CN102288978B - Continuous operational reference system (CORS) base station cycle slip detection and recovering method - Google Patents

Abstract

The invention discloses a continuous operational reference system (CORS) base station cycle slip detection and recovering method, which comprises the following steps that: firstly, an ionized layer residual method is used for carrying out cycle slip detection, a satellite with the cycle slip and the corresponding observation value are determined, then, a single-epoch dual-frequency observation equation is built according to the cycle slip detection results, the single-epoch dual-frequency observation equation is divided into two types, the first type is cycle-slip-free observation equations, the second type is cycle slip observation equations, the cycle slip generated by a non-reference satellite is used as a gross error, the cycle slip generated by a reference satellite is used as a system error, the first type observation equations are used for carrying out parameter estimation, the cycle slip of the reference satellite is determined, the estimated parameters are introduced into thesecond type observation equations, correction numbers are calculated, the cycle slip values of the reference satellite are obtained, and finally, the cycle slip base station observation data is recovered according to the relationship between the base lines in a CORS triangular net. Because the error time strong correlation of the precise coordinate, the dual-frequency convection layer, the ionized layer and the like is directly utilized, the cycle slip detection and recovery can be precisely carried out.

Description

A kind of CORS base station cycle slip is surveyed and restorative procedure

Technical field

The present invention relates to GNSS network differential location technology, relate in particular to a kind of CORS base station (CORS) cycle slip and survey and restorative procedure, is the important component part of CORS system completeness monitoring.

Background technology

GNSS network differential location technology is the hot technology in present satnav field, be widely used in industries such as mapping and survey of territorial resources, be that the network differential technology of representative is risen with virtual reference station (VRS) technology, make and set up the recent tendency that base station network type GPS service system becomes Current GPS technology application development.The VRS technology is as the GPS real-time dynamic positioning technology under many base stations environment, be that collection Internet technology, wireless communication technique, computer networking technology and GPS technology are the network RTK location technology of one, also be wide, the most successful representative high-tech achievement of current application, the VRS technical system has represented the conventional RTK developing direction of location technology of new generation afterwards.

The basic skills of VRS technological orientation is: each reference station continuous acquisition observation data, and be real-time transmitted to data and handle database with control center, carry out network calculations; The ambiguity of carrier phase value of each individual baseline in control center's online resolving GPS reference station net; Data processing centre (DPC) utilizes the two difference composition errors on every baseline of reference station net carrier phase observation data calculating, and sets up the spatial parameter model apart from correlated error accordingly; The rough coordinates of the NMEA form that the movement station user will obtain by single-point location sends to control center, and a virtual reference station (VRS) is created at this coordinate position by control center; Control center is according to the relative geometrical relation of reference station, user and gps satellite, obtains space correlation error between movement station and reference station by the interpolation computation model, generates the dummy observation at VRS place again according to the dummy observation computation model; Control center sends to the movement station user to dummy observation as network differential correcting information; User's movement station receives network differential information and VRS constitutes short baseline, carries out difference by conventional RTK computation model and resolves, and determines customer location, sees shown in Figure 1.

In VRS, the correct forecast of troposphere and ionosphere two difference correction is the pinpoint basis of user, and in real time data processing, the existence of cycle slip will make the predicted value of troposphere and ionosphere two difference correction produce Systematic Errors.For the research that cycle slip is surveyed and repaired, method is a lot, and typical cycle slip detection method has two classes, and a class is to survey cycle slip by the continuity that checks observation data and linear combination thereof, because cycle slip has been destroyed the continuity of data.Relatively more classical in these class methods have high order difference method, polynomial fitting method, a wavelet analysis method.Inspected number comprises ionosphere combination, two subtractive combinations etc.Another kind of is to utilize the rough error Detection Techniques to survey cycle slip, Kalman filtering method is arranged, intend accurate checking method.Above method all is to concentrate on to use the data of single station, single satellite to carry out the detection of cycle slip, after detecting cycle slip, re-uses cycle slip rehabilitation method reparation.

Summary of the invention

The invention discloses a kind of CORS base station cycle slip and survey and restorative procedure, adopt following technical scheme:

A kind of CORS base station cycle slip is surveyed and restorative procedure, it is characterized in that: according to known integer ambiguity after the temporal correlation of accurate coordinates known in the CORS net and troposphere, ionospheric error and the initialization, according to the non-character that occurs Systematic Errors in all two difference observation equations that causes with reference to satellite with reference to satellite causes that rough error appears in single two difference observation equation, using the Ionosphere Residual Error method to carry out cycle slip surveys, according to the cycle slip result of detection, set up single epoch of two difference observation equation, carry out the cycle slip reparation at last, may further comprise the steps:

1) carries out the detection of cycle slip according to the Ionosphere Residual Error method, determine to exist satellite and the corresponding observed reading of cycle slip, set up single epoch of two difference observation equations;

2) two poor observation equations are divided into two classes, the first kind is the two difference of no cycle slip observation equations, and second class is the two difference observation equations that have cycle slip, with non-cycle slip with reference to the satellite generation as rough error, with reference to the cycle slip of satellite as systematic error;

3) use the two difference of first kind observation equation to carry out parameter estimation, determine the cycle slip with reference to satellite;

4) parameter that the two difference of first kind observation equation is estimated is brought the two difference of second class observation equation into, calculates correction, obtains non-cycle slip value with reference to satellite;

5) according to the base station observation data that concerns reparation generation cycle slip between baseline in the CORS triangulation network.

