complex signal rn. Application of an FFT algorithm-based acquisition process to a baseband complex signal rnAnd performing correlation function calculation to obtain a decision quantity with a peak value, wherein the Doppler frequency and the code phase corresponding to the decision value are the frequency offset and the code phase which need to compensate the received signal.
The invention relates to improvement of FFT operation data, namely, the peak value of decision quantity is obtained by optimizing the data participating in the calculation of a correlation function with lower sampling frequency and lower system complexity, and the carrier frequency offset and the code phase are obtained.
Referring to fig. 3, the steps of implementing FFT optimization in high dynamic weak continuous phase modulation signal acquisition of the present invention include the following:
step 1, at a sending end, a section of information sequence is subjected to CA code spread spectrum operation to form a group of spread spectrum sequences, and the sequences are subjected to shaping offset quadrature phase shift keying SOQPSK modulation and up-conversion to obtain a sent radio frequency signal.
The code length of the CA code adopted in the embodiment of the invention is 1024, the code rate is 1.024MHz, and the information sequence length is 200 bits. And spreading the information sequence and then carrying out SOQPSK modulation to obtain a transmitted baseband complex signal:
s(t)＝sI(t)+jsQ(t) in which sI(t) and sQ(t) in-phase component signals and quadrature component signals, respectively;
and then up-converting the transmitted baseband complex signal s (t) to obtain a transmitted radio frequency signal.
Step 2, at a receiving end, filtering, down-converting and digitally sampling the received radio frequency signal in sequence to obtain a baseband complex signal rnExpressed as:
rn＝s(tn-ts)·exp[j2π·fd·tn]+xn，
wherein r isnIs in discrete time case, at tnSampled value at time, s (t)n-ts) Is a complex baseband signal obtained by SOQPSK modulation of a CA code, tsIs a baseband complex signal s (t)n-ts) Is also a measure of its code phase, fdIs the Doppler frequency, tn＝nTsWherein T iss＝1/fsOr Ts＝tn-tn-1Is a sampling interval, fsIs the sampling rate of the signal, xnIs a complex Gaussian random variable with zero mean and variance of delta2＝N0/2，N0Is the noise single-sided power spectral density.
Sampling rate f in this embodiments4.096MHz, carrier frequency offset fdThe code phase is 128 chips wide at 18 KHz.
Step 3, the baseband complex signal r is processednAnd performing frequency difference compensation.
(3a) The assumed Doppler frequency estimate is calculated as follows
Wherein L ═ fd max-fd min)/δf+1，δf＝2/5TCOH，TCOHIs a coherent accumulation period, fd min-120KHz is the minimum value of the doppler frequency estimate, fd max120KHz is the maximum value of the doppler frequency estimate.
(3b) Estimate based on assumed Doppler frequencyObtaining a complex carrier signal by using a complex carrier generator:
wherein t isnIs the nth sampling instant, j is the imaginary unit;
(3c) using complex carrier signalsFor baseband complex signal rnAnd (3) compensating to obtain a compensated signal:
wherein N is 0,1,2.
And 4, obtaining a frequency domain sampling sequence of the received signal according to the compensated signal.
For compensated signalPerforming N-point FFT calculation to obtain the first 1/4 calculated data, and setting the rest 3/4 data to zero to obtain the frequency domain sampling sequence [ Y ] of the received signal0,Y1...Yi...YN-1]N-1, where N is the compensated signalNumber of points for FFT calculation, YiIs the ith data in the frequency domain sampling sequence of the received signal, and Y can be determined according to the value change of iiTaking different values:
if it isThen Y isiIs a compensated signalThe ith data is calculated through N-point FFT;
if it isThen Y isiIs 0.
And step 5, obtaining a local frequency domain sampling sequence according to the local CA code.
(5a) SOQPSK modulation is carried out on the CA code used in the step 1, N-point FFT operation is carried out on the modulated data, and a local frequency domain sampling sequence [ S ] is obtained0,S1...Sm...SN-1]N-1, wherein S is 0,1,2mIs the mth data of the modulated signal after N-point FFT calculation,
the mathematical representation of this step is:
wherein [ s ]0,s1...sN-1]Is a CA code modulated by SOQPSK;
(5b) leaving a sequence of local frequency domain samples S0,S1...SN-1]The first 1/4 data, the rest 3/4 data are set as zero, and the complex conjugate of all the data is calculated to obtain the local frequency domain sampling sequenceThe method is characterized in that h-th data in a local frequency domain sampling sequence, wherein h is 0,1,2Taking different values:
if it isThenIs the complex conjugate of the h data after the modulated data is processed by N-point FFT calculation;
if it isThenIs 0.
