CN112415550A - Low-orbit satellite real-time precise orbit determination method and system based on Beidou short message - Google Patents

Abstract

The invention belongs to the technical field of communication and positioning, and discloses a real-time precise orbit determination method and system for low-orbit satellites based on Beidou short messages. The ground monitoring station obtains the basic navigation and positioning of the ground monitoring station by collecting basic navigation and positioning information of the satellite navigation system The information is sent to the ground main control station; the ground main control station generates the satellite navigation system differential correction information according to its own physical location information and the basic navigation and positioning information of the ground monitoring station, and sends it to the uplink injection station; the uplink injection station converts the satellite navigation system differential correction information The correction information is sent to the Beidou-3 satellite; the Beidou-3 satellite uses the short message communication function to broadcast the differential correction information of the satellite navigation system; after the low-orbit satellite receives the differential correction information of the satellite navigation system, the low-orbit satellite receives the satellite on-board reception. The basic navigation and positioning information of low-orbit satellites received by the aircraft is used for real-time precise orbit determination. The invention has the advantages of not relying on external communication links, completely autonomous, safe and cost-effective.

Description

A real-time precise orbit determination method and system for low-orbit satellites based on Beidou short messages

technical field

The invention relates to the technical field of communication and positioning, in particular to a real-time precise orbit determination method and system for low-orbit satellites based on Beidou short messages.

Background technique

In the past few decades, low-orbit satellites and their constellations have been widely used in the fields of resource remote sensing, atmospheric exploration, ocean development, military reconnaissance, etc. It plays an irreplaceable role in social development and national security. In recent years, with the sharp increase in the demand for global communication and scientific research, many low-orbit constellation plans have sprung up, such as Oneweb, Iridium, SpaceX in the United States, Hongyan, Hongyun and CentiSpace in China, and South Korea's Samsung et al. Therefore, it is necessary to study the real-time precise orbit determination of low-orbit satellites around the world.

Spaceborne GNSS technology has developed into the mainstream means of precise orbit determination of low-orbit satellites due to its advantages of improving the autonomy of space missions, reducing the cost of ground operations, and reducing the burden of ground equipment. However, spaceborne GNSS orbit determination based on GNSS basic navigation service products usually can only achieve meter-level accuracy, and cannot meet real-time data processing requirements such as ocean altimetry and atmospheric occultation inversion. In order to improve the real-time orbit determination accuracy of spaceborne GNSS, it is usually necessary to provide real-time GNSS precision orbit clock error products by means of external communication.

In order to realize real-time distribution of precision products, existing real-time systems often use communication methods such as mobile networks, radio stations and communication satellites. However, mobile networks and radio stations are limited by the distribution of base stations, and are generally deployed in densely populated areas. In sparsely populated areas or uninhabited areas, the coverage of base stations is not in place, not only the operating distance is limited, but also vulnerable to bad weather. Although communication satellites can ensure large-scale all-weather real-time communication, the communication cost is too expensive. At the same time, these communication links are easily interfered by hostile forces, and the security of communication cannot be fully guaranteed.

SUMMARY OF THE INVENTION

By providing a real-time precise orbit determination method and system for low-orbit satellites based on Beidou short messages, the present invention solves the problem that the basic navigation service accuracy of the GNSS system in the prior art is limited, the coverage of the communication link is small, the cost is high, and the safety worse problem.

The present invention provides a real-time precise orbit determination method for low-orbit satellites based on Beidou short messages, and configures an on-board receiver for low-orbit satellites, including the following steps:

S11, the ground monitoring station obtains the basic navigation and positioning information of the ground monitoring station by collecting the basic navigation and positioning information of the satellite navigation system, and sends the basic navigation and positioning information of the ground monitoring station to the ground master control station;

S12, the ground master control station generates satellite navigation system differential correction information according to its own physical location information and the ground monitoring station basic navigation and positioning information, and sends the satellite navigation system differential correction information to the uplink injection station;

S13, the uplink injection station sends the satellite navigation system differential correction information to the Beidou-3 satellite;

S14, the Beidou-3 satellite uses the short message communication function to broadcast the differential correction information of the satellite navigation system;

S15. After receiving the differential correction information of the satellite navigation system, the low-orbit satellite combines the basic navigation and positioning information of the low-orbit satellite received by the onboard receiver of the low-orbit satellite to perform real-time precise orbit determination.

