KR100780392B1 - Synchronous Pseudo Satellite Precise Navigation System Using Two-way Pseudo Satellite - Google Patents

Abstract

A pseudolite-based precise positioning system using synchronized two-way pseudolites is provided to enable each sub pseudolite to correct a clock of each sub pseudolite independently by generating visual correction information of a pseudolite at a reference station for pseudolite visual synchronization. A main two-way pseudolite module(701) has a reference clock of a synchronous pseudolite-based precise positioning system(700). At least one sub two-way pseudolite module(702a,702b,702c) is visually synchronized to the reference clock of the main two-way pseudolite module. A moving object(703) determines own position with a single positioning algorithm on the basis of a signal received from the main two-way pseudolite module and the sub two-way pseudolite module, without correction information through data link from a base station.

Description

Pseudolite-based Precise Positioning System using Synchronized Two-way Pseudolites

1 is a block diagram of a precision navigation system using a pseudo-satellite according to the prior art.

2 is a configuration diagram of the pseudo satellite of FIG. 1.

3 is a block diagram of a moving body in the pseudo-satellite system of FIG.

Figure 4a is a block diagram of a precision navigation system using a synchronous pseudo-satellite to synchronize the time of the pseudo-satellite in the reference station according to the prior art.

4B is a block diagram illustrating an algorithm for synchronizing time in the system of FIG. 4A.

5a to 5d is a block diagram of a bidirectional pseudosatellite module according to the present invention.

6 is a switching timing diagram when the transmission and reception antennas are integrated.

7a to 7c is a block diagram of a synchronous pseudo-satellite precision navigation system using a bidirectional pseudo-satellite according to the present invention.

8 is a block diagram showing the configuration of a mobile body in the synchronous pseudo-satellite system of FIG.

9 is a block diagram illustrating a visual error calculation method of a bidirectional pseudo satellite.

10 is a block diagram showing a time synchronization process (time synchronization module and clock providing module).

11 is a conceptual diagram related to a sub pseudosatellite module.

※ Explanation of codes for main parts of drawing

100: precision navigation system using pseudo-satellite

101a, 101b, 101c, 101d: pseudosatellite 103: reference station for visual correction

105, 404, 703: Moving object 107: Visual correction information

301, 801: GPS receiver 302: wireless data link

303, 802: position calculation module

400: Precision Navigation System Using Synchronous Pseudo Satellites

401: primary pseudo satellite module 402a, 402b, 402c: secondary pseudosatellite module

403: reference station for time synchronization 405: precision frequency control clock means

501: antenna 502: antenna switching

503, 900, 901: receiver 504, 902: time synchronization module

505, 903, 904: Clock providing module 506, 905, 906: Pseudosatellite

507: wireless data link

700: Pseudo Satellite Navigation System Using Bi-directional Pseudo Satellite Module

701: main bidirectional pseudosatellite module

702, 702a, 702b, 702c: secondary bidirectional pseudosatellite module

704a, 704b, 704c, 704d: bidirectional pseudosatellite module

705: GPS satellite

1000: visual error calculation unit 1001: visual synchronous loop filter means

1002: reference clock generation unit 1003: numerical control clock generation unit

The present invention relates to a precision navigation system using two-way Pseudolite, and more particularly, to perform a navigation algorithm using a two-way pseudo satellite precisely synchronized with time without the position information of the pseudo satellite. The present invention relates to a precise navigation system using synchronized bidirectional satellites.

Research on satellite navigation systems, which began with the Pentagon's opening of signals from the Global Positioning System (GPS) to the private sector, has now moved beyond research and development to commercialization. For example, the vehicle navigation system or the navigation system of an aircraft or a ship. It is a great advantage of the satellite navigation system that a GPS receiver can know its position relatively accurately anywhere on earth.

However, the conventional GPS can be used only in an area where GPS satellite signals can be received, that is, an area where the GPS satellites are visible from the antenna of the receiver. .

In other words, since the strength of radio waves transmitted from GPS satellites is weak, if satellites are not observed due to the terrain or features and the radio waves are not received, position measurement by GPS is impossible, and GPS is generally used only outdoors when satellites are observed. This is possible and not available indoors, such as inside a building, inside a factory.

According to the navigation system using pseudo-satellite to solve the problem of GPS, the position of the moving object can be measured by receiving the pseudo-satellite signal through the GPS receiver from the pseudo-satellite which generates the same signal as the signal received from the GPS satellite in the room. Can be.

Unlike GPS or Global Navigation Satellite System (GNSS) satellites, pseudo-satellites can be used freely indoors and outdoors, and can be used appropriately in fields such as indoor navigation systems. In addition, when used outdoors, it is possible to construct a navigation system that can operate independently of existing GPS or GNSS satellites.

However, unlike GPS or GNSS systems, pseudo-satellite systems do not synchronize their clocks with each other, which causes very large pseudo-satellite visual errors, making navigation impossible. For this reason, in the pseudo satellite system using the conventional technology, a reference station for generating correction information for correcting the visual error of the pseudo satellite has been installed and operated. The reference station generates correction information for the clock difference of the pseudo-satellite and transmits it to the moving object to enable positioning of the moving object.

1 is a block diagram of a precision navigation system 100 using a pseudo satellite according to the prior art. As shown in the figure, the precision navigation system using pseudo satellites includes pseudo satellites 101a to 101d, a reference station 103, and a moving body 105. As shown in FIG.

As shown in the figure, the pseudo satellites 101a to 101d, which are devices which generate the same signal as the GPS satellite signals, transmit the same signal as the GPS to assist the GPS or in an area where GPS signals cannot be received. It is a component for.