Concrete grammar is:

1) the Ionosphere Residual Error method is carried out the cycle slip detection

The basic observation equation of the non-difference observation of gps carrier phase place is:

Wherein, t is epoch of observation; I represents corresponding L1 and L2 carrier wave;

The expression carrier phase observation data; R represents the geometric distance between satellite and the receiver; λ represents wavelength; N represents the integer ambiguity of carrier phase observation data; T represents tropospheric error; I represents ionospheric error; ε represents non-model error;

Ask difference to get L1 and L2 carrier phase observation data:

Wherein I is the poor of L1 and L2 carrier wave observation ionospheric error; ε is L1 and the single poor non-model error of L2 carrier wave observation;

The difference of above-mentioned ionospheric error is carried out asking poor between epoch, can get:

According to ionospheric character, it is 1 second CORS system for sampling rate, at short notice, ionosphere is changed to small quantity, when observed reading cycle slip does not take place, Ionosphere Residual Error can not surpass for 0.1 week, if surpassed for 0.1 week, then think to have cycle slip in the observed reading, thereby detect cycle slip, according to this cycle slip result of detection, two poor observed readings are classified;

2) two poor observation equation classification

Use two difference observation equations of carrier phase observation, this pair difference observation equation is:

${\mathrm{\δ}}_{A,B}^{i,j}\left(t_i\right)=-\▿{\mathrm{\ΔI}}_{A,B}^{i,j}\left(t_i\right)+\mathrm{\Δ}{\▿T}_{A,B}^{i,j}\left(t_i\right)+\mathrm{\Δ}\▿{\mathrm{\δm}}_{A,B}^{i,j}\left(t_i\right)+\mathrm{\Δ}\▿{\mathrm{\ϵ}}_{A,B}^{i,j}\left(t_i\right)---\left(5\right)$

Wherein,

Be two difference observed readings of carrier phase,

Be two differences station star distance, Be two poor integer ambiguities,

Be two poor ionosphere delays,

Be two poor tropospheric delay,

The error that causes for two poor multipath effects,

Be the non-model error of two differences;

In the CORS net, two poor integer ambiguities obtain after initialization.According to high sampling rate in the CORS net, the strong correlation of error between epoch, two difference tropospheres and ionospheric error value by a last epoch are approximate, as formula (6);

The coordinate of a station A in the baseline of supposing to form in the CORS base station net is accurately known, and the coordinate of another one station B estimates as parameter, under the known situation of no cycle slip and two poor blur level, then can obtain error equation and is:

$V_{A,B}^{i,j}=\mathrm{Bx}-L_{A,B}^{i,j}---\left(7\right)$

Wherein

X=[dx dy dz] ^T, B is matrix of coefficients;

In above error equation, suppose to have one non-ly at a certain website cycle slip to take place with reference to satellite, then can cause rough error, if with reference to satellite cycle slip has taken place, then this cycle slip will be brought into all error equations, thereby produces Systematic Errors, and (7) formula is added systematic parameter can be got:

$V_{A,B}^{i,j}=\mathrm{Bx}+\mathrm{Ey}-L_{A,B}^{i,j}---\left(8\right)$

Wherein, y=[y ₁, y ₂] ^TBe respectively with reference to the cycle slip in satellite L1 and the L2 carrier phase observation data;

Suppose in a certain epoch, traced into n satellite, and in previous epoch, the integer ambiguity of this n satellite is all fixing, the error equation group that then can obtain this epoch is:

$\underset{(n-1)\&times;1}{V_1}=\underset{(n-1)\&times;3}{B}\underset{3\&times;1}{x}+\underset{(n-1)\&times;1}{E_1}\underset{1\&times;1}{{\mathrm{<figure-callout\; id="1"\; label="y"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">y</figure-callout>}}_1}-\underset{(n-1)\&times;1}{L_1}$ (9)

$\underset{(n-1)\&times;1}{V_2}=\underset{(n-1)\&times;3}{B}\underset{3\&times;1}{x}+\underset{(n-1)\&times;1}{E_2}\underset{1\&times;1}{{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">y</figure-callout>}}_2}-\underset{(n-1)\&times;1}{L_2}$

