阅读说明：本技术 一种差分式伪卫星网络时间同步系统与方法 (A kind of differential type pseudo satellite, pseudolite network timing synchronization systems and method ) 是由 王磊 陈锐志 付文举 许钡榛 李涛 周海涛 韩毅 于 2019-08-28 设计创作，主要内容包括：本发明属于导航定位与通信技术领域,公开了一种差分式伪卫星网络时间同步系统与方法,在伪卫星网络中的一个或多个坐标已知的点上安装定位终端设备作为参考站,计算参考站到各个基站的等效基站钟差和钟速参数,将t时刻参考站求解的等效基站钟差数据Dt编制成数据帧,通过通信链路播发给用户；伪卫星终端接收t时刻来自参考站的等效基站钟差数据,利用等效钟差相关信息修正观测到的距离观测值,实现基站的时间同步；用户端进一步求解高精度定位结果。本发明无需改造基站,不依赖具体测距信号体制,简便易行,低成本,高精度,保密性好,部署灵活；本发明不增加伪卫星基站的布设成本和设计成本,实现了升级改造费用低效果。(The invention belongs to navigator fixs and field of communication technology, disclose a kind of differential type pseudo satellite, pseudolite network timing synchronization systems and method, installation positioning terminal equipment is as reference station on point known to one or more coordinates in pseudo satellite, pseudolite network, equivalent base clock deviation and clock rate parameter of the calculating reference station to each base station, the equivalent base clock deviation data Dt that t moment reference station solves is compiled into data frame, is broadcast by communication link to user；Pseudo satellite, pseudolite terminal receive equivalent base clock deviation data of the t moment from reference station, using equivalent clock deviation relevant information amendment observe apart from observation, realize the time synchronization of base station；User terminal further solves high accuracy positioning result.The present invention does not depend on specific distance measuring signal system, simple and easy to do, low cost, high-precision, good confidentiality, deployment is flexibly it is not necessary that base station is transformed；The present invention does not increase the deployment cost and design cost of pseudo satellite, pseudolite base station, realizes the inefficient fruit of upgrading expense.)

1. a kind of differential type pseudo satellite, pseudolite method for synchronizing network time, which is characterized in that the differential type pseudo satellite, pseudolite network time is same One step process includes:

Step 1, installation positioning terminal equipment is as reference on point known to one or more coordinates in pseudo satellite, pseudolite network It stands, obtains equivalent base clock deviation and clock rate parameter of the reference station to each base station, the equivalent base clock that t moment reference station is solved Difference data Dt is compiled into data frame, is broadcast by communication link to user；

Step 2, pseudo satellite, pseudolite terminal are received the equivalent base clock deviation data of t moment reference station, are repaired using equivalent clock deviation relevant information Just observing apart from observation, realize the time synchronization of base station；

Step 3, user terminal further solve high accuracy positioning result.

2. differential type pseudo satellite, pseudolite method for synchronizing network time as described in claim 1, which is characterized in that in step 1, the ginseng The equivalent base clock deviation and clock rate parameter acquiring method stood to each base station is examined to specifically include:

1) equivalent base clock deviation is solved using reference station:

It indicates the equivalent base clock deviation that reference station solves, is different from view of the receiver clock-offsets of each receiver, therefore will ginseng The receiver clock-offsets for examining station are denoted as δ t_R；

2) reference station calculates equivalent base clock deviation change rate, i.e. equivalent base clock rate, calculation method are as follows:

Wherein t moment equivalent base clock rate is denoted asΔ t is the time interval at t and t-1 moment；

3) reference station resolves the equivalent base clock deviation and equivalent base clock rate of each base station of t moment one by one, is denoted as:

Wherein N is the quantity for the base station that reference station can observe.

3. differential type pseudo satellite, pseudolite method for synchronizing network time as described in claim 1, which is characterized in that in step 1, the number According to frame format are as follows:

Data frame format uses time synchronization frame, is encoded using fixed frame length, is verified frame by frame using cyclic redundancy check code；

Synchronous code is designed before frame, is used for time synchronization between reference station and rover station；

Content frame includes time identifier, synchronous for the whole second between reference station and rover station；

The pulse of frame swynchronization code is along for time precise synchronization.