The configuration for pseudolites 101a-101d in FIG. 1 is shown in FIG. 2. Referring to the configuration of the pseudo satellite shown in FIG. 2, each of the pseudo satellites 101a to 101d includes a CPU 201, a C / A code generator 202, a PLL module 203, an L1 filter 204, and an antenna. It can be seen that it is configured to include a (205), the reference clock is supplied to the C / A code generator 202 and PLL module 203 in the direction of the arrow. As shown in FIGS. 1 and 2, the pseudo satellites 101a to 101d modulate a carrier signal by modulating a C / A code and a navigation message, that is, a PRN (Pseudo Random Number) code and a data message, on a carrier of L1 (1575.42 MHz). Is transmitted to the reference station 103 and the moving object 105. That is, the pseudo satellites 101a to 101d serve as another GPS satellite by generating the same signal as the GPS satellites.

In the precision navigation system 100 using the pseudo satellite shown in FIG. 1, the coordinates of the places where the pseudo satellites 101a to 101d are installed are calculated in advance through precise measurement.

The reference station 103 transmits the carrier correction information to the mobile unit 105 using the carrier satellite information received from the pseudo satellites 101a to 101d, and the mobile unit 105 receives the carrier information received from the pseudo satellites 101a to 101d. And its own position using the carrier correction information received from the reference station 103. Here, the carrier correction information is generated using the difference among them.

The moving object 105 does not need a separate receiver and can measure its position by receiving radio waves from the pseudo satellites 101a to 101d using a conventional GPS receiver. The precision navigation system 100 using the pseudo satellites 101a to 101d can be effectively used to track the location of a person in a building and to track the location of a mobile robot that runs inside a factory. When the moving object moving in the outdoor moves in the position can be measured continuously.

The conventional pseudo-satellite navigation system determines the position of a moving object using pseudo-synchronized satellites that are not visually synchronized, and calculates pseudo-satellite clock error correction information included in pseudo-range and carrier phase caused by visual asynchronous between pseudo-satellites. In order to eliminate the error, a reference station that measures clock difference information between all pseudolites, that is, pseudorange and carrier phase correction information, is required.In order to transmit such correction information to a moving object, a data link must be established between the reference station and the moving object. And an additional algorithm must be provided for sampling time synchronization between the mobile station and the reference station according to data link setup.

)와 도플러 측정치(

)는 수학식 1과 같다.Carrier phase (P1R) measurement value of the first satellite 101a measured at the reference station 103 of the conventional pseudo-satellite navigation system 100 as shown in FIG.

) And Doppler measurements (

) Is the same as Equation 1.

here,

: 제1의사위성(101a)의 신호 송출 안테나와 기준국(103)의 수신기 안테나간 거리

: Distance between signal transmitting antenna of first satellite 101a and receiver antenna of reference station 103

: 기준국(103)의 수신기 클럭 바이어스

: Receiver clock bias of reference station 103

: 제1의사위성(101a) 클럭 바이어스

: First Satellite (101a) Clock Bias

: 반송파의 파장(

)

Is the wavelength of the carrier (

)

: 제1의사위성(101a)과 이동체(105)간의 반송파 위상 미지정수

: Carrier phase unknown constant between first satellite 101a and moving object 105

: 반송파 위상 측정 잡음

: Carrier Phase Measurement Noise

: 기준국(103)의 수신기 클럭 드리프트

: Receiver clock drift of the reference station 103

: 제1의사위성(101a) 클럭 드리프트

: First satellite 101a clock drift

: 도플러 측정 잡음

Doppler Measurement Noise

)와 도플러 측정치(

)는 수학식 2와 같다.The carrier phase (P2R) measurement value of the second satellite 101b measured by the reference station 103 (

) And Doppler measurements (

) Is the same as Equation 2.

here,

: 제2의사위성(101b)의 신호 송출 안테나와 기준국(103)의 수신기 안테나간 거리

: Distance between signal transmitting antenna of second satellite 101b and receiver antenna of reference station 103

: 기준국(103)의 수신기 클럭 바이어스

: Receiver clock bias of reference station 103

: 제2의사위성(101b)의 클럭 바이어스

: Clock bias of the second satellite 101b

: 반송파의 파장(

)

Is the wavelength of the carrier (

)

: 제2의사위성(101b)과 이동체(105)간의 반송파 위상 미지정수

: Carrier phase unknown constant between second satellite 101b and moving object 105

: 반송파 위상 측정 잡음

: Carrier Phase Measurement Noise

: 기준국(103)의 수신기 클럭 드리프트

: Receiver clock drift of the reference station 103

: 제2의사위성(101b)의 클럭 드리프트

: Clock drift of the second satellite 101b

: 도플러 측정 잡음

Doppler Measurement Noise

The reference station 103 performs a differential operation on the carrier phase value and the Doppler value measured as in Equation 1 and Equation 2 as in Equation 3.

은 미지수가 아닌 상수항이 된다.In Equation 3, it is assumed that the positions of the signal transmitting antennas of the pseudo satellites 101a to 101d and the receiver antenna positions of the reference station 103 are known correctly. In practice, the position of each antenna can be determined accurately by positioning. therefore

Is a constant term rather than an unknown.

) 및 클럭 차이의 속도(

)를 연산 수행한다.The reference station 103 rounds up the carrier phase difference in Equation 3 using the characteristic that the carrier phase unknown constant is an integer so that the clock difference between the first and second satellites 101a and 101b as shown in Equation 4

) And the speed of the clock difference (

Operation).