Be respectively the error equation on L1 and the L2 carrier wave;

According to Ionosphere Residual Error method cycle slip result of detection, real-time two difference carrier wave observed readings are divided into four groups, first group of pair error equation that poor observation equations constitute for the L1 of no cycle slip used L ₁₁Expression, weights are P ₁₁, second group is pair error equation that the difference observation equations constitute that has the L1 of cycle slip, uses L ₂₁Expression, weights are P ₂₁, the 3rd group of error equation for two difference observation equations formations of the L2 of no cycle slip used L ₁₂Expression, weights are P ₁₂, the 4th group is pair error equation that the difference observation equations constitute that has the L2 of cycle slip, uses L ₂₂Expression, weights are P ₂₂Then can get error equation is:

$\left.\begin{array}{c}{V}_{11}=B_{11}x+E_{11}{y}_1-l_{11}\\ V_{21}=B_{21}x+E_{21}{y}_1-l_{21}\\ V_{12}=B_{12}x+E_{12}{y}_2-l_{12}\\ V_{12}=B_{22}x+E_{22}{y}_2-l_{22}\end{array}\right\}$ $P=\left(\begin{array}{cccc}{P}_{11}& O& O& O\\ O& P_{21}& O& O\\ O& O& P_{12}& O\\ O& O& O& P_{22}\end{array}\right)---\left(10\right)$

The error equation that above-mentioned four groups of two difference observation equations are constituted is further divided into two classes, be that the first kind is the L1 of no cycle slip and pair error equation that the difference observation equations constitute of L2, second class is to have the L1 of cycle slip and pair error equation that the difference observation equations constitute of L2, and then following formula can be expressed as:

$\left.\begin{array}{c}{V}_1=B_{1}x+E_{1}y-l_1\\ V_2=B_{2}x+E_{2}y-l_2\end{array}\right\}$ $P=\left(\begin{array}{cc}{P}_1& O\\ O& P_2\end{array}\right)---\left(11\right)$

Wherein:

${\mathrm{<figure-callout\; id="1"\; label="V"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">V</figure-callout>}}_1=\left(\begin{array}{c}{V}_{11}\\ V_{12}\end{array}\right)$ ${\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">V</figure-callout>}}_2=\left(\begin{array}{c}{V}_{21}\\ V_{22}\end{array}\right),$ ${\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">B</figure-callout>}}_1=\left(\begin{array}{c}{B}_{11}\\ B_{12}\end{array}\right)$ ${\mathrm{<figure-callout\; id="2"\; label="B"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">B</figure-callout>}}_2=\left(\begin{array}{c}{B}_{21}\\ B_{22}\end{array}\right),$ ${\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">l</figure-callout>}}_1=\left(\begin{array}{c}{l}_{11}\\ l_{12}\end{array}\right)$ ${\mathrm{<figure-callout\; id="2"\; label="l"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">l</figure-callout>}}_2=\left(\begin{array}{c}{l}_{21}\\ l_{22}\end{array}\right)$

$E_1=\left(\begin{array}{c}{E}_{11}\\ E_{12}\end{array}\right)$ $E_2=\left(\begin{array}{c}{E}_{21}\\ E_{22}\end{array}\right),$ $y=\left(\begin{array}{c}{y}_1\\ y_2\end{array}\right),$ ${\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">P</figure-callout>}}_1=\left(\begin{array}{cc}{P}_{11}& O\\ O& P_{12}\end{array}\right),$ $P_2=\left(\begin{array}{cc}{P}_{21}& O\\ O& P_{22}\end{array}\right)$

X is rover station coordinate correction parameter, and y is with reference to the cycle slip in satellite L1 and the L2 carrier wave observed reading;

3) error equation that constitutes with the two difference of first kind observation equation carries out parameter estimation

Exist the L1 of cycle slip and two difference observation equations of L2 to handle as the observation equation that has rough error second class, then suppose P ₂=0, also namely in resolving, cut little ice, then can directly use the first kind not have the L1 of cycle slip and the carrier wave observation equation of L2 resolves x and y parameter, press criterion of least squares V ^TPV=min can get normal equation:

$\left(\begin{array}{cc}{B}_1^T{P}_1{B}_1& B_1^T{P}_1{E}_1\\ E_1^T{P}_1{B}_1& E_1^T{P}_1{E}_1\end{array}\right)\left(\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right)=\left(\begin{array}{c}{B}_1^T{P}_1{l}_1\\ E_1^T{P}_1{l}_1\end{array}\right)---\left(12\right)$

