CN106814601B

CN106814601B - A kind of Noise Filter method of signal specific

Info

Publication number: CN106814601B
Application number: CN201710182251.XA
Authority: CN
Inventors: 傅德锦; 刘胜; 方军涛; 李俊; 王毅
Original assignee: Xiamen Nine Magnificent Communication Equipment Factory
Current assignee: Xiamen Nine Magnificent Communication Equipment Factory
Priority date: 2017-03-24
Filing date: 2017-03-24
Publication date: 2019-06-04
Anticipated expiration: 2037-03-24
Also published as: CN106814601A

Abstract

A kind of Noise Filter method of signal specific, according to observation A_m, it is assumed that observation A_mIt is exactly true value Z_m, the guess value T with certain precision can be released by mapping relationship f (m-n)_m‑n=A_m+ f (m-n), because of observed quantity A_mIt has been superimposed random noise, has often led to guess value T_m‑nThere is biggish deviations, or because speculate the increasing deviation of the accumulation that points increase.The basic principle of filtering algorithm of the invention assumes observation A_mEqual to Z_m, then according to observation A_mObtained a series of guess value and observed difference score value should be equal to random noise r_m, amplitude 80% falls between [- R R], whether exceeds [- R R] to T according to difference value_mIncrement or decreasing amount adjustment are carried out, increases T with adjustment number_mIt can become closer to Z_m。

Description

A kind of Noise Filter method of signal specific

Technical field

The present invention relates to field of signal processing, the Noise Filter method of especially a kind of signal specific.

Background technique

In time service field, either Beidou time service, GPS time service, GLONASS time service, PTP time service, long-wave time service or short Wave time service carries out temporal frequency transmission using wireless or wire channel, because receiver clock is unstable, system clock deviation, passes The time service information of the factors cause receivers such as the delay jitter of defeated channel reduction often has certain randomized jitter.Passive fixed Position field, the arrival time of the time pulse in time domain received often because signal strength or weakness variation and there are biggish waves It is dynamic.

Traditional linear filter method can effectively filter out random noise, but the useful component of some gradual changes simultaneously It is passivated together, becomes insensitive, the gradual change of the time service information as caused by the clock deviation of time dissemination system, such as the Doppler in passive location The gradual change of pulse arrival time caused by effect.Traditional linear filter method such as Kalman filtering has ratio just for linear signal Preferable effect.

Summary of the invention

It is a primary object of the present invention to overcome drawbacks described above in the prior art, propose a kind of according to a series of observation Value obtains the Noise Filter method of the signal specific of more accurate guess value, can effectively weaken random noise influence.

The present invention adopts the following technical scheme:

A kind of Noise Filter method of signal specific, it is characterised in that: preset T_mIndicate Discrete Periodic Signals M-th of supposition amount, A_mFor m-th of observation with certain error, K is filtering depth, and △ is adjustment stepping, and R is discrete week The jitter amplitude of phase signal, filter step are as follows:

1) when initial, T is enabled_m=A_m, n=1；

2) according to current observation A_mWith the relationship of mapping function f (m-n), guess value T is obtained_m-n, and by T_m-nWith M-n observation A_m-nIt makes comparisons, if T_m-n+ R < A_m-n, then according to adjustment stepping △ to T_mCarry out increasing amount adjustment；If T_m-n+ R > A_m-n, then to T_mCarry out decreasing amount adjustment；N=n+1；

3) n < K is judged, if so, returning to 2)；If it is not, then exporting T_m。

Preferably, Z is preset_mFor the true value of m-th of not no error, mapping relations: Z are obeyed_m-n=Z_m+f(m- n)；In step 2), it is assumed that current observation is equal to true value, then the current observation and mapping function f (m-n) Relationship is A_m-n=A_m+ f (m-n), the guess value obtained are T_m-n=T_m+f(m-n)。

Preferably, it is described according to adjustment stepping △ to T_mCarry out increasing amount adjustment, including the two add, is subtracted, is multiplied or Division operation.

Preferably, it is described according to adjustment stepping △ to T_mCarry out decreasing amount adjustment, including the two add, is subtracted, is multiplied or Division operation.

Preferably, the R is related to the statistical properties of random noise.

Preferably, the R takes the 75%-85% of the random noise of the jitter amplitude of Discrete Periodic Signals.

By the above-mentioned description of this invention it is found that compared with prior art, the invention has the following beneficial effects:

Filtering method of the invention is according to a series of observation A_mObtained a series of guess value T_m, in conjunction with discrete periodic Guess value is compared by the jitter amplitude R of signal with observation, according to comparison result to T_mIncrement or decreasing amount adjustment are carried out, with Adjustment number increase, T_mIt can become closer to Z_m, can effectively weaken random noise r_mIt influences.In addition, filtering side of the invention Method has relatively good filter effect to linear signal and nonlinear properties (such as periodic signal).

Detailed description of the invention

Fig. 1 is the flow chart of filtering method of the invention；

Fig. 2 is linear signal filter effect figure of the invention；

Fig. 3 is cyclical signal filter effect figure of the invention.