) 및 클럭 차이의 속도(

)는 다음과 같은 성질을 갖는다.In the related art, the clock difference (the clock difference)

) And the speed of the clock difference (

) Has the following properties:

) 및 클럭 차이의 속도(

)를 연산 수행하여 기준국(103)과 이동체(105)간에 설정된 데이터 링크를 통해 이동체(105)로 전송해야 하며, 이 때, 이동체(105)와 기준국(103) 수신기의 샘플링 시각 동기를 위해 별도의 방법을 사용하여야 한다.Accordingly, in order to calculate pseudorange clock error correction information included in pseudoranges and carrier phases caused by asynchronous time between pseudolites, the reference station 103 is used for all pseudolites in all pseudolites. Clock difference

) And the speed of the clock difference (

) Must be performed and transmitted to the moving object 105 through the data link established between the reference station 103 and the moving object 105, and at this time, for the sampling time synchronization between the moving object 105 and the reference station 103 receiver. A separate method should be used.

) 및 클럭 차이의 속도(

))를 계산하기 위하여 별도의 기준국을 사용해야 한다는 문제점이 있으며, 이러한 클럭차이정보를 이동체에 전송하기 위해서는 기준국과 이동체간에 데이터 링크가 설정됨으로써 이동체의 장비 복잡성, GPS 수신 이외의 기준국-이동체간 데이터 링크 추가로 인한 가격 상승, 잦은 고장이 유발된다는 문제점이 있다. In other words, since pseudo satellites use a low temperature oscillator (TCXO) unlike GPS satellites, the position of the mobile body is calculated using a pseudo satellite group whose time between all pseudo satellites is not exactly synchronized. Pseudo-distance and carrier phase correction information caused by asynchronous time between pseudo-satellites (clock difference between i-th satellite and j-th satellite)

) And the speed of the clock difference (

There is a problem that a separate reference station should be used to calculate)), and in order to transmit the clock difference information to the moving object, a data link is established between the reference station and the moving object. There is a problem that a price increase and frequent failure are caused by the addition of interbody data link.

3 is a block diagram showing the configuration of a mobile body in the pseudo-satellite system of FIG. As can be seen in Figure 3, the moving object is a GPS receiver 301 for receiving a GPS or pseudo-satellite signal, a wireless data link 302 for receiving a vision correction message, and all of them are integrated to calculate the position of the moving object. It is composed of a position calculation module 303. As such, additional radio data link 302 equipment is necessary for the mobile device in the asynchronous pseudo-satellite system.

In addition, there is a problem that an additional algorithm must be provided for sampling time synchronization between the mobile station and the reference station. If the time between the pseudo satellites is not synchronized, the time between the reference station and the moving object is also not synchronized so that the reference station and the moving object sample the signals received from the pseudo satellite at different times. In this case, a time-tag error occurs by calibrating navigation with data sampled at different times. In order to solve this problem, a navigation message frame of master pseudolite is used as a reference. Another method is to synchronize the sampling time of the station and the mobile.

In order to solve the problems of the asynchronous pseudo-satellite system described above, a synchronous pseudo-satellite precision navigation system is proposed. It divides the pseudo satellite group into the main pseudo satellite and the sub pseudo satellites equipped with the precision frequency control means, and receives the signals of all pseudo satellites from the reference station, and the clocks of other sub satellites are added to the clock of the pseudo satellite selected as the main pseudo satellite. By synchronizing, it is a system that can perform navigation algorithm using pseudo-synchronized with accurate time synchronization.

Figure 4a shows a precise navigation system using a synchronous pseudo-satellite to synchronize the time of the pseudo-satellite in the reference station according to the prior art as described above.

The synchronous pseudo-satellite system of FIG. 4A receives the signals of the main pseudo satellite 401 and the sub pseudo satellites 402a to 402c from the reference station 403 to generate a time synchronization command, and uses them to clock the sub-satellite clock. It is a system that synchronizes the clock of the main pseudo-satellite. When using this system, it is possible to synchronize the time of the sub pseudo satellites with the time of the main pseudo satellite using the reference station, and as a result, the clock between all pseudo satellites is synchronized. Therefore, the mobile unit 404 can be independently navigated with only the pseudo-satellite signal received by the receiver without any additional information. The reference station estimates the visual error between each pseudo-satellite, generates the visual synchronization information based on this, and sends it to each sub-satellite and sends the clock of each sub- pseudo-satellite using the precision frequency control clock means. Motivate to

For a method of calculating the visual error in the above navigation system, refer to FIGS. 4B and 4. The reference station 403 receives signals from the main pseudo satellite 401 and the sub pseudo satellite 402, respectively. And visual error is calculated by Equation 4. Using this error, visual synchronization information is generated and sent to the precision frequency control clock means to provide a synchronized clock to the sub satellite.

The above invention has the great advantage that the moving object can perform navigation without any correction information from the outside by synchronizing the clock of the pseudo satellite. The moving object is capable of single-level navigation at the m or cm level without any correction information, and can continuously monitor and synchronize the pseudo-satellite clock at the reference station.

However, the key to pseudo-satellite clock synchronization algorithm in the above invention is to find out the difference between pseudo-satellite clocks. As shown in Equation 4, the difference of the actual distance from the difference of the distance measured by the signal between the main and sub-satellite satellites is calculated. The subtracted value is regarded as the clock difference between pseudolites. That is, the clock difference can never be known without the pseudo satellite and the position information of the reference station. Therefore, the position of the pseudosatellite should always be fixed and the reference station should also be in a fixed position. In addition, because the reference station must always be present, if a problem occurs in the reference station, the entire system is shut down. This means that the whole system is absolutely dependent on the reference station. In addition, the visibility of the pseudosatellite in the reference station should not be affected since the reference station must continue to receive signals from the pseudosatellite.

