CN104330806A - Inter-satellite system difference calibration method based on Ka range finding mode - Google Patents

Abstract

The invention provides an inter-satellite system difference calibration method based on a Ka range finding mode. The method comprises: first of all, solving a satellite-ground clock error, and correcting a satellite-ground radio pseudo range error; then solving an inter-satellite clock error, and correcting an inter-satellite radio pseudo range error; and finally obtaining an inter-satellite equipment system difference through the difference between the inter-satellite clock error obtained through a satellite-ground two-way link and an inter-satellite clock error obtained through an inter-satellite two-way link. According to the invention, the inter-satellite equipment system deviation can be calibrated, the RMS is better than 1 ns, the inter-satellite time synchronization precision can be improved, and the autonomous navigation precision can be accordingly enhanced.

Description

Based on Ka distance measurement mode star between System level gray correlation scaling method

Technical field

The present invention relates to a kind of method that between star, System level gray correlation is demarcated, belong to field of satellite navigation.

Background technology

Along with the maturation day by day that each large satellite navigational system is built, the compatible interoperation of people not only between attention location system, also turns one's attention to the independent navigation ability of satellite navigation system more.Building inter-satellite link is the precondition realizing independent navigation, has landmark meaning to the development of satellite navigation system.Current inter-satellite link is operated in UHF and Ka two wave bands, UHF antenna beam semi-cone angle is wider, traffic rate is low, be easily disturbed etc., and inherent shortcoming has obviously fettered the flourish of GPS technology, and under Ka pattern, effectively can reduce interference, strengthen link security, GPS III has planned to replace UHF distance measurement mode with Ka distance measurement mode.Due to the limitation that Ka band beam is narrow, can only realize measuring one to one between star, want to obtain more H_2O maser information, just need correspondingly to increase H_2O maser equipment.When satellite starts independent navigation, inter-satellite link only relies on H_2O maser equipment to execute the task, and inevitably there is System level gray correlation or relative device time delay between on-board equipment, accurately must deduct each System level gray correlation or equipment delay just can obtain correct navigational parameter.The document just about between GPS star in Time synchronization algorithm that foreign scholar delivers, does not also have relevant report for how demarcating device systems deviation between star.The domestic research about inter-satellite link is in the junior stage, and in the past for the GPS H_2O maser pattern of system of finding range based on UHF in the consideration Main Basis document of device systems deviation between star, not yet considers for Ka distance measurement mode.The System level gray correlation of Ka distance measurement mode demarcates the difficult point becoming numerous scholar's research.

Summary of the invention

In order to overcome the deficiencies in the prior art, the invention provides a kind of method that between star based on Ka distance measurement mode, System level gray correlation is demarcated, the method two-way with star ground radio demarcates device systems deviation between star, device systems deviation between star can be demarcated, its RMS is better than 1ns, timing tracking accuracy between star can be improved, thus improve independent navigation precision.

The technical solution adopted for the present invention to solve the technical problems comprises the following steps:

Step 1: resolving of star ground clock correction

IGS the website precise clock correction, precise ephemeris and the weather data that provide are provided, select two the same day Continuous Observation segmental arc be no less than halfhour gps satellite A and B, so that the land station of satellite-ground link can be set up as surface-based observing station with these two satellites; Land station C is relative to the star ground clock correction of satellite A $T_{\mathrm{CA}}=\frac{1}{2}[R_C-R_A]+\frac{1}{2}[{\mathrm{\τ}}_C^T+{\mathrm{\τ}}_A^R-{\mathrm{\τ}}_A^T-{\mathrm{\τ}}_C^R]+\frac{1}{2}[{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{tro}}+{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{ion}}+{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{sag}}+{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{geo}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{tro}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{ion}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{sag}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{geo}}];$ Wherein, for the transmitting time delay of land station C, for the transmitting time delay of satellite A, for the receive time delay of land station C, for the receive time delay of satellite A, for land station C is to the tropospheric delay of satellite A, for land station C is to the ionosphere delay of satellite A, for the Sagnac effect of land station C to satellite A, for the space geometry distance of land station C to satellite A, for satellite A is to the tropospheric delay of land station C, for satellite A is to the ionosphere delay of land station C, for the Sagnac effect of satellite A to land station C, for the space geometry distance of satellite A to land station C, R _afor the Signal transmissions time delay of satellite A to land station C, R _cfor the Signal transmissions time delay of land station C to satellite A;

