Area enhanced positioning time service method and system based on air platform

Abstract

The invention discloses a regional enhanced positioning time service method and system based on an air platform, and relates to a navigation enhanced positioning time service technology, and the method comprises the steps: controlling a ground station and the air platform to complete the positioning time service of time-frequency reference equipment through receiving an air navigation signal, so as to obtain the positioning time service information of the ground station and the air platform; controlling bidirectional time synchronization between the ground station and any air platform to keep time synchronization between the air platforms, and acquiring clock difference information between the air platforms and the ground station; any air platform forms the positioning time service information and the clock error information of the air platform into a telegraph text frame, and sends an area enhancement signal to the ground user terminal; and the ground user terminal receives the area enhancement signal so as to obtain the distance from any air platform to the ground user terminal and the positioning time service information of the air platform, and positioning time service is completed through calculation. According to the invention, the positioning time service problem of the navigation terminal in a satellite navigation signal rejection environment can be effectively solved.

Description

Technical Field

[0001] This application relates to the technical field of navigation enhanced positioning and timing, and particularly to a method and system for regional enhanced positioning and timing based on an airborne platform. Background Art

[0002] Since the signal level of satellite navigation signals reaching the user terminal is very weak and is easily affected by jamming, the navigation positioning and timing functions of the user terminal cannot be used properly. Currently, the navigation interference problem is usually solved by equipping an anti-jamming antenna on the user terminal side, while the civil navigation signal level cannot be increased on the satellite system side. Summary of the Invention

[0003] The embodiments of this application provide a method and system for regional enhanced positioning and timing based on an airborne platform to solve the positioning and timing problems of navigation terminals in a satellite navigation signal denial environment.

[0004] The embodiments of this application provide a method for regional enhanced positioning and timing based on an airborne platform, which is used for a regional enhanced positioning and timing system based on an airborne platform. The timing system includes at least one ground station and multiple airborne platforms. The timing method includes the following steps:

[0005] Control the ground station and the airborne platforms to complete positioning and timing of the time-frequency reference device by receiving airborne navigation signals, so as to obtain their own positioning and timing information;

[0006] Control two-way time synchronization between the ground station and any one of the airborne platforms to keep the airborne platforms time-synchronized with each other, and obtain the clock difference information between the airborne platforms and the ground station;

[0007] Any one of the airborne platforms forms a message frame with its own positioning and timing information and the clock difference information, and sends a regional enhanced signal to the ground user terminal, where the ground user terminal needs to receive regional enhanced signals from more than four airborne platforms simultaneously;

[0008] The ground user terminal receives the regional enhanced signal to obtain the distance from any one of the airborne platforms to the ground user terminal and the positioning and timing information of the airborne platform, and completes positioning and timing by calculation.

[0009] Optionally, the ground station includes a system monitoring device, a regional enhanced monitoring device, a time-frequency reference device, a two-way time synchronization device, an enhanced receiving antenna, and an uplink synchronization antenna;

[0010] The airborne platform includes a regional enhanced generation device, a time-frequency reference device, a two-way time synchronization device, a navigation receiving antenna, an airborne transmitting antenna, and a downlink synchronization antenna.

[0011] Optionally, it further includes:

[0012] Determine the service area and the flight layout area, and determine the layout positions of the airborne platforms through a genetic intelligent optimization algorithm to optimize the flight positions of the airborne platforms.

[0013] Optionally, control the ground station and the airborne platforms to complete positioning and timing of the time-frequency reference device by receiving airborne navigation signals, so as to obtain their own positioning and timing information, including:

[0014] The ground station receives the airborne satellite navigation signal through an enhanced receiving antenna and connects it to the time-frequency reference device. The time-frequency reference device completes its own positioning and timing through the built-in satellite navigation receiver to establish the space-time reference of the entire system;

[0015] The airborne platform receives the airborne satellite navigation signal through a navigation receiving antenna and connects it to the time-frequency reference device. The time-frequency reference device completes its own positioning, speed measurement and timing through the built-in satellite navigation receiver.