In other words, the conventional synchronous pseudo-satellite navigation system has a problem that the reference station must exist and the pseudo satellite can be synchronized only by knowing the position of the pseudo satellite and the position of the reference station, so that the pseudo satellite has a limitation that it must be fixed. have.

Therefore, the present invention can independently perform pseudo-satellite clock generation in the reference station by calibrating the clocks of the pseudo-satellite satellites in the conventional station for pseudo-satellite visual synchronization. It was designed to make it possible.

The present invention can perform a navigation algorithm using a pseudo satellite precisely synchronized with other clocks by synchronizing its own clock with the pseudo satellite clock selected as the main pseudo satellite among the pseudo satellite groups without any correction information. The purpose is to provide a precise navigation system using a synchronous pseudo-satellite.

In the present invention, in order to synchronize its own clock with an external pseudo satellite or a main pseudo satellite, the secondary pseudo satellite is a bidirectional pseudo satellite so that the clock can be synchronized with only a received signal without using any position information including its own position. Develop and use

Since the synchronization algorithm proposed by the present invention does not use any position information, even if the bidirectional pseudo-satellite is mounted on a moving mobile object, there is no problem in performing synchronization between pseudo-satellites. That is, even if the bidirectional pseudo-satellite proposed in the present invention is mounted on a moving object, the visual synchronization of the pseudo-satellite is not affected. In other words, we propose a moving satellite.

Those skilled in the art to which the present invention pertains can easily recognize other objects and advantages of the present invention from the drawings, the detailed description of the invention, and the claims.

The present invention relates to a synchronous pseudo-satellite precision navigation system for determining the position of a moving object using a visually synchronized pseudo-satellite, comprising: a main bidirectional pseudo-satellite module having a reference clock of a navigation system; At least one sub-bidirectional pseudosatellite module visually synchronized with a reference clock of the primary bidirectional pseudosatellite module; And a moving body for determining a magnetic position by a mononavigation algorithm based on signals received from the main bidirectional pseudo satellite module and the sub bidirectional pseudo satellite module without correction information through a data link from a reference station.

The main difference between the conventional synchronous pseudosatellite system and the present invention is the difference between the presence of a reference station, the installation method of the pseudosatellite module, and the visual synchronization algorithm. In order to solve all three problems, the present invention introduces a two-way Pseudolite module. Bi-directional pseudo-satellite module supplies pseudo-satellite to generate and transmit signals, receiver to receive signals from external pseudo-satellite or GPS satellites, visual synchronization module to calculate visual errors between pseudo-satellites, clock to pseudo-satellite and receiver, It consists of a clock providing module that can adjust the clock.

Structure, description and implementation method of bidirectional pseudosatellite module

In the bidirectional pseudosatellite module proposed in the present invention, the main pseudo satellite module and the sub pseudo satellite module have slight differences, but the core matters are the same. Therefore, the description will be based on the pseudo-satellite module. This is because the main pseudosatellite module only needs to remove the visual synchronization module from the subsatellite module.

The main feature of a bidirectional pseudosatellite is that it can shoot and receive signals. You should be able to generate and transmit your own signals and receive your own signals as well as signals from other pseudo-satellite or satellite navigation systems. In addition, it should be possible to synchronize the signal by adjusting the clock of the pseudo satellite which is the transmitter. In consideration of these points, the bidirectional pseudo-satellite module should include a pseudo-satellite, a receiver, a receiver, and a time synchronization module and a clock providing module.

To sum it up again, the bidirectional pseudo-satellite module is composed of four modules as shown below.

The first is the pseudo satellite, which is the transmitter. Pseudosatellite generates and transmits a signal suitable for its setting by the clock supplied from the clock providing module. Pseudosatellite is not very different from the conventional pseudosatellite, but the clock provided by the external clock providing module should be available as the main clock, and the control signal should be generated for the antenna switching.

Second is a receiver which is a receiver. The receiver is responsible for receiving its own signals and satellite signals from external pseudosatellite and satellite navigation systems. This is not much different from the conventional receiver, but in order to minimize pseudo-satellite and phase noise of the receiver, it is preferable to share a clock such as pseudo-satellite, and therefore, a clock provided by an external clock providing module should be used.

Third, the time synchronization module generates a time synchronization command through the time synchronization loop filter means by deriving a time error from the information received from the receiver. This part is much different from the conventional invention, and the algorithm therein will be described later.

The fourth is a clock providing module that substantially generates a clock and supplies a reference clock to the pseudo satellite and the receiver. The clock providing module adjusts and generates a clock based on the time synchronization command generated by the time synchronization module, and supplies the adjusted clock. It has a reference clock. Based on the stability of the reference clock, it generates a desired clock based on the time synchronization command and supplies it to the pseudo satellite and the receiver.

Through these four modules, the bidirectional pseudo-satellite module generates a signal synchronized with the reference signal.

The bidirectional pseudo-satellite module proposed in the present invention has various methods for its implementation. In the present invention proposal, four representative examples of FIGS. 5A to 5D are illustrated. Of course, there may be various implementation methods in addition to the four proposed in the present invention, but considering the most important, it can be divided into four, other methods can be said to use these four.

All four of FIGS. 5A-5D show a bidirectional pseudosatellite module. 5A and 5B show that the pseudo satellite 506 as the transmitter and the receiver 503 as the receiver use independent antennas. FIGS. 5C and 5D show the pseudo satellite 506 as the transmitter and the receiver 503 as the receiver. One antenna is used in common. 5A and 5C show a method of using a separate wireless data link 507 device for data exchange between pseudo satellites, and FIGS. 5B and 5D show a method of using pseudo satellite data messages for data exchange between pseudo satellites. . When you mix these two most basic things, you come up with four different approaches.