Step 2: star ground radio pseudorange error corrects

Troposphere time delay in step 1 is corrected by Sa Sitamoning model; By ionospheric grid, spatial interpolation is carried out to ionospheric delay and temporal interpolation corrects; Admittedly be that coordinate corrects to Sagnac effect by the ground of survey station and satellite; The position relationship of propagated asymmetric error by the satellite velocities in precise ephemeris and survey station and satellite is corrected;

Step 3: between star, clock correction resolves

Satellite A transmits, measurement pseudorange when being received by satellite B

${\mathrm{\ρ}}_{\mathrm{AB}}={\mathrm{\ρ}}_{0\mathrm{AB}}+{\mathrm{\δ}}_A\left(t_e\right)-{\mathrm{\δ}}_B\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}+{\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R+{\mathrm{\ϵ}}_{\mathrm{AB}};$

Satellite B transmits, measurement pseudorange when being received by satellite A

${\mathrm{\ρ}}_{\mathrm{BA}}={\mathrm{\ρ}}_{0\mathrm{BA}}+{\mathrm{\δ}}_B\left(t_e\right)-{\mathrm{\δ}}_A\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}}+{\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R+{\mathrm{\ϵ}}_{\mathrm{BA}};$

Wherein, ρ _0ABfor satellite A transmits signals to the geometric distance of satellite B, ρ _0BAfor satellite B is transmitted into the geometric distance of satellite A, δ _a(t _r) for satellite A is at Signal reception moment t _rclock correction, δ _b(t _e) for satellite B is at signal x time t _eclock correction, δ _a(t _e) for satellite A is at signal x time t _eclock correction, δ _b(t _r) for satellite B is at Signal reception moment t _rclock correction, δ _{rel_BA}, δ _{rel_AB}for satellite clock periodically relativistic effect, for satellite B receiving end time delay, for satellite A transmitting terminal time delay, for satellite B transmitting terminal time delay, for satellite A receiving end time delay, ε _bAand ε _aBit is random noise.

Clock correction between the star obtaining satellite A, B

${\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right)=\frac{1}{2}[({\mathrm{\ρ}}_{\mathrm{AB}}-{\mathrm{\ρ}}_{\mathrm{BA}})-({\mathrm{\ρ}}_{0\mathrm{AB}}-{\mathrm{\ρ}}_{0\mathrm{BA}})-({\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}-{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}})-({\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R)+({\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R)]+\mathrm{\ϵ};$ ε represents random noise;

Step 4: by the bi-directional pseudo between satellite A, B apart from naturalization to same epoch;

Step 5: between star, radio pseudorange error corrects

Relativistic effect correction and the asymmetric correction of travel path are adopted to clock correction between the star of satellite A, B that step 3 obtains,

Relativistic effect correction formula is:

δ _{rel_AB}＝-2X _A(t _r)·V _A(t _r)/c，

δ _{rel_BA}＝-2X _B(t _r)·V _B(t _r)/c；

Wherein: X _a(t _r) and X _b(t _r) be respectively satellite A, B position in the time of reception, V _a(t _r) and V _b(t _r) be respectively satellite A, B speed in the time of reception;

The asymmetric correction formula of travel path is:

ρ _0AB＝|X _B(t _r)-X _A(t _e)|＝|X _B(t _r)-X _A(t _r)|+(X _B(t _r)-X _A(t _r))·V _B(t _r)/c，

ρ _0BA＝|X _A(t _r)-X _B(t _e)|＝|X _A(t _r)-X _B(t _r)|+(X _A(t _r)-X _B(t _r))·V _A(t _r)/c，

Finally obtain clock correction between star $\begin{array}{c}{\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right)=\frac{1}{2}[{\mathrm{\ρ}}_{\mathrm{AB}}-{\mathrm{\ρ}}_{\mathrm{BA}}-\frac{X_B\left(t_r\right)-X_A\left(t_r\right)}{C}(V_A\left(t_r\right)+V_B\left(t_r\right))\\ -\frac{2}{C}(X_B\left(t_r\right)\·V_B\left(t_r\right)-X_A\left(t_r\right)\·V_A\left(t_r\right))-({\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R)+({\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R)]+\mathrm{\ϵ}\end{array};$

Step 6: between star, device systems difference is demarcated

By clock correction mutual deviation between clock correction between star ground A, B star of obtaining of two-way link and A, B star of being obtained by two-way link between star, can finally obtain device systems between star poor.

