CN102680985B - Phase discrimination method for suppressing multipath signals in global navigation satellite system - Google Patents

Abstract

The invention discloses a phase discrimination method for suppressing multipath signals in the global navigation satellite system and belongs to the technical field of global navigation satellite systems. The method includes: receiving GNSS (global navigation satellite system) signals containing the multipath signals and performing analog-digital conversion after down-conversion is performed to generate low-intermediate frequency signals; and performing carrier stripping for the GNSS signals subjected to the analog digital conversion to obtain signals of a path I and a path Q and performing code stripping for the signals of the path I and the path Q. In a code tracking loop during GNSS signal processing, after cross-correlation power of the multipath signals is obtained, the multipath signals can be suppressed effectively by adopting the phase discrimination method based on precise TK (teager-kaiser) sample intervals, and precision improvement of a GNSS receiver can be achieved.

Description

The phase detecting method that suppresses multipath signal in GLONASS (Global Navigation Satellite System)

Technical field

The present invention relates to GLONASS (Global Navigation Satellite System) technical field, particularly a kind of phase detecting method that suppresses multipath signal in GLONASS (Global Navigation Satellite System).

Background technology

In the application of GLONASS (Global Navigation Satellite System) (GNSS, Global Navigation Satellite System), the raising of receiver performance is the prerequisite of promotion and application industry.For improving the receptivity of navigation signal, need filtering via different reflectings surface or through multiple reflections and the multipath signal coming.In the fields such as mapping, choking coils, the narrow technology such as relevant of adopting are suppressed multipath signal more; And in fields such as remote sensing, adopt the special left-handed antenna that receives reflected signal to process the reflected signal receiving, and then remote sensing is carried out in ocean, land etc.

Multipath is one of main source of error in GNSS, although developed multiple multipath, reduces and delay estimation technology, and the application of short delay multipath in high precision, indoor and intensive urban environment is still serious.In these regions, the quantity in medium path is not only many, and has the caused dynamic of natural forms by compact arranged fixing and mobile reflection, for example receiving antenna people, plant, building structure and vehicle around.Therefore, need a kind of high-precision disposal route effectively to suppress GNSS multipath signal, and then reach the effect that improves GNSS receiver precision.

Summary of the invention

In view of this, the object of the present invention is to provide a kind of phase detecting method that suppresses multipath signal in GLONASS (Global Navigation Satellite System), for effectively suppressing GNSS multipath signal, reach the effect that improves GNSS receiver precision.

The invention provides a kind of phase detecting method that suppresses multipath signal in GLONASS (Global Navigation Satellite System), comprising:

The global navigation satellite system GNSS signal that reception comprises multipath signal, carries out down coversion and generates after Low Medium Frequency signal, carries out analog to digital conversion; GNSS signal after analog to digital conversion is carried out to carrier wave and peel off, obtain the signal on I road and Q road, described I road and Q road signal are carried out to code and peel off.

The present invention proposes a kind of phase detecting method that suppresses multipath signal in GNSS signal, in the code tracking loop of GNSS signal processing, obtain after the simple crosscorrelation power of multipath signal, the phase detecting method of employing based on accurate TK sampling interval, multipath signal can be effectively suppressed, the object that improves GNSS receiver precision can be reached.

Accompanying drawing explanation

Fig. 1 is the structural principle schematic diagram of GNSS signal receiver in the embodiment of the present invention;

The phase detecting method process flow diagram that suppresses multipath signal in GNSS that Fig. 2 provides for the embodiment of the present invention;

Fig. 3 carries out to I road and Q road signal the circuit theory schematic diagram that code is peeled off in the embodiment of the present invention;

Fig. 4 is the code tracking error envelope diagram that uses TK-EML5 phase detector in the embodiment of the present invention;

Fig. 5 is the code tracking error envelope diagram that uses EML phase detector in the embodiment of the present invention.

Embodiment

For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, the present invention is described in further detail.

The embodiment of the present invention has proposed a kind of phase detecting method that suppresses multipath signal in GNSS signal, in the code tracking loop of GNSS signal processing, obtain after the simple crosscorrelation power of multipath signal, the phase detecting method of employing based on accurate TK sampling interval, multipath signal can be effectively suppressed, the object that improves GNSS receiver precision can be reached.