Order $N_{11}=B_1^T{P}_1{\mathrm{<figure-callout\; id="1"\; label="B"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">B</figure-callout>}}_1,$ $N_{12}=N_{21}^T=B_1^T{P}_1{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">E</figure-callout>}}_1,$ $N_{22}=E_1^T{P}_1{\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">E</figure-callout>}}_1,$ ${\mathrm{<figure-callout\; id="1"\; label="W"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">W</figure-callout>}}_1=B_1^T{P}_1{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">l</figure-callout>}}_1,$ ${\mathrm{<figure-callout\; id="2"\; label="W"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">W</figure-callout>}}_2=E_1^T{P}_1{\mathrm{<figure-callout\; id="1"\; label="l"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">l</figure-callout>}}_1,$

Then following formula can be written as:

$\left(\begin{array}{cc}{N}_{11}& N_{12}\\ N_{21}& N_{22}\end{array}\right)\left(\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right)\left(\begin{array}{c}{W}_1\\ W_2\end{array}\right)---\left(13\right)$

Got by the piecemeal formula of inverting

$\left(\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right)\left(\begin{array}{cc}{N}_{11}^{-1}+N_{11}^{-1}{N}_{12}{M}^{-1}{N}_{21}{N}_{11}^{-1}& -N_{11}^{-1}{N}_{12}{M}^{-1}\\ -M^{-1}{N}_{21}{N}_{11}^{-1}& M^{-1}\end{array}\right)\left(\begin{array}{c}{W}_1\\ W_2\end{array}\right)---\left(14\right)$

In the formula

$M=N_{22}-N_{21}{N}_{11}^{-1}{N}_{12}---\left(15\right)$

If do not have cycle slip with reference to satellite, then

$\hat{x}=N_{11}^{-1}{W}_1---\left(16\right)$

Valuation according to systematic error

Obtain with reference to the cycle slip value on satellite L1 and the L2 carrier wave be:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="1"\; label="Slip"\; filenames="HDA0000076975510000031.png,HDA0000076975510000032.png"\; state="\{\{state\}\}">Slip</figure-callout>}}_1=\frac{{\hat{y}}_1}{{\mathrm{\&lambda;}}_1}\\ {\mathrm{<figure-callout\; id="2"\; label="Slip"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">Slip</figure-callout>}}_2=\frac{{\hat{y}}_2}{{\mathrm{\&lambda;}}_2}\end{array}\right.---\left(17\right)$

Slip wherein ₁, Slip ₂Represent the cycle slip with reference to satellite L1 and L2 carrier phase observation data respectively;

4) non-calculating with reference to satellite cycle slip reparation value

Will

And

Bring V into ₂=B ₂X+E ₂Y-l ₂, can get corresponding non-cycle slip value with reference to satellite and be:

$\left\{\begin{array}{c}{\mathrm{<figure-callout\; id="2"\; label="slip"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">slip</figure-callout>}}_2=\frac{V_{21}}{{\mathrm{\&lambda;}}_1}\\ {\mathrm{<figure-callout\; id="2"\; label="slip"\; filenames="HDA0000076975510000012.png,HDA0000076975510000031.png"\; state="\{\{state\}\}">slip</figure-callout>}}_2=\frac{V_{22}}{{\mathrm{\&lambda;}}_2}\end{array}\right.---\left(18\right)$

Slip wherein ₁, slip ₂Represent non-cycle slip with reference to satellite L1 and L2 carrier phase observation data respectively;

5) determine the base station of cycle slip generation and the reparation of cycle slip

After the cycle slip satellite in detecting baseline, occurring, determine to occur the base station of cycle slip according to two baselines of base station correspondence in the triangulation network, as triangulation network ABC, three baseline A → B are arranged, B → C, C → A, if detected cycle slip among baseline A → B, also there is cycle slip in baseline B → C, and the equal and opposite in direction of cycle slip, opposite in sign, then cycle slip appears on the B of base station, and resolving as reference point in baseline according to the base station still is the sign that pour point resolves to judge cycle slip, in a baseline, if cycle slip occurs on the reference point, then the cycle slip result is just in time opposite with the residual values symbol, if occur on the pour point, then the cycle slip result is identical with the residual values symbol, in baseline A → B, the B point is as pour point, so the cycle slip value that baseline A → B is detected is as the cycle slip reparation value of base station B.Same method is according to the cycle slip of baseline C → A and baseline A → B reparation base station A, according to the cycle slip value of baseline B → C and baseline C → A reparation base station C.

Advantage of the present invention and beneficial effect:

The cycle slip that the present invention is based on the classification least-squares estimation is surveyed and restorative procedure, owing to directly utilized the time strong correlation of the accurate coordinates of CORS net and two poor troposphere, ionosphere equal error, the very effective minimizing other system error of energy is to the influence of model, thereby can accurately carry out detection and the reparation of cycle slip, be the whole method of surveying and repairing of a kind of very effective cycle slip.Experiment based on CORS laboratory reference station, Tianjin network shows: traditional cycle slip detection method is comparatively difficult for the detection of little cycle slip, is 0.01 week and survey the precision that can survey with restorative procedure based on the cycle slip of classification least-squares estimation.This patent comes from state natural sciences fund (41074021): the completeness monitoring of CORS system theoretical and method research and Eleventh Five-Year Plan national science and technology supporting plan main project: the sub-problem of " rural holding real time monitoring research and system development ": network digital technique for investigation exploitation.