The invention has the beneficial effects as follows: carry out device systems difference between star due to step 5 and demarcate, carrying out before time synchronized, this part system difference being deducted between star, timing tracking accuracy between star can be improved, thus improve independent navigation precision.The invention solves relative clock correction between star and lack the problem of time reference, timing tracking accuracy is at nanosecond order.

Accompanying drawing explanation

Fig. 1 is that between star, device systems deviation demarcates schematic diagram;

Fig. 2 is the two-way Time transfer receiver schematic diagram of star ground radio;

Fig. 3 is two-way Time transfer receiver schematic diagram between star;

Fig. 4 is method flow diagram of the present invention.

Embodiment

Below in conjunction with drawings and Examples, the present invention is further described, the present invention includes but be not limited only to following embodiment.

Device systems deviation calibration principle between star: as shown in Figure 1, known satellite A, B and have the land station C of external atomic frequency standard, two-way link between star (it is considered herein that two stars can set up inter-satellite link under visual condition) can be set up between AB, star ground two-way link between AC, BC, can be set up.By two star ground two-way link AC and BC, resolve the star ground clock correction t obtaining certain moment land station C and satellite A, B respectively _cA, t _cBif think that land station C clock correction is zero, easily carved satellite A, B clock correction t relative to land station C at this moment _a, t _b; On the other hand, resolve by two-way link AB between star the clock correction t ' obtaining synchronization satellite A, B _a, t ' _b, device systems deviation between star can be obtained:

δ _AB＝(t _A-t _B)-(t′ _A-t′ _B)

Between the star in fact obtained, device systems deviation is that combination is poor, expands into:

${\mathrm{\δ}}_{\mathrm{AB}}=\frac{(d_A^T+d_B^R)-(d_B^T+d_A^R)}{2}$

Wherein: represent the transmitting time delay of satellite A and B respectively; represent the receive time delay of satellite A and B respectively.

The present invention proposes a kind of method that between star based on Ka distance measurement mode, System level gray correlation is demarcated, demarcate difficulty for distance-measuring equipment system deviation between Ka range finding system culminant star thus affect the problem of independent navigation precision, the method two-way with star ground radio demarcates device systems deviation between star, by two stars ground two-way links with set up two-way link between a star at these two inter-satellites and demarcate, comprise the following steps:

Step 1:

The basis of hi-Fix orbit determination software BERNESE is write the module of pseudorange between emulation star voluntarily, and the coordinate file inputting the Precise Orbit of IGS, precise clock correction, earth rotation parameter (ERP) and IGS station obtains pseudorange between star;

Step 2:

Correction of Errors and naturalization epoch are carried out to pseudorange between the star obtained, clock correction between star can be obtained;

Step 3:

Matlab Programming with Pascal Language obtains star ground pseudorange;

Step 4:

Every error source in star ground radio pseudorange is corrected.Troposphere time delay is corrected by Sa Sitamoning model.Ionospheric delay carries out spatial interpolation by ionospheric grid and temporal interpolation corrects.Sagnac effect is that coordinate corrects by the ground of survey station and satellite admittedly.Propagated asymmetric error is corrected by the position relationship of the satellite velocities in precise ephemeris and survey station and satellite; Satellite equipment time delay is demarcated on ground before launching, and the equipment delay of land station equally also can be demarcated in advance, and this part work can be implemented before star ground radio two-way pumping station, can obtain star ground clock correction after completing the correction of every error source;

Step 5:

Deviation of equipments between star can be obtained after clock correction and star ground clock correction mutual deviation between star.

Specifically, step of the present invention is as follows:

Step 1: the generation of the two-way pseudorange value of star ground radio

Adopt precise clock correction, precise ephemeris and weather data that IGS website provides; Select two at the longer gps satellite of Continuous Observation segmental arc on the same day, with certain land station for surface-based observing station, emulation generates L-band star ground bi-directional pseudo distance.

