阅读说明：本技术 同步伪卫星定位方法及系统 (Synchronous pseudolite positioning method and system ) 是由 王大鹏 刘愿 刘矗 张元刚 于 2020-06-11 设计创作，主要内容包括：本公开提供一种同步伪卫星定位方法及系统,涉及卫星导航领域,能够解决与现有GNSS系统、GNSS信号、GNSS接收机兼容的问题。具体技术方案为：伪卫星组网配置,伪卫星GNSS复现信号进行定位。采用普通的GNSS接收机以及普遍采用的GNSS系统定位方法,可实现伪卫星定位。实现在遮蔽环境下利用伪卫星信号定位,同时保持GNSS接收机硬件兼容性和底层软件兼容性。本发明用于GNSS接收机硬件兼容的伪卫星定位。(The invention provides a synchronous pseudo-satellite positioning method and system, relates to the field of satellite navigation, and can solve the problem of compatibility with the existing GNSS system, GNSS signals and GNSS receivers. The specific technical scheme is as follows: and (4) pseudolite networking configuration and pseudolite GNSS reproduction signals are positioned. The pseudo satellite positioning can be realized by adopting a common GNSS receiver and a commonly adopted GNSS system positioning method. The positioning by utilizing the pseudo satellite signals under the shielding environment is realized, and meanwhile, the compatibility of GNSS receiver hardware and the compatibility of bottom layer software are kept. The method is used for pseudo satellite positioning with GNSS receiver hardware compatibility.)

1. A method of synchronized pseudolite positioning, the method comprising:

pseudo satellite networking configuration, wherein under the environment shielded by GNSS signals, the pseudo satellite I number of the GNSS receiver provides GNSS recurrent signals S_iT is obtained by analytic calculation_uThree-dimensional position of time of day

Wherein, t_uA receiver clock; three dimensional positionIs PL_iEstimating a coordinate point;

by means of said pseudolite GNSS reproduction signal S_iPositioning is carried out, the GNSS reproduction signal S_iIs the phase center coordinate point PL of the pseudo satellite transmitting antenna_iPL without being blocked on the connection line of the phase center coordinate point of the GNSS satellite antenna _iAnd the coordinate point receives the arrival signals of the GNSS satellite in real time.

2. The method of claim 1, wherein the pseudolite networking configuration is networking using M pseudolites in a GNSS signal obscured environment to provide positioning signals for GNSS receivers entering the environment; wherein M represents the number of pseudolites in the network and satisfies

M is greater than or equal to the positioning dimension +1

The location dimension may take 1, or 2, or 3, depending on the environmental characteristics or user requirements.

3. The method of claim 2, wherein the phase centers of the networked pseudolite transmit antennas are position-calibrated in a geocentric geostationary coordinate system;

PL for calibrated coordinates of phase center of each pseudolite transmitting antenna_iRepresents where i ∈ [1, 2, …, M]Numbering networked satellites, PL_iCorresponding to pseudolite No. i; satellite-borne signal generator SG of No. i pseudo satellite_iReal-time generation of PL_iThe GNSS recurrent signal S of the coordinate point_iAnd transmitted through the antenna.

4. The method of claim 3, wherein the PL_iGNSS reproduction signal S of coordinate point_iMeans PL_iThe connection line between the coordinate point and the GNSS satellite antenna phase center coordinate point is not provided with Under the condition of shielding, the GNSS satellite transmits signals to directly reach PL_iCoordinate point, PL_iL received in real time by coordinate point_iThe arrival waves of the satellites are combined into a signal,

wherein the content of the first and second substances,to set the GNSS satellite signal to reach PL directly_iIn the case of coordinate points, pseudolite No. i is at PL_iReceived coordinate pointsAn arrival signal transmitted by a satellite; l is_iThe number of GNSS satellites selected for the ith pseudolite.

5. The method of claim 4, wherein the PL is known based on_iCoordinate points generated by conventional signal source and transmitting the said pseudo satellite No. i at PL_iGNSS reproduction signal S of coordinate point_iThe synchronization of the pseudo satellite signal generator clock and the GNSS system clock can be realized by a satellite-borne GNSS receiver timing method of the pseudo satellite.