Description of drawings

Fig. 1 is VRS and reference station net graph of a relation;

Fig. 2 is that cycle slip is surveyed process flow diagram;

Fig. 3 is that Tianjin CORS test reference station network distributes;

Fig. 4 is the baseline resolution error;

Fig. 5 baseline DG → XQ cycle slip result of detection, wherein Fig. 5 (a) is the cycle slip result of detection of No. 30 satellites, Fig. 5 (b) is the cycle slip result of detection of No. 32 satellites;

Fig. 6 baseline XQ → NH cycle slip result of detection, wherein Fig. 6 (a) is the cycle slip result of detection of No. 30 satellites, Fig. 6 (b) is the cycle slip result of detection of No. 32 satellites.

Embodiment

The inventive method is according to known accurate coordinates and troposphere in the CORS net, known integer ambiguity after the temporal correlation of ionospheric error and the initialization, cause that with reference to satellite rough error appears in single two difference observation equation according to non-, and cause all two character that occur Systematic Errors in observation equations that differ from reference to satellite, at first using the Ionosphere Residual Error method to carry out cycle slip surveys, determine to exist satellite and the corresponding observed reading of cycle slip, then according to the cycle slip result of detection, set up single epoch of two difference observation equation, list two difference epoch observation equation is divided into two classes, the first kind is no cycle slip equation, second class be exist cycle slip equation, with the non-cycle slip that produces with reference to satellite as rough error, the cycle slip that produces with reference to satellite is as systematic error, use first kind equation to carry out parameter estimation, determine the cycle slip with reference to satellite, bring the parameter that first kind equation estimates into second class equation, calculate correction, obtain non-cycle slip value with reference to satellite, last according to the base station observation data that concerns reparation generation cycle slip between baseline in the CORS triangulation network.Cycle slip is surveyed and is repaired process flow diagram referring to shown in Figure 2.

Embodiment: in Tianjin CORS test reference station, use this method, Tianjin CORS test reference station network comprises huge port (DG), west blue or green (XQ), NH 15 CORSs such as (NH), DG, the XQ in the net on Dec 11st, 2009, the data of three base stations of NH are adopted in experiment, sampling interval 1s gets wherein 5 minutes data.As shown in Figure 3.Wherein, cycle slip does not all take place in all tracking satellites, surveys and the ability of repairing for analyzing cycle slip, and artificial adding cycle slip wherein, has been selected at reference satellite PRN=14, and elevation angle is 60 ° PRN=30 satellite, and elevation angle is 10 ° PRN=32 satellite.Concrete cycle slip value sees the following form 1:

All jumping figures to be detected that table 1 adds

Use the Ionosphere Residual Error method to carry out the detection of cycle slip, according to the cycle slip result of detection observed reading is classified, using this method that the baseline in the net is carried out list resolves epoch, estimate the changes in coordinates amount and with reference to the cycle slip value of satellite, table 2 expression DG → XQ cycle slip result of detection, table 3 expression baseline XQ → NH carries out result of detection.

Table 2 baseline DG → DL cycle slip result of detection

Table 3 baseline DL → TG cycle slip result of detection

As can be seen, the cycle slip value that adds in the result that cycle slip is surveyed and the table 1 has very strong consistance, illustrates that this method is very effective to the reparation of cycle slip from table 2 and table 3.

Fig. 4 represents the result that resolves to baseline DG → XQ (Fig. 4 (a)) and baseline XQ → NH (Fig. 4 (b)), and the result shows that cycle slip is very little to resolve influence by the baseline that carries out after the classification.By result of calculation as can be known, the residual error method can judge in two subtractive combination observations whether have cycle slip, so which station to go up generation to, also need to compare according to the front and back baseline and just can determine the website at cycle slip place and the size of cycle slip, if such as in baseline DG → XQ, having detected cycle slip, and in baseline XQ → NH, do not detect, illustrate that cycle slip appears on the DG of base station, after detecting the website of cycle slip appearance, also needing to resolve as the base station in baseline according to website still is the sign that rover station resolves to judge cycle slip, add 1 cycle slip (as epoch 40) such as the reference satellite in the base station, the residual error result of detection is negative value, add 1 cycle slip (as epoch 120) at rover station with reference to satellite, residual result sign unanimity, can obtain as drawing a conclusion according to analysis of experimental data: (1) is if latter linked baseline detects cycle slip simultaneously before two, and cycle slip equal and opposite in direction, opposite in sign, illustrate that cycle slip appears on the common site, detected cycle slip if having only in the baseline, illustrated that cycle slip occurs on the non-common site of this baseline; (2) in the baseline, if cycle slip occurs on the base station, then the cycle slip result is just in time opposite with the residual values symbol, if occur in rover station, then the cycle slip result is identical with the residual values symbol.