As shown in Figure 1, GNSS signal receiver is mainly comprised of antenna, radio-frequency front-end, high-speed AD converter, FPGA correlator, DSP digital signal processor and storer.The method of reseptance process flow diagram of the high-precision GNSS signal that Fig. 2 provides for the present embodiment, comprising:

Step 201, antenna reception GNSS signal.The signal that GNSS receiver antenna receives comprises direct signal and multipath signal, and direct signal is from satellite, directly to pass to the signal of receiver; Multipath signal is that antenna is except receiving from GNSS satellite launch the electromagnetic wave signal by rectilinear propagation, also may receive one or more by this electromagnetic wave the signal after clutter reflections around, and each reflected signal may be through once or arrive antenna after multiple reflections.

Step 202, the GNSS signal that comprises multipath signal enter radio-frequency front-end and carry out down coversion, generate Low Medium Frequency signal, and carry out analog to digital conversion.

Step 203, the GNSS signal after analog to digital conversion carry out carrier wave to be peeled off, and obtains the signal on I road and Q road.Because GNSS signal is in generative process, first be that navigation information and C/A code are modulated (multiplying each other), the information generating is modulated with carrier wave again, so will carry out demodulation (peeling off of carrier wave is exactly the demodulation to carrier wave in fact) to carrier wave after receiving, to will obtain the signal on I, Q road in the demodulating process of carrier wave because of phase relation.

Step 204, I road and Q road signal are carried out to code peel off.Referring to Fig. 3, code is peeled off specifically and is comprised the following steps:

Step 2041, by C/A code generator, copy one and there is the C/A coded signal of same phase with I road and Q road signal, and the distance obtaining between adjacent two-way C/A by delay is 5 road C/A codes of 1/4 chip, respectively: Very Early road, Early road, Prompt road, Late road, Very Late road.

Step 2042,5 road C/A codes and described I road and Q road signal are carried out related calculation.Specifically comprise:

The signal receiving due to GNSS receiver comprises direct signal and multipath signal, ignores that in the situation of noise, (s (t) is GNSS signal, s _d(t), s _m(t) represent respectively direct signal and the multipath signal in GNSS signal):

s(t)＝s _d(t)+s _m(t)

＝Ag[(1+ξ)t-γ]exp{t[(ω _d+ω _c)t+φ ₁]}+αAg[{(1+ξ)t-γ-Δτ _m]exp{t[(ω _d+ω _c)t+φ ₁+β]}

（1）

Wherein, ω _ccarrier frequency, ω wherein _dfor Doppler shift, φ ₁for carrier phase.A is the amplitude of GNSS direct signal, and g (t) is ± 1, represents the value of C/A code, and α is the ratio of multipath signal amplitude and direct signal amplitude, Δ τ _mtime delay for the relative direct signal of multipath signal.β=(ω _d+ ω _c) Δ τ _m+ Δ θ _mfor the multipath signal phase compensation causing because of reflection, Δ θ _mfor the phase deviation causing because of reflection, t is the time.J is imaginary number scalar, and γ is the time delay of original signal, is to be caused to the distance receiver by GNSS satellite.

After through radio-frequency front-end down coversion, above formula becomes:

s _db(t)＝Ag[(1+ξ)t-γ]exp(jψ)+αAg[(1+ξ)t-γ-Δτ _m]exp[j(ψ+β)]

（2）

Wherein, it is the phase differential between direct signal phase place and multipath signal phase place. it is the phase place of multipath signal.

The result of formula (2), after analog to digital conversion and carrier wave are peeled off, will generate I road and Q road signal, and the equally spaced 5 road C/A codes synthetic with this locality (are respectively Very Early roads, Early road, Prompt road, Late road, Very Late road) carrying out related calculation obtains following formula:

$I_{\mathrm{VE}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ}-\mathrm{\Δ}{\mathrm{\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_E=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_P=\frac{A}{\sqrt{2}}R\left(\mathrm{\τ}\right)\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_L=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_{\mathrm{VL}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ}-\mathrm{\Δ}{\mathrm{\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$Q_{\mathrm{VE}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ}-\mathrm{\Δ}{\mathrm{\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_E=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_P=\frac{A}{\sqrt{2}}R\left(\mathrm{\τ}\right)\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ}{\mathrm{\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_L=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_{\mathrm{VL}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ}-\mathrm{\Δ}{\mathrm{\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})---\left(3\right)$

Wherein, the amplitude that A is direct signal, R is the cross correlation function of two-way C/A code, and τ is the code delay difference between direct signal and multipath signal, and Δ is the distance between Early road and Late road.