6. The method of claim 1, wherein the user clock offsetIncluding conventional clock error terms of GNSS receivers

The user clock floatIncluding GNSS receiver conventional clock drift term

Wherein, the user floats

Wherein the content of the first and second substances,

7. The method of claim 6, wherein the GNSS receiver is a same source clock, and the clock difference value and the clock drift value are only related to the GNSS receiver clock, such that there is a relationship

User clock error

8. The method of claim 7, wherein in the clock-synchronized networked pseudolite system, the pseudolite clock has a constant offset from the GNSS system clock,

at the user clock errorIn, GNSS receiver and said pseudolite PL_iWith respect to the pseudolite PL, the distance-induced signal propagation delay with respect to the pseudolite PL_iEach GNSS signal broadcast is the same and is addressed to the pseudolite PL by the GNSS receiver _iPseudo satellite signal propagation delay obtained after broadcast signal is subjected to positioning analysis calculation

At the user clock driftIn relation to said pseudolite PL, a GNSS receiver_iIs superimposed on the pseudolite PL, and a doppler effect caused by the projection component of the velocity in the direct direction of (b) is superimposed on the pseudolite PL_iAt each GNSS signal frequency broadcast and to pseudolite PL via said GNSS receiver_iPseudo satellite signal propagation delay rate obtained after broadcast signal is subjected to positioning analysis calculation

9. The method according to any of claims 1-8, wherein the GNSS signals transmitted by each pseudolite in the network are sorted and grouped according to:

the GNSS satellite selected by each pseudolite can be used for the satellite of any system of global positioning or regional positioning;

the geometric layout formed by the GNSS satellites selected by the pseudolites in respective orbits meets the condition that the GNSS receiver can normally position after receiving a single pseudolite signal;

the GNSS satellite and the signal selected by each pseudolite select the same GNSS satellite and the same signal carrier frequency transmitted by the same pseudolite, but the carrier modulation modes are different.

10. A system for synchronized pseudolite positioning, the system comprising a signal generator 201, an integrated pseudolite system 202, a configuration pseudolite system 203, a pseudolite clock synchronization and correction system 204;

The signal generator 201 is a multi-system, multi-frequency-point and multi-navigation signal system signal generator;

the integrated pseudolite system 202 is used for integrating the signal generator 201 with a network communication unit, a reference receiver, a processing unit, a clock synchronization calibration unit and a software component to form an integrated pseudolite system;

the pseudo satellite system 203 is configured to configure the pseudo satellite system simulation GNSS system, the satellite number, the frequency and the modulation mode respectively;

the pseudolite clock synchronization and correction system 204 is configured to set a clock synchronization filter for synchronizing the pseudolite time at the transmitting end, and to control the accurate frequency control clock of each pseudolite to be finely adjusted to achieve synchronization by referring to the measurement parameters sent by the receiver.

Technical Field

The present disclosure relates to the field of satellite navigation, and in particular, to a method and a system for positioning a pseudolite synchronously.

Background

Satellite navigation is a technique for performing one-way ranging on GNSS signals and combining satellite orbit estimation for user position, velocity, and time determination. The satellite navigation receiver can accurately position by utilizing good incident signals, the common single-point positioning precision is 5-10 meters, and the RTK positioning precision can reach centimeter level. However, satellite signals are shielded by buildings and terrains, when the receiver is in environments such as 'urban canyons', tunnels, indoor and deeper mining areas, the number of visible satellites is reduced, the geometrical layout of the constellation is poor, and the usability, integrity and reliability of satellite positioning are seriously reduced.

In response to some of the deficiencies of satellite navigation, pseudolite positioning technology has been developed to some extent. The pseudolite generally adopts a ground-based signal transmitter to provide a GNSS-like positioning signal in an area where a satellite navigation signal is weak or missing, and assists in enhancing the satellite navigation positioning function or realizing independent positioning. The GNSS satellite navigation system can be effectively enhanced by utilizing the pseudolite technology, the number of visible satellites is increased, the geometrical layout of a constellation is improved, and meanwhile, the pseudolite has the characteristics of strong anti-jamming capability, flexible networking and the like.

The design of a pseudolite hardware system emphasizes synchronous pseudolites, reverse pseudolites and forwarding pseudolites according to different functions. The synchronous pseudolite refers to a time system which can keep approximate synchronization with a GNSS satellite clock; the reverse pseudolite is that a pseudolite device transmits signals on a moving platform, and a plurality of fixed receivers receive the signals for positioning; the principle of the repeater pseudolite is that received real GNSS signals are re-transmitted in different places after being amplified, the GNSS signals from different directions are converged at the position of a receiving antenna of the repeater pseudolite, the arrival time of each satellite signal is fixed, and almost no method is available for adjusting through extra processing, so that if the repeater signals are directly used for positioning, the obtained resolving data is the position of the receiving antenna and is irrelevant to the position of a user.