Although the reason will be mentioned later in describing the synchronization algorithm of the bidirectional pseudo-satellite, the synchronization algorithm proposed by the present invention should receive not only the signal of the counterpart pseudo-satellite but also its own signal (see FIG. 9). Therefore, the pseudo-satellite should be a structure that can receive both its own signal and an external signal, and the method of implementing this method is to integrate the antenna of the transceiver and the transmitter and receiver in a large way. There is a way.

Independently using the transmitter and the receiver antennas has the advantage of being easy to implement, while there is a possibility that signal interference occurs because the distance between the two antennas is too close. One way to minimize this is to use a pulsing technique for pseudo-satellite signals. The pulsing technique does not emit pseudo-satellite signals continuously, but emits signals only for a certain period of time within 1ms, and does not transmit signals at other times. Transmit signal only for 5-20% of the time. Since the pulsing technique is already popularized in the research field related to the present invention, a detailed description thereof will be omitted.

The use of one antenna by integrating the antenna of the transmitter and the receiver is relatively difficult compared to the former, but has the advantage of low interference. In order to use a single antenna, the antenna must be able to perform both a transmitter and a receiver. To this end, an antenna switching module is introduced. That is, the antenna plays a role of a transmitting antenna at some time, and serves as a receiving antenna at other times. The key to this antenna switching algorithm is that the switching timing of the antenna must match the pulsing timing of the pseudosatellite. As shown in FIG. 6, when the pulsing of the pseudo satellite is turned on, the receiver can receive only a signal of the corresponding pseudo satellite (pseudo-satellite in the same module), and the antenna switching module operates so that external signals cannot be received. On the other hand, if pulsing of the pseudo satellite is turned off, the receiver can only receive external signals. When the antenna switching module is used, the bidirectional pseudo-satellite module can receive both its own signal and external signals while using one antenna.

Another consideration in implementing a bidirectional pseudosatellite module is that data must be exchanged between pseudolites. This is also necessary for the implementation of the synchronization algorithm proposed in the present invention, for which two communication schemes can be implemented.

The first is to mount an independent wireless data link module on the bidirectional pseudo-satellite module. 5A and 5C illustrate this implementation. Secondly, the data is included in the data message included in the signal and transmitted. In this case, the counterpart receiver may extract the desired data by receiving the corresponding signal, thereby enabling data communication. 5B and 5D are implementations thereof. Of course, in order to implement the method of FIGS. 5B and 5D, there is a clue that the stability of the pseudo-satellite clock must be very high or the data rate must be high.

To summarize the configuration of the pseudo-satellite module and its implementation, FIG. 5C can be described as a representative. In the antenna switching module 502, the antenna 501 may be switched to a transmitter or a receiver, and the switching is performed by a pulsing signal of the pseudo satellite 506.

The receiver 503 transmits the data received by the receiver 503 to the time synchronization module 504 and also to other pseudo satellites through the wireless data link 507. In addition, a signal from the receiver of another pseudo-satellite or primary pseudo-satellite module entered via the wireless data link 507 is also transmitted to the time synchronization module 504. The time synchronization module 504 calculates a time error, thereby generating a time synchronization command and transmitting it to the clock providing module 505. In the clock providing module 505, the main clock is supplied to the receiver 503 and the pseudo satellite 506, and the stable main clock is supplied to the receiver 503, and the pseudo satellite 506 is controlled by a time synchronization command. Will supply the clock. The pseudosatellite 506 is thus supplied with a controlled clock, which generates and transmits a signal. Through this process, the signal of the pseudo satellite 506 is synchronized with the signal of the main pseudo satellite or the satellite navigation system.

Bidirectional Pseudo Satellite Navigation System Description

The pseudosatellite precision navigation system 700 using the bidirectional pseudosatellite module proposed by the present invention is capable of synchronizing the clock of a moving pseudosatellite. 7A-7C all show a pseudosatellite precision navigation system 700 using a bidirectional pseudosatellite module. The implementation is divided into many ways, but the core algorithms are almost the same.

System for moving pseudosatellite modules

The pseudosatellite precision navigation system 700 of FIG. 7A is based on a moving bidirectional pseudosatellite module. That is, FIG. 7A is represented in the form of an instrument to shape a moving bidirectional satellite module. As shown in the figure, the bidirectional pseudo-satellite module is composed of a main bidirectional pseudosatellite module 701, a bidirectional pseudosatellite module 702a, 702b, and 702c, and a moving object 703. Each bidirectional pseudo-satellite module transmits its own signal, receives each other's signal and its own signal, and compares its own signal with the signal of the main bidirectional pseudo-satellite module 701 to transmit its own signal. The signal of the pseudo satellite module 701 is synchronized. In addition, when the main bidirectional pseudo-satellite module 701 and the sub bidirectional pseudosatellite modules 702a, 702b, and 702c are synchronized with each other, even if a problem occurs in the visibility of the main bidirectional pseudosatellite module 701, the subdirectional bidirectional satellite modules 702a and 702b , 702c) can be synchronized with each other, thereby maintaining the stability of the clocks. As already mentioned, the bidirectional pseudosatellite modules are all moving, and the moving object 703 is also moving. The bidirectional pseudosatellite modules in motion can synchronize their clocks without each other's position information, thereby allowing the mobile unit 703 to obtain its position with a mononavigation algorithm without clock correction information.