The value of step 2043, related operation enters code phase Discr. after by integration-remover, and whether the amplitude that code phase Discr. detects the value of related operation reaches maximum, and therefrom estimates the phase differential copying between C/A code and reception C/A code.

The present embodiment adopts TK-EML5(Teager-Kaiser Early-Minus-late 5, leading and the hysteresis road of Teager-Kaiser, 5 represent all to need 5 correlators for I road and Q road) phase demodulation mode, TK-ELM5 phase demodulation mode and general ELP(Early-Late Power Discriminatory, subtracting in advance after-power type phase detector) phase demodulation mode compares, can effectively suppress multipath signal, and then reach the effect that improves GNSS receiver precision.

Want to obtain accurately final navigation message, just C/A code perfect restitution should be fallen, according to the character of C/A code, want completely the demodulation of C/A code to be fallen, just require local synthetic C/A code in full accord with the C/A phase place receiving, and can not be in full accord in actual conditions, can only try one's best consistent.The output valve of TK-EML5 be exactly the C/A code that copies with respect to the phase difference value that receives C/A code, specifically comprise:

For discrete signal x (n) arbitrarily, carry out following computing:

${\mathrm{\Ψ}}_d\left[x\left(n\right)\right]=x\left(n\right)x^{*}\left(n\right)-\frac{1}{2}[x(n-1)x^{*}(n+1)+x(n+1)x^{*}(n-1)]---\left(4\right)$

Wherein, x ^*(n) represent the conjugate function of x (n), x (n-1) and x (n+1) are respectively x (n) the move to right function of Yi Ge unit, the Yi Ge unit that moves to left, in like manner x ^*and x (n+1) ^*(n-1) be respectively the conjugate function of x (n+1) and x (n-1).

Code phase Discr. based on TK-EML5 is output as:

D _TKE(τ)＝Ψ _E-Ψ _L （5）

Wherein, Ψ _eand Ψ _lrespectively that (concrete is a setting here with the cross correlation function that receives C/A code in signal respectively for the local synthetic C/A code on Early road and the C/A code on Late road, the character of C/A code determines, two-way C/A code multiplies each other, what obtain is exactly a related function, a triangular waveform) result after code phase Discr..In the present embodiment, for I road signal and Q road signal, adopt respectively 5 correlators, adopted accurate sampling clock T here _t=Δ/2, Δ is the distance between Early road and Late road, is the half-chip length of C/A.

Local synthetic Early road C/A code and the cross correlation function that receives signal the Late road and the cross correlation function that receive signal synthetic with this locality (result that two-way C/A code is relevant can represent with R (τ)) through the computing of (4) formula, obtains following result in code phase Discr.:

${\mathrm{\ψ}}_E\left(\mathrm{\τ}\right)\∝R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})R^{*}(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})-\frac{1}{2}[R\left(\mathrm{\τ}\right)R^{*}(\mathrm{\τ}+\mathrm{\Δ})+R^{*}\left(\mathrm{\τ}\right)R(\mathrm{\τ}+\mathrm{\Δ})]---\left(6\right)$

${\mathrm{\ψ}}_L\left(\mathrm{\τ}\right)\∝R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})R^{*}(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})-\frac{1}{2}[R\left(\mathrm{\τ}\right)R^{*}(\mathrm{\τ}-\mathrm{\Δ})+R^{*}\left(\mathrm{\τ}\right)R(\mathrm{\τ}-\mathrm{\Δ})]---\left(7\right)$

In the present embodiment, for I road signal and Q road signal, having adopted respectively 5 correlators, is respectively Very Early road, Early road, and Prompt road, Late road, Very Late road, the distance between adjacent two-way is Δ/2, namely 1/4 C/A chip lengths; Distance between Early road and Late road is Δ, namely 1/2 C/A chip lengths; Distance between Very Early road and Very Late road is 2 Δs, namely 1 C/A chip lengths.So Ψ _eand Ψ _lcan be expressed as following formula:

${\mathrm{\ψ}}_E\left(\mathrm{\τ}\right)=(I_E+j{Q}_E)(I_E-j{Q}_E)-\frac{1}{2}[(I_P-j{Q}_P)(I_{\mathrm{VE}}+j{Q}_{\mathrm{VE}})+](I_P+j{Q}_P)(I_{\mathrm{VE}}-j{Q}_{\mathrm{VE}})---\left(8\right)$