When designing a pseudolite positioning system, particularly a pseudolite transmitter, the first problem is how to realize compatibility with the existing GNSS system, GNSS signals and GNSS receivers. In the various pseudolite positioning systems described above, the reverse pseudolite is in principle incompatible with existing GNSS receivers; the transponder pseudolite is best compatible but does not give a dynamic user position, only a fixed position of the pseudolite antenna.

Disclosure of Invention

The disclosed embodiment provides a synchronous pseudolite positioning method and system, which can solve the problem that a reverse pseudolite is incompatible with the existing GNSS receiver in principle in various pseudolite positioning systems; the transponder pseudolite is best compatible but cannot give dynamic user position, only the fixed position of the pseudolite antenna. The method comprises the design and deployment of a pseudo satellite transmitter and a software change scheme of a universal GNSS receiver, realizes the positioning by utilizing pseudo satellite signals in a shielding environment, and simultaneously keeps the hardware compatibility and the bottom layer software compatibility of the GNSS receiver. The technical scheme is as follows:

according to a first aspect of embodiments of the present disclosure, there is provided a method for synchronized pseudolite positioning, the method comprising:

The pseudolite networking configuration is that the pseudolite provides a GNSS recurrent signal S through the No. i pseudolite of a GNSS receiver_iObtaining t by resolving_uThree-dimensional position of time of day

Three dimensional velocityUser clock errorAnd user's clock float

Wherein, t_uA receiver clock; three dimensional position

Is PL_iEstimating a coordinate point;

reproduction of signals S by pseudolite GNSS_iPositioning is carried out, GNSS reproduction signal S_iiRefers to the pseudolite transmissionAntenna phase center coordinate point PL_iPL without being blocked on the connection line of the phase center coordinate point of the GNSS satellite antenna_iAnd the coordinate point receives the arrival signals of the GNSS satellite in real time.

In one embodiment, pseudolite networking configuration refers to networking using M pseudolites in a GNSS signal-obscured environment to provide positioning signals for a GNSS receiver entering the environment;

wherein M represents the number of pseudolites in the network and satisfies

M is greater than or equal to the positioning dimension +1

The location dimension may take 1, or 2, or 3, depending on the environmental characteristics or user requirements.

In one embodiment, the phase center of the networking pseudo satellite transmitting antenna is subjected to position calibration under a geocentric geostationary coordinate system, so that the pseudo satellite positioning coordinate frame is compatible with a GNSS system;

PL for calibrated coordinates of phase center of each pseudolite transmitting antenna _iRepresents where i ∈ [1, 2, …, M]Numbering networked satellites, PL_iCorresponding to pseudolite No. i; satellite-borne signal generator SG of No. i pseudo satellite_iReal-time generation of PL_iGNSS reproduction signal S of coordinate point_iAnd transmitted through the antenna.

In one embodiment, PL_iGNSS reproduction signal S of coordinate point_iMeans PL_iUnder the condition that a connection line between a coordinate point and a GNSS satellite antenna phase center coordinate point is not blocked, the GNSS satellite transmits a signal to directly reach PL_iCoordinate point, PL_iL received in real time by coordinate point_iThe arrival waves of the satellites are combined into a signal,

wherein the content of the first and second substances,to set the GNSS satellite signal to reach PL directly_iIn case of a coordinate point, pseudolite No. iAt PL_iReceived coordinate points

An arrival signal transmitted by a satellite; l is_iThe number of GNSS satellites selected for the ith pseudolite is defined.

According to known PL_iCoordinate points generated and transmitted at PL using a conventional signal source for pseudolite number i_iGNSS reproduction signal S of coordinate point_iThe synchronization between the clock of the pseudo satellite signal generator and the clock of the GNSS system can be realized by a satellite-borne GNSS receiver timing method of the pseudo satellite.

In one embodiment, the user's clock differenceIncluding conventional clock error terms of GNSS receiversPseudolite clock delay Pseudolite PL_iSignal propagation delay of coordinate point from GNSS receiver antenna phase centerAnd clock error noise term of unmodeled errorThe user clock errorIs shown as

User clock float

Including conventional clock drift term of GNSS receiverPseudolite clock delayPseudolite PL_iDoppler generated by relative motion between coordinate point and GNSS receiver antenna phase center

And clock drift noise term for unmodeled errorsUser clock floatIs shown as

Wherein the content of the first and second substances,and

respectively setting the phase center of the GNSS receiver antenna at any PL_iCoordinate point at the same t_uClock difference value and clock drift value of time positioning calculation.

