CN101526608A - Method for combining tri-band code wave pseudorange with carrier phase in satellite navigation and positioning - Google Patents

Abstract

The invention provides a method for combining a tri-band code wave pseudorange with a carrier phase in satellite navigation and positioning, relating to the technology of the satellite navigation and positioning. The method comprises the following steps of: using terminal equipment to receive the satellite downlink three code wave pseudoranges and the carrier phase; obtaining a code wave combined pseudorange and a carrier combined phase according to an integral coefficient combination, selecting a positive combination coefficient or a negative combination coefficient according to the principle that the time which is influenced by an ionosphere for closing to and solving ambiguity is short, and fast solving the ambiguity by the positive combination or the negative combination; and according to the principle that an ionosphere influence in a satellite-ground distance can be fast removed, selecting the combination coefficient to set up a double positive combination carrier wave which is used for removing the ionosphere influence in the satellite-ground distance, and using more than four (including four) pseudorange observation equations to solve the real position of the receiving terminal. The invention can set up a new system which not only can realize the high dynamic state of the code wave but also has the high precision of the carrier wave.

Description

The combined method of three frequency sign indicating number ripple pseudoranges and carrier phase in the satellite navigation location

Technical field

The present invention relates to satellite navigation positioning technical field, is three combined methods of sign indicating number ripple pseudoranges and carrier phase frequently in carrier wave measuring method, the especially satellite navigation in the navigator fix.

Background technology

In Global Navigation Satellite System (GNSS), because the error of satellite clock, receiver clock and radio signal are through the delay in ionosphere and the troposphere, the actual distance of measuring and satellite have certain difference to the geometric distance of receiver, and the distance of practical measurement is called pseudorange.Can highly dynamically find range with the sign indicating number wave measurement, but precision is not high, receiving terminal can only be realized the pseudo range measurement precision of 1-10 rice magnitude.Because the wavelength ratio ranging code wavelength of carrier wave is wanted much shorter, therefore, utilize the carrier wave measuring technique can realize the precise navigation location.The complete cycle number of satellite carrier signal phase change on travel path can't be directly measured in carrier phase observation, has the complete cycle uncertain problem, finds the solution chronic (several hours, several days even longer) of integer ambiguity usually.Handling on the carrier phase basis of two survey stations in real time, real time dynamic measurement (RTK) technology is arisen at the historic moment.The ultimate principle of RTK location technology is that base station sends its observed reading and survey station coordinate information to rover station together by data chainning.Rover station not only by the data of data chainning reception from base station, also will be gathered the GNSS observation data, and forms the difference observed reading and handle in real time in system.This location technology is based on the real-time dynamic positioning technology of carrier phase observation data, and it can provide the three-dimensional localization result of survey station in specified coordinate system in real time, and reaches the decimeter grade precision.But this technology can only be confined to use in certain zone, and general application region is about about the 15-20 kilometer.

The rapid solving of integer ambiguity was the difficult point and the focus of domestic and international GNSS expert's research always during carrier wave was measured, and the method for integer ambiguity occurred finding the solution such as double frequency pseudorange method, THE AMBIGUITY FUNCTION METHOD USED, least square search procedure, the blur level covariance tactical deployment of troops etc.Double frequency pseudorange method is the physical combination realization ambiguity resolution by two carrier frequencies, and principle is simple and easy, is easy to use.In addition several to ask the method for integer ambiguity be a kind of algorithm, is mostly that it is very slow to find the solution speed from mathematical algorithm improved method in addition.

Adopt carrier phase and sign indicating number ripple pseudorange to make up the complete cycle number of finding the solution in the carrier wave measurement, for dual-frequency system, two carrier frequencies " add " " the narrow lane " and " wide lane " of " subtracting " formation though combination can realize ionospheric elimination fully, when but the carrier wave of determining " narrow lane " is measured integer ambiguity, consume for up to dozens of minutes, cause the real-time of carrier phase measurement relatively poor, can not satisfy the needs of high Kinematic Positioning.Carry out in the observation process at the receiver tracking Navsat,, recover also very slow for issuable complete cycle saltus step phenomenon.This all will make data processing complexization, and this method is difficult to adapt to high dynamic application.