Therefore ${\mathrm{\ψ}}_E\left(\mathrm{\τ}\right)=I_E^2+Q_E^2-(I_{\mathrm{VE}}*I_P+Q_{\mathrm{VE}}*Q_P)---\left(9\right)$

${\mathrm{\ψ}}_L\left(\mathrm{\τ}\right)=(I_L+j{Q}_L)(I_L-j{Q}_L)-\frac{1}{2}[(I_P-j{Q}_P)(I_{\mathrm{VL}}+j{Q}_{\mathrm{VL}})+](I_P+j{Q}_P)(I_{\mathrm{VL}}-j{Q}_{\mathrm{VL}})---\left(10\right)$

Therefore ${\mathrm{\ψ}}_L\left(\mathrm{\τ}\right)=I_L^2+Q_L^2-(I_{\mathrm{VL}}*I_P+Q_{\mathrm{VL}}*Q_P)---\left(11\right)$

So code phase Discr. is output as:

$D_{\mathrm{TKE}}\left(\mathrm{\τ}\right)=(I_E^2+Q_E^2)-(I_L^2+Q_L^2)-(I_{\mathrm{VE}}*I_P+Q_{\mathrm{VE}}*Q_P)+(I_{\mathrm{VL}}*I_P+Q_{\mathrm{VL}}*Q_P)---\left(12\right)$

The value of formula (12) is the phase difference value between time channel C/A code and input signal C/A code videlicet.

Step 2044, code phase difference are after Loop filter, through assisting of carrier loop, as the control inputs of C/A yardage controlled oscillator; Last C/A code generator, under the driving of yardage controlled oscillator, regulates the frequency that copies C/A code and the phase place of exporting in time, makes to copy C/A code in C/A code and input signal and is constantly consistent.

Above by copy one with pseudo-code (being conventionally the defaulted as C/A code here) pseudo-code that phase place is consistent receiving in signal, then allow acknowledge(ment) signal to copy pseudo-code and multiply each other relevant, to peel off the pseudo-code receiving in signal, and therefrom obtain GNSS and locate this important measured value of necessary pseudorange.

In GNSS receiver code track loop, TK-EML5 phase detecting method is a kind of phase detecting method based on TK algorithm, it is compared with general ELP phase detecting method, can be in the situation that not knowing multipath signal information, estimate multipath signal with respect to the multidiameter distance of direct signal, and then in phase demodulation process, effectively suppressed multipath signal, and then improved the precision of GNSS receiver.

Fig. 4 and Fig. 5 are respectively emulation TK-EML5 phase detector out and the multipath error envelope diagram of ELP phase detector.Multipath error envelope diagram is the figure that shows to be caused by multipath code tracking limit of error value.Horizontal ordinate in figure is multidiameter, and ordinate is tracking error.Solid line in figure is the code phase measuring error of the spacing between leading road (Early) and hysteresis road (Late) while being 1/4 chip, dotted line is the code phase measuring error of the spacing between leading road (Early) and hysteresis road (Late) while being 1/2 chip, and dotted line is the code phase measuring error of the spacing between leading road (Early) and hysteresis road (Late) while being 3/4 chip.Code phase measuring error under the effect of homophase reflection wave is that figure intermediate value is a positive broken line, code phase measuring error under the effect of antiphase reflection ripple is that value is a negative broken line, and when transmitted wave carrier phase is worth for other, code phase measuring error is between these upper and lower two broken lines.By Fig. 4 and Fig. 5, can be found out, for same multipath situation, if the correlator spacing that code ring adopts is narrower, code phase multipath measuring error is just less.From Fig. 4 and Fig. 5, contrasted, under square one, because TK-EML5 phase detector code tracking error envelope is less than ELP phase detector code tracking error envelope, therefore aspect the inhibition of multipath signal, especially short to time delay multi-path signal inhibition aspect, TK-EML5 phase detector has better effect than ELP phase detector.

In a word, the foregoing is only preferred embodiment of the present invention, be not intended to limit protection scope of the present invention.