Fig. 5 represents No. 30 satellites (Fig. 5 (a)) to baseline DG → XQ and the cycle slip result of detection of No. 32 satellites (Fig. 5 (b)).Fig. 6 represents No. 30 satellites (Fig. 6 (a)) to baseline DG → XQ and the cycle slip result of detection of No. 32 satellites (Fig. 6 (b)).At last determine to occur the base station of cycle slip according to the relation between the baseline in the triangulation network, and observation data is carried out the reparation of cycle slip.If such as in baseline DG → XQ, having detected cycle slip, and in baseline XQ → NH, also there is cycle slip to detect, illustrate that cycle slip appears on the XQ of base station, detect the website that cycle slip occurs after, in baseline, resolve sign that still pour point resolve judge cycle slip as reference point according to website.Add 1 cycle slip (as epoch 40) such as the reference satellite in the base station, the residual error result of detection is negative value, add 1 cycle slip (as epoch 120) at rover station with reference to satellite, residual result sign unanimity, in baseline DG → XQ, DG is as reference point, so the result that baseline DG → XQ is detected gets negative sign as the cycle slip reparation value of base station DG.

Show that according to above experiment this method can be implemented in accurate detection and the reparation when multi-satellite cycle slip occurs simultaneously in the epoch, very low when the satellite altitude angle, when 10 ° of left and right sides, still can accurately survey, and calculate the cycle slip value.

Claims (1)

1. a CORS base station cycle slip is surveyed and restorative procedure, it is characterized in that: according to known integer ambiguity after the temporal correlation of accurate coordinates known in the CORS net and troposphere, ionospheric error and the initialization, according to the non-character that occurs Systematic Errors in all two difference observation equations that causes with reference to satellite with reference to satellite causes that rough error appears in single two difference observation equation, using the Ionosphere Residual Error method to carry out cycle slip surveys, according to the cycle slip result of detection, set up single epoch of two difference observation equation, carry out the cycle slip reparation at last, may further comprise the steps:

1) carries out the detection of cycle slip according to the Ionosphere Residual Error method, determine to exist satellite and the corresponding observed reading of cycle slip, set up single epoch of two difference observation equations;

2) two poor observation equations are divided into two classes, the first kind is the two difference of no cycle slip observation equations, and second class is the two difference observation equations that have cycle slip, with non-cycle slip with reference to the satellite generation as rough error, with reference to the cycle slip of satellite as systematic error;

3) use the two difference of first kind observation equation to carry out parameter estimation, determine the cycle slip with reference to satellite;

4) parameter that the two difference of first kind observation equation is estimated is brought the two difference of second class observation equation into, calculates correction, obtains non-cycle slip value with reference to satellite;

5) according to the base station observation data that concerns reparation generation cycle slip between baseline in the CORS triangulation network;

Concrete grammar in the above-mentioned steps is as follows:

1) the Ionosphere Residual Error method is carried out the cycle slip detection

The basic observation equation of the non-difference observation of gps carrier phase place is:

Wherein, t is epoch of observation; I represents corresponding L1 and L2 carrier wave;

The expression carrier phase observation data; R represents the geometric distance between satellite and the receiver; λ represents wavelength; N represents the integer ambiguity of carrier phase observation data; T represents tropospheric error; I represents ionospheric error; ε represents non-model error;

Ask difference to get L1 and L2 carrier phase observation data:

I(t wherein) is the poor of L1 and L2 carrier wave observation ionospheric error; ε is L1 and the single poor non-model error of L2 carrier wave observation;

The difference of above-mentioned ionospheric error is carried out asking poor between epoch, can get:

According to ionospheric character, it is 1 second CORS system for sampling rate, at short notice, ionosphere is changed to small quantity, when observed reading cycle slip does not take place, Ionosphere Residual Error can not surpass for 0.1 week, if surpassed for 0.1 week, then think to have cycle slip in the observed reading, thereby detect cycle slip, according to this cycle slip result of detection, two poor observed readings are classified;

2) two poor observation equation classification

Use two difference observation equations of carrier phase observation, this pair difference observation equation is:

Wherein,

Be two difference observed readings of carrier phase,

Be two differences station star distance,

Be two poor integer ambiguities,

Be two poor ionosphere delays,

Be two poor tropospheric delay, The error that causes for two poor multipath effects,

Be the non-model error of two differences;

In CORS net, two poor integer ambiguities obtain after initialization, and according to high sampling rate in the CORS net, the strong correlation of error between epoch, two difference tropospheres and ionospheric error value by a last epoch are approximate, i.e. formula (6);