4. differential type pseudo satellite, pseudolite method for synchronizing network time as described in claim 1, which is characterized in that in step 2, the benefit Realize that the time synchronization of base station specifically includes apart from observation with what the amendment of equivalent clock deviation relevant information observed:

(1) when equivalent base clock deviation data are identical with the terminal observation moment, the amendment observation of equivalent base clock deviation can directly be utilized Value indicates are as follows:

In formulaFor after pseudo satellite, pseudolite end correction apart from observation；

From the above equation, we can see that in revised Pseudo-range Observations only include geometric distance, the receiver clock-offsets of terminal and reference station, and Two receiver clock-offsets are all identical to all base stations in synchronization, then equivalent terminal clock deviation are as follows:

Dt=c (δ t_R-δt_U)；

Wherein dt is the equivalent terminal clock deviation as unit of distance；Equivalent terminal clock deviation is taken back formula (5), and that the time can be obtained is same Terminal after step is apart from observation:

r_i=ρ_i+dt+∈_Pi；

Wherein r_iIt is the terminal after time synchronization to i-th base station apart from observation；Terminal after then synchronizing is apart from observation Surplus geometric distance and equivalent terminal clock deviation two, it is all unrelated with the time of base station, it is believed that the distance measuring signal number from different base station Time synchronization on；

(2) when the signal of the equivalent base clock deviation of the reference station and terminal observation moment is not exactly the same, then first by equivalent base Observation moment of the reference moment reduction of clock deviation to terminal, Reduction are as follows:

Wherein t_UIt is terminal signaling observation moment, t_RIt is the reference moment of the equivalent clock deviation of reference station；The reference moment of reference station is equivalent Base station clock deviation observes the moment by equivalent base clock rate linear extrapolation reduction to terminal signaling, is brought directly to formula (5) for correcting Terminal signaling observe the moment apart from observation；

Pseudo satellite, pseudolite terminal completes the observation amendment of each distance one by one, obtains the observation of the distance after all base station times synchronize Value.

5. when a kind of differential type pseudo satellite, pseudolite network for applying differential type pseudo satellite, pseudolite method for synchronizing network time as described in claim 1 Between synchronization system, which is characterized in that the differential type pseudo satellite, pseudolite network timing synchronization systems specifically include:

Pseudo satellite, pseudolite base station: it for receiving the equivalent base clock deviation data from reference station, is corrected using equivalent clock deviation relevant information Observe apart from observation, realize the time synchronization of base station；

Reference station: having real-time communication link between user's positioning terminal, for calculating equivalent base clock deviation data, and will meter The data organization of calculation issues user's positioning terminal by communication link at data frame；

User's positioning terminal: for obtaining more accurately positioning result.

6. differential type pseudo satellite, pseudolite network timing synchronization systems as claimed in claim 5, which is characterized in that user's positioning terminal It specifically includes:

User's positioning terminal can directly carry out the solution of positioning result by noniterative algorithm, can also be eliminated by way of TDOA Equivalent terminal clock deviation parameter recycles location algorithm to carry out location Calculation.

7. a kind of terminal, which is characterized in that the terminal, which is carried, realizes that differential type puppet described in Claims 1 to 4 any one is defended The processor of star method for synchronizing network time, the differential type pseudo satellite, pseudolite method for synchronizing network time include:

Step 1, on point known to one or more coordinates in pseudo satellite, pseudolite network installation positioning terminal equipment as reference station, Obtain equivalent base clock deviation and clock rate parameter of the reference station to each base station, the equivalent base clock deviation that t moment reference station is solved Data Dt is compiled into data frame, is broadcast by communication link to user；

Step 2, pseudo satellite, pseudolite terminal receives the equivalent base clock deviation data of t moment reference station, is repaired using equivalent clock deviation relevant information Just observing apart from observation, realize the time synchronization of base station；

Step 3, user terminal further solves high accuracy positioning result.