In one embodiment, since the GNSS receiver is a same source clock and the clock difference value and the clock drift value are only related to the GNSS receiver clock, there is a relationship

User clock error

Clock drift with userAre respectively contained

And

the components are common-mode measurement errors of all pseudolites in the network.

In one embodiment, in a clock-synchronized networked pseudolite system, the pseudolite clock has a constant offset from the GNSS system clock,component andthe components also belong to common mode measurement errors of all pseudolites in the network group;

clock error of user

In, GNSS receiver and said pseudolite PL _iWith respect to the pseudolite PL, the distance-induced signal propagation delay with respect to the pseudolite PL_iEach GNSS signal broadcast is the same and is addressed to the pseudolite PL by the GNSS receiver_iPseudo satellite signal propagation delay output after broadcast signal positioning calculation

Float on user's clockIn relation to said pseudolite PL, a GNSS receiver_iIs superimposed on the pseudolite PL, Doppler effect due to the projection component of the velocity in the direct direction_iAt each GNSS signal frequency broadcast and to pseudolite PL via said GNSS receiver_iBroadcast signal is positioned, analyzed and calculatedLate acquired pseudolite signal propagation delay rate

The GNSS signal matching principle and grouping transmitted by each pseudolite in the networking are as follows:

the GNSS satellite selected by each pseudolite can be used for the satellite of any system of global positioning or regional positioning;

the geometric layout formed by the GNSS satellites selected by the pseudolites in respective orbits meets the condition that the GNSS receiver can normally position after receiving a single pseudolite signal;

the GNSS satellite and the signal selected by each pseudolite should select the same GNSS satellite and the same signal carrier frequency transmitted by the same pseudolite.

The synchronous pseudolite positioning method provided by the embodiment of the disclosure can realize GNSS signal compatibility. The signal compatibility means that signal air interface compatibility is realized, and positioning under a GNSS signal shielding environment can be realized by using a networking pseudolite only through a small amount of top-layer software modification; and GNSS system compatibility can be realized. Because the networking pseudo satellite clock system and the GNSS system have constant deviation (quasi-synchronization) and the networking pseudo satellite virtual constellation is consistent with and real-time synchronous with the GNSS system constellation, the GNSS receiver can quickly recapture and track signals for positioning when entering a GNSS shielding environment after outdoor positioning; GNSS system compatibility is also reflected in positioning framework consistency, i.e., the receiver can achieve cold start positioning in a networked pseudolite environment.

According to a second aspect of embodiments of the present disclosure, there is provided a synchronized pseudolite positioning system comprising: the system comprises a signal generator, an integrated pseudolite system, a configuration pseudolite system and a pseudolite clock synchronization and correction system;

the signal generator is a multi-system, multi-frequency-point and multi-navigation signal system signal generator;

the integrated pseudo satellite system is formed by integrating a signal generator, a network communication unit, a reference receiver, a processing unit, a clock synchronization calibration unit and a software component;

Configuring a pseudo satellite system, and respectively configuring a pseudo satellite system simulation GNSS system, a satellite number, a frequency and a modulation mode;

a pseudo satellite clock synchronization and correction system is provided, a clock synchronization filter is arranged for realizing pseudo satellite time synchronization at a transmitting end, and accurate frequency control clocks of all pseudo satellites are controlled to be finely adjusted to achieve synchronization through measurement parameters sent by a reference receiver.

The networking pseudo satellite system provided by the synchronous pseudo satellite positioning system provided by the embodiment of the disclosure is seamlessly compatible with a GNSS system positioning principle framework, and the pseudo satellite positioning can be realized by adopting a common GNSS receiver and a commonly adopted GNSS system positioning method.

Each GNSS satellite orbit can be precisely extrapolated through a long-term orbit prediction algorithm, so that a pseudo-satellite signal generator can generate signals in advance and buffer the signals, the calculation burden of a system is relieved, or an effective way is provided for low-cost application. In a GNSS receiver pseudolite coordinate calculation program, the prior condition of pseudolite stillness is fully utilized, and the algorithm performance and the accuracy of a result are enhanced.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a flow chart of a method of synchronized pseudolite positioning provided by an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a synchronous pseudolite positioning system according to an embodiment of the present disclosure.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.