Claims (4)

1. in GLONASS (Global Navigation Satellite System), suppress a phase detecting method for multipath signal, it is characterized in that, comprising:

The global navigation satellite system GNSS signal that reception comprises multipath signal, carries out down coversion and generates after Low Medium Frequency signal, carries out analog to digital conversion; GNSS signal after analog to digital conversion is carried out to carrier wave and peel off, obtain the signal on I road and Q road, described I road and Q road signal are carried out to code and peel off;

Describedly described I road and Q road signal carried out to the step that code peels off specifically comprise:

By C/A code generator, copy one and there is the C/A coded signal of same phase with described I road and Q road signal, and the distance obtaining between adjacent two-way C/A by delay is 5 road C/A codes of 1/4 chip, respectively: Very Early road, Early road, Prompt road, Late road, Very Late road;

Described 5 road C/A codes and described I road and Q road signal are carried out related calculation;

The value of described related operation enters the amplitude that code phase Discr. detects this value after by integration-remover and whether reaches maximum, and therefrom estimates the phase differential copying between C/A code and reception C/A code;

Input using described phase differential as C/A yardage controlled oscillator, copies frequency and the phase place of C/A code described in adjusting, copies C/A code and be consistent with the moment that receives C/A code described in making;

The step of described related operation specifically comprises:

The GNSS signal receiving comprises direct signal and multipath signal:

s(t)=s _d(t)+s _m(t)

=Ag[(1+ξ)t-γ]exp{f[(ω _d+ω _c)t+φ ₁])+αAg[(1+ξ)t-γ-Δτ _m]exp{f[(ω _d+ω _c)t+φ ₁+β])

Wherein, s (t) is GNSS signal, s _d(t), s _m(t) represent respectively direct signal and the multipath signal in GNSS signal, ω _ccarrier frequency, ω _dfor Doppler shift, a be GNSS direct signal amplitude, g (t) is ± 1, represents the value of C/A code, φ ₁for carrier phase, α is the ratio of multipath signal amplitude and direct signal amplitude, Δ τ _mfor the time delay of the relative direct signal of multipath signal, β=(ω _d+ ω _c) Δ τ _m+ Δ θ _mfor the multipath signal phase compensation causing because of reflection, Δ θ _mfor the phase deviation causing because of reflection, t is the time, and j is imaginary number scalar, and γ is the time delay of original signal;

After radio-frequency front-end down coversion, obtain:

s _db(t)=Ag[(1+ξ)t-γ]exp(jψ)+αAg[(1+ξ)t-γ-Δτ _m]exp[j(ψ+β)]

Wherein, the phase differential between direct signal phase place and multipath signal phase place, it is the phase place of multipath signal;

After analog to digital conversion and carrier wave are peeled off, generate I road and Q road signal, carry out related calculation and obtain with the synthetic equally spaced 5 road C/A codes in this locality:

$I_{\mathrm{VE}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_E=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\α\Δ}}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_F=\frac{A}{\sqrt{2}}R\left(\mathrm{\τ}\right)\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\α\Δ}}{\sqrt{2}}R(\mathrm{\τ}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_L=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\α\Δ}}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$I_{\mathrm{VL}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ})\cos \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ}-{\mathrm{\Δ\τ}}_m)\cos (\mathrm{\ψ}+\mathrm{\β})$

$Q_{\mathrm{VE}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}+\mathrm{\Δ}-{\mathrm{\Δ\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_E=\frac{A}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\α\Δ}}{\sqrt{2}}R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_F=\frac{A}{\sqrt{2}}R\left(\mathrm{\τ}\right)\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\α\Δ}}{\sqrt{2}}R(\mathrm{\τ}-{\mathrm{\Δ\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_L=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\α\Δ}}{\sqrt{2}}R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2}-{\mathrm{\Δ\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

$Q_{\mathrm{VL}}=\frac{A}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ})\sin \left(\mathrm{\ψ}\right)+\frac{\mathrm{\αA}}{\sqrt{2}}R(\mathrm{\τ}-\mathrm{\Δ}-{\mathrm{\Δ\τ}}_m)\sin (\mathrm{\ψ}+\mathrm{\β})$

Wherein, R is the cross correlation function of two-way C/A code, and τ is the code delay difference between direct signal and multipath signal, and Δ is the distance between Early road and Late road.

2. the phase detecting method that suppresses multipath signal in GLONASS (Global Navigation Satellite System) according to claim 1, is characterized in that, to the sampling clock of described I road and the employing of Q road signal, is T _t=Δ/2, Δ is the distance between Early road and Late road, Δ equals the half-chip length of C/A code.

