CN103176190B - High-precision timing system and high-precision timing method based on satellite navigation and Kalman filter - Google Patents

Abstract

The invention designs a high-precision timing system and a high-precision timing method based on satellite navigation and Kalman filter. The system comprises a data resolving portion and a timing filter portion. The data resolving portion adopts a traditional least square method to resolve positional information and clock error information of a Beidou second-generation receiver, then a Kalman filter is used for filtering the clock error information to obtain phase error information and frequency error information of a second signal generator, and initial phase and frequency meter digit of the second signal generator are regulated by the aid of the phase error information and the frequency error information, obtained by filtering, of the second signal generator, so that a high-prevision timing function is achieved. The system and the method solve the problems that timing precision under conditions of the prior art is poor, and the second signal generator is easily affected by crystal oscillator frequency errors.

Description

Based on the high precision time service method of satellite navigation and Kalman filter

Technical field

The present invention relates to field of satellite navigation and the communications field, be specially a kind of high precision time dissemination system based on satellite navigation and Kalman filter and method, utilize Kalman filter technology and satellite navigation to correct the phase error of second signal generator and frequency error, realize high-precision time service function.

Background technology

In recent years, along with the development of satellite navigation system, satellite navigation system has occupied more and more consequence in routine work with life.Satellite navigation system is while realization location and constant speed function, the clocking error information of local receiver can be resolved out in the lump, utilize local control information can to receiver second signal generating circuit phase information revise, realize the function of time service.But traditional time dissemination system is subject to the impact of positioning precision, there is larger shake.Traditional time service method does not consider that Crystal Oscillator Errors is for the impact that second, signal caused simultaneously, and a nearly step reduces the precision of time dissemination system.Such as just do not relate to estimation for Crystal Oscillator Errors thanking to the time service method mentioned in firm " GPS principle and Receiver Design " book.

Summary of the invention

The technical matters solved

For directly utilizing clock correction information, the larger shortcoming of correction error is carried out to signal second, and the clocking error that Crystal Oscillator Errors brings, the present invention proposes a kind of high precision time dissemination system based on satellite navigation and Kalman filter and method, Kalman filter is carried out to clock correction, reduce the shake of clock, utilize filtering to obtain second frequency control word of signal frequency error to second signal generator to adjust simultaneously, improve the precision of time signal.

Technical scheme

Technical scheme of the present invention is:

The described high precision time dissemination system based on satellite navigation and Kalman filter, comprises satellite reception module, positioning calculation module, Kalman filter and second signal generator, described satellite reception module accepts satellite position information and pseudo-range information, and pass to positioning calculation module, positioning calculation module obtains the clock correction information of satellite reception module according to satellite position information and pseudo-range information, and the clock correction information of satellite reception module is passed to Kalman filter, the clock correction information of Kalman filter to satellite reception module carries out Kalman filter, according to the phase control words and the frequency control word that obtain clock correction information and frequency difference information and obtain second signal generator, the phase control words obtained and frequency control word are passed to second signal generator by Kalman filter, realize high precision time service.

Method in the present invention comprises positioning calculation, Kalman filter, clock correction three parts.Positioning calculation adopts traditional least square method to resolve positioning result, obtains satellite receiver clock correction information simultaneously, carries out filtering by Kalman filter to the clock correction information that positioning calculation obtains.The result utilizing filtering to obtain corrects second signal generator, obtains accurate clock information.

The described high precision time service method based on satellite navigation and Kalman filter, adopts following steps:

Step 1: satellite reception module accepts satellite position information and pseudo-range information, according to satellite position information and pseudo-range information, adopts least square method to resolve the clock correction information δ t of satellite reception module _g;

Step 2: carry out Kalman filter to the clock correction information of satellite reception module is as follows for kth time filtering concrete steps:

The time renewal process of step 2.1:Kalman filtering:

To state vector X _k-1=[δ t _k-1δ f _k-1] estimate, obtain state estimation wherein δ t _k-1for clock correction information, the δ f of second signal generator _k-1for second signal generator frequency difference information, estimator is $A=\left[\begin{array}{cc}1& 1\\ 0& 1\end{array}\right],$ As k=1, X _k-1value is [0 0]; According to formula obtain covariance matrix P _k-1prediction matrix wherein Q is process noise covariance battle array;

The measurement renewal process of step 2.2:Kalman filtering:

According to formula obtain gain matrix K _k, wherein C=[1 0], R are measurement noise covariance matrix; According to formula obtain filtered state vector matrix X _k, according to formula obtain the covariance matrix P after upgrading _k, wherein I is two-dimentional unit matrix;

Step 3: the clock correction information of the second signal generator utilizing filtering each time to obtain is multiplied by the frequency f of crystal oscillator ₀obtain the phase control words N of second signal generator _padjustment amount Δ N _p, use N _pdeduct adjustment amount Δ N _pobtain the phase control words of accurate second signal generator; The frequency difference information of the second signal generator utilizing filtering each time to obtain is multiplied by the frequency f of crystal oscillator ₀obtain the frequency control word N of second signal generator _fadjustment amount Δ N _f, use N _fdeduct adjustment amount Δ N _fobtain the frequency control word of accurate second signal generator; According to phase control words and the frequency control word of the accurate second signal generator obtained, realize high precision time service.