The coordinate of a station A in the baseline of supposing to form in the CORS base station net is accurately known, and the coordinate of another one station B estimates as parameter, under the known situation of no cycle slip and two poor blur level, then can obtain error equation and is:

$V_{A,B}^{i,j}=\mathrm{Bx}-L_{A,B}^{i,j}---\left(7\right)$

Wherein

X=[dx dy dz] ^T, B is matrix of coefficients;

In above error equation, suppose to have one non-ly at a certain website cycle slip to take place with reference to satellite, then can cause rough error, if with reference to satellite cycle slip has taken place, then this cycle slip will be brought into all error equations, thereby produces Systematic Errors, and (7) formula is added systematic parameter can be got:

$V_{A,B}^{i,j}=\mathrm{Bx}+\mathrm{Ey}-L_{A,B}^{i,j}---\left(8\right)$

Wherein, y=[y ₁, y ₂] ^TBe respectively with reference to the cycle slip in satellite L1 and the L2 carrier wave observed reading;

Suppose in a certain epoch, traced into n satellite, and in previous epoch, the integer ambiguity of this n satellite is all fixing, the error equation group that then can obtain this epoch is:

$\underset{(n-1)\&times;1}{V_{L1}}=\underset{(n-1)\&times;3}{B}\underset{3\&times;1}{x}+\underset{(n-1)\&times;1}{E_{L1}}\underset{1\&times;1}{y_1}-\underset{(n-1)\&times;1}{L_{L1}}$ $\left(9\right)$

$\underset{(n-1)\&times;1}{V_{L2}}=\underset{(n-1)\&times;3}{B}\underset{3\&times;1}{x}+\underset{(n-1)\&times;1}{E_{L2}}\underset{1\&times;1}{y_2}-\underset{(n-1)\&times;1}{L_{L2}}$

Be respectively the error equation on L1 and the L2 carrier wave;

According to Ionosphere Residual Error method cycle slip result of detection, real-time two difference carrier wave observed readings are divided into four groups, first group of pair error equation that poor observation equations constitute for the L1 of no cycle slip used L ₁₁Expression, weights are P ₁₁, second group is pair error equation that the difference observation equations constitute that has the L1 of cycle slip, uses L ₂₁Expression, weights are P ₂₁, the 3rd group of error equation for two difference observation equations formations of the L2 of no cycle slip used L ₁₂Expression, weights are P ₁₂, the 4th group is pair error equation that the difference observation equations constitute that has the L2 of cycle slip, uses L ₂₂Expression, weights are P ₂₂Then can get error equation is:

$\left.\begin{array}{c}{V}_{11}=B_{11}x+E_{11}{y}_1-l_{11}\\ V_{21}=B_{21}x+E_{21}{y}_1-l_{21}\\ V_{12}=B_{12}x+E_{12}{y}_2-l_{12}\\ V_{22}=B_{22}x+E_{22}{y}_2-l_{22}\end{array}\right\}$ $P=\left(\begin{array}{cccc}{P}_{11}& O& O& O\\ O& P_{21}& O& O\\ O& O& P_{12}& O\\ O& O& O& P_{22}\end{array}\right)---\left(10\right)$

P is weight matrix, the error equation that above-mentioned four groups of two difference observation equations are constituted is further divided into two classes, the first kind is the L1 of no cycle slip and pair error equation that the difference observation equations constitute of L2, second class is to have the L1 of cycle slip and pair error equation that the difference observation equations constitute of L2, and then following formula can be expressed as:

$\left.\begin{array}{c}V1=B_{1}x+E_{1}y-l_1\\ V2=B_{2}x+E_{2}y-l_2\end{array}\right\}$ $P=\left(\begin{array}{cc}{P}_1& O\\ O& P_2\end{array}\right)---\left(11\right)$

Wherein:

$V1=\left(\begin{array}{c}{V}_{11}\\ V_{12}\end{array}\right)$ $V2=\left(\begin{array}{c}{V}_{21}\\ V_{22}\end{array}\right),$ $B_1=\left(\begin{array}{c}{B}_{11}\\ B_{12}\end{array}\right)$ $B_2=\left(\begin{array}{c}{B}_{21}\\ B_{22}\end{array}\right),$ $l_1=\left(\begin{array}{c}{l}_{11}\\ l_{12}\end{array}\right)$ $l_2=\left(\begin{array}{c}{l}_{21}\\ l_{22}\end{array}\right)$

$E_1=\left(\begin{array}{c}{E}_{11}\\ E_{12}\end{array}\right)$ $E_2=\left(\begin{array}{c}{E}_{21}\\ E_{22}\end{array}\right),$ $y=\left(\begin{array}{c}{y}_1\\ y_2\end{array}\right),$ $P_1=\left(\begin{array}{cc}{P}_{11}& O\\ O& P_{12}\end{array}\right),$ $P_2=\left(\begin{array}{cc}{P}_{21}& O\\ O& P_{22}\end{array}\right)$