FIG. 8 is a configuration diagram of the mobile body 703 in the synchronous pseudo-satellite system of FIG. Compared with the configuration diagram of the mobile body of the asynchronous pseudo-satellite system 100 (FIG. 3), the mobile body 703 of the pseudo-satellite precision navigation system using the bidirectional pseudo-satellite module according to the present invention does not require additional wireless data link equipment. Therefore, a simpler use is possible from the user's point of view, and the cost is much greater.

System for Fixed Pseudo Satellite Module

If FIG. 7A is for a moving pseudosatellite, FIG. 7B is a pseudosatellite navigation system 700 using a fixed bidirectional satellite module. Referring to the system of FIG. 7B, all pseudosatellite modules are in a fixed state, and are similar to the synchronous pseudosatellite precision navigation system 400 according to the prior art of FIG. 4, except that there is no reference station.

However, the conventional synchronous pseudo-satellite navigation system generates visual synchronization information by receiving signals of each pseudo-satellite from the reference station, while the pseudo-satellite navigation system using the fixed bidirectional satellite module according to the present invention has no reference station. The bidirectional pseudo-satellite module generates time synchronization information by itself and adjusts its clock to the clock of the main bidirectional pseudo-satellite module 701. In addition, while the conventional synchronization algorithm uses the position information of each pseudo satellite and the reference station, the synchronization algorithm of the present invention synchronizes the clock of the pseudo satellite without using any position information.

Therefore, in the conventional synchronization algorithm, the positional error of the pseudo-satellite affects the pseudo-satellite time synchronization, whereas the positional error of each pseudo-satellite does not affect the time-synchronization in the time synchronization algorithm proposed by the present invention. This enables more accurate time synchronization.

Integrated system of satellite navigation system and pseudosatellite module

In addition, the system proposed in the present invention can be integrated with the satellite navigation system. Satellite navigation systems include the current GPS in the US, GLONASS in Russia and Galileo in Europe. Focusing on the most popular and popular GPS, the biggest limitation in using GPS and pseudo-satellite is that the clock is not synchronized. This results in very large clock errors.

One way to correct this is to calculate the clock error and send it to the mobile. When using this method, the mobile device must have additional data link equipment, which causes problems in terms of utility. Another way is to synchronize the pseudolite's clock with GPS. In this method, since the moving object can find its position by a single navigation algorithm, the utility greatly increases. For this purpose, the clock synchronization of the GPS and the pseudo satellite must be solved first. When using the bidirectional pseudo satellite module proposed in the present invention, it is possible to synchronize the clock of the pseudo satellite with the GPS.

7C illustrates a navigation system incorporating a GPS satellite 705 and a bidirectional pseudosatellite module 704a through 704d in accordance with one embodiment of the present invention. The clock synchronization algorithms of the GPS satellites 705 and the bidirectional pseudosatellite modules 704a to 704d are slightly different from the synchronization algorithms of the bidirectional pseudosatellite modules. In the case of this algorithm, the location information of the GPS satellite 705 and the bidirectional pseudosatellite modules 704a to 704d should be used.

Time synchronization  algorithm - Visual error  Calculation plan

The synchronization algorithm, which is the core of the present invention, will now be described. The pseudosynchronous clock synchronization algorithm proposed in the present invention uses a bidirectional distance positioning technique. 9 is a block diagram illustrating a clock synchronization algorithm of a bidirectional pseudo-satellite module. When the left side of FIG. 9 is referred to as the main bidirectional pseudo-satellite module 701 and the right side is referred to as the sub-bidirectional pseudosatellite module 702, the main bidirectional pseudosatellite module 701 becomes a reference clock, thus eliminating the need for a visual synchronization module. . Therefore, only the secondary bidirectional pseudo-satellite module 702 includes the time synchronization module 902. In order to implement this synchronization algorithm, the bidirectional pseudo-satellite module should be able to receive not only the signal of the other party but also its own signal. Refer to the equation below to understand this mathematically.

In fact, the delay exists because it takes time to send the measurements of the primary bidirectional pseudosatellite module 701 to the secondary bidirectional pseudosatellite module 702, but since the value can be assumed to be very small, ignore this.

First, a single difference with respect to the pseudorange measurement can be obtained as shown in Equation 6 below.

Then, two equations obtained in equation (6) are added and the equations are summed up to obtain equation (7).

)이다. 의사거리의 잡음 수준이 약 1m 정도 이므로, 위의 방법으로 부 양방향 의사위성 모듈(702)의 클럭을 주 양방향 의사위성 모듈(701)의 클럭에 동기시킬 경우, 약 1-2m 정도의 정확도로 동기가 가능하다.In Equation 7, the value we can obtain is the visual error value between the primary bidirectional pseudo-satellite module 701 and the secondary bidirectional pseudo-satellite module 702.

)to be. Since the noise level of the pseudorange is about 1 m, when the clock of the sub-bidirectional pseudo-satellite module 702 is synchronized with the clock of the main bi-directional pseudo-satellite module 701 by the above method, it is synchronized with an accuracy of about 1-2 m. Is possible.

Similarly to pseudorange, the following equation 8 can be obtained by single difference of the carrier phase measurement.

)을 얻을 수 있다. 게다가 반송파 위상 측정치의 잡음 수준이 약 3mm인 것을 감안할 때, 반송파 위상 측정치를 이용하여 클럭을 동기시키면 mm 수준의 클럭 동기가 가능하다.The sum of the single difference values of the measured values of Equation 8 is added together, and the visual error between the main two-way pseudo satellite module 701 and the second two-way pseudo satellite module 702 as shown in Equation 9 similarly to Equation 7 using the pseudo distance measurement. Value (

) Can be obtained. In addition, considering that the noise level of the carrier phase measurement is about 3 mm, clock synchronization using the carrier phase measurement enables clock synchronization at the mm level.