Hatch (1996) and Harris (1997) have tentatively inquired into three and have utilized sign indicating number ripple pseudorange and carrier phase in conjunction with finding the solution the method for integer ambiguity in the satellite navigation system frequently.1999, the U.S. announced will set up the 3rd civil signal on the novel work satellite of GPS.In recent years, the research of three frequency sign indicating number ripple pseudoranges and carrier phase combination becomes the new forward position of GNSS carrier wave measuring technique development.Three present combinations frequently are confined to not have the influence combination of single order ionosphere, and available combination is considerably less.The greatest weakness of combination is that noise is exaggerated in combination, suppress noise, and just only reliable long-time integration could be realized, has seriously limited the high dynamic application of system.Therefore, high dynamic, high-precision carrier wave measuring method is a problem demanding prompt solution in the current satellite navigation location in the wide area.

Summary of the invention

The objective of the invention is to overcome the defective of prior art, three combined methods of sign indicating number ripple pseudoranges and carrier phase are frequently disclosed in a kind of satellite navigation, in satellite navigation, be applicable to three the choosing of three carrier frequencies in the satellite navigation systems frequently, more approaching according to ionosphere influence, can the rapid solving integer ambiguity, can reduce principle such as ionospheric delay error fast and select combination coefficient structure " just " combination, " bear " combination and two " just " combined carriers, with realize wide area, high dynamically, high precision, need not the navigator fix of difference support.

For achieving the above object, technical solution of the present invention is:

Three combined methods of sign indicating number ripple pseudoranges and carrier phase frequently in a kind of satellite navigation location, be applicable to wide area, high dynamically, high precision, need not the navigator fix that difference is supported; It may further comprise the steps:

A. terminal device receives three descending sign indicating number ripple pseudoranges of Navsat and carrier phase;

Principle b. approaching by the ionosphere influence in receiving terminal inside, that find the solution integer ambiguity time weak point is selected combination coefficient, obtains yard a ripple combination pseudorange and a carrier combination phase place; " just ", " bearing " according to the ionosphere influence define " just " combination and " bearing " combination;

C. utilize b) " just " combination or " bear " of obtaining in the step make up the rapid solving integer ambiguity;

D. in receiving terminal inside, select for use combination coefficient to make up two " just " combined carriers, adopt the quick ionosphere influence of eliminating in the star ground distance of this pair " just " combination according to the principle that can reduce ionosphere delay error fast;

E. utilize c) step and d) go on foot four (containing) the above pseudorange observation equation of eliminating the ionosphere influence that obtains, resolve the actual position of receiving terminal.

Described method in its described a) step, is used for choosing of three carrier frequencies of three frequency satellite navigation systems, and these three carrier frequencies need more evenly to distribute, and can reduce ionospheric delay error fast.

Described method, its described b) in the step, the ionosphere of combinational code ripple and combined carriers influences more approaching, as to find the solution integer ambiguity time weak point in " just " combination or " bearing " combination, improves the high dynamic performance of system.

Described method, its described d) in the step, two " just " combined carriers can be eliminated the ionosphere influence in the star ground distance fast.

The combined method of three frequency sign indicating number ripple pseudoranges and carrier phase in the satellite navigation of the present invention location is to realize high dynamic, high-precision satellite navigation location in wide scope.The inventive method need not various differential technique supports, when three carrier frequencies more evenly distribute, can significantly reduce ionosphere delay error fast, thereby improves the high dynamic performance of three frequency satellite navigation systems.

Description of drawings

Fig. 1 is the 3rd synoptic diagram that carrier frequency is chosen of the inventive method; Wherein: horizontal ordinate is the 3rd carrier frequency of selecting for use, and ordinate is for to be reduced to 1 centimetre of time that is consumed to ionosphere delay error.