X is rover station coordinate correction parameter, and y is with reference to the cycle slip in satellite L1 and the L2 carrier wave observed reading;

3) error equation that constitutes with the two difference of first kind observation equation carries out parameter estimation

Exist the L1 of cycle slip and two difference observation equations of L2 to handle as the observation equation that has rough error second class, then suppose P ₂=0, also namely in resolving, cut little ice, then can directly use the first kind not have the L1 of cycle slip and the carrier wave observation equation of L2 resolves x and y parameter, press criterion of least squares V ^TPV=min can get normal equation:

$\left(\begin{array}{cc}{B}_1^T{P}_1{B}_1& B_1^T{P}_1{E}_1\\ E_1^T{P}_1{B}_1& E_1^T{P}_1{E}_1\end{array}\right)\left(\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right)=\left(\begin{array}{c}{B}_1^T{P}_1{l}_1\\ E_1^T{P}_1{l}_1\end{array}\right)---\left(12\right)$

Order $N_{11}=B_1^T{P}_1{B}_1,$ $N_{12}=N_{21}^T=B_1^T{P}_1{E}_1,$ $N_{22}=E_1^T{P}_1{E}_1,$ $W_1=B_1^T{P}_1{l}_1,$ $W_2=E_1^T{P}_1{l}_1,$ Then following formula can be written as:

$\left(\begin{array}{cc}{N}_{11}& N_{12}\\ N_{21}& N_{22}\end{array}\right)\left(\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right)=\left(\begin{array}{c}{W}_1\\ W_2\end{array}\right)---\left(13\right)$

Got by the piecemeal formula of inverting

$\left(\begin{array}{c}\hat{x}\\ \hat{y}\end{array}\right)=\left(\begin{array}{cc}{N}_{11}^{-1}+N_{11}^{-1}{N}_{12}{M}^{-1}{N}_{21}{N}_{11}^{-1}& -N_{11}^{-1}{N}_{12}{M}^{-1}\\ -M^{-1}{n}_{21}{N}_{11}^{-1}& M^{-1}\end{array}\right)\left(\begin{array}{c}{W}_1\\ W_2\end{array}\right)---\left(14\right)$

In the formula

$M=N_{22}-N_{21}{N}_{11}^{-1}{N}_{12}---\left(15\right)$

If do not have cycle slip with reference to satellite, then

$\hat{x}=N_{11}^{-1}{W}_1---\left(16\right)$

Valuation according to systematic error Obtain with reference to the cycle slip value on satellite L1 and the L2 carrier wave be:

$\left\{\begin{array}{c}{\mathrm{Slip}}_1=\frac{{\hat{y}}_1}{{\mathrm{\&lambda;}}_1}\\ {\mathrm{Slip}}_2=\frac{{\hat{y}}_2}{{\mathrm{\&lambda;}}_2}\end{array}\right.---\left(17\right)$

Slip wherein ₁, Slip ₂Represent the cycle slip with reference to satellite L1 and L2 carrier phase observation data respectively;

4) non-calculating with reference to satellite cycle slip reparation value

Will

And

Bring V2=B into ₂X+E ₂Y-l ₂, can get corresponding non-cycle slip value with reference to satellite and be:

$\left\{\begin{array}{c}{\mathrm{slip}}_1=\frac{V_{21}}{{\mathrm{\&lambda;}}_1}\\ s{\mathrm{lip}}_2=\frac{V_{22}}{{\mathrm{\&lambda;}}_2}\end{array}\right.---\left(18\right)$

Slip wherein ₁, slip ₂Represent non-cycle slip with reference to satellite L1 and L2 carrier phase observation data respectively;

5) determine the base station of cycle slip generation and the reparation of cycle slip

After the cycle slip satellite in detecting baseline, occurring, determine to occur the base station of cycle slip according to two baselines of base station correspondence in the triangulation network, triangulation network ABC, three baseline A → B are arranged, B → C, C → A, if detected cycle slip among baseline A → B, also there is cycle slip in baseline B → C, and the equal and opposite in direction of cycle slip, opposite in sign, then cycle slip appears on the B of base station, and resolving as reference point in baseline according to the base station still is the sign that pour point resolves to judge cycle slip, in a baseline, if cycle slip occurs on the reference point, then the cycle slip result is just in time opposite with the residual values symbol, if occur on the pour point, then the cycle slip result is identical with the residual values symbol, in baseline A → B, the B point is as pour point, so the cycle slip value that baseline A → B is detected is as the cycle slip reparation value of base station B; Same method is according to the cycle slip of baseline C → A and baseline A → B reparation base station A, according to the cycle slip value of baseline B → C and baseline C → A reparation base station C.

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