The two-way Time transfer receiver principle of star ground radio: first distance measuring signal is carried out Pseudo Code Spread Spectrum modulation by land station, then by earth station equipment, signal is transmitted to satellite.After satellite reception to ground station signals, by correlation technique process despread-and-demodulation measure ground station signals to satellite transmission the time delay of process, and this delay data is sent to land station by communication link, meanwhile, atomic time signal transmits through Pseudo Code Spread Spectrum modulation ground station by satellite, land station also can measure satellite-signal to land station transmit the time delay of process.Obtain two kinds of data are subtracted each other by land station, remove various time delay influence, can obtain high-precision star ground clock correction.

As shown in Figure 2, satellite S to the time delay of land station's a-signal transmission is:

$R_S=T_S-T_A+{\mathrm{\τ}}_A^T+{\mathrm{\τ}}_S^R+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{sag}}+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{tro}}+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{ion}}+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{rel}}+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{geo}}---\left(3\right)$

The time delay of land station A to satellite S Signal transmissions is:

$R_A=T_A-T_S+{\mathrm{\τ}}_S^T+{\mathrm{\τ}}_A^R+{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{sag}}+{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{tro}}+{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{ion}}+{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{rel}}+{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{geo}}---\left(4\right)$

Wherein:

T _a: relative to the clock correction of system time during the clock face of land station A;

T _s: relative to the clock correction of system time during the clock face of satellite S;

the transmitting time delay of land station A;

the transmitting time delay of satellite S;

the receive time delay of land station A;

the receive time delay of satellite S;

land station A is to the tropospheric delay of satellite S;

land station A is to the ionosphere delay of satellite S;

the Sagnac effect of land station A to satellite S;

the space geometry distance of land station A to satellite S;

satellite S is to the tropospheric delay of land station A;

satellite S is to the ionosphere delay of land station A;

the Sagnac effect of satellite S to land station A;

the space geometry distance of satellite S to land station A;

R _s: the Signal transmissions time delay of satellite S to land station A;

R _a: the Signal transmissions time delay of land station A to satellite S.

(3), (4) two formulas are subtracted each other and obtain the star ground clock correction formula of land station A relative to satellite clock S:

$\begin{array}{c}{T}_{\mathrm{AS}}=T_A-T_S=\frac{1}{2}[R_A-R_S]+\frac{1}{2}[{\mathrm{\τ}}_A^T+{\mathrm{\τ}}_S^R-{\mathrm{\τ}}_S^T-{\mathrm{\τ}}_A^R]+\frac{1}{2}[{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{tro}}+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{ion}}+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{sag}}+{\mathrm{\τ}}_{\mathrm{AS}}^{\mathrm{geo}}\\ -{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{tro}}-{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{ion}}-{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{sag}}-{\mathrm{\τ}}_{\mathrm{SA}}^{\mathrm{geo}}]\end{array}---\left(5\right)$

Satellite equipment time delay is demarcated on ground before launching, and the equipment delay of land station equally also can be demarcated in advance, and this part work can complete before star ground radio two-way pumping station.

Step 2: star ground radio pseudorange error corrects

Every error source in star ground radio pseudorange is corrected.Troposphere time delay is corrected by Sa Sitamoning model.Ionospheric delay carries out spatial interpolation by ionospheric grid and temporal interpolation corrects.Sagnac effect is that coordinate corrects by the ground of survey station and satellite admittedly.Propagated asymmetric error is corrected by the position relationship of the satellite velocities in precise ephemeris and survey station and satellite.

Step 3: the generation of the two-way pseudorange value of radio between star

Because line between star is away from earth surface, only need during analogue observation value to consider relativistic effect, travel path asymmetrical effect two error effects.Equipment delay is comparatively slow in satellite transit phase change, can think a constant.

The two-way Time transfer receiver principle of star ground radio: as shown in Figure 3, inter-satellite link uses for reference the two-way measurement pattern of satellite, two satellites mutually send signal and find range, by exchanging measurement data, resolve, obtain relative clock correction, most of systematic error of H_2O maser of can eliminating the effects of the act like this and correlation error.The backwardness of satellite borne equipment Development Level causes two satellites to be difficult to accomplish to receive and dispatch ranging data simultaneously.In order to carry out Time transfer receiver, need bi-directional pseudo apart from naturalization to same epoch.