Embodiment

The combined method of a kind of three frequency sign indicating number ripple pseudoranges of the present invention and carrier phase is utilized three frequency sign indicating number ripple pseudoranges and carrier phase to form " just " and is made up or " bearing " combination the rapid solving integer ambiguity.Simultaneously because available " just ", " bearing " number of combinations of being invented are a lot, can select can the rapid solving integer ambiguity combination.Two " just " combined carriers among the present invention can be eliminated the ionosphere influence in the star ground distance fast, and realization is high dynamically, the precise navigation location.Ask star ground apart from the time, in order reduce to eliminate the needed time of ionosphere delay error significantly, the inventive method points out when three carrier frequencies evenly distribute, to have the shortest processing time, can significantly improve the high dynamic performance of satellite navigation system.

The specific embodiment of the present invention is as follows:

1. the integer ambiguity of rapid solving combined carriers

The multifrequency carrier wave of satellite navigation can make up and obtain the virtual portfolio ripple, and the combination pseudorange of the combinatorial phase of multicarrier and many yards ripples can be expressed as:

Φ _c＝Φ _l，m，n＝l·Φ ₁+m·Φ ₂+n·Φ ₃+ ......(1)

$R_c=R_{l,n,m}={\mathrm{\λ}}_c(l\·\frac{R_1}{{\mathrm{\λ}}_1}+m\·\frac{R_2}{{\mathrm{\λ}}_2}+n\·\frac{R_3}{{\mathrm{\λ}}_3}+......)---\left(2\right)$

Wherein, Φ _i, λ _iBe respectively the phase place of i carrier wave and wavelength (i=1,2,3 ...), R _iBe respectively i the sign indicating number ripple pseudorange (i=1,2,3 ...), l, m, n are integer arbitrarily, Φ _cAnd R _cBe respectively combined carriers and combinational code ripple.The frequency f of combined carriers _cAnd wavelength X _cBe respectively:

$f_c=l\·f_1+m\·f_2+n\·f_3+......,{\mathrm{\λ}}_c=\frac{c}{f_c}=1/(\frac{l}{{\mathrm{\λ}}_1}+\frac{m}{{\mathrm{\λ}}_2}+\frac{n}{{\mathrm{\λ}}_3}+......)---\left(3\right)$

Wherein, c is the light velocity in the vacuum, f _iBe carrier wave Φ _iFrequency (i=1,2,3 ...).For simplicity, regulation f ₁＞f ₂＞f ₃＞

If carrier wave Φ _iInteger ambiguity be designated as N _i(i=1,2,3 ...), the integer ambiguity N of combined carriers then _cFor:

N _c＝l·N ₁+m·N ₂+n·N ₃+...... (4)

Carrier wave Φ ₁With sign indicating number ripple R ₁Single order ionosphere influence be designated as dI respectively _{Φ, 1}, dI _{R, 1}, combined carriers Φ then _c, combinational code ripple R _cIonosphere influence be respectively (is unit with rice [m]):

${\mathrm{dI}}_{\mathrm{\Φ},c}\left[m\right]=(\frac{l}{f_1}+\frac{m}{f_2}+\frac{n}{f_3}+......)\·\frac{f_1^2}{f_c}\·{\mathrm{dI}}_{\mathrm{\Φ},1}\left[m\right]---\left(5\right)$

${\mathrm{dI}}_{R,c}\left[m\right]=(\frac{l}{f_1}+\frac{m}{f_2}+\frac{n}{f_3}+......)\·\frac{f_1^2}{f_c}\·{\mathrm{dI}}_{R,1}\left[m\right]---\left(6\right)$

If with all numbers [cycle] is unit, have:

${\mathrm{dI}}_{\mathrm{\Φ},c}=(\frac{l}{f_1}+\frac{m}{f_2}+\frac{n}{f_3}+...)\·\frac{1}{{\mathrm{\λ}}_1}\·{\mathrm{dI}}_{\mathrm{\Φ},1}\left[\mathrm{cycle}\right]---\left(7\right)$

${\mathrm{dI}}_{R,c}=(\frac{l}{f_1}+\frac{m}{f_2}+\frac{n}{f_3}+...)\·\frac{1}{{\mathrm{\λ}}_1}\·{\mathrm{dI}}_{R,1}\left[\mathrm{cycle}\right]---\left(8\right)$

It should be noted that dI _{Φ, 1}[m] (dI _{Φ, 1}[cycle]) and dI _{R, 1}[m] (dI _{R, 1}[cycle]) opposite in sign, equal and opposite in direction.So, dI _{Φ, c}With dI _{R, c}Opposite symbol is also arranged.