[0016] Optionally, control two-way time synchronization between the ground station and any airborne platform to keep the airborne platforms in time synchronization and obtain the clock difference information between the airborne platforms and the ground station, including:

[0017] The two-way time synchronization device of the ground station broadcasts an uplink synchronization signal to the airborne area through an uplink synchronization antenna;

[0018] The two-way synchronization device of the airborne platform receives the uplink synchronization signal through a downlink synchronization antenna to complete uplink synchronization ranging;

[0019] The two-way synchronization device of the airborne platform broadcasts a downlink synchronization signal to the ground service area through a downlink synchronization antenna;

[0020] The two-way synchronization device of the ground station receives the downlink synchronization signal through an uplink synchronization antenna to complete downlink synchronization ranging;

[0021] Compare the uplink synchronization ranging value and the downlink synchronization ranging value to complete two-way time synchronization, so as to obtain the clock difference information between the airborne platform and the ground station:

[0022]

[0023] Among them, ρ up is the uplink synchronization ranging value, ρ down is the downlink synchronization ranging value, td sta_rec is the receiving zero value of the ground station two-way synchronization device, td sta_tran is the transmitting zero value of the ground station two-way synchronization device, td sat_rec is the receiving zero value of the airborne platform two-way synchronization device, td sat_tran is the transmitting zero value of the airborne platform two-way synchronization device.

[0024] Optionally, the ground user terminal receives the area enhancement signal to obtain the distance from any aerial platform to the ground user terminal and the positioning and timing information of the aerial platform. The completion of positioning and timing calculation includes:

[0025] The ground user terminal receives the area enhancement signal to obtain the pseudorange measurement value:

[0026] ρ c = ρ + c·δt u

[0027] where ρ c is the pseudorange measurement value, ρ is the spatial geometric distance, and δt u is the clock difference between the pseudosatellite and the user receiver;

[0028] The geometric distance r from any aerial platform to the user receiver satisfies:

[0029]

[0030] where X = [x, y, z] T is the coordinate position vector of the user receiver, and X n = [x n , y n , z n T is the coordinate position vector of the nth space-based platform;

[0031] Solve the following non-linear equations to obtain the positioning information:

[0032]

[0033] where (x, y, z) is the receiver coordinate quantity.

[0034] Optionally, the control ground station monitors and evaluates the availability of the area enhancement signal through monitoring equipment and adjusts the area enhancement signal

[0035] The embodiment of the present application also proposes an area enhancement positioning and timing system based on an aerial platform, which is used for the area enhancement positioning and timing system based on an aerial platform. The timing system includes at least one set of ground stations and multiple sets of aerial platforms. Both the ground stations and the aerial platforms include a processor and a memory. A computer program is stored on the memory. When the computer program is executed by the processor, it jointly implements the steps of the area enhancement positioning and timing method based on an aerial platform as described above.

[0036] ​In the embodiments of the present application, area augmentation signals are broadcast by multiple sets of near-earth aerial platforms. The user terminal calculates the position information, time information broadcast by the aerial platforms, and the distance information from each set of aerial platforms to the user terminal, so as to obtain its own positioning position and timing information in real time, and solve the positioning and timing problems of navigation terminals in the satellite navigation signal denial environment.

[0037] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are specifically given below. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0039] Figure 1 is a schematic diagram of the architecture of the area augmentation positioning and timing system based on aerial platforms according to the embodiments of the present application;

[0040] Figure 2 is a schematic diagram of the process of the area augmentation positioning and timing method based on aerial platforms according to the embodiments of the present application;

[0041] Figure 3 is a schematic diagram of the principle of direct two-way time synchronization between the ground station and the aerial platform according to the embodiments of the present application;

[0042] Figure 4 is a schematic diagram of the principle of area augmentation positioning and timing calculation according to the embodiments of the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] Hereinafter, exemplary embodiments of the present disclosure will be described in more detail with reference to the drawings. Although the exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0044] The embodiments of the present application provide an area augmentation positioning and timing method based on aerial platforms, which is used for an area augmentation positioning and timing system based on aerial platforms. As Figure 1 shown, the timing system includes at least one set of ground stations and multiple sets of aerial platforms. In the embodiments of the present application, an example is given in which the timing system includes one set of ground stations and more than four sets of aerial platforms. As Figure 2As shown, the timing method includes the following steps:

[0045] In step S101, control the ground station and the airborne platform to complete positioning and timing of the time-frequency reference device by receiving airborne navigation signals, so as to obtain their own positioning and timing information. The positioning and timing information of itself includes its own high-precision position, speed, acceleration information and time information.

[0046] In step S102, control two-way time synchronization between the ground station and any airborne platform, so that the airborne platforms maintain time synchronization, and obtain the clock difference information between the airborne platform and the ground station. For example, direct two-way time synchronization is carried out between the ground station and any airborne platform relying on two-way time synchronization equipment.

[0047] In step S103, any airborne platform composes the positioning and timing information of itself and the clock difference information into a message frame, and sends a regional augmentation signal to the ground user terminal, where the ground user terminal needs to receive more than four sets of airborne platform regional augmentation signals at the same time.