${\mathrm{\ρ}}_{\mathrm{AB}}={\mathrm{\ρ}}_{0\mathrm{AB}}+{\mathrm{\δ}}_A\left(t_e\right)-{\mathrm{\δ}}_B\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}+{\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R+{\mathrm{\ϵ}}_{\mathrm{AB}}---\left(6\right)$

${\mathrm{\ρ}}_{\mathrm{BA}}={\mathrm{\ρ}}_{0\mathrm{BA}}+{\mathrm{\δ}}_B\left(t_e\right)-{\mathrm{\δ}}_A\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}}+{\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R+{\mathrm{\ϵ}}_{\mathrm{BA}}---\left(7\right)$

Wherein:

ρ _aB: satellite A transmit B receive time measurement pseudorange;

ρ _bA: satellite B transmit A receive time measurement pseudorange;

ρ _0AB: satellite A transmit B receive time geometric distance;

ρ _0BA: satellite B transmit A receive time geometric distance;

T _r: the Signal reception moment;

T _e: signal x time;

δ _a(t _r): satellite A is at Signal reception moment t _rclock correction;

δ _b(t _e): satellite B is at signal x time t _eclock correction;

δ _a(t _e): satellite A is at signal x time t _eclock correction;

δ _b(t _r): satellite B is at Signal reception moment t _rclock correction;

δ _{rel_BA}, δ _{rel_AB}: satellite clock is relativistic effect periodically;

satellite B receiving end time delay;

satellite A transmitting terminal time delay;

satellite B transmitting terminal time delay;

satellite A receiving end time delay;

ε _bAand ε _aBit is random noise.

Degree of stability and the accuracy of spaceborne clock are higher, and the signal transmission delay of signal between two satellites is no more than 0.3 second, and in the extremely short time, the change of satellite clock correction is negligible.

(6), (7) two formulas can be rewritten as:

${\mathrm{\ρ}}_{\mathrm{AB}}={\mathrm{\ρ}}_{0\mathrm{AB}}+{\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}+{\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R+{\mathrm{\ϵ}}_{\mathrm{AB}}---\left(8\right)$

${\mathrm{\ρ}}_{\mathrm{BA}}={\mathrm{\ρ}}_{0\mathrm{BA}}+{\mathrm{\δ}}_B\left(t_r\right)-{\mathrm{\δ}}_A\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}}+{\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R+{\mathrm{\ϵ}}_{\mathrm{BA}}---9)$

(8), (9) two formulas are subtracted each other and can be obtained

${\mathrm{\ρ}}_{\mathrm{AB}}-{\mathrm{\ρ}}_{\mathrm{BA}}={\mathrm{\ρ}}_{0\mathrm{AB}}-{\mathrm{\ρ}}_{0\mathrm{BA}}+2({\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right))+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}-{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}}+{\mathrm{\ϵ}}_{\mathrm{AB}}-{\mathrm{\ϵ}}_{\mathrm{BA}}+({\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R)-({\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R)---\left(10\right)$

Clock correction formula between the star that namely (10) formula of arrangement obtains A, B:

${\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right)=\frac{1}{2}[({\mathrm{\ρ}}_{\mathrm{AB}}-{\mathrm{\ρ}}_{\mathrm{BA}})-({\mathrm{\ρ}}_{0\mathrm{AB}}-{\mathrm{\ρ}}_{0\mathrm{BA}})-({\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}-{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}})-({\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R)+({\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R)]+\mathrm{\ϵ}---\left(11\right)$

(11) comprise relativistic effect and travel path asymmetric error in formula, these two systematic errors can adopt strict formula to revise.

Relativistic effect correction formula is:

δ _{rel_AB}＝-2X _A(t _r)·V _A(t _r)/c (12)

δ _{rel_BA}＝-2X _B(t _r)·V _B(t _r)/c (13)

Wherein:

X _i(t _r): satellite is in the position of the time of reception;

V _i(t _r): satellite is in the speed of the time of reception.

