CN106849992B - A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum - Google Patents

A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum Download PDF

Info

Publication number
CN106849992B
CN106849992B CN201611140233.7A CN201611140233A CN106849992B CN 106849992 B CN106849992 B CN 106849992B CN 201611140233 A CN201611140233 A CN 201611140233A CN 106849992 B CN106849992 B CN 106849992B
Authority
CN
China
Prior art keywords
detection
spectrum
signal
mean
value
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201611140233.7A
Other languages
Chinese (zh)
Other versions
CN106849992A (en
Inventor
杨伟超
平一帆
林伟
杨新权
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Xian Institute of Space Radio Technology
Original Assignee
Xian Institute of Space Radio Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xian Institute of Space Radio Technology filed Critical Xian Institute of Space Radio Technology
Priority to CN201611140233.7A priority Critical patent/CN106849992B/en
Publication of CN106849992A publication Critical patent/CN106849992A/en
Application granted granted Critical
Publication of CN106849992B publication Critical patent/CN106849992B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H04B1/7097—Interference-related aspects

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Noise Elimination (AREA)

Abstract

A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum of the present invention, comprising: 1, calculate the Generalized Quadratic power spectrum for receiving signal, and using accordingly result as detection spectrum；2, it will test amplitude zero setting at spectrum zero-frequency；3, maximum value V is searched in detection spectrum after treatmentmax, and seek the mean value V of the filtered signalmean；4, with maximum value VmaxWith mean value VmeanRatio is as detection characteristic value E, i.e. E=Vmax/Vmean；5, the threshold value e of characteristic value E and setting are detectedthresholdIt is compared judgement: if E > ethreshold, then judge to receive signal for direct sequence signal.This method take full advantage of the transformation of generalization in Generalized Quadratic power spectrum to pseudo-code component in the inhibiting effect and Direct Sequence Spread Spectrum Signal of Alpha Stable distritation noise frequency domain and time domain periodicity, to reduce influence of the noise to detection performance, method realization is simple, be easy to Project Realization and signal detection is high-efficient.