8. a kind of computer program product, which is characterized in that the computer program product runs on the processing of claim 7 Device, in processor operation, differential type pseudo satellite, pseudolite method for synchronizing network time step described in perform claim requirement 7.

9. a kind of terminal, which is characterized in that the terminal, which is carried, realizes that differential type puppet described in claim 1-4 any one is defended The processor of star method for synchronizing network time.

10. a kind of computer readable storage medium, including instruction, when run on a computer, so that computer executes such as Differential type pseudo satellite, pseudolite method for synchronizing network time described in claim 1-4 any one.

Technical field

The invention belongs to navigator fix and field of communication technology more particularly to a kind of differential type pseudo satellite, pseudolite network time synchronizations System and method for.

Background technique

Currently, the prior art commonly used in the trade is such that

GPS (GNSS) is able to solve the orientation problem of most of Outdoor Scene, however since signal hides The problems such as gear and electromagnetic interference, still there are many scenes not to be available GNSS location technology.Supplement and expansion as GNSS technology Exhibition, pseudo satellite technology can lay base station according to application scenarios, the orientation problem of special scenes be efficiently solved, especially in room The interior and underground space is widely used.It is limited by cost, pseudo satellite, pseudolite tends not to equip high property as navigation satellite The clock of energy, usually using the crystal oscillator of low cost.Pseudolite positioning multiple pseudo satellite, pseudolite base stations in need cooperate, therefore how Realize that time synchronization accurate between pseudo satellite, pseudolite becomes the bottlenecks and key technology of pseudolite systems performance.

It is designed by signal system, can effectively be promoted using the precision of electromagnetic distance measurement, however different pseudo satellite, pseudolite bases The timing tracking accuracy but restriction by the technology of time synchronization and cost between standing.The pseudo satellite, pseudolite time of mainstream is same at present One step process includes that optical fiber time is synchronous, and GNSS regards method time synchronization altogether, and two-way time comparison time synchronizes, however its cost and Application scenarios are restricted.Optical fiber time synchronization accuracy highest, but fiber plant between base station is needed, deployment cost is higher, Which also limits the distance between base stations.GNSS can realize several nanoseconds of timing tracking accuracy depending on method time synchronization altogether, however its Need can receive the scene of GNSS signal.It is underwater that many closing scenes is waited not to be available in underground.Two-way time comparison time It synchronizes and needs to establish individual time comparison communication link between base station, can also reach relatively high timing tracking accuracy, still This requires phase intercommunication video between base station, limits the distance between base station, and the time synchronization module cost between base station is high It is expensive, it is at high cost.Therefore, the ultimate challenge of the cost and positioning accuracy that restrict pseudolite systems be exactly between pseudo satellite, pseudolite base station when Between it is synchronous.If there is a kind of Time synchronization technique of low-cost and high-precision, so that it may the cost of pseudolite systems is greatly lowered, And promote the positioning performance of pseudolite systems.

In conclusion problem of the existing technology is:

Need the time synchronization implementation by dedicated optical fiber or Radio Link between pseudo satellite, pseudolite base station, time synchronization at This height.

For realizing the synchronous pseudolite systems of chronometer time using GNSS signal, application scenarios are limited.In closed-loop Border, the region that can not receive GNSS signal such as underwater are not available.

Most of the time synchronous method is more demanding to the clock stability of base station.It is same that the stability of clock will affect the time Walk precision, it is therefore desirable to equip expensive clock and realize precise synchronization.

Existing method for synchronizing time depends on the signal system of distance measuring signal, cannot achieve different system signals or different The collaboration chronometer time of structure signal network is synchronous.

Existing pseudolite systems are limited by Time synchronization technique and cost, application scenarios various aspects, cannot achieve essence Close time synchronization.