Specific embodiment

Below by way of specific embodiment, the invention will be further described.

For signal specific, it is assumed that it is superimposed with the random noise that 75%-85% (preferably 80%) amplitude is [- R, R].It should The mathematical model of signal specific is A_m=Z_m+r_m,r_mFor 80% between section [- R ,+R] random signal m-th of value, A_mIt is The m observations with certain error, Z_mFor the true value of m-th of not error, Z_mObey known mapping relations Z_m-n= Z_m+f(m-n).For example, indicating f (m-n)=C (m-n) when linear signal, C is constant；Indicate f (m-n)=0 when periodic signal, As m-n=NT, N is integer, T is the period.

Referring to Fig.1, the Noise Filter method of a kind of signal specific of the invention presets K as filtering depth, △ To adjust stepping, R is the jitter amplitude of Discrete Periodic Signals.Can basis signal sample fluctuation characteristic, choose suitable K, △, R, filter step are as follows:

1) when initial, T is enabled_m=A_m, n=1.

2) assume that current observation is equal to true value, then the current observation and the relationship of mapping function f (m-n) are A_m-n=A_m+ f (m-n), the guess value obtained are T_m-n=T_m+ f (m-n) (n=NT, N are integer when periodic signal, and T is the period). By T_m-nWith the m-n observation A_m-nIt makes comparisons, if T_m-n+ R < A_m-n, then according to adjustment stepping △ to T_mIncreasing amount adjustment is carried out, That is T_m=T_m+△；If T_m-n+ R > A_m-n, then to T_mCarry out decreasing amount adjustment, i.e. T_m=T_m-△；N=n+1.

3) n < K is judged, if so, returning to 2)；If it is not, then exporting T_m.With increasing for adjustment number, the T of output_mIt will be more Come closer to Z_m, therefore observation A can be replaced_mIt exports as a result.

Method of the invention, above-mentioned increasing amount adjustment and decreasing amount adjustment also can be used other operation modes such as multiplication, division real It is existing.

Applicating example

Such as there is the 1PPS shake model of navigation time dissemination system similar in the signal specific model with the application.Its A_m=Z_m+ r_m, Z_m-n=Z_m+ (m-n) * 1*f, f are the precise frequencies of local clock, r_mIt is random between section [- 100ns ,+100ns] Noise.A_mFor the observation of m-th of arrival time of 1PPS, Z_mFor the true value of m-th of arrival time of 1PPS, r_mFor time service of navigating The random clock deviation of the 1PPS of system.It can obtain a series of being substantially better than 1PPS arrival time and observing by the filtering algorithm of the application Measure A_mSupposition arrival time T_m, and then restore the 1PPS that precision is better than ± 100ns.

It is linear signal filter effect figure, the sample of signal are as follows: f (m-n)=0, r referring to Fig. 2_mFor fluctuation in [- 10 10] Random noise be superimposed one [- 50 50] infrequent noise.Abscissa is signal serial number, ordinate signal value.

It is cyclical signal filter effect figure, sample of signal referring to Fig. 3 are as follows: the period is the cosine wave of 50 signaling points, i.e. f (m-n)=0, working as n=NT, N is integer, when T=50, r_mRandom noise to fluctuate in [- 10 10] is superimposed one [- 50 50] Infrequent noise.Abscissa is signal serial number, ordinate signal value.

The above is only a specific embodiment of the present invention, but the design concept of the present invention is not limited to this, all to utilize this Design makes a non-material change to the present invention, and should all belong to behavior that violates the scope of protection of the present invention.

Claims

1. a kind of Noise Filter method of signal specific, it is characterised in that: preset T_mIndicate Discrete Periodic Signals m A supposition amount, A_mFor m-th of observation with certain error, K is filtering depth, and △ is adjustment stepping, and R is discrete periodic letter Number jitter amplitude, filter step is as follows:

1) when initial, T is enabled_m=A_m, n=1；

2. a kind of Noise Filter method of signal specific as described in claim 1, it is characterised in that: preset Z_mFor The true value of m-th of not no error obeys mapping relations: Z_m-n=Z_m+f(m-n)；In step 2), it is assumed that current observation Value is equal to true value, then the current observation and the relationship of mapping function f (m-n) are A_m-n=A_m+ f (m-n), obtains Guess value is T_m-n=T_m+f(m-n)。

3. a kind of Noise Filter method of signal specific as described in claim 1, it is characterised in that: in step 2), It is described according to adjustment stepping △ to T_mIncreasing amount adjustment is carried out, including the two add, is subtracted, is multiplied or division operation.

4. a kind of Noise Filter method of signal specific as described in claim 1, it is characterised in that: in step 2), It is described according to adjustment stepping △ to T_mDecreasing amount adjustment is carried out, including the two add, is subtracted, is multiplied or division operation.

5. a kind of Noise Filter method of signal specific as described in claim 1, it is characterised in that: the R and random The statistical properties of noise are related.

6. a kind of Noise Filter method of signal specific as described in claim 1, it is characterised in that: the R takes discrete The 75%-85% of the random noise of the jitter amplitude of periodic signal.