[0048] In step S104, the ground user terminal receives the regional augmentation signal to obtain the distance from any airborne platform to the ground user terminal and the positioning and timing information of the airborne platform, and completes positioning and timing by calculation.

[0049] In some embodiments, the ground station includes a system monitoring device, a regional augmentation monitoring device, a time-frequency reference device, a two-way time synchronization device, an enhanced receiving antenna, and an uplink synchronization antenna;

[0050] The airborne platform includes a regional augmentation generation device, a time-frequency reference device, a two-way time synchronization device, a navigation receiving antenna, an airborne transmitting antenna, and a downlink synchronization antenna.

[0051] In a specific example, the system monitoring device in the ground station completes the control setting and status monitoring of all software and hardware devices inside the system; the regional augmentation monitoring device is used to monitor the availability of the regional augmentation signal broadcast by the airborne platform, and complete the comprehensive evaluation of the system service performance; the time-frequency reference device selects a high-precision atomic clock to maintain the space-time reference of the whole system; the two-way time synchronization device uses the method of ranging and comparison of uplink and downlink spreading codes to complete the two-way time synchronization between the ground station and the airborne platform.

[0052] The regional augmentation generation device of the airborne platform is used to generate regional augmentation signals, and the regional augmentation signals adopt a spread spectrum system; the time-frequency reference device selects a high-precision atomic clock and receives space navigation signals to complete the positioning and timing of the airborne platform itself; the two-way time synchronization device uses the method of ranging and comparison of uplink and downlink spreading codes to complete the two-way time synchronization between the airborne platform and the ground station.

[0053] In some embodiments, before the ground station and the aerial platform receive the aerial navigation signal, it further includes:

[0054] Determine the service area and the flight layout area, and determine the layout position of the space-based platform through a genetic intelligent optimization algorithm to optimize the flight position of the aerial platform. Determine the layout position of the space-based platform through the optimization algorithm to minimize the positioning accuracy factors such as the PDOP value at the user reception position within the service area.

[0055] In some embodiments, controlling the ground station and the aerial platform to complete time-frequency reference device positioning and timing through receiving the aerial navigation signal to obtain their own positioning and timing information includes:

[0056] The ground station receives the aerial satellite navigation signal through an enhanced receiving antenna and connects it to the time-frequency reference device. The time-frequency reference device completes its own positioning and timing through the built-in satellite navigation receiver to establish the spatio-temporal reference of the entire system;

[0057] The aerial platform receives the aerial satellite navigation signal through a navigation receiving antenna and connects it to the time-frequency reference device. The time-frequency reference device completes its own positioning, speed measurement and timing through the built-in satellite navigation receiver.

[0058] In some embodiments, controlling two-way time synchronization between the ground station and any aerial platform to keep the aerial platforms in time synchronization and obtain the clock difference information between the aerial platform and the ground station includes:

[0059] The two-way time synchronization device of the ground station broadcasts an uplink synchronization signal to the aerial area through an uplink synchronization antenna. In a specific example, the uplink synchronization signal adopts a spread spectrum ranging technology system.

[0060] The two-way synchronization device of the aerial platform receives the uplink synchronization signal through a downlink synchronization antenna to complete uplink synchronization ranging. As Figure 3 shown, define its ranging value as ρ up .

[0061] The two-way synchronization device of the aerial platform broadcasts a downlink synchronization signal to the ground service area through a downlink synchronization antenna. This downlink synchronization signal also adopts a spread spectrum ranging technology system.

[0062] The two-way synchronization device of the ground station receives the downlink synchronization signal through an uplink synchronization antenna to complete downlink synchronization ranging. As Figure 3 shown, define the ranging value as ρ down .

[0063] Compare the uplink synchronization ranging value and the downlink synchronization ranging value to complete two-way time synchronization, thereby obtaining the clock difference information between the aerial platform and the ground station:

[0064]

[0065] Among them, ρ up is the uplink synchronization ranging value, and ρ down is the downlink synchronization ranging value, td sta_rec is the ground station two-way synchronization device reception zero value, and td sta_tran is the ground station two-way synchronization device transmission zero value, and td sat_rec is the airborne platform two-way synchronization device reception zero value, and td sat_tran is the airborne platform two-way synchronization device transmission zero value.

[0066] Furthermore, in step S103, any airborne platform forms a message frame with its own positioning and timing information and clock difference information, and sends a regional augmentation signal to the ground user terminal. Specifically, the airborne platform uses a regional augmentation generation device to form a message frame with its own position, speed, acceleration, time information, and clock difference information. After radio frequency modulation, the augmentation signal is generated. The augmentation signal uses a signal with a different frequency from that of frequency band 1 and is broadcast to the ground through an airborne transmitting antenna.