Solve the difficulty of above-mentioned technical problem:

Pseudo satellite, pseudolite base station time synchronize be pseudo satellite, pseudolite network positions key problem, it usually needs special time synchronization is set Standby and wireless signal transceiver guarantees synchronization accuracy.It realizes low cost, does not depend on the time synchronization skill of distance measuring signal system Art is extremely difficult.

Solve the meaning of above-mentioned technical problem:

The production and lower deployment cost for reducing pseudo satellite, pseudolite base station, are conducive to the application of the popularization of pseudolite systems.

Suitable for it is not necessary that existing base station is transformed, increasing several reference stations on the basis of existing base station is netted be can be realized Base station synchronization, especially suitable for utilizing mobile communications network, the existing infrastructure building positioning such as DTV and digital broadcasting System.

This method is not limited the time synchronization, it can be achieved that between anomeric signals source by ranging signal system.

For this method convenient for providing authorization positioning service, carrying out encryption by the correction broadcast reference station can be realized clothes Business authorization.It is unauthorized to be used to not positioning by distance measuring signal.

Summary of the invention

In view of the problems of the existing technology, the present invention provides a kind of differential type pseudo satellite, pseudolite network timing synchronization systems with Method.

The invention is realized in this way a kind of differential type pseudo satellite, pseudolite network timing synchronization systems and method, the differential type Pseudo satellite, pseudolite method for synchronizing network time includes:

Step 1, installation positioning terminal equipment is as ginseng on point known to one or more coordinates in pseudo satellite, pseudolite network Station is examined, equivalent base clock deviation and clock rate parameter of the reference station to each base station, the equivalent base that t moment reference station is solved are calculated Clock deviation data Dt is compiled into data frame, is broadcast by communication link to user.

Step 2, pseudo satellite, pseudolite terminal receive equivalent base clock deviation data of the t moment from reference station, utilize equivalent clock deviation phase Close Information revision observe apart from observation, realize the time synchronization of base station.

Step 3, user terminal further solve high accuracy positioning result.

Further, in step 1, the equivalent base clock deviation and clock rate calculation method of parameters of the reference station to each base station It specifically includes:

1) equivalent base clock deviation is solved using reference station:

It indicates the equivalent base clock deviation that reference station solves, is different from view of the receiver clock-offsets of each receiver, therefore The receiver clock-offsets of reference station are denoted as δ t_R。

2) reference station calculates equivalent base clock deviation change rate, i.e. equivalent base clock rate, calculation method are as follows:

Wherein t moment equivalent base clock rate is denoted asΔ t is the time interval at t and t-1 moment.

3) reference station resolves the equivalent base clock deviation and equivalent base clock rate of each base station of t moment one by one, is denoted as

Wherein N is the quantity for the base station that reference station can observe.

Further, in step 1, the data frame format are as follows:

Data frame format use time synchronization frame, encoded using fixed frame length, using cyclic redundancy check code (CRC) by Frame check.

Synchronous code is designed before frame, is used for time synchronization between reference station and rover station.

Content frame includes time identifier, synchronous for the whole second between reference station and rover station.

The pulse of frame swynchronization code is along for time precise synchronization.

Further, described to realize base apart from observation using what the amendment of equivalent clock deviation relevant information observed in step 2 The time synchronization stood specifically includes:

(1) it when equivalent base clock deviation data are identical with the terminal observation moment, can directly be corrected using equivalent base clock deviation Observation indicates are as follows:

In formulaFor after pseudo satellite, pseudolite end correction apart from observation.

From the above equation, we can see that only including geometric distance, the receiver clock of terminal and reference station in revised Pseudo-range Observations Difference, and two receiver clock-offsets are all identical to all base stations in synchronization, then equivalent terminal clock deviation are as follows:

Dt=c (δ t_R-δt_U)

Wherein dt is the equivalent terminal clock deviation as unit of distance.When equivalent terminal clock deviation, which is taken back formula (5), can be obtained Between synchronize after terminal apart from observation:

r_i=ρ_i+dt+∈_Pi

Wherein r_iIt is the terminal after time synchronization to i-th base station apart from observation.Terminal distance after then synchronizing is seen Measured value only remains geometric distance and equivalent terminal clock deviation two, all unrelated with the time of base station, it is believed that the ranging from different base station Signal mathematically time synchronization.