If the phase measurement error of each carrier wave is s, then the noise of combined carriers amplifies s _cFor:

$s_c=\sqrt{l^2+m^2+n^2+......}\·s---\left(9\right)$

The noise s of combinational code ripple _{Code, c}For:

$s_{\mathrm{code},c}=\sqrt{\frac{l^2}{{\mathrm{\λ}}_1^2}\·s_{\mathrm{code},1}^2+\frac{m^2}{{\mathrm{\λ}}_2^2}\·s_{\mathrm{code},2}^2+\frac{n^2}{{\mathrm{\λ}}_3^2}\·s_{\mathrm{code},3}^2+......}---\left(10\right)$

In the formula, s _{Code, 1}, s _{Code, 2}, s _{Code, 3}... be respectively a yard ripple R ₁, R ₂, R ₃... the measurement noise.

When utilizing a plurality of carrier combination, the influence of the ionosphere of combinational code ripple and combined carriers is widely different.Two definition among the present invention are below described:

(1) " just " combination: in the multifrequency combined system, carrier combination no matter, still sign indicating number ripple combination, the symbol of its ionosphere single order influence is " just ", promptly locates " hysteresis " state.

(2) " bear " combination: in the multifrequency combined system, carrier combination no matter, still sign indicating number ripple combination, the symbol of its ionosphere single order influence is " bearing ", promptly locates " in advance " state.

If ionospheric single order influence is zero, be called " zero " combination.It is exactly a kind of " zero " combination that three common frequencies do not have the ionosphere combination.

Further rewriting formula (1) and (2), " just " combinational code ripple R ₊Observed reading be:

$R_{+}={\mathrm{\ρ}}^{*}+I_{R_{+}}---\left(11\right)$

In the formula, ρ ^*It is the distance terms that comprises all and frequency-independent error.

Be combinational code ripple R ₊Single order ionosphere influence.Correspondingly, " just " combined carriers Φ ₊Satisfy:

$({\mathrm{\Φ}}_{+}+N_{+}){\mathrm{\λ}}_{{\mathrm{\Φ}}_{+}}={\mathrm{\ρ}}^{*}+I_{{\mathrm{\Φ}}_{+}}---\left(12\right)$

In the formula, N ₊,

With

Be respectively combined carriers Φ ₊Integer ambiguity, wavelength and the influence of single order ionosphere.

If $I_{R_{+}}=I_{{\mathrm{\Φ}}_{+}},$ By formula (11) and formula (12), have

From R _cIn can find the numerical approximation of ionosphere influence to equate " just " combinational code ripple R ₊Thereby, find the solution complete cycle and count N ₊.

Find the solution N ₊Unit's number during the measurement that needs, mainly by

And Φ ₊Two-part measuring error decision.If combinational code ripple R ₊The combination noise be n ₊[m], then first

Noise be $\mathrm{\Δ}{\mathrm{\φ}}_{R+}=n_{+}/{\mathrm{\λ}}_{{\mathrm{\Φ}}_{+}}\left[\mathrm{cycle}\right];$ Second portion Φ ₊The measurement noise be Δ φ ₊[cycle]; The resultant error ΔΦ of formula (13) then ₊For:

${\mathrm{\Δ\Φ}}_{+}=\sqrt{{\left({\mathrm{\Δ\φ}}_{R,+}\right)}^2+{\left(\mathrm{\Δ}{\mathrm{\φ}}_{+}\right)}^2}---\left(14\right)$

In order to find the solution integer ambiguity, the influence of resultant error should be less than half cycle, simultaneously in order to ensure 100% success ratio, to the requirement of resultant error is $3\mathrm{\&sigma;}<\frac{1}{2}\left[\mathrm{cycle}\right].$ At this moment, need to measure at least (6 Φ ₊) ²Inferior.In formula (13), the ionosphere influence has also kept the part deviation, and this causes by the ionosphere amplification coefficient is unequal, general in the method this coefficients deviation is less than 0.0001, if get the influence of C-band ionosphere less than 20 meters, then above-mentioned deviation only has less than 2 millimeters, and this deviation is designated as ε _I, therefore, when when asking integer ambiguity, considering integral time, should increase this ε _IInfluence, need to measure

Inferior, could successfully find the solution complete cycle and count N ₊.