The asymmetric correction formula of travel path is:

ρ _0AB＝|X _B(t _r)-X _A(t _e)|＝|X _B(t _r)-X _A(t _r)|+(X _B(t _r)-X _A(t _r))·V _B(t _r)/c (14)

ρ _0BA＝|X _A(t _r)-X _B(t _e)|＝|X _A(t _r)-X _B(t _r)|+(X _A(t _r)-X _B(t _r))·V _A(t _r)/c (15)

Finally obtain clock correction formula between star as follows:

$\begin{array}{c}{\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right)=\frac{1}{2}[{\mathrm{\ρ}}_{\mathrm{AB}}-{\mathrm{\ρ}}_{\mathrm{BA}}-\frac{X_B\left(t_r\right)-X_A\left(t_r\right)}{C}(V_A\left(t_r\right)+V_B\left(t_r\right))\\ -\frac{2}{C}(X_B\left(t_r\right)\·V_B\left(t_r\right)-X_A\left(t_r\right)\·V_A\left(t_r\right))-({\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R)+({\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R)]+\mathrm{\ϵ}\end{array}---\left(16\right)$

Step 4: between star, radio pseudorange error corrects

Relativistic effect is corrected by the satellite position in IGS precise ephemeris and speed.Propagated asymmetric error is corrected by the position relationship of the satellite velocities in precise ephemeris and survey station and satellite.

Step 5: System level gray correlation is demarcated

Demarcating by star ground two-way link the System level gray correlation average that between star, two-way link obtains is 39.8448ns, and its standard deviation is 40.3653ns, and the System level gray correlation error finally calibrated is less than 1ns.

As shown in Figure 4, embodiments of the invention comprise the following steps:

(1) precise clock correction in the 1 day January in 2011 adopting IGS website to provide and precise ephemeris; Select and the gps satellite setting up satellite-ground link synchronization: 09 and 14, bi-directional pseudo distance between the Ka distance measurement mode emulation star adopted with GPS III;

(2) precise clock correction in 1 day January in 2011 providing of IGS website, precise ephemeris and weather data are provided; Select two at the longer gps satellite of Continuous Observation segmental arc on the same day: 09 and 14, with station, Fangshan, Beijing for surface-based observing station, emulation generates L-band star ground bi-directional pseudo distance;

(3) after utilizing Lagrange's interpolation to carry out naturalization epoch to star ground radio pseudorange, then carry out Correction of Errors, comprise troposphere time delay, ionospheric delay, Sagnac effect and propagated asymmetric error, obtain star ground clock correction;

(4) between star, radio pseudorange error corrects, and comprises relativistic effect and propagated asymmetric error, obtains clock correction between star;

(5) with clock correction between star ground clock correction calibration star, System level gray correlation between star is obtained.

Claims (1)

1. based on Ka distance measurement mode star between a System level gray correlation scaling method, it is characterized in that comprising the steps:

Step 1: resolving of star ground clock correction

IGS the website precise clock correction, precise ephemeris and the weather data that provide are provided, select two the same day Continuous Observation segmental arc be no less than halfhour gps satellite A and B, so that the land station of satellite-ground link can be set up as surface-based observing station with these two satellites; Land station C is relative to the star ground clock correction of satellite A $T_{\mathrm{CA}}=\frac{1}{2}[R_C-R_A]+\frac{1}{2}[{\mathrm{\τ}}_C^T+{\mathrm{\τ}}_A^R-{\mathrm{\τ}}_A^T-{\mathrm{\τ}}_C^R]+\frac{1}{2}[{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{tro}}+{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{ion}}+{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{sag}}+{\mathrm{\τ}}_{\mathrm{CA}}^{\mathrm{geo}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{tro}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{ion}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{sag}}-{\mathrm{\τ}}_{\mathrm{AC}}^{\mathrm{geo}}];$ Wherein, for the transmitting time delay of land station C, for the transmitting time delay of satellite A, for the receive time delay of land station C, for the receive time delay of satellite A, for land station C is to the tropospheric delay of satellite A, for land station C is to the ionosphere delay of satellite A, for the Sagnac effect of land station C to satellite A, for the space geometry distance of land station C to satellite A, for satellite A is to the tropospheric delay of land station C, for satellite A is to the ionosphere delay of land station C, for the Sagnac effect of satellite A to land station C, for the space geometry distance of satellite A to land station C, R _afor the Signal transmissions time delay of satellite A to land station C, R _cfor the Signal transmissions time delay of land station C to satellite A;

Step 2: star ground radio pseudorange error corrects

Troposphere time delay in step 1 is corrected by Sa Sitamoning model; By ionospheric grid, spatial interpolation is carried out to ionospheric delay and temporal interpolation corrects; Admittedly be that coordinate corrects to Sagnac effect by the ground of survey station and satellite; The position relationship of propagated asymmetric error by the satellite velocities in precise ephemeris and survey station and satellite is corrected;