Preferably, the step S12 includes the following sub-steps:

S121, the ground master control station generates the precise orbit and clock error products of the satellite navigation system according to its own physical location information and the basic navigation and positioning information of the ground monitoring station;

S122. The ground master control station calculates and generates the satellite navigation system differential correction information according to the satellite navigation system precise orbit, clock error product and the satellite navigation system broadcast ephemeris in the basic navigation and positioning information of the ground monitoring station, and Sending the satellite navigation system differential correction information to the uplink injection station.

Preferably, the specific implementation of the step S121 is:

Build the observation model of the satellite navigation system;

The ground main control station performs linearization processing on the observation model according to its own physical location information and the basic navigation and positioning information of the ground monitoring station;

The least squares method is used to calculate the linearized observation model to generate the precise orbit and clock error products of the satellite navigation system.

Preferably, before using the least squares method to calculate the linearized observation model, a reference constraint condition is preconfigured; under the reference constraint condition, the least squares method is used to calculate the linearized observation model.

Preferably, the specific implementation of the step S122 is:

Calculate the satellite position of the precise ephemeris and the satellite clock difference of the precise clock difference according to the precise orbit and clock difference product of the satellite navigation system, and calculate and obtain the satellite position and broadcast ephemeris of the broadcast ephemeris according to the broadcast ephemeris of the satellite navigation system satellite clock error;

The satellite position of the precise ephemeris and the satellite position of the broadcast ephemeris are processed to make a difference, and the coordinate correction number in the XYZ direction of the fixed system of the agreement is generated, and the satellite clock difference of the precise clock difference is compared with the broadcast satellite. The satellite clock error of the calendar is processed to generate a clock error correction number;

Convert the coordinate correction numbers in the XYZ directions of the ground-fixed system according to the protocol to the radial, tangential and normal directions of the satellites, respectively, to generate satellite navigation system orbit differential correction information;

Performing averaging processing on the clock error correction number to obtain an average value of the clock error correction number, and subtracting the clock error correction number average value from the clock error correction number to obtain satellite navigation system clock error differential correction information;

The satellite navigation system orbit differential correction information and the satellite navigation system clock differential correction information constitute the satellite navigation system differential correction information.

Preferably, the specific implementation of the step S14 is:

On a global scale, broadcast and broadcast the satellite navigation system differential correction information of the visible satellite of the low-orbit satellite through the global short message function of the Beidou-3 satellite;

At the same time, in the domestic and surrounding areas, through the regional short message function of the Beidou-3 satellite, the differential correction information of the satellite navigation system of the entire constellation is broadcast and broadcast.

Preferably, on a global scale, the Beidou-3 satellite obtains the visible satellite information of the low-orbit satellite according to the predicted orbit of the low-orbit satellite and the predicted orbit of the satellite navigation system.

The present invention provides a real-time precise orbit determination system for low-orbit satellites based on Beidou short messages, including:

The ground monitoring station is used to collect the basic navigation and positioning information of the satellite navigation system, obtain the basic navigation and positioning information of the ground monitoring station, and send the basic navigation and positioning information of the ground monitoring station to the ground main control station;

The ground master control station is used to generate satellite navigation system differential correction information according to its own physical location information and the basic navigation and positioning information of the ground monitoring station, and send the satellite navigation system differential correction information to the uplink injection station;

an uplink injection station for sending the differential correction information of the satellite navigation system to the Beidou-3 satellite;

The Beidou-3 satellite is used to broadcast the differential correction information of the satellite navigation system by using the short message communication function;

The low-orbit satellite is used to perform real-time precise orbit determination in conjunction with the basic navigation and positioning information of the low-orbit satellite received by the on-board receiver of the low-orbit satellite after receiving the differential correction information of the satellite navigation system;

The real-time precise orbit determination system for low-orbit satellites based on Beidou short messages is used to implement the steps in the above-mentioned method for real-time precise orbit determination of low-orbit satellites based on Beidou short messages.