[0067] In some embodiments, the ground user terminal receives the regional augmentation signal to obtain the distance from any airborne platform to the ground user terminal and the positioning and timing information of the airborne platform. The completion of positioning and timing calculation includes:

[0068] The ground user terminal receives the regional augmentation signal to obtain the pseudorange measurement value:

[0069] ρ c =ρ + c·δt u (2)

[0070] Among them, ρ c is the pseudorange measurement value, ρ is the spatial geometric distance, and δt u is the clock difference between the pseudosatellite and the user receiver;

[0071] As Figure 4 shown, the geometric distance r from any airborne platform to the user receiver satisfies:

[0072]

[0073] Among them, X = [x, y, z] T is the user receiver coordinate position vector, and X n = [x n , y n , z n T is the coordinate position vector of the nth space-based platform;

[0074] Solve the following non-linear equations to obtain the positioning information:

[0075] ​

[0076] Among them, (x, y, z) are the receiver coordinate quantities. There are four unknowns in formula (4): the receiver coordinate quantities (x, y, z) and the receiver clock error δt u , if the receiver is observed by four or more visible pseudosatellites, then the receiver can solve these four unknowns of the equations, thereby realizing positioning and timing.

[0077] Further, in step S105, the ground station is controlled to monitor and evaluate the availability of the area augmentation signal through the monitoring device, and adjust the area augmentation signal. Specifically, the system monitoring device is used to monitor the working states of all devices in the entire system and control the working parameters, and the area augmentation monitoring device is used to monitor the area augmentation signal and evaluate the availability of the augmentation signal.

[0078] In the embodiment of the present application, multiple sets of near-earth airborne platforms broadcast area augmentation signals. The user terminal calculates the position information, time information broadcast by the airborne platforms, and the distance information from each set of airborne platforms to the user terminal, so as to obtain its own positioning position and timing information in real time, and solve the positioning and timing problems of navigation terminals in the satellite navigation signal rejection environment.

[0079] The method of the present application can continuously provide navigation positioning and timing (PNT) services for the user receiver in a complex electromagnetic environment with navigation rejection, and improve the PNT anti-interference ability of the user receiver from the perspective of the system service capability.

[0080] The embodiment of the present application also proposes an area augmentation positioning and timing system based on an airborne platform, which is used for the area augmentation positioning and timing system based on an airborne platform. The timing system includes at least one set of ground stations and multiple sets of airborne platforms. Both the ground station and the airborne platform include a processor and a memory. A computer program is stored on the memory, and when the computer program is executed by the processor, it jointly implements the steps of the area augmentation positioning and timing method based on an airborne platform as described above.

[0081] The system of the embodiment of the present application can be independently applied, and at the same time has the ability to be compatible with the existing satellite navigation system. By tracing the time to the satellite navigation system, the system can be complementary to the existing satellite navigation system and jointly locate, thereby improving the anti-occlusion application of the existing navigation system under complex terrain conditions such as canyons and hills.

[0082] It should be noted that in the embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device. Without further limitations, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article or device including such element.

[0083] The serial numbers of the embodiments of the present application above are only for description and do not represent the superiority or inferiority of the embodiments.

[0084] Through the description of the above embodiments, those skilled in the art can clearly understand that the above embodiment methods can be implemented by means of software plus a necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, in essence, or the part that makes a contribution to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disc) and includes several instructions for causing a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of the present application.

[0085] The embodiments of the present application have been described above in conjunction with the accompanying drawings. However, the present application is not limited to the above specific embodiments. The above specific embodiments are only illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims. All of these are within the protection scope of the present application.