It (2), then first will be equivalent when the signal of the equivalent base clock deviation of the reference station and terminal observation moment is not exactly the same To the observation moment of terminal, Reduction is as follows for the reference moment reduction of base station clock deviation:

Wherein t_UIt is terminal signaling observation moment, t_RIt is the reference moment of the equivalent clock deviation of reference station.The reference moment of reference station Equivalent base clock deviation observes the moment by equivalent base clock rate linear extrapolation reduction to terminal signaling, is brought directly to formula (5) and is used for Correct terminal signaling observation the moment apart from observation.

(3) pseudo satellite, pseudolite terminal complete one by one each distance observation amendment, obtain after all base station times synchronize away from From observation.

Further, the differential type pseudo satellite, pseudolite network timing synchronization systems specifically include:

Pseudo satellite, pseudolite base station: for receiving the equivalent base clock deviation data from reference station, equivalent clock deviation relevant information is utilized Correct observe apart from observation, realize the time synchronization of base station.

Reference station: having real-time communication link between user's positioning terminal, for calculating equivalent base clock deviation data, and The data organization of calculating is issued into user's positioning terminal by communication link at data frame.

User's positioning terminal: for obtaining more accurately positioning result.

Further, user's positioning terminal specifically includes:

User's positioning terminal can directly carry out the solution of positioning result by noniterative algorithm, can also be by way of TDOA Equivalent terminal clock deviation parameter is eliminated, other location algorithms is recycled to carry out location Calculation.

Another object of the present invention is to provide a kind of terminal, the terminal, which is carried, realizes the differential type pseudo satellite, pseudolite network The processor of method for synchronizing time, the differential type pseudo satellite, pseudolite method for synchronizing network time include:

Step 1, installation positioning terminal equipment is used as ginseng on point known to one or more coordinates in pseudo satellite, pseudolite network Station is examined, equivalent base clock deviation and clock rate parameter of the reference station to each base station, the equivalent base that t moment reference station is solved are obtained Clock deviation data Dt is compiled into data frame, is broadcast by communication link to user.

Step 2, pseudo satellite, pseudolite terminal receives the equivalent base clock deviation data of t moment reference station, is believed using equivalent clock deviation correlation Breath amendment observe apart from observation, realize the time synchronization of base station.

Step 3, user terminal further solves high accuracy positioning result.

Another object of the present invention is to provide a kind of computer program product, the computer program product runs on place Device is managed, in processor operation, executes the differential type pseudo satellite, pseudolite method for synchronizing network time step.

Another object of the present invention is to provide a kind of terminal, the terminal, which is carried, realizes the differential type pseudo satellite, pseudolite net The processor of network method for synchronizing time.

Another object of the present invention is to provide a kind of computer readable storage mediums, including instruction, when it is in computer When upper operation, so that computer executes the differential type pseudo satellite, pseudolite method for synchronizing network time.

In conclusion advantages of the present invention and good effect are as follows:

The application range of pseudo satellite, pseudolite method for synchronizing network time provided by the invention is not limited by ranging signal system, packet Include but be not limited to 2G, 3G, 4G, 5G mobile communication signal, Wi-Fi, bluetooth, UWB, ZigBee signal, acoustic signals and other tools The special signal of standby TOA distance measurement function.Clock synchronization system of the invention can be used for above-mentioned all signal systems ranging and The time synchronization of pseudo satellite, pseudolite network.

Communication link between reference station of the present invention and user by signal system and is not broadcast form and is limited, and can pass through Broadcast point-to-point is broadcast.And reference station can be laid on the known point in any position, as long as equivalent clock deviation letter can be calculated Breath carries out base station time and synchronizes, and can play the part of the role of reference station.Reference station can pass through the Communications Relay Set outside connection It realizes communication, built-in communication device also can be used.