Preferably, the ground main control station includes:

a computing unit, configured to generate the precise orbit and clock error products of the satellite navigation system according to its own physical location information and the basic navigation and positioning information of the ground monitoring station;

The processing unit is configured to calculate and generate the differential correction information of the satellite navigation system according to the precise orbit of the satellite navigation system, the clock error product and the satellite navigation system broadcast ephemeris in the basic navigation and positioning information of the ground monitoring station, and calculate the satellite navigation system differential correction information. The satellite navigation system differential correction information is sent to the upstream injection station.

Preferably, the Beidou-3 satellite includes:

The GEO satellite is used to broadcast and broadcast the differential correction information of the satellite navigation system of the entire constellation in the territory and surrounding areas by using the Beidou-3 satellite regional short message communication function after receiving the differential correction information of the satellite navigation system;

The MEO satellite is used to broadcast and broadcast the satellite navigation of the visible satellite of the low-orbit satellite on a global scale by using the global short message communication function of the Beidou-3 satellite after receiving the differential correction information of the satellite navigation system. System differential correction information.

One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

In the invention, a low-orbit satellite is equipped with an on-board receiver, and the ground monitoring station obtains the basic navigation and positioning information of the ground monitoring station by collecting the basic navigation and positioning information of the satellite navigation system, and sends it to the ground main control station; the ground main control station according to its own The physical location information and the basic navigation and positioning information of the ground monitoring station generate the differential correction information of the satellite navigation system, and send it to the uplink injection station; the uplink injection station sends the differential correction information of the satellite navigation system to the Beidou-3 satellite; Beidou-3 satellite uses short Message communication function, broadcast and broadcast the differential correction information of satellite navigation system; after the low-orbit satellite receives the differential correction information of the satellite navigation system, the basic navigation and positioning information of the low-orbit satellite received by the on-board receiver of the low-orbit satellite is combined to perform real-time precision. Orbit. The invention utilizes the global short message communication function of my country's Beidou No. 3 system, broadcasts real-time high-precision satellite orbit, clock error and other correction information through it, and configures on-board receivers on the low-orbit satellite constellation to achieve global low Real-time precise orbit determination of orbiting satellites. The invention takes full advantage of the wide coverage of short message communication of the Beidou No. 3 system, and has the advantages of not relying on external communication links, complete autonomy, security and high cost performance.

Description of drawings

1 is a flowchart of a real-time precise orbit determination method for low-orbit satellites based on Beidou short messages according to an embodiment of the present invention;

2 is a subdivision flowchart of step S12 in a real-time precise orbit determination method for low-orbit satellites based on Beidou short messages according to an embodiment of the present invention;

3 is a schematic structural diagram of a real-time precise orbit determination system for low-orbit satellites based on Beidou short messages according to an embodiment of the present invention;

4 is a schematic diagram of an internal structure of a ground master control station in a real-time precise orbit determination system for low-orbit satellites based on Beidou short messages according to an embodiment of the present invention.

Detailed ways

With the continuous construction of my country's Beidou-3 system, the three GEO satellites of the Beidou-3 system can provide regional short message communication services in the Asia-Pacific region, and the MEO satellites can expand the scope of short message services to the world. In order to solve the problems that the basic navigation service accuracy of the existing GNSS system is limited, and the general communication link has the disadvantages of small coverage, high cost, poor security, etc., the invention discloses a Beidou global short message based low orbit. Satellite real-time precise orbit determination method and system. The present invention utilizes the global short message communication function of my country's Beidou No. 3 system, and broadcasts real-time high-precision satellite orbit, clock error and other correction information to realize real-time precise orbit determination of low-orbit satellites on a global scale. At the same time, the invention takes full advantage of the wide coverage of short message communication of the Beidou No. 3 system, and has the advantages of not relying on external communication links, complete autonomy, high security and high cost performance.

In order to better understand the above technical solutions, the above technical solutions will be described in detail below with reference to the accompanying drawings and specific embodiments.

In the embodiment of the present invention, an onboard receiver is configured for a low-orbit satellite in a low-orbit constellation. Referring to FIG. 1 , an embodiment of the present invention provides a real-time precise orbit determination method for a low-orbit satellite based on Beidou short messages, which specifically includes the following steps :

S11. The ground monitoring station obtains the basic navigation and positioning information of the ground monitoring station by collecting the basic navigation and positioning information of the satellite navigation system, and sends the basic navigation and positioning information of the ground monitoring station to the ground main control station.