Description

A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum
Technical field
The present invention relates to signal of communication process fields, the in particular to signal processing under Alpha Stable distritation noise, are used for The detection of direct sequence signal under Alpha Stable distritation noise.
Background technique
The detection of signal of communication is one of the key technology in electronic reconnaissance field.The task of signal detection seeks to determination and connects It whether there is useful signal in the collection of letters number.Detection process may be subjected to the interference of noise, and need known portions modulation intelligence. Effective detection can be to identify, analyze or carry out the follow-up work such as interfering provide foundation.
Direct Sequence Spread Spectrum (DSSS) is a kind of channel transmission technique widely applied in modern communications, is had very high Processing gain.Source signal is often hidden among noise after direct expansion is handled, and this special nature determines that it is difficult to detect.Often Direct spreading signal detection method includes the methods of Cyclic Spectrum, Higher Order Cumulants, cepstrum.
Secondary power composes the modified that can regard cepstrum as, and computation complexity is slightly below cepstrum.Secondary power spectrum is used for The detection of direct sequence signal is that pseudo-code component in Direct Sequence Spread Spectrum Signal is utilized to pass through two in the periodicity of frequency domain and time domain It is secondary to seek power spectrum, this periodicity is displayed in pseudo- time domain or inverted frequency domain, becomes the useful feature for detecting signal.
In previous signal processing research, mostly using Gaussian Profile as signal or noise model, certain Gauss assumes It is reasonable in many cases.Moreover, Gaussian Profile meets central-limit theorem, it is convenient for analytical calculation.
Although Gaussian Profile can be good at simulating some signals and noise, it is also commonly encountered many in practical applications Non-Gaussian signal and noise have the case where significant spiking characteristics.The statistical property of this kind of nongausian process is in spike Under the influence of significantly deviate Gaussian Profile, especially its probability density function attenuation ratio Gaussian Profile it is many slowly, can make At significant hangover.In practice, this relatively conventional class process have low-frequency atmospheric, thunder and lightning noise, strong jamming impulsive noise, Artificial impulsive noise, sea clutter etc..More and more researchs have shown that Alpha Stable distritation is that a kind of more effectively description is practical The valid model of ambient noise.
Alpha Stable distritation sequence does not have second order or more each rank statistic, this property determines previous many direct expansion Signal detecting method will all fail, and Fig. 1 is illustrated this by taking DS-BPSK signal secondary power spectrum as an example.
Summary of the invention
Technical problem solved by the present invention is having overcome the deficiencies of the prior art and provide a kind of Alpha Stable distritation noise The detection method of lower direct sequence signal.This method reduces noise to secondary power by the generalization transformation in Generalized Quadratic power spectrum Then the influence of spectrum extracts the pulse spectral line characteristic in Generalized Quadratic power spectrum as detection feature, finally realizes direct sequence signal Effective detection.Method And Principle is simple, is easy to Project Realization, and to insensitive for noise, signal detection is high-efficient.
The technical scheme is that a kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum, including with Lower step:
(1), the Generalized Quadratic power spectrum for receiving signal is calculated, and is composed as detection；
(2), amplitude zero setting at the detection spectrum zero-frequency obtained to step (1)；
(3), step (2) treated detection spectrum in search maximum value Vmax, and seek mean value Vmean；
(4), with maximum value VmaxWith mean value VmeanRatio is as detection characteristic value E, i.e. E=Vmax/Vmean；
(5), by the threshold value e of step (4) obtained detection characteristic value E and settingthresholdIt is compared judgement: if E > ethreshold, then judge to receive signal for direct sequence signal.
In step (1), the calculation formula for detecting spectrum is as follows:
G2Px=| FFT | FFT (f (x)) |2|2；
Wherein, G2PxFor the detection spectrum being calculated；For generalization transforming function transformation function, H () indicates Hilbert transform,FFT represents Fourier transformation operation.
In step (5), threshold value ethresholdValue range be 20~25.
Compared with prior art, the present invention having the advantage that
(1), noise background is become the Alpha Stable distritation noise more to tally with the actual situation, and the noise packet by the patent Gaussian noise, Gaussian noise Just One Of Those Things kind spy column are included.The algorithm designed under this noise background has more in practical applications Good robustness.
(2), the patent has carried out generalization improvement to original secondary power spectrum.Generalization transformation is not changing signal phase Signal amplitude is mapped to a finite interval in the case where position.This illustrates that Alpha Stable distritation noise is tended to nothing by the transformation Poor big amplitude compression has secondary power spectrum to a finite value after converting it, meanwhile, there is no change direct sequence signal to expand Frequency code cyclophysis, Generalized Quadratic power spectrum is inevitable and traditional secondary power spectrum has similar spectral property.In practical application level For, this improve is expanded to original direct spreading signal detection method use scope based on secondary power spectrum by Gaussian noise Alpha Stable distritation noise background, for theoretic, perfect detection of DS theoretical system.
Detailed description of the invention
Fig. 1 (a) is that DS-BPSK signal secondary power is composed under noise-free case, and Fig. 1 (b) is Alpha Stable distritation noise feelings DS-BPSK signal secondary power is composed under condition；
Fig. 2 DS-BPSK signal Generalized Quadratic power spectrum；
The noisy DS-BPSK signal Generalized Quadratic power spectrum of Fig. 3；
The detection feature Distribution value of Fig. 4 signals and associated noises and noise；
Specific embodiment
The present invention is described in further detail in the following with reference to the drawings and specific embodiments:
Direct spreading signal detection method of the invention takes full advantage of generalization transformation to the inhibiting effect and direct sequence of noise Pseudo-code component extracts characteristic quantity and detects direct sequence signal in the periodicity of frequency domain and time domain in column spread-spectrum signal.Concrete principle is as follows:
The noisy direct sequence signal that receiver receives can indicate are as follows:
Wherein, A is spread-spectrum signal amplitude；For information code sequence, it is General ± 1 stochastic variable collection such as one independence, TdFor its code-element period, gdFor pulse-shaping function；Indicate spread spectrum code sequence, TpFor its code-element period, pseudo- spread spectrum sequence is defined The column period is T0=NTp, Direct-Spread is that an information code is modulated by the frequency expansion sequence of a cycle mostly, therefore T0=Td, gpFor pulse-shaping function；ωcFor carrier frequency,For initial phase, n (t) is Alpha Stable distritation noise.
Here start with from the generalized autocorrelation functions of x (t) to study its generalized power spectral density, the generalized autocorrelation functions are as follows:
GRx(t+ τ, t)=E [f { x (t+ τ) } f*{x(t)}]
=(arctan2A)Rs(t+τ,t)+Rn(t+τ,t)+(arctanA)Rsn(t+τ,t)+(arctanA)Rns(t+τ,t)
Because x (t) and n (t) are independently of each other, there is Rsn(t+ τ, t)=Rns(t+ τ, t)=0.In addition, spread-spectrum signal In, information code, spreading code and carrier wave three are independent mutually, then receiving signal can simplify are as follows:
GRx(t+ τ, t)=(arctan2A)Rs(t+τ,t)+Rn(t+τ,t)
=(arctan2A)Rd(t+τ,t)Rp(t+τ,t)Rc(t+τ,t)+Rn(t+τ,t)
Rc(t+ τ, t) is the auto-correlation function of carrier wave, be may be expressed as:
Rc(t+ τ, t)=cos (ωcτ)/2
Information code is binary random sequence, and auto-correlation function can indicate are as follows:
The auto-correlation function of spread spectrum code sequence can indicate are as follows:
It is as follows according to power Spectral Estimation theory and above-mentioned analysis, the power spectrum that carrier wave, information code and spreading code can be obtained:
Pc(ω)=π [δ (ω-ωc)+δ(ω+ωc)]/2
Wherein, Sa (x)=sin (x)/x.
According to the Convolution Properties of Fourier transformation, can obtain
Consider one-sided power spectrum, it may be assumed that
In view of N > > 1, andThen above formula is just like lower aprons representation:
Power spectrum is asked to above formula again, the Generalized Quadratic power spectrum of signal can be obtained as a result, as follows:
By above formula as it can be seen that in the Generalized Quadratic power spectrum of direct sequence signal, signal energy is gathered in some more sharp three At the pulse train of angle, as shown in Figure 2.And the width between these trains of pulse is exactly the period of spreading code.Fig. 3 gives and Fig. 1 (b) Generalized Quadratic power spectrum chart in the case of same noise, it can be seen from the figure that spectral property has very big improvement, therefore, extensively Adopted secondary power spectrum can be used as the detection feature of direct sequence signal under Alpha Stable distritation noise.
For the Generalized Quadratic power spectrum of direct sequence signal, by a large amount of simulation analysis, maximum value and in proposed adoption spectral domain The ratio of value describes its poop characteristic, and using the ratio as detection feature, i.e.,
The detection feature Distribution value of signals and associated noises and noise is as shown in figure 4, noise characteristic index α=1.5 in figure.It can by figure Know, when selection decision threshold is 25, effective detection of the direct sequence signal under certain mixing signal-to-noise ratio can be realized.Of the invention is straight Spreading signal detection method the following steps are included:
1) the Generalized Quadratic power spectrum for receiving signal, is calculated, and is composed Generalized Quadratic power spectrum as detection.In this implementation The detection spectrum calculation formula provided in example is as follows:
G2Px=| FFT | FFT (f (x)) |2|2
Wherein, G2PxFor the detection spectrum being calculated；For generalization transforming function transformation function, H () Indicate Hilbert transform,FFT represents Fourier transformation operation.
(2), amplitude zero setting at the detection spectrum zero-frequency obtained step (1), to avoid the influence of DC component；
(3), maximum value V is searched in step (2) filtered signalmax, and seek mean value Vmean；
(4), with maximum value VmaxWith mean value VmeanRatio is as detection characteristic value E, i.e. E=Vmax/Vmean；
(5), by the threshold value e of step (4) obtained detection characteristic value E and settingthresholdIt is compared judgement: if E > ethreshold, then judge to receive signal for direct sequence signal.Wherein, generally according to signal environment given threshold ethresholdEqual to 20~ 25.It in the present embodiment, can be with given threshold e according to Fig. 4threshold=25, to realize the detection of direct sequence signal.
The above, a specific embodiment only of the invention, but scope of protection of the present invention is not limited thereto, appoints In the technical scope disclosed by the present invention, any changes or substitutions that can be easily thought of, all by what those familiar with the art It is covered by the protection scope of the present invention.
The content that description in the present invention is not described in detail belongs to the well-known technique of professional and technical personnel in the field.