)을 풀어야 한다. 미지정수를 해결하는 방법은 여러 가지가 있으므로 여기서는 이에 대한 것은 생략하겠다.Of course, in order to use the carrier phase measurement,

) Must be solved. There are several ways to solve the unknown, so I will skip this here.

Using Equations 7 and 9 above, it is possible to obtain a visual error between the main bidirectional pseudo-satellite module 701 and the secondary bidirectional pseudo-satellite module 702 without any positional information. Therefore, clock synchronization between the pseudo satellite modules is possible even for the pseudo satellite module moving as shown in FIG. 7A.

Time synchronization  algorithm - Time synchronization  process

Equations (7) and (9) can be used to determine the clock difference between each pseudosatellite module. Thereafter, a procedure for synchronizing clocks using clock differences between pseudosatellite modules is described, which is described with reference to FIG. 10.

)를 계산하고, 시각동기루프필터수단(1001)을 통해 시각동기명 령(U _k )을 생성하여 이를 클럭제공모듈(904)에 보내게 된다.The time synchronizing module 902 generates a clock synchronizing command using a time error. The time synchronizing module 902 is largely divided into two parts, a time error calculating unit 1000 and a time synchronizing loop filter means 1001. The time error calculator 1000 calculates a time error between pseudo-satellite modules from data from the receiver, and the time synchronization loop filter means 1001 generates a time synchronization command using the calculated time error. That is, the time synchronization module 902 receives the measurement value of the receiver and the time error between each pseudo-satellite module through the time error calculation unit 1000 (

), And generate the time synchronization command ( U _k ) through the time synchronous loop filter means 1001 and send it to the clock providing module 904.

The clock providing module 904 is largely composed of two parts, one of which is the reference clock generating unit 1002 that generates the reference clock Ref CLK, and by the time synchronization command U _k using the reference clock. The numerical control clock generator 1003, which generates a properly controlled clock, is another part. The numerical control clock generation unit 1003 generates a desired clock and supplies it to the pseudo satellite module. Through this process, the clock of the pseudo satellite module is synchronized with the clock of another pseudo satellite module.

Overview of the invention

Referring to FIG. 11, according to the present invention, a receiver 901 of each sub-bidirectional pseudo-satellite module 702 simultaneously receives a signal from the main pseudo-satellite module and a magnetic signal, and the clock synchronization module 902 receives the clock. The difference is calculated, and a synchronization command for correcting the difference is generated and sent to the clock providing module 904. The clock providing module 904 generates a clock according to the command received from the time synchronization module 902, and provides the clock to the pseudo satellite 906 and the receiver 901 so that the pseudo satellite can control its clock. Will be.

As a result, if each pseudo-satellite group is motivated to the main pseudo-satellite, the moving object can be positioned with the accuracy of about centimeter or meter without correction information generated by the reference station, and connects the reference station and the mobile to transmit the correction information. It is possible to implement a precision navigation system that does not require a data link. As already mentioned, in the optical synchronization algorithm of the present invention, the pseudo-satellite clock can be synchronized without using the pseudo satellite and any other positional information, so that the pseudo-satellite clock can be synchronized even when the moving satellite is mounted on the moving satellite.

That is, according to the present invention, it is possible to implement a navigation system that can accurately calculate its position without receiving correction information by accurately synchronizing the clock of a pseudo satellite that transmits the same signal as a GPS satellite.

In addition, the bidirectional pseudo-satellite module of the present invention is capable of visual synchronization with existing or developed satellite navigation systems such as the GPS of the United States, GLONASS of Russia, and Galileo of Europe. In this case, the bidirectional satellite module of the present invention may be integrated with the satellite navigation system. . In the user particle, weakness or accuracy of the satellite navigation system can be corrected by the bidirectional satellite system.

Therefore, according to the present invention, since the pseudo-satellite navigation system determines the position of the moving object using the time-synchronized pseudo-satellite, a reference station for measuring clock difference information between pseudo-satellites, that is, pseudo range and carrier phase correction information, is unnecessary. In order to transmit information to the mobile, no data link is required between the reference station and the mobile. In addition, an additional algorithm is unnecessary to synchronize the sampling time of the mobile station and the reference station according to the data link setting between the reference station and the mobile station. In addition, since the pseudo-satellite can be mounted on a moving vehicle, the pseudo-satellite can be overcome.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes are possible in the technical field of the present invention without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

As described above, by synchronizing the pseudo-satellite clock in the navigation system using the bi-directional pseudo-satellite module according to the present invention, the pseudo-satellite visual errors included in the carrier phase or pseudo-distance are all the same, and thus the mobile body is no longer subject to correction information of the reference station. You can calculate your position accurately without relying on it.

In addition, since synchronization is possible without using any distance information or position information, it becomes possible to mount and use a bidirectional pseudo-satellite module on a moving object.

That is, according to the present invention, since the pseudo-satellite navigation system determines the position of the moving object using the time-synchronized bidirectional pseudo-satellite module, a reference station for measuring clock difference information between pseudo satellites, that is, pseudo range and carrier phase correction information, is unnecessary. In order to transmit the correction information to the moving object, no data link is required between the reference station and the moving object. Further, an additional algorithm is also unnecessary for synchronizing the sampling time of the mobile station and the reference station according to the data link setting between the reference station and the mobile station.