The effect of its time synchronization of pseudo satellite, pseudolite network timing synchronization systems provided by the invention with method is equivalent not by base station Clock deviation broadcasts the influence of form.The information that reference station is broadcast may include the equivalent clock deviation in base station, the equivalent clock rate in base station or base station Between the information such as differentiated equivalent clock deviation, but it realizes the synchronous effect of base station time in user terminal by broadcasting equivalent clock deviation It is identical.

Pseudo satellite, pseudolite network timing synchronization systems provided by the invention and method time synchronization effect are not positioned by user terminal to be calculated Method influences, the method that TOA or TDOA can be used in user terminal, when not influenced between base station using iterative algorithm or noniterative algorithm Between synchronous effect.

Centralized pseudolite systems time synchronization had both may be implemented in the present invention, and it is synchronous that Distributed Time also may be implemented.In In centralized pseudolite systems, the equivalent clock deviation in base station can be calculated and be broadcast in server end, each in distributed pseudolite systems Reference station voluntarily calculates and broadcasts equivalent clock deviation.

Method for synchronizing time provided by the invention is without changing the infrastructure such as existing pseudo satellite, pseudolite base station, it is only necessary in puppet Several reference stations are laid in satellite network, and the time synchronization of pseudolite systems can be realized.Has low cost, high-performance is not necessarily to The advantages that changing existing infrastructure, not limited by Pseudolite signal system.

The present invention is also equipped with following advantages:

(1) without changing the infrastructure such as existing pseudo satellite, pseudolite base station, not increasing the deployment cost of pseudo satellite, pseudolite base station and setting Cost is counted, the upgrading expense of existing base station is low.

(2) compatible various distance measuring signal systems, including 2G, 3G, 4G, 5G mobile communication signal, Wi-Fi, bluetooth, UWB, ZigBee signal, acoustic signals have the signal of TOA distance measurement function with other.

(3) good confidentiality.Encryption mechanism can be designed in a broadcast signal, so that only positioning can be used in authorized user Service, unauthorized user is receiving Pseudolite signal because time irreversibility leads to not directly carry out location Calculation.

(4) deployment is convenient, at low cost.Whole network only passes through one common broadcast communications link of increase and just solves base Chronometer time stationary problem between standing is not necessarily to high-performance clock, without Technology of Precision Measurement.

(5) flexibly, the distance of pseudo satellite, pseudolite base station is unrestricted, between base station, is all not necessarily between reference station and user for deployment Intervisibility, low to environmental requirement, deployment is flexible and convenient.

(6) it is not influenced by base station spacing size, is not also influenced by user's motion state.

Detailed description of the invention

Fig. 1 is differential type pseudo satellite, pseudolite method for synchronizing network time flow chart provided in an embodiment of the present invention.

Fig. 2 is differential type pseudo satellite, pseudolite method for synchronizing network time schematic diagram provided in an embodiment of the present invention.

Fig. 3 is differential type pseudo satellite, pseudolite network timing synchronization systems structural schematic diagram provided in an embodiment of the present invention.

In figure: 1, pseudo satellite, pseudolite base station；2, reference station；3, user's positioning terminal.

Fig. 4 is differential type pseudo satellite, pseudolite network timing synchronization systems schematic diagram provided in an embodiment of the present invention.

Fig. 5 is the locating effect comparison of the embodiment of the present invention, and the figure illustrates use differential type pseudo satellite, pseudolite time synchronization side The relationship of positioning accuracy and geometric dilution of precision (GDOP) before and after method.

Specific embodiment

In order to make the objectives, technical solutions, and advantages of the present invention clearer, with reference to embodiments, to the present invention It is further elaborated.It should be appreciated that the specific embodiments described herein are merely illustrative of the present invention, it is not used to Limit the present invention.

Existing pseudolite systems are limited by Time synchronization technique and cost, application scenarios various aspects, cannot achieve essence Close time synchronization.