In fact, R ₊With Φ ₊To influence the combination that numerical approximation equates very many in ionosphere, it is right therefrom to select the some groups of basic combinations that equate of ionosphere influence, approaching according to ionosphere influence, find the solution complete cycle and count short principle of time, select combination coefficient, the integer ambiguity of rapid solving combined carriers.By above-mentioned derivation as can be known, this method is applicable to " bearing " combination too.

2. eliminate the ionosphere influence in the star ground distance fast, realize high dynamic, high-precision satellite navigation location

When only considering that the ionosphere single order influences, to combined carriers Φ _C1And Φ _C2, have

${\mathrm{\&rho;}}^{*}=(N_{c1}+{\mathrm{\&Phi;}}_{c1}){\mathrm{\&lambda;}}_{c1}+(\frac{l_{c1}}{f_1}+\frac{m_{c1}}{f_2}+\frac{n_{c1}}{f_3}+......)\&CenterDot;\frac{f_1^2}{f_{c1}}\&CenterDot;{\mathrm{dI}}_{\mathrm{\&Phi;},1}---\left(15\right)$

${\mathrm{\&rho;}}^{*}=(N_{c2}+{\mathrm{\&Phi;}}_{c2}){\mathrm{\&lambda;}}_{c2}+(\frac{l_{c2}}{f_1}+\frac{m_{c2}}{f_2}+\frac{n_{c2}}{f_3}+......)\&CenterDot;\frac{f_1^2}{f_{c2}}\&CenterDot;{\mathrm{dI}}_{\mathrm{\&Phi;},1}---\left(16\right)$

In the formula, ρ ^*Be the distance terms that comprises all and frequency-independent error, N _C1, N _C2Be respectively combined carriers Φ _C1, Φ _C2The complete cycle number, dI _{Φ, 1}Be carrier wave Φ ₁Single order ionosphere influence, (l _C1, m _C1, n _C1...), (l _C2, m _C2, n _C2...) be respectively Φ _C1, Φ _C2Combination coefficient, $(\frac{l_{c1}}{f_1}+\frac{m_{c1}}{f_2}+\frac{n_{c1}}{f_3}+......)\&CenterDot;\frac{f_1^2}{f_{c1}},$ $(\frac{l_{c2}}{f_1}+\frac{m_{c2}}{f_2}+\frac{n_{c2}}{f_3}+......)\&CenterDot;\frac{f_1^2}{f_{c2}}$ Be designated as I respectively _C1, I _C2, then formula (15) and formula (16) can be rewritten as:

ρ ^*＝(N _c1+Φ _c1)λ _c1+I _c1·dI _Φ，1 (17)

ρ ^*＝(N _c2+Φ _c2)λ _c2+I _c2·dI _Φ，1 (18)

Further, have

Following formula substitution (17) formula, can obtain ρ ^*.

ρ ^*Measuring error by combined carriers Φ _C1And Φ _C2Measuring error cause, therefore, when selecting two " just " combined carriers, should choose I _C1And I _C2Gap is big as far as possible, Φ _C1And Φ _C2The error little combination of trying one's best, like this, can eliminate the influence of ionosphere delay error in the short period of time, improve the measuring accuracy of star ground distance, and find the solution the coordinate of receiving terminal by the pseudorange observation equation more than four (containing).

In first on formula (20) right side, Φ _C1For the direct combination of the measured value of carrier wave obtains; Complete cycle is counted N _C1Can obtain in a short period of time, static initialization is obtained N _C1After, if cycle slip, N do not take place _C1Be constant; When cycle slip takes place, also can calculate N at short notice _C1.

Second on formula (20) right side influences part for ionosphere, ionosphere delay error in the zone changes unhappy usually, can adopt smoothing processing, after solving the ionosphere influence during static initialization, adopt the method for slip treated, can obtain the output more than tens times in one second, realize high dynamic navigator fix.When cycle slip takes place when, reject the exceptional value that occurs, adopt former measured value to make smoothing processing, utilize four (containing) above pseudorange observation equation of having eliminated the ionosphere influence in conjunction with normal measured value, resolve the actual position of receiving terminal, realize high dynamic, precise navigation location.