S12. The ground master control station generates satellite navigation system differential correction information according to its own physical location information and the ground monitoring station basic navigation and positioning information, and sends the satellite navigation system differential correction information to the uplink injection station.

S13. The uplink injection station sends the differential correction information of the satellite navigation system to the Beidou-3 satellite.

S14. After receiving the differential correction information of the satellite navigation system, the Beidou-3 satellite broadcasts the differential correction information of the satellite navigation system by using the short message communication function of the Beidou-3 satellite.

S15. After receiving the differential correction information of the satellite navigation system, the low-orbit satellite combines the basic navigation and positioning information of the low-orbit satellite received by the onboard receiver of the low-orbit satellite to perform real-time precise orbit determination.

In this embodiment of the present invention, as shown in FIG. 2 , step S12 specifically includes the following steps:

S121. The ground main control station generates a satellite navigation system precise orbit and clock error product according to its own physical location information and the basic navigation and positioning information of the ground monitoring station.

S122. The ground master control station calculates the satellite navigation system differential correction information according to the satellite navigation system precise orbit, clock error product and the satellite navigation system broadcast ephemeris in the basic navigation and positioning information of the ground monitoring station, and converts the satellite navigation system to the satellite navigation system. The satellite navigation system differential correction information is sent to the uplink injection station.

Further, the ground master control station generates the precise orbit and clock error products of the satellite navigation system according to its own physical location information and the basic navigation and positioning information of the ground monitoring station, which is realized through the following specific process:

Build the observation model of the satellite navigation system;

The ground main control station performs linearization processing on the observation model according to its own physical location information and the basic navigation and positioning information of the ground monitoring station;

The least squares method is used to calculate the linearized observation model to generate the precise orbit and clock error products of the satellite navigation system.

In another embodiment, the method of calculating the linearized observation model by using the least squares method to generate the precise orbit and clock error products of the satellite navigation system further includes the following steps: preconfiguring reference constraints; Next, the least squares method is used to calculate the linearized observation model.

Further, the step S122 is realized by the following specific process:

Calculate the satellite position of the precise ephemeris and the satellite clock difference of the precise clock difference according to the precise orbit and clock difference products of the satellite navigation system, and simultaneously calculate the satellite position of the broadcast ephemeris and the difference of the broadcast ephemeris according to the broadcast ephemeris of the satellite navigation system. satellite clock difference;

The satellite position of the precise ephemeris and the satellite position of the broadcast ephemeris are processed to make a difference, and the coordinate correction number in the XYZ direction of the fixed system of the agreement is generated, and the satellite clock difference of the precise clock difference is compared with the broadcast satellite. The satellite clock error of the calendar is processed to generate a clock error correction number;

Convert the coordinate correction numbers in the XYZ directions of the ground-fixed system according to the protocol to the radial, tangential and normal directions of the satellites, respectively, to generate satellite navigation system orbit differential correction information;

At the same time, the clock error correction number is averaged to obtain an average clock error correction number, and the clock error correction number is subtracted from the clock error correction number average value to obtain satellite navigation system clock error differential correction information;

The satellite navigation system orbit differential correction information and the satellite navigation system clock differential correction information constitute the satellite navigation system differential correction information.

The generation of the precise orbit and clock error products of the satellite navigation system by the ground main control station according to its own physical position information and the basic navigation and positioning information of the ground monitoring station will be described in detail below through a specific embodiment.

The basic GNSS navigation and positioning information collected by the ground main control station and received by the ground monitoring station, including the multi-frequency pseudorange ρ and carrier phase φ observations. The pseudorange and phase observations from satellite s to station a at frequency i can be expressed as:

为卫星和测站间几何距离，T_a为测站天顶方向对流层延迟参数，其相应的映射函数为

c为真空中光速，δt^s和δt_a分别为卫星和接收机钟差，

f_i为频点i的载波频率，其相应波长为

为倾斜电离层延迟，

和

分别为接收机端伪距和载波相位硬件延迟，相应的

和

为卫星端伪距和载波相位硬件延迟，

为整周模糊度参数。In formula (1),

is the geometric distance between the satellite and the station, T _a is the tropospheric delay parameter in the zenith direction of the station, and its corresponding mapping function is

c is the speed of light in vacuum, δt ^s and δt _a are the satellite and receiver clock differences, respectively,

f _i is the carrier frequency of frequency point i, and its corresponding wavelength is

is the tilted ionospheric delay,

and

are the receiver-side pseudorange and carrier phase hardware delay, respectively, and the corresponding

and

for the satellite pseudorange and carrier phase hardware delay,

is the integer ambiguity parameter.