The mathematical representation of this step is:
where, conj denotes taking complex conjugate.
And 6, obtaining a correlation function according to the frequency domain sampling sequence of the received signal and the local frequency domain sampling sequence.
A sequence [ Y ] of frequency domain samples of a received signal0,Y1...Yi...YN-1]And local frequency domain sampling sequenceMultiplying, and performing N-point IFFT calculation on the multiplication result to obtain all code phasesCorresponding correlation function
And 7, accumulating the correlation function.
(7a) Setting correlation function of r spreading code periodComprises the following steps:
whereinIs a signalThe simplified form of (1) represents the complex conjugate of the local CA code after SOQPSK modulation, k is 0,1,2COH，NCOH1,2,3.. is the number of accumulation cycles to accumulate;
(7b) will NCOHCorrelation function of one periodThe accumulation is carried out, and the obtained correlation function is as follows:
and 8, obtaining a decision value according to the accumulated correlation function.
To remove the effect of carrier phase offset, the correlation function is adjustedPerforming a square operation to obtain a decision value
The effects of the present invention can be further illustrated by the following simulations:
1. simulation system parameter setting
Matlab 7.6 simulation software is used for simulation, simulation parameter setting is consistent with parameters used in the embodiment, namely a channel model adopts a Gaussian white noise channel with additional carrier frequency offset and phase offset, an information sequence is 200 bits long, and a Doppler frequency search range is as follows: [ -120KHz ], chip rate 1.024Mchip/s, carrier Doppler shift 18 KHz.
2. Emulated content
Emulation 1, setting code phase t added by channelsAfter FFT operation on the data for 128 chips width, select all 4096 points of data to calculate the magnitude of the cross-correlation function at different frequency offsets and code phases, and the result is shown in fig. 4.
As can be seen from fig. 4, a distinct peak occurs at the point where the code phase is 128 chips wide and the frequency offset is 18KHz, indicating successful acquisition.
Emulation 2, setting the code phase t added by the channelsFor 128 chips wide, after performing FFT operation on the data, the first 1024 points of all 4096 point data are left, and the remaining 3072 point data are set to 0, and the other operations are consistent with simulation 1, resulting in the size of the cross-correlation function at different frequency offsets and code phases, as shown in fig. 5.
As can be seen from fig. 5, a distinct peak occurs at the point where the code phase is 128 chips wide and the frequency offset is 18KHz, indicating successful acquisition.
Claims (2)
1. A method for optimizing FFT (fast Fourier transform) in high-dynamic weak continuous phase modulation signal acquisition comprises the following steps:
(1) at a sending end, a section of information sequence is subjected to CA code spread spectrum operation to form a group of spread spectrum sequences, and the sequences are subjected to shaping offset quadrature phase shift keying SOQPSK modulation and up-conversion in sequence to obtain a sent radio frequency signal;
(2) at a receiving end, filtering, down-conversion and digital sampling are sequentially carried out on the received radio frequency signal to obtain a baseband complex signal rn；
(3) For baseband complex signal rnAnd (3) frequency difference compensation is carried out:
(3a) calculating a hypothetical Doppler frequency estimateThe method is carried out according to the following formula:
wherein L ═ fdmax-fdmin)/δf+1，δf＝2/5TCOH，TCOHIs a coherent accumulation period, fdmin-120KHz is the minimum value of the doppler frequency estimate, fdmax120KHz is the maximum value of the doppler frequency estimate;
and obtaining complex carrier signal by using complex carrier generatorWherein t isnIs the nth sampling instant;
(3b) using complex carrier signalsFor baseband complex signal rnCompensating to obtain compensated signal
(4) For compensated signalPerforming N-point FFT calculation to obtain the first 1/4 calculated data, and setting the rest 3/4 data to zero to obtain frequency domain sampling sequence Y0,Y1...Yi...YN-1]N-1, where N is the compensated signalPerforming FFT calculationThe number of points; if it isThen Y isiIs a compensated signalThe ith data calculated by N-point FFT, ifThen Y isiIs 0;
(5) SOQPSK modulation is carried out on the CA code used in the step (1), N-point FFT calculation is carried out on the modulated data, the first 1/4 calculated data are left, the rest 3/4 data are set to be zero, complex conjugates of all the data are calculated, and a frequency domain sampling sequence is obtainedIf it isThenIs the complex conjugate of the h data after the modulated data is processed by N-point FFT calculation, if soThenIs 0;
(6) will [ Y0,Y1...Yi...YN-1]Andmultiplying, and performing N-point IFFT calculation on the multiplication result to obtain all code phasesCorresponding correlation function
(7) Correlation function to adjacent spreading code periodsAccumulating to obtain processed correlation function
(8) For correlation functionPerforming a square operation to obtain a decision valueAnd then whether the capture is successful is confirmed according to the judgment value: if it isIf a distinct peak exists, the acquisition is considered successful, otherwise, the acquisition is considered failed.