In addition, since the two-way pseudo-satellite module is mounted on the mobile body, visual synchronization between pseudo-satellites is possible, and thus the implementation and operation of the bi-directional pseudo-satellite module are much smaller than those of the prior art. It becomes very wide.

Claims (21)

In a synchronous pseudo-satellite precision navigation system for determining the position of a moving object using visually synchronized pseudo-satellite, A main bidirectional pseudosatellite module having a reference clock of the navigation system; At least one sub-bidirectional pseudo-satellite module visually synchronized with a reference clock of the main bi-directional pseudosatellite module; And Synchronous pseudo-satellite precision navigation system including a moving object for determining a magnetic position by a mono-navigation algorithm based on signals received from the primary bidirectional pseudo-satellite module and the secondary bidirectional pseudo-satellite module without correction information through a data link from a reference station. . The method of claim 1, The main bidirectional pseudosatellite module, A pseudo satellite generating a signal suitable for its setting according to a reference clock and transmitting the same; A receiver capable of receiving both its own signal and a signal from an external pseudosatellite; And And a clock providing module for supplying a reference clock to the pseudo satellite and the receiver. The method of claim 1, The secondary bidirectional pseudo-satellite module, A pseudo satellite generating a signal suitable for its setting according to a reference clock and transmitting the same; A receiver capable of receiving both its own signal and a signal from an external pseudosatellite; A time synchronization module for calculating a time error based on the information received from the receiver, and generating a time synchronization command using the same; And And a clock providing module for generating a clock by receiving a time synchronization command from the time synchronization module and supplying a reference clock to the pseudo satellite and the receiver. The method of claim 3, The time synchronization module, Visual error between pseudo satellites based on pseudo range information and carrier phase information received from the receiver (

A visual error calculation unit for calculating); And And a time synchronous loop filter means for generating a time synchronous command ( U _k ) by using the time error calculated by the time error calculator. The method according to claim 2 or 3, The clock providing module, A reference clock generation unit generating a reference clock; And A numerically controlled clock generator for generating a clock controlled by the time synchronization command by using the reference clock; And generating a clock synchronized to synchronize the clock of the sub-satellite module with a reference clock of the main pseudo-satellite module. The method of claim 1, The bidirectional pseudo-satellite module is a synchronous pseudo-satellite precision navigation system, characterized in that the transmitter and the receiver use independent antennas. The method of claim 1, The bidirectional pseudo-satellite module is a synchronous pseudo-satellite precision navigation system, characterized in that the transmitter and the receiver uses a single antenna in common. The method of claim 7, wherein The bidirectional pseudo-satellite module, in which a transmitter and a receiver share one antenna in common, uses a pseudo satellite pulsing signal for antenna switching between a transmitter and a receiver. When the pulsing signal of the pseudo-satellite is turned on, the antenna serves as a transmission and the receiver in the bidirectional pseudo-satellite module receives only the pseudo-satellite signal in the bidirectional pseudo-satellite module When the pulsing signal of the pseudo-satellite is turned OFF, the antenna serves as a reception, and the receiver in the bidirectional pseudo-satellite module receives only the external pseudo-satellite signal, not the pseudo-satellite signal in the bidirectional pseudo-satellite module. A synchronous pseudo-satellite precision navigation system. The method of claim 1, The bidirectional pseudo-satellite module includes an independent wireless data link means therein, A synchronous pseudo-satellite precision navigation system, characterized in that data is exchanged between two-way pseudo-satellite via said wireless data link means. The method of claim 1, The bidirectional pseudo-satellite module does not include independent data link means, A synchronous pseudo-satellite precision navigation system, comprising transmitting data between two-way pseudo-satellites in a data message of a pseudo-satellite signal. The method of claim 1, The two-way pseudo-satellite module is a synchronous pseudo-satellite precision navigation system, characterized in that mounted on the moving body. The method of claim 1, The bidirectional pseudo-satellite module is fixed synchronous pseudo satellite precise navigation system, characterized in that the fixed. The method of claim 1, The bidirectional pseudo-satellite module is a synchronous pseudo-satellite precision navigation system, characterized in that can be used in combination with the one mounted on the mobile body. The method of claim 1, The bidirectional pseudosatellite module can be installed both indoors and outdoors, A synchronous pseudo-satellite precision navigation system, operating as an independent radio navigation system. The method of claim 14, When the bidirectional pseudo-satellite module is installed outdoors, a synchronous pseudo-satellite precision navigation system comprising a navigation system integrated with a satellite navigation system (GPS, GLONASS, Galileo, etc.). The method of claim 1, The moving object is a synchronous pseudo-satellite precision navigation system, characterized in that for determining the magnetic position by the error in meters unit by a single navigation algorithm using the pseudo-range information received from the synchronized two-way pseudo-satellite module. The method of claim 1, The moving object is a synchronous pseudo-satellite precision navigation system, characterized in that by using the carrier phase information received from the synchronized bi-directional pseudo satellite module to determine the magnetic position by the error in centimeters unit. The method of claim 1, Visual error between pseudo satellites by the following equation using pseudo range measurement without position information of the bidirectional pseudo satellite module (

Synchronous pseudo-satellite precision navigation system.

The method of claim 1, Visual error between pseudo-satellites by the following equation using a carrier phase measurement value without position information of the bidirectional pseudo-satellite module (

Synchronous pseudo-satellite precision navigation system.

The method according to claim 1 or 2, The external pseudo satellite includes a satellite of a satellite navigation system (GPS, GLONASS, Galileo, etc.). The method of claim 1, The two-way pseudo-satellite module is a synchronous pseudo-satellite precision navigation system, characterized in that consisting of hardware or software.

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