3. the phase detecting method that suppresses multipath signal in GLONASS (Global Navigation Satellite System) according to claim 2, is characterized in that, described code phase Discr. adopts the phase detecting method of TK-EML5.

4. the phase detecting method that suppresses multipath signal in GLONASS (Global Navigation Satellite System) according to claim 3, is characterized in that, described in the step that copies C/A code described in estimating and receive the phase difference between C/A code specifically comprise:

For discrete signal x (n) arbitrarily, carry out following computing:

${\mathrm{\Ψ}}_d\left[x\left(n\right)\right]=x\left(n\right)x^{*}\left(n\right)-\frac{1}{2}[x(n-1)x^{*}(n+1)+x(n+1)x^{*}(n-1)]$

Wherein, x ^*(n) represent the conjugate function of x (n), x (n-1) and x (n+1) are respectively the move to right function of Yi Ge unit, the Yi Ge unit that moves to left of x (n); x ^*and x (n+1) ^*(n-1) be respectively the conjugate function of x (n+1) and x (n-1);

Code phase Discr. based on TK-EML5 is output as:

D _TKE(τ)=Ψ _E-Ψ _L

Wherein, Ψ _eand Ψ _lbe respectively the local synthetic C/A code on Early road and the C/A code on Late road respectively with the cross correlation function that receives C/A code in signal;

Local synthetic Early road C/A code and the cross correlation function that receives signal the Late road and the cross correlation function that receive signal synthetic with this locality in code phase Discr., after computing, obtain:

${\mathrm{\ψ}}_E\left(\mathrm{\τ}\right)\∝R(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})R^{*}(\mathrm{\τ}+\frac{\mathrm{\Δ}}{2})-\frac{1}{2}[R\left(\mathrm{\τ}\right)R^{*}(\mathrm{\τ}+\mathrm{\Δ})+R^{*}\left(\mathrm{\τ}\right)R(\mathrm{\τ}+\mathrm{\Δ})]$

${\mathrm{\ψ}}_L\left(\mathrm{\τ}\right)\∝R(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})R^{*}(\mathrm{\τ}-\frac{\mathrm{\Δ}}{2})-\frac{1}{2}[R\left(\mathrm{\τ}\right)R^{*}(\mathrm{\τ}-\mathrm{\Δ})+R^{*}\left(\mathrm{\τ}\right)R(\mathrm{\τ}-\mathrm{\Δ})]$

Ψ _eand Ψ _lfor:

${\mathrm{\ψ}}_E\left(\mathrm{\τ}\right)=(I_E+{\mathrm{jQ}}_E)(I_E-{\mathrm{jQ}}_E)-\frac{1}{2}[(I_P-{\mathrm{jQ}}_P)(I_{\mathrm{VE}}+{\mathrm{jQ}}_{\mathrm{VE}})+](I_P+{\mathrm{jQ}}_P)(I_{\mathrm{VE}}-{\mathrm{jQ}}_{\mathrm{VE}})$

Therefore ${\mathrm{\ψ}}_E\left(\mathrm{\τ}\right)=I_E^2+Q_E^2-(I_{\mathrm{VE}}*I_P+Q_{\mathrm{VE}}*Q_P)$

${\mathrm{\ψ}}_L\left(\mathrm{\τ}\right)=(I_L+{\mathrm{jQ}}_L)(I_L-{\mathrm{jQ}}_L)-\frac{1}{2}[(I_P-{\mathrm{jQ}}_P)(I_{\mathrm{VL}}+{\mathrm{jQ}}_{\mathrm{VL}})+](I_P+{\mathrm{jQ}}_P)(I_{\mathrm{VL}}-{\mathrm{jQ}}_{\mathrm{VL}})$ Therefore ${\mathrm{\ψ}}_L\left(\mathrm{\τ}\right)=I_L^2+Q_L^2-(I_{\mathrm{VL}}*I_P+Q_{\mathrm{VL}}*Q_P)$

The phase difference value of code phase Discr. output is:

$D_{\mathrm{TKE}}\left(\mathrm{\τ}\right)=(I_E^2+Q_E^2)-(I_L^2+Q_L^2)-(I_{\mathrm{VE}}*I_P+Q_{\mathrm{VE}}*Q_P)+(I_{\mathrm{VL}}*I_P+Q_{\mathrm{VL}}*Q_P).$