2. The method of claim 1, wherein step (7) comprises correlating adjacent spreading code periods with a functionPerforming accumulation according to the following steps:
(7a) setting correlation function of r spreading code periodComprises the following steps:
whereinIs a signalThe simplified form of (1) r N represents the complex conjugate of the local CA code after SOQPSK modulationCOH，NCOH1,2,3.. is the number of accumulation cycles to accumulate;
(7b) will NCOHCorrelation function of one periodThe accumulation is carried out, and the obtained correlation function is as follows:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710494935.3A CN107370705B (en) | 2017-06-26 | 2017-06-26 | FFT optimization method in high-dynamic weak continuous phase modulation signal capture |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710494935.3A CN107370705B (en) | 2017-06-26 | 2017-06-26 | FFT optimization method in high-dynamic weak continuous phase modulation signal capture |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107370705A CN107370705A (en) | 2017-11-21 |
| CN107370705B true CN107370705B (en) | 2019-12-31 |
Family
ID=60305834
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710494935.3A Active CN107370705B (en) | 2017-06-26 | 2017-06-26 | FFT optimization method in high-dynamic weak continuous phase modulation signal capture |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107370705B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111865363B (en) * | 2020-07-13 | 2022-04-19 | 南京理工大学 | High-dynamic code capture method based on conjugate frequency modulation |
| CN112965090B (en) * | 2021-02-08 | 2024-06-18 | 南京航空航天大学 | Spread spectrum CPM signal capturing method with modulation index h >1 and h being half integer |
| CN113422635B (en) * | 2021-06-15 | 2022-09-20 | 南京邮电大学 | Collision-tolerant random access method for satellite Internet of things system in high-load scene |
| CN114553656B (en) * | 2022-02-21 | 2023-07-28 | 西安电子科技大学 | Weak signal capturing method based on unequal-length double-block zero padding algorithm |
| CN115426230B (en) * | 2022-04-27 | 2024-06-18 | 湖南开放大学(湖南网络工程职业学院、湖南省干部教育培训网络学院) | CSK modulation efficient demodulation algorithm based on partial output FFT |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101834632A (en) * | 2010-04-16 | 2010-09-15 | 西安电子科技大学 | Method for capturing synchronization in frequency hopping communication |
| CN103645483A (en) * | 2013-12-09 | 2014-03-19 | 西安电子科技大学昆山创新研究院 | Beidou signal capturing method in weak signal environment |
| CN104253774A (en) * | 2014-09-16 | 2014-12-31 | 重庆邮电大学 | System and method for estimating Doppler frequency offset under high-dynamic environment |
| CN104360357A (en) * | 2014-11-24 | 2015-02-18 | 四川九洲电器集团有限责任公司 | Quick Beidou satellite signal capturing method and system based on circulation mode |
| CN106547005A (en) * | 2015-09-18 | 2017-03-29 | 北京大学 | A kind of method and device for capturing for sinusoidal binary offset carrier (boc) modulated signals |
| CN106646546A (en) * | 2016-12-20 | 2017-05-10 | 南京六九零二科技有限公司 | Multi-dimensional fast acquisition method and system for satellite signals |
-
2017
- 2017-06-26 CN CN201710494935.3A patent/CN107370705B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101834632A (en) * | 2010-04-16 | 2010-09-15 | 西安电子科技大学 | Method for capturing synchronization in frequency hopping communication |
| CN103645483A (en) * | 2013-12-09 | 2014-03-19 | 西安电子科技大学昆山创新研究院 | Beidou signal capturing method in weak signal environment |
| CN104253774A (en) * | 2014-09-16 | 2014-12-31 | 重庆邮电大学 | System and method for estimating Doppler frequency offset under high-dynamic environment |