Step 3: between star, clock correction resolves

Satellite A transmits, measurement pseudorange when being received by satellite B

${\mathrm{\ρ}}_{\mathrm{AB}}={\mathrm{\ρ}}_{0\mathrm{AB}}+{\mathrm{\δ}}_A\left(t_e\right)-{\mathrm{\δ}}_B\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}+{\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R+{\mathrm{\ϵ}}_{\mathrm{AB}};$

Satellite B transmits, measurement pseudorange when being received by satellite A

${\mathrm{\ρ}}_{\mathrm{BA}}={\mathrm{\ρ}}_{0\mathrm{BA}}+{\mathrm{\δ}}_B\left(t_e\right)-{\mathrm{\δ}}_A\left(t_r\right)+{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}}+{\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R+{\mathrm{\ϵ}}_{\mathrm{BA}};$

Wherein, ρ _0ABfor satellite A transmits signals to the geometric distance of satellite B, ρ _0BAfor satellite B is transmitted into the geometric distance of satellite A, δ _a(t _r) for satellite A is at Signal reception moment t _rclock correction, δ _b(t _e) for satellite B is at signal x time t _eclock correction, δ _a(t _e) for satellite A is at signal x time t _eclock correction, δ _b(t _r) for satellite B is at Signal reception moment t _rclock correction, δ _{rel_BA}, δ _{rel_AB}for satellite clock periodically relativistic effect, for satellite B receiving end time delay, for satellite A transmitting terminal time delay, for satellite B transmitting terminal time delay, for satellite A receiving end time delay, ε _bAand ε _aBit is random noise.

Clock correction between the star obtaining satellite A, B

${\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right)=\frac{1}{2}[({\mathrm{\ρ}}_{\mathrm{AB}}-{\mathrm{\ρ}}_{\mathrm{BA}})-({\mathrm{\ρ}}_{0\mathrm{AB}}-{\mathrm{\ρ}}_{0\mathrm{BA}})-({\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{AB}}-{\mathrm{\δ}}_{\mathrm{rel}\_\mathrm{BA}})-({\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R)+({\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R)]+\mathrm{\ϵ};$ ε represents random noise;

Step 4: by the bi-directional pseudo between satellite A, B apart from naturalization to same epoch;

Step 5: between star, radio pseudorange error corrects

Relativistic effect correction and the asymmetric correction of travel path are adopted to clock correction between the star of satellite A, B that step 3 obtains,

Relativistic effect correction formula is:

δ _{rel_AB}＝-2X _A(t _r)·V _A(t _r)/c，

δ _{rel_BA}＝-2X _B(t _r)·V _B(t _r)/c；

Wherein: X _a(t _r) and X _b(t _r) be respectively satellite A, B position in the time of reception, V _a(t _r) and V _b(t _r) be respectively satellite A, B speed in the time of reception;

The asymmetric correction formula of travel path is:

ρ _0AB＝|X _B(t _r)-X _A(t _e)|＝|X _B(t _r)-X _A(t _r)|+(X _B(t _r)-X _A(t _r))·V _B(t _r)/c，

ρ _0BA＝|X _A(t _r)-X _B(t _e)|＝|X _A(t _r)-X _B(t _r)|+(X _A(t _r)-X _B(t _r))·V _A(t _r)/c，

Finally obtain clock correction between star $\begin{array}{c}{\mathrm{\δ}}_A\left(t_r\right)-{\mathrm{\δ}}_B\left(t_r\right)=\frac{1}{2}[{\mathrm{\ρ}}_{\mathrm{AB}}-{\mathrm{\ρ}}_{\mathrm{BA}}-\frac{X_B\left(t_r\right)-X_A\left(t_r\right)}{C}(V_A\left(t_r\right)+V_B\left(t_r\right))\\ -\frac{2}{C}(X_B\left(t_r\right)\·V_B\left(t_r\right)-X_A\left(t_r\right)\·V_A\left(t_r\right))-({\mathrm{\δ}}_A^T+{\mathrm{\δ}}_B^R)+({\mathrm{\δ}}_B^T+{\mathrm{\δ}}_A^R)]+\mathrm{\ϵ}\end{array};$

Step 6: between star, device systems difference is demarcated

By clock correction mutual deviation between clock correction between star ground A, B star of obtaining of two-way link and A, B star of being obtained by two-way link between star, can finally obtain device systems between star poor.