Claims (2)

1. a kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum, it is characterised in that the following steps are included:
(1), the Generalized Quadratic power spectrum for receiving signal is calculated, and is composed as detection；
(2), amplitude zero setting at the detection spectrum zero-frequency obtained to step (1)；
(3), step (2) treated detection spectrum in search maximum value Vmax, and seek mean value Vmean；
(4), with maximum value VmaxWith mean value VmeanRatio is as detection characteristic value E, i.e. E=Vmax/Vmean；
(5), by the threshold value e of step (4) obtained detection characteristic value E and settingthresholdIt is compared judgement: if E > ethreshold, then judge to receive signal for direct sequence signal；
In step (1), the calculation formula for detecting spectrum is as follows:
G2Px=| FFT | FFT (f (x)) |2|2；
Wherein, G2PxFor the detection spectrum being calculated；For generalization transforming function transformation function, H () is indicated Hilbert transform,FFT represents Fourier transformation operation.
2. a kind of detection method of direct sequence signal based on Generalized Quadratic power spectrum according to claim 1, feature exist In: in step (5), threshold value ethresholdValue range be 20~25.
CN201611140233.7A 2016-12-12 2016-12-12 A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum Active CN106849992B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201611140233.7A CN106849992B (en) 2016-12-12 2016-12-12 A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201611140233.7A CN106849992B (en) 2016-12-12 2016-12-12 A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum

Publications (2)