Beneficial effect

The present invention designs the high precision time dissemination system based on satellite navigation and Kalman filter, by carrying out Kalman filter to satellite receiver clock correction information, reduce the shake of second signal generator, improve time service precision, the frequency meter numeral of second signal generator is adjusted simultaneously, compensate the time service error that crystal oscillator frequency difference causes.

Accompanying drawing explanation

Fig. 1: the high precision time dissemination system conceptual scheme based on satellite navigation and Kalman filter of the present invention's design;

Fig. 2: method flow diagram of the present invention.

Embodiment

Below in conjunction with specific embodiment, the present invention is described:

Embodiment:

The specific embodiments figure of the present embodiment as shown in Figure 1, carries out Kalman filter to the clock correction information that satellite receiver obtains, realizes the calibration to second signal generator.Concrete module comprises satellite reception module, positioning calculation module, Kalman filter and second signal generator, described satellite reception module accepts satellite position information and pseudo-range information, and pass to positioning calculation module, positioning calculation module obtains the clock correction information of satellite reception module according to satellite position information and pseudo-range information, and the clock correction information of satellite reception module is passed to Kalman filter, the clock correction information of Kalman filter to satellite reception module carries out Kalman filter, according to the phase control words and the frequency control word that obtain clock correction information and frequency difference information and obtain second signal generator, the phase control words obtained and frequency control word are passed to second signal generator by Kalman filter, realize high precision time service.

High precision time service method step specifically based on satellite navigation and Kalman filter is:

Step 1: satellite reception module accepts satellite position information and pseudo-range information, according to satellite position information and pseudo-range information, adopts least square method to resolve the clock correction information δ t of satellite reception module _g;

Step 2: carry out Kalman filter to the clock correction information of satellite reception module is as follows for kth time filtering concrete steps:

The time renewal process of step 2.1:Kalman filtering:

To state vector X _k-1=[δ t _k-1δ f _k-1] estimate, obtain state estimation wherein δ t _k-1for clock correction information, the δ f of second signal generator _k-1for second signal generator frequency difference information, estimator is $A=\left[\begin{array}{cc}1& 1\\ 0& 1\end{array}\right],$ As k=1, X _k-1value is [0 0]; According to formula obtain covariance matrix P _k-1prediction matrix wherein Q is process noise covariance battle array; For covariance matrix, as k=1, P _k-1value does not retrain, and gets in the present embodiment $P_{k-1}=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right];$

The measurement renewal process of step 2.2:Kalman filtering:

According to formula obtain gain matrix K _k, wherein C=[1 0], R are measurement noise covariance matrix; According to formula obtain filtered state vector matrix X _k, according to formula obtain the covariance matrix P after upgrading _k, wherein I is two-dimentional unit matrix;

Step 3: the clock correction information of the second signal generator utilizing filtering each time to obtain is multiplied by the frequency f of crystal oscillator ₀obtain the phase control words N of second signal generator _padjustment amount Δ N _p, use N _pdeduct adjustment amount Δ N _pobtain the phase control words of accurate second signal generator; The frequency difference information of the second signal generator utilizing filtering each time to obtain is multiplied by the frequency f of crystal oscillator ₀obtain the frequency control word N of second signal generator _fadjustment amount Δ N _f, use N _fdeduct adjustment amount Δ N _fobtain the frequency control word of accurate second signal generator; According to phase control words and the frequency control word of the accurate second signal generator obtained, realize high precision time service.

Claims (1)

1., based on a high precision time service method for satellite navigation and Kalman filter, adopt following steps:

Step 1: satellite reception module accepts satellite position information and pseudo-range information, according to satellite position information and pseudo-range information, adopts least square method to resolve the clock correction information δ t of satellite reception module _g;

Step 2: carry out Kalman filter to the clock correction information of satellite reception module is as follows for kth time filtering concrete steps:

The time renewal process of step 2.1:Kalman filtering:

To state vector X _k-1=[δ t _k-1δ f _k-1] estimate, obtain state estimation wherein δ t _k-1for clock correction information, the δ f of second signal generator _k-1for second signal generator frequency difference information, estimator is $A=\left[\begin{array}{cc}1& 1\\ 0& 1\end{array}\right],$ As k=1, X _k-1value is [0 0]; According to formula obtain covariance matrix P _k-1prediction matrix wherein Q is process noise covariance battle array;

The measurement renewal process of step 2.2:Kalman filtering:

According to formula obtain gain matrix K _k, wherein C=[1 0], R are measurement noise covariance matrix; According to formula obtain filtered state vector matrix X _k, according to formula obtain the covariance matrix P after upgrading _k, wherein I is two-dimentional unit matrix;

Step 3: the clock correction information of the second signal generator utilizing filtering each time to obtain is multiplied by the frequency f of crystal oscillator ₀obtain the phase control words N of second signal generator _padjustment amount Δ N _p, use N _pdeduct adjustment amount Δ N _pobtain the phase control words of accurate second signal generator; The frequency difference information of the second signal generator utilizing filtering each time to obtain is multiplied by the frequency f of crystal oscillator ₀obtain the frequency control word N of second signal generator _fadjustment amount Δ N _f, use N _fdeduct adjustment amount Δ N _fobtain the frequency control word of accurate second signal generator; According to phase control words and the frequency control word of the accurate second signal generator obtained, realize high precision time service.