3. three selection principles of three carrier frequencies in the satellite navigation systems frequently

A satellite navigation system is at the establishment initial stage, perhaps for having the satellite navigation system of changing frequently, changing the magnitude characteristics, can select carrier frequency in allowed limits, the combined method of three frequency sign indicating number ripple pseudoranges and carrier phase in a kind of satellite navigation of the present invention location, when three navigation frequencys in the three frequency satellite navigation systems that are suitable for more evenly distribute, can reduce the influence of ionosphere delay error very fast, improve the high dynamic performance of system.

With regional positioning system CAPS is example.At present, two carrier frequencies of CAPS employing are 405f ₀And 374f ₀(reference frequency f ₀=10.23MHz), serve as the two ends frequency of intending making up three frequency systems with them, carry out l-G simulation test at choosing of the 3rd frequency, and finally choose 389f ₀Be the 3rd carrier frequency.Fig. 1 has provided and has concluded the principle schematic of deriving.Among the figure: 405f ₀And 374f ₀Be the maximum frequency and the minimum frequency of three frequency systems, the 3rd carrier frequency is at 405f ₀And 374f ₀Between choose, calculate respectively star ground apart from ionosphere delay error be reduced to the interior time (remainder error of setting is 1 centimetre) that is consumed of allowed band here.When the 3rd frequency is intermediate frequency 389f ₀The time, when adopting two " just " combined carriers deion layers influence the time of consumption the shortest, one minute with the interior influence that just can reduce ionosphere delay error (consuming time be about 35 seconds), and try to achieve star ground distance fast.The carrier combination of selecting for use is (409f ₀, 387f ₀, 366f ₀) time, can be in 15 seconds in the hope of the star ground distance of no ionosphere influence.After considering additional navigation frequency range (5010-5030MHz), select carrier combination (491f for use ₀, 405f ₀, 374f ₀) can shorten to the time of reducing ionosphere delay error in 0.3 second.As seen, this frequency distribution principle can increase substantially the high dynamic performance of satellite navigation system.

Above-mentioned consuming time just having provided during the static initialization, the time of eliminating ionosphere delay error.As previously mentioned, the ionosphere delay error in the zone changes unhappy usually, can adopt smoothing processing.The static initialization process just can reduce the influence of ionosphere delay error after finishing in a short period of time, finds the solution the star ground distance of eliminating the ionosphere influence, and realization is high dynamically, the precise navigation location.

Claims (4)

1. three combined methods of sign indicating number ripple pseudoranges and carrier phase frequently in the satellite navigation location, be applicable to wide area, high dynamically, high precision, need not the navigator fix that difference is supported; It is characterized in that, may further comprise the steps:

A. terminal device receives three descending sign indicating number ripple pseudoranges of Navsat and carrier phase;

B. define " just " combination and " bearing " combination in inner combinational code ripple pseudorange of terminal device and carrier phase, and according to " just ", " bearing " of ionosphere influence;

C. utilize b) " just " combination or " bear " of obtaining in the step make up the rapid solving integer ambiguity;

D. in two " just " combined carriers of receiving terminal internal build, adopt the quick ionosphere influence of eliminating in the star ground distance of this pair " just " combination;

E. utilize c) step and d) go on foot four (containing) above pseudorange observation equation of having been eliminated the ionosphere influence, resolve the actual position of receiving terminal.

2. the method for claim 1 is characterized in that, in the described a) step, is used for choosing of three carrier frequencies of three frequency satellite navigation systems, and these three carrier frequencies need more evenly to distribute, and can reduce ionospheric delay error fast.

3. the method for claim 1, it is characterized in that, described b) in the step, the ionosphere influence time more approaching, that find the solution integer ambiguity of combinational code ripple and combined carriers shortens widely in " just " combination or " bearing " combination, has improved the high dynamic performance of system.

4. the method for claim 1 is characterized in that, described d) in the step, two " just " combined carriers can be eliminated the ionosphere influence in the star ground distance fast.

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