| CN104360357A (en) * | 2014-11-24 | 2015-02-18 | 四川九洲电器集团有限责任公司 | Quick Beidou satellite signal capturing method and system based on circulation mode |
| CN106547005A (en) * | 2015-09-18 | 2017-03-29 | 北京大学 | A kind of method and device for capturing for sinusoidal binary offset carrier (boc) modulated signals |
| CN106646546A (en) * | 2016-12-20 | 2017-05-10 | 南京六九零二科技有限公司 | Multi-dimensional fast acquisition method and system for satellite signals |
Non-Patent Citations (3)
| Title |
|---|
| Weak GPS signal detection in the presence of strong signals with varying relative Doppler and long integration gain;Md Sohrab Mahmud;《2016 IEEE/ION Position,Location and Navigation Symposium(PLANS)》;20160530;全文 * |
| 低信噪比下CPM信号捕获研究;徐晓红;《中国优秀硕士学位论文全文数据库信息科技辑》;20170315;I136-401 * |
| 高动态扩频信号的快速捕获算法研究;黄健;《中国优秀硕士学位论文全文数据库信息科技辑》;20160228;I136-237 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107370705A (en) | 2017-11-21 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107370705B (en) | FFT optimization method in high-dynamic weak continuous phase modulation signal capture | |
| CN109802912B (en) | Synchronization method, apparatus, device and storage medium for broadband wireless communication system | |
| CN105162493B (en) | Doppler domain and the two-dimentional catching method of delay domain and device | |
| CN103580718B (en) | Quick time-frequency synchronizing method under low signal-to-noise ratio | |
| US11075783B2 (en) | Communication method for phase separation differential chaos shift keying based on second order hybrid system | |
| CN1169310C (en) | Doppler spread estimation system | |
| CN108880609B (en) | Pseudo code synchronization method based on burst spread spectrum signal | |
| CN101969321B (en) | FFT (Fast Fourier Transform) based large frequency offset secondary catching method of direct sequence spread spectrum system | |
| CN104125190A (en) | OFDM (orthogonal frequency division multiplexing) system symbol timing synchronization realizing method suitable for low-signal-to-noise-ratio channel environments | |
| CN107493117B (en) | The two-dimentional joint acquisition method of direct expansion msk signal under a kind of high dynamic | |
| CN107241286A (en) | A kind of combination frequency domain and the carrier synchronization method of time domain estimation | |
| CN104767706A (en) | MIMO OFDM timing synchronization device | |
| CN109412644B (en) | Doppler frequency estimation method for direct sequence spread spectrum MSK signal | |
| CN109586761B (en) | Tracking demodulation method of high dynamic spread spectrum signal | |
| CN111147102B (en) | Low signal-to-noise ratio code capturing method based on frequency modulation signal | |
| CN104092642A (en) | Carrier phase synchronization method and device for non-coherent demodulation circuit | |
| CN110300079B (en) | MSK signal coherent demodulation method and system | |
| CN112203347A (en) | Continuous phase modulation preamble design and synchronization method and device thereof | |
| CN103023831A (en) | Carrier frequency offset estimation method applicable to burst waveforms | |
| CN107247276B (en) | Weak signal capturing method based on overlapped multi-block zero-filling algorithm | |
| CN102098114B (en) | Method and device for measuring signal-to-noise ratio of system | |
| CN108900445B (en) | Method and device for estimating signal symbol rate | |
| CN1327621C (en) | A novel method for receiving ultra wideband signal | |
| CN112953593B (en) | LoRa advanced receiver | |
| CN100581151C (en) | Multiple differential demodulator using weighting value |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |