CN104298860B - Method for calculating deviation of GEO satellite forwarded signal codes and carrier phases - Google Patents

Abstract

The invention provides a method for calculating deviation of GEO satellite forwarded signal codes and carrier phases. The method includes the steps that firstly, a carrier large-loop code pseudo-range equation and a carrier phase pseudo-range equation are established, then, ionized layer parameters are calculated through observation results of double-frequency codes and the carrier phases, the offset of the code on the carrier C1 and the carrier phase and the offset of the code on the carrier C2 and the carrier phase are calculated respectively, and finally, the real-time control quantity of the codes on the carrier C1 and the carrier C2 and the carrier phases is acquired through filtering. According to the method, the GEO satellite forwarded signal codes and the carrier phases can be identical.

Description

A kind of computational methods of GEO satellite forward signal code and carrier phase deviation

Technical field

The present invention relates to a kind of control method, protects can GEO satellite transponder exit signal code and the phase place of carrier wave Hold consistent.

Background technology

The eighties in 20th century, the U.S. build up GPS, and the former Soviet Union builds up GLONASS (Global Navigation Satellite system, GLONASS).Both are placed with high performance satellite atomic clock on star,

In the positioning network that regional alignment system (CAPS), U.S.'s WAAS system and Europe include GEO satellite, All it is mode of operation signal forwarded using GEO satellite.GEO satellite is to utilize satellite to the mode of operation that signal is forwarded Transparent forwarding function, by ground produce navigation signal user is transmitted to by satellite, which is more than general GPS navigation signal One up-link.Cause the code and load from ground launch navigation signal due to the impact of the up-link and satellite repeater The concordance of wave phase is destroyed.In order to ensure based on the navigation of GEO satellite, time dissemination system can more preferable service user, The dependency relation for specifying the code and carrier phase of satellite transmitting antenna phase center is the key problem that these systems must be solved.

The content of the invention

In order to overcome the deficiencies in the prior art, the present invention to provide a kind of GEO satellite signal ground master station code and carrier wave phase The computational methods of position deviation, allow users to accurately know the dependency relation of satellite exit code and carrier phase.

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

Step 1. sets up the big loop code pseudorange of carrier wave and carrier phase pseudorange equation,

The big ring observational equation P of described code phase_loop=ρ+I_up+I_dp+ε_Pi, the big ring observational equation λ of carrier phase_dΦ_loop =ρ+I_uφ+S_φ+I_dφ+Nλ_d+ε_φ, wherein, P_loopAnd Φ_loopRepresent signal from ground launch base band Jing radio frequency transmitting channel, space The code and carrier phase pseudorange of the forwarding of up, satellite, descending space, radio frequency reception channel and synthetical baseband receiving terminal, ρ=ρ_u +ρ_d+T_up+T_dp+E_u+E_d+S_p=ρ_u+ρ_d+T_uφ+T_dφ+E_u+E_d+S_φ, ρ_uRepresent from ground launch antenna phase center to GEO satellite The geometric distance of reception antenna phase center, ρ_dBe from GEO satellite transmitting antenna phase center in terrestrial receiving antenna phase place The geometric distance of the heart, T_up、Respectively from ground launch antenna phase center to GEO satellite, experienced troposphere is in code phase With the additional delay produced in carrier phase, T_dp、Respectively experience from GEO satellite transmitting antenna phase center to earth station The delay that troposphere is produced on code phase and carrier phase, E_uAnd E_dRepresent master station up transmitting equipment in ground with respectively The processing delay of row receiving device, S_pRepresent satellite repeater equipment delay, S_φRepresent the carrier phase that satellite repeater causes Change, I_up、I_uφRespectively from ground launch antenna phase center to GEO satellite, experienced ionosphere is in code phase and carrier wave phase The additional delay produced on position, I_dp、I_dφRespectively experience ionosphere from GEO satellite transmitting antenna phase center to earth station to exist The delay produced on code phase and carrier phase, ε_PiAnd ε_φiThe code noise and carrier phase measurement cumulative noise of receiver are represented, N be it is descending measurement exist integer ambiguity, λ_dFor the corresponding wavelength of downstream frequency；

Step 2. adopts dual-frequency code and the observed result of carrier phase to resolve Ionospheric Parameters；

Wherein, the carrier frequency of the dual-frequency code be C1, C2, P_{Loop, c1}And P_{Loop, c2}C1 and C2 frequency signals are represented respectively Big ring code pseudo range observed quantity；Φ_{Loop, c1}And Φ_{Loop, c2}The carrier phase observed quantity of C1 and C2 frequency signals is represented respectively；f_{C1, u} And f_{C1, d}, f_{C2, u}And f_{C2, d}The uplink and downlink carrier frequency of C1 and C2 frequency signals is represented respectively；N_c1And N_c2C1 is represented respectively With the integer ambiguity of C2 frequency signal carrier phase observed quantities；λ_{C1, d}And λ_{C2, d}Represent that C1 and C2 frequencies downstream signal is carried respectively Ripple wavelength；

Resolve Ionospheric Parameters

Step 3. calculates the side-play amount of code and carrier phase on C1 carrier waves

Calculate the side-play amount of the code and carrier phase on C2 carrier waves

Step 4. is carried out respectively smoothing, is estimated to the side-play amount of code and carrier phase on C1, C2 carrier wave using wave filter, obtained Obtain the real-time control amount on C1 carrier wavesWith it is real-time on C2 carrier waves Controlled quentity controlled variableWherein τ is filter constants, and T is the sampling interval, Δ_c1(k)、Δ_c2K () is the current pre-adjustment amount of C1, C2 carrier wave before filtering, Δ_c1(k-1)、L_c1(k-1) it is respectively previous moment Filter the pre-adjustment amount of forward and backward C1 carrier waves, Δ_c2(k-1)、L_c2(k-1) it is respectively previous moment and filters forward and backward C2 carrier waves Pre-adjustment amount.

The invention has the beneficial effects as follows：Code and carrier wave phase at satellite transmitting antenna phase center are calculated based on the method The deviation of position, by control of the earth station to code and carrier wave, is capable of achieving GEO satellite forward signal code consistent with carrier phase Property, the system signal is made similar to the satellite straight hair signal of same frequency and do not interfere with each other, can be used as the increasing of same-frequency satellite straight hair signal Strong signal；And the system forwards signal is made similar to gps signal, so as to the existing achievement in research of GPS system can be used for reference, further The performance of the system is improved, shortens search time of the system using high precision technology.

Description of the drawings

Fig. 1 is GEO satellite forward signal navigation system schematic diagram.

Specific embodiment

The present invention is further described with reference to the accompanying drawings and examples, and the present invention includes but are not limited to following enforcements Example.

A kind of code and carrier phase concordance control method of GEO satellite forward signal, step are as follows：

Step 1：Code and the big ring observational equation of carrier phase are set up, including

The big ring observational equation of code phase：

P_loop=ρ_u+E_u+I_up+T_up+S_p+ρ_d+I_dp+T_dp+E_d+m_p+ε_p (1)

The big ring observational equation of carrier phase：

Φ_loop=ρ_u+E_u+I_uφ+T_uφ+S_p+S_φ+ρ_d+I_dφ+T_dφ+E_d+m_φ+ε_φ (2)

Wherein P_loopAnd Φ_loopRepresent signal from ground launch base band Jing radio frequency transmitting channel, space be up, satellite forwarding, Space is descending, the code and carrier phase pseudorange of radio frequency reception channel and synthetical baseband receiving terminal, referred to as big ring measured value；ρ_uTable Show the geometric distance from ground launch antenna phase center to GEO satellite reception antenna phase center, ρ_dIt is to launch from GEO satellite Geometric distance of the antenna phase center to terrestrial receiving antenna phase center；I_up、I_uφRespectively from ground launch antenna phase The additional delay that the heart is produced on code phase and carrier phase to the experienced ionosphere of GEO satellite；T_up、Respectively from ground Transmitting antenna phase center is to GEO satellite the experienced troposphere (additional delay produced on code phase and carrier phase；I_dp、 I_dφRespectively experience ionosphere from GEO satellite transmitting antenna phase center to produce on code phase and carrier phase to earth station Delay；T_dp、Troposphere is experienced from GEO satellite transmitting antenna phase center to earth station respectively in code phase and carrier wave The delay produced in phase place；E_uAnd E_dThe processing delay of the up transmitting equipment of ground master station and downlink reception equipment is represented respectively； D_upAnd D_dpIn representing signal uplink and downlink transmission process respectively, the pseudo-code time delay that Doppler causes；D_uφAnd D_dφRepresent respectively In signal uplink and downlink transmission process, the carrier wave time delay that Doppler causes；m_P、m_φRespectively multipath is to code phase and carrier wave phase The error that position influence is produced；ε_PAnd ε_φRepresent the code noise and carrier phase measurement cumulative noise of receiver, N_dDeposit for descending measurement Integer ambiguity, λ_dFor the corresponding wavelength of downstream frequency.S_pRepresent satellite repeater equipment delay, S_φRepresent satellite forwarding The carrier phase change that device causes.

Step 2：According to the different affecting factors of parameter in step 1, observational equation is simplified.

The concordance of main research satellite exit code of the invention and carrier phase, by transmitting baseband Time synchronization technique Can ensure in the consistent of both transmitter exits, on the transmit path, code and the phase relation of carrier wave can be made to change Principal element is ionosphere and transponder, and other are such as transmitting and receiving apparatus, transmission geometric path, troposphere, transponder device Time delay etc. can make whole signal produce delay, but the phase relation of the two will not be made to change.Therefore, in formula (1) and (2) In, the error that multipath causes is included into into receiver measurement noise, ε is designated as respectively to the noise of pseudo-code and carrier phase_PiAnd ε_φi； Will be above-mentioned irrelevant with frequency, do not affect pseudo-code and the factor of carrier phase relationship to be all attributed in geometric distance, be set to ρ, then：

ρ=ρ_u+ρ_p+T_up+T_dp+E_u+E_d+S_p=ρ_u+ρ_d+T_uφ+T_dφ+E_u+E_d+S_p (3)

Then formula (1) and (2) can be written as：

P_loop=ρ+I_up+I_dp+ε_Pi (4)

λ_dΦ_loop=ρ+I_uφ+S_φ+I_dφ+Nλ_d+ε_φi (5)

Step 3：Double frequency (setting carrier frequency as C1, C2) code and the observed result of carrier phase is adopted to resolve ionosphere ginseng Number.

As ionosphere shifts to an earlier date carrier phase observed quantity, make yard pseudo range observed quantity delayed, and value is equal.Therefore, electricity Absciss layer is to the first-order lag of carrier phase and code pseudo range observed quantityAnd it is in opposite direction.Wherein I=40.3TEC, TEC are The total electron number of observed direction, f represent signal frequency.As the influence amounts such as second order, three ranks are small, can disregard.Therefore, formula (5) observed quantity of (6) in two frequencies of C1, C2 can be written as respectively：

In formula, P_{Loop, cl}And P_{Loop, c2}The big ring code pseudo range observed quantity of C1 and C2 frequency signals is represented respectively；Φ_{Loop, c1}With Φ_{Loop, c2}The carrier phase observed quantity of C1 and C2 frequency signals is represented respectively；f_{Cl, u}And f_{C1, d}, f_{C2, u}And f_{C2, d}Respectively represent C1 and The uplink and downlink carrier frequency of C2 frequency signals；N_c1And N_c2C1 and C2 frequency signal carrier phase observed quantities are represented respectively Integer ambiguity；λ_{C1, d}And λ_{C2, d}C1 and C2 frequency downstream signal carrier wavelengths are represented respectively.

Obtained according to formula (6), (7)：

Its result has eliminated the impact of troposphere and multipath, and precision is only relevant with pseudo-code accuracy of observation and observation noise. There is no P code privacy problems in CAPS earth stations, obtain higher accuracy of observation using P codes, while can also adopt carrier phase Smooth method further improves its precision.

Step 4：Calculate the departure of code and carrier phase.

C1 frequencies code is similar with C2 frequencies with the calculating process of carrier phase departure, is said here by taking C1 frequencies as an example It is bright.

Using formula (6)-(8), the deviation of C1 frequencies code and carrier phase is obtained：

The purpose of this method is to ensure that satellite outlet code is consistent with carrier phase, accordingly, it would be desirable to up-link, i.e., The code and carrier phase that link causes before satellite transmitting antenna phase center deviates, i.e., up ionosphere and satellite repeater draw The bias for rising, is calculated as：

In satellite repeater system, the time-frequency of ground master station transmitting and receiving apparatus with reference to homologous, by transmission signal Code and the carrier phase deviation that big ring closed-loop causes is obtained accurately with the code and carrier phase variable quantity for receiving signal, i.e., greatly There is no integer ambiguity in the code and carrier phase deviation of ring closed-loop.Ignore the difference of observation noise, uplink pass The bias of the code and carrier phase that rise is represented by：

Step 5：The side-play amount of code and carrier phase on C1, C2 carrier wave is carried out respectively smoothing, estimated using wave filter, obtained The real-time pre- deviator on each carrier wave is obtained, so as to keep code and carrier phase on two carrier waves one to be kept in GEO satellite exit Cause.

With the result of formula (13) as input, pre-adjustment is carried out to earth station transmitting carrier wave NCO and code NCO, satellite can be made Outlet code and carrier phase are consistent, and in order to improve circuit to being input into the transient response of adjustment amount, we adopt second order LTI (Linear Time Invariant) wave filter is smoothed to the pre-adjustment amount being input into, to reduce the response time of circuit, and Eliminate the impact of High-frequency Interference.So as to obtain code and carrier phase offset adjustment amount (referred to as " pre-adjustment amount ") estimator output (Laplace conversion) is：

With the difference between pre-adjustment amount state as input, pre-estimation is carried out to NextState and is obtained：

Wherein τ₁, τ₂For filter constants, T is the sampling interval, and Δ (k), L (k) are respectively the current pre-adjustment before and after filtering Amount, Δ (k-1), L (k-1) are respectively previous moment and filter forward and backward pre-adjustment amount.

In specific implementation process, adopt double frequency (setting carrier frequency as C1, C2) to build in national time service center (NTSC) Into regional navigation system CAPS (Chinese area positioning system) be experiment porch.Such as Fig. 1 institutes Show, the system composition of the present embodiment includes upward signal transmitting, GEO satellite forwarding, the reception of satellite forward signal and measurement, code Four part of calculating method is estimated with carrier phase deviation.

The reception of satellite forward signal and measurement part mainly complete the reception of satellite converting downlink signal, and docking is accepted The code and carrier phase pseudorange of row signal and big ring signal is measured, and obtains code and carrier phase Pseudo-range Observations.

Code and load that code and carrier phase deviation are estimated calculating method and separately won with the reception of satellite forward signal and Measurement portion Wave phase Pseudo-range Observations are input, calculate the pre- deviator of code and carrier phase, and using wave filter to code on C1, C2 carrier wave and The side-play amount of carrier phase carries out respectively smoothing, estimates, obtains the real-time pre- deviator on each carrier wave.

The control section of code and carrier wave NCO the real-time pre- deviator of calculating method acquisition is estimated as defeated with code and carrier phase deviation Enter, realize the control to code and carrier wave NCO, ensure consistent with carrier phase in satellite exit code through the control.

Upward signal emitting portion completes the up-conversion of signal and transmits signals to satellite through antenna, forwards through satellite Signal is transmitted to downlink reception equipment by device, constitutes the closed loop of signal.

Implement this method by taking the system as an example, specific implementation step is as follows：

Step 1：Set up the big ring loop code pseudorange of C1, C2 carrier wave and carrier phase observational equation：

Step 2：Resolve Ionospheric Parameters.

Step 3：Calculate the side-play amount of the code and carrier phase on C1, C2 carrier wave.

Step 4：The real-time control amount of the code and carrier phase on C1, C2 carrier wave is obtained after filtering.

Code or carrier phase are controlled with the controlled quentity controlled variable, make code and carrier phase that transmission signal exported in transmitter Deviation is produced, after up-link and satellite repeater, it is ensured that code is consistent with carrier phase in satellite repeater exit.

Claims (1)

1. computational methods of a kind of GEO satellite forward signal code and carrier phase deviation, it is characterised in that comprise the steps：

Step 1. sets up the big loop code pseudorange of carrier wave and carrier phase pseudorange equation,

The big ring observational equation P of code phase_loop=ρ+I_up+I_dp+ε_Pi, the big ring observational equation λ of carrier phase_dΦ_loop=ρ+I_uφ+S_φ+ I_dφ+Nλ_d+ε_φ, wherein, ε_φFor carrier phase measurement cumulative noise；P_loopAnd Φ_loopRepresent that signal is penetrated from ground launch base band Jing The code and load of frequency transmission channel, up space, satellite forwarding, descending space, radio frequency reception channel and synthetical baseband receiving terminal Wave phase pseudorange, ρ=ρ_u+ρ_d+T_up+T_dp+E_u+E_d+S_p=ρ_u+ρ_d+T_uφ+T_dφ+E_u+E_d+S_φ, ρ_uRepresent from ground launch antenna Geometric distance of the phase center to GEO satellite reception antenna phase center, ρ_dIt is from GEO satellite transmitting antenna phase center to ground The geometric distance of face reception antenna phase center, T_upBy troposphere is experienced from ground launch antenna phase center to GEO satellite The additional delay produced on code phase, T_dpIt is that troposphere is experienced from GEO satellite transmitting antenna phase center to earth station in code The delay produced in phase place, E_uAnd E_dThe processing delay of the up transmitting equipment of ground master station and downlink reception equipment is represented respectively, S_pRepresent satellite repeater equipment delay, S_φRepresent the carrier phase change that satellite repeater causes, I_up、I_uφRespectively from ground The additional delay that surface launching antenna phase center is produced on code phase and carrier phase to the experienced ionosphere of GEO satellite, I_dp、 I_dφRespectively experience ionosphere from GEO satellite transmitting antenna phase center to produce on code phase and carrier phase to earth station Delay, ε_PiAnd ε_φiThe code noise and carrier phase measurement cumulative noise of receiver are represented, N is the complete cycle that descending measurement is present Fuzziness, λ_dFor the corresponding wavelength of downstream frequency；

Step 2. adopts dual-frequency code and the observed result of carrier phase to resolve Ionospheric Parameters；

$P_{loop,c1}=\mathrm{\ρ}+\frac{I}{f_{c1,u}^2}+\frac{I}{f_{c1,d}^2}+{\mathrm{\ϵ}}_{Pi}$

$P_{loop,c2}=\mathrm{\ρ}+\frac{I}{f_{c2,u}^2}+\frac{I}{f_{c2,d}^2}+{\mathrm{\ϵ}}_{Pi}$

${\mathrm{\λ}}_{c1,d}{\mathrm{\Φ}}_{loop,c1}=\mathrm{\ρ}-\frac{I}{f_{c1,u}^2}+S_{\mathrm{\φ}}-\frac{I}{f_{c1,d}^2}+N_{c1}\·{\mathrm{\λ}}_{c1,d}+{\mathrm{\ϵ}}_{\mathrm{\φ}i}$

${\mathrm{\λ}}_{c2,d}{\mathrm{\Φ}}_{loop,c2}=\mathrm{\ρ}-\frac{I}{f_{c2,u}^2}+S_{\mathrm{\φ}}-\frac{I}{f_{c2,d}^2}+N_{c2}\·{\mathrm{\λ}}_{c2,d}+{\mathrm{\ϵ}}_{\mathrm{\φ}i}$

Wherein, the carrier frequency of the dual-frequency code be C1, C2, P_loop,c1And P_loop,c2The big of C1 and C2 frequency signals is represented respectively Ring code pseudo range observed quantity；Φ_loop,c1And Φ_loop,c2The carrier phase observed quantity of C1 and C2 frequency signals is represented respectively；f_c1,uWith f_c1,d, f_c2,uAnd f_c2,dThe uplink and downlink carrier frequency of C1 and C2 frequency signals is represented respectively；N_c1And N_c2Respectively represent C1 and The integer ambiguity of C2 frequency signal carrier phase observed quantities；λ_c1,dAnd λ_c2,dC1 and C2 frequency downstream signal carrier waves are represented respectively Wavelength；

Resolve Ionospheric Parameters

Step 3. calculates the side-play amount of code and carrier phase on C1 carrier waves

${\mathrm{\Δ}}_{c1}=\frac{2I}{f_{c1,u}^2}-S_{\mathrm{\φ},c1}=P_{loop,c1}-{\mathrm{\λ}}_{c1,d}{\mathrm{\Φ}}_{loop,c1}-\frac{2I}{f_{c1,d}^2};$

Calculate the side-play amount of the code and carrier phase on C2 carrier waves

${\mathrm{\Δ}}_{c2}=\frac{2I}{f_{c2,u}^2}-S_{\mathrm{\φ},c2}=P_{loop,c2}-{\mathrm{\λ}}_{c2,d}{\mathrm{\Φ}}_{loop,c2}-\frac{2I}{f_{c2,d}^2};$

The C1 carrier phases change that satellite repeater causes is represented, in the same mannerRepresent 2 carrier waves of C that satellite repeater causes Phase place change；

Step 4. carried out respectively smoothing, estimated to the side-play amount of code and carrier phase on C1, C2 carrier wave using wave filter, obtains C1 Real-time control amount on carrier waveWith the real-time control on C2 carrier waves AmountWherein τ is filter constants, and T is the sampling interval, Δ_c1 (k)、Δ_c2K () is the current pre-adjustment amount of C1, C2 carrier wave before filtering, Δ_c1(k-1)、L_c1(k-1) it is respectively previous moment filtering The pre-adjustment amount of forward and backward C1 carrier waves, Δ_c2(k-1)、L_c2(k-1) it is respectively previous moment and filters the pre- of forward and backward C2 carrier waves Adjustment amount.