Claims

1. A regional enhanced positioning and timing method based on an aerial platform, characterized in that, A regional enhanced positioning and timing system based on an aerial platform. The timing system includes at least one ground station and multiple aerial platforms. The timing method includes the following steps: Control the ground station and the aerial platforms to complete positioning and timing of the time-frequency reference equipment by receiving aerial navigation signals, so as to obtain their own positioning and timing information; Control two-way time synchronization between the ground station and any one of the aerial platforms to keep the aerial platforms time-synchronized with each other and obtain the clock difference information between the aerial platforms and the ground station; Any one of the aerial platforms forms a message frame with its own positioning and timing information and the clock difference information, and sends a regional enhancement signal to the ground user terminal, where the ground user terminal needs to receive regional enhancement signals from more than four aerial platforms simultaneously; The ground user terminal receives the regional enhancement signal to obtain the distance from any one of the aerial platforms to the ground user terminal and the positioning and timing information of the aerial platform, and completes positioning and timing through calculation; 2. The method for area enhanced positioning and timing based on an aerial platform according to claim 1, wherein The ground station includes a system monitoring device, a regional enhancement monitoring device, a time-frequency reference device, a two-way time synchronization device, an enhanced receiving antenna, and an uplink synchronization antenna; The aerial platform includes a regional enhancement generation device, a time-frequency reference device, a two-way time synchronization device, a navigation receiving antenna, an airborne transmitting antenna, and a downlink synchronization antenna; 3. The area enhancement positioning and timing method based on an aerial platform according to claim 1, characterized in that It also includes: Determine the service area and the flight layout area, and determine the layout positions of the space-based platforms through a genetic intelligent optimization algorithm to optimize the flight positions of the aerial platforms; 4. The area enhancement positioning and timing method based on an aerial platform according to claim 2, wherein Control the ground station and the aerial platforms to complete positioning and timing of the time-frequency reference equipment by receiving aerial navigation signals, so as to obtain their own positioning and timing information, including: The ground station receives the aerial satellite navigation signal through the enhanced receiving antenna and connects it to the time-frequency reference device. The time-frequency reference device completes its own positioning and timing through the built-in satellite navigation receiver, and establishes the spatio-temporal reference of the entire system; The aerial platform receives the aerial satellite navigation signal through the navigation receiving antenna and connects it to the time-frequency reference device. The time-frequency reference device completes its own positioning, speed measurement, and timing through the built-in satellite navigation receiver; 5. The area enhanced positioning and timing method based on an aerial platform according to claim 2, wherein Control two-way time synchronization between the ground station and any one of the aerial platforms to keep the aerial platforms time-synchronized with each other and obtain the clock difference information between the aerial platforms and the ground station, including: The two-way time synchronization device of the ground station broadcasts an uplink synchronization signal to the aerial area through the uplink synchronization antenna; The two-way synchronization device of the aerial platform receives the uplink synchronization signal through the downlink synchronization antenna to complete uplink synchronization ranging; The two-way synchronization device of the aerial platform broadcasts a downlink synchronization signal to the ground service area through the downlink synchronization antenna; The two-way synchronization device of the ground station receives the downlink synchronization signal through the uplink synchronization antenna to complete downlink synchronization ranging; Compare the uplink synchronization ranging value and the downlink synchronization ranging value to complete two-way time synchronization, so as to obtain the clock difference information between the aerial platform and the ground station site; Among them, ρ up is the uplink synchronous ranging value, ρ down is the downlink synchronous ranging value, td sta_rec is the receiving zero value of the ground station two-way synchronous device, td sta_tran is the transmitting zero value of the ground station two-way synchronous device, td sat_rec is the receiving zero value of the airborne platform two-way synchronous device, td sat_tran is the transmitting zero value of the airborne platform two-way synchronous device.

6. The area enhancement positioning and timing method based on an aerial platform according to claim 5, wherein The ground user terminal receives the regional enhancement signal to obtain the distance from any one of the aerial platforms to the ground user terminal and the positioning and timing information of the aerial platform, and completes positioning and timing through calculation, including: The ground user terminal receives the regional enhancement signal to obtain the pseudorange measurement value; ρ c = ρ + c·δt u Among them, ρ c is the pseudorange measurement value, ρ is the spatial geometric distance, and δt u is the clock difference between the pseudosatellite and the user receiver; The geometric distance r from any airborne platform to the user receiver satisfies: where X = [x, y, z] T is the coordinate position vector of the user receiver, X n = [x n , y n , z n T is the coordinate position vector of the nth empty base platform;​ Solve the following non-linear equations to obtain positioning information: where (x, y, z) are the receiver coordinate quantities.

7. The method for area enhanced positioning and timing based on an aerial platform according to claim 1, characterized in that, It also includes controlling the ground station to monitor and evaluate the availability of the area augmentation signal through monitoring equipment, and adjusting the area augmentation signal.

8. An area enhanced positioning and timing system based on an aerial platform, characterized in that, A regional augmentation positioning and timing system based on an airborne platform, the timing system includes at least one set of ground stations and multiple sets of airborne platforms, both the ground stations and the airborne platforms include a processor and a memory, and a computer program is stored on the memory. When the computer program is executed by the processor, it jointly implements the steps of the regional augmentation positioning and timing method based on an airborne platform according to any one of claims 1 to 7.

Images