Publication Number Publication Date
CN106849992A CN106849992A (en) 2017-06-13
CN106849992B true CN106849992B (en) 2019-06-18

Family

ID=59140850

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201611140233.7A Active CN106849992B (en) 2016-12-12 2016-12-12 A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum

Country Status (1)

Country Link
CN (1) CN106849992B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112436863B (en) * 2020-10-29 2023-05-02 西安空间无线电技术研究所 Signal rapid detection search method based on frequency spectrum dispersion analysis

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6795490B2 (en) * 2002-04-17 2004-09-21 Thomson Licensing S.A. Signal detection in a direct-sequence spread spectrum transmission system
CN101388687A (en) * 2008-03-11 2009-03-18 电子科技大学 Chip implementing fast high-efficient non-cooperative signal-noise ratio direct spreading signal detection method
CN102412862A (en) * 2010-09-21 2012-04-11 中国科学院上海微系统与信息技术研究所 Direct sequence spread spectrum (DSSS) communication pseudo code capture method used in wireless sensor network (WSN)
CN104270167A (en) * 2013-12-20 2015-01-07 张冬 Signal detection and estimation method based on multi-dimensional characteristic neural network
CN105071830A (en) * 2015-07-17 2015-11-18 西安空间无线电技术研究所 DSSS signal detection identification method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6795490B2 (en) * 2002-04-17 2004-09-21 Thomson Licensing S.A. Signal detection in a direct-sequence spread spectrum transmission system
CN101388687A (en) * 2008-03-11 2009-03-18 电子科技大学 Chip implementing fast high-efficient non-cooperative signal-noise ratio direct spreading signal detection method
CN102412862A (en) * 2010-09-21 2012-04-11 中国科学院上海微系统与信息技术研究所 Direct sequence spread spectrum (DSSS) communication pseudo code capture method used in wireless sensor network (WSN)
CN104270167A (en) * 2013-12-20 2015-01-07 张冬 Signal detection and estimation method based on multi-dimensional characteristic neural network
CN105071830A (en) * 2015-07-17 2015-11-18 西安空间无线电技术研究所 DSSS signal detection identification method

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
"直扩信号检测和参数估计技术研究";陶雷、武传华;《舰船电子对抗》;20060228;第35-39页

Also Published As

Publication number Publication date
CN106849992A (en) 2017-06-13

Similar Documents

Publication Publication Date Title
CN109167746B (en) Continuous wave and pulse signal quick identification device
CN102279390B (en) Intra-pulse modulation and recognition method of low signal-to-noise radar radiation source signal
CN110133632B (en) Composite modulation signal identification method based on CWD time-frequency analysis
CN110187313B (en) Radar signal sorting and identifying method and device based on fractional order Fourier transform
CN109085614A (en) Based on when-spectrum value smoothly with the GNSS interference characteristic discrimination method and system of segmentation
CN106357574A (en) BPSK (Binary Phase Shift Keying)/QPSK (Quadrature Phase Shift Keying) signal modulation blind identification method based on order statistic
CN104270167A (en) Signal detection and estimation method based on multi-dimensional characteristic neural network
Jiang et al. Differential spectral amplitude modulation and its applications in rolling bearing fault diagnosis
CN106849992B (en) A kind of detection method of the direct sequence signal based on Generalized Quadratic power spectrum
Yang et al. Radar emitter signal recognition based on time-frequency analysis
CN105656511B (en) Differential correlation acquisition method suitable for environment with frequency offset and low signal-to-noise ratio
Yang et al. LPI radar signal detection based on the combination of FFT and segmented autocorrelation plus PAHT
CN107728167A (en) A kind of anti-drying method of GPS satellite navigation receiver analyzed based on cyclostationary characteristic with circulating filtering
Jennison Performance of a linear frequency-modulated signal detection algorithm
Yu et al. Period estimation of PN sequence for weak DSSS signals based on improved power spectrum reprocessing in non-cooperative communication systems
CN106595835A (en) Sound beacon signal extraction method and system based on dislocation superposition algorithm
Bai et al. The estimation of the PN sequence's period of the DSSS signals in narrowband interference environment
Zhang et al. A speech endpoint detection method based on wavelet coefficient variance and sub-band amplitude variance
He et al. Blind estimation for PN code of LFM-PRBC signal based on DPT and spectrum shifting
Lei et al. A new hop duration blind estimation algorithm for frequency-hopping signals
CN112929053B (en) Frequency hopping signal feature extraction and parameter estimation method
Wang Research on recognition algorithm for intra pulse modulation of radar signals
CN105158737B (en) A kind of frequency-stepped signal time-frequency detection method
Zun et al. A Decision Tree based Detection method for DSSS signal under jamming environment
Qin et al. A new method of parameter estimation of frequency-hopping signal

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