Error corrections such as antenna phase deviation and variation, phase wrapping, relativistic effects of satellite clock errors, and errors such as multipath and observation noise are ignored in the above formula.

In Equation (1), the zenith tropospheric delay parameter Ta and receiver clock error δt _a are only related to the station, the satellite clock error δt _s is only related to the satellite, and the inclined ionospheric delay parameter I _a ^s is ^related to the station and the satellite, The hardware delay parameters of pseudorange and carrier phase at the satellite end or receiver end are mainly related to the station, satellite, observation type and tracking frequency, respectively.

In navigation satellite data processing, different types of phase and pseudorange observation value combinations are often constructed according to the needs. Among them, the ionospheric elimination combination eliminates the first-order ionospheric influence, so it is widely used to construct high-precision data processing observation models. It can be expressed as:

和

分别为消电离层组合伪距和相位观测值，

和

分别为接收机端消电离层组合伪距和相位观测值硬件延迟，其值为：In the formula,

and

are the ionospheric combined pseudorange and phase observations, respectively,

and

are the hardware delay of the combined pseudorange and phase observations at the receiver side to cancel the ionosphere, respectively, and their values are:

和

分别为：Similarly, satellite-side cancels the ionosphere to combine pseudorange and phase observations with hardware delay

and

They are:

为消电离层组合观测值波长，

为相应的整周模糊度参数，其值为：In the formula,

is the wavelength of the combined observations of the ionosphere,

is the corresponding integer ambiguity parameter whose value is:

Considering the correlation between each parameter in Equation (2) and the station, satellite and signal frequency, so for multi-system observations, Equation (2) can be extended as:

In the formula, S represents the GNSS system. For GPS, GALILEO, Beidou and other navigation satellite systems using code division multiple access technology, the carrier frequencies of different satellites are the same, so the hardware delay of the pseudorange and carrier phase observations at the receiver is the same for all single-system satellites. However, since the GLONASS system adopts the frequency division multiple access technology, the pseudorange and phase hardware delay of the corresponding receiver are also related to the satellite (frequency). Different GLONASS satellites (frequency) correspond to different hardware delays of the receiver.

而接收机端的伪距硬件延迟会被接收机钟差所吸收

此时观测模型为：Since in the precise orbit determination model, the navigation satellite clock error will absorb the pseudo-range hardware delay of the satellite side when estimating

The pseudorange hardware delay at the receiver side will be absorbed by the receiver clock error

At this time, the observation model is:

当多模导航系统联合处理时，一般仅估计一个接收机钟差参数，但是前述表明接收机钟差参数会吸收伪距观测值在接收机端的硬件延迟，而此延迟参数与信号频率和导航系统相关，因此导致不同系统对应不同的接收机钟差

如果以GPS系统对应的接收机钟差

为基准，则其他系统观测模型可以改写为：In the formula,

When the multi-mode navigation system is jointly processed, generally only one receiver clock error parameter is estimated, but the above shows that the receiver clock error parameter will absorb the hardware delay of the pseudorange observation value at the receiver side, and this delay parameter is related to the signal frequency and the navigation system. Correlation, thus causing different systems to correspond to different receiver clock errors

If the receiver clock difference corresponding to the GPS system is used

As the benchmark, other system observation models can be rewritten as:

即为两个系统在接收机端伪距硬件延迟之差，也即码偏差。如果考虑不同导航系统间时间基准的差异，此时需要额外引入一个常量偏差参数，其与DCB参数将构成系统间偏差(Inter-System Bias，ISB)参数。对于采用码分多址的导航系统，其所有卫星对应相同的ISB参数，而由于GLONASS系统采用频分多址技术，因此其不同卫星(频率)对应不同的ISB参数，此时ISB参数实际为不同系统间码偏差、时间基准差和GLONASS系统内不同卫星频间偏差(Inter-Frequency Bias，IFB)的组合。In the formula,

That is, the difference between the pseudorange hardware delays of the two systems at the receiver end, that is, the code deviation. If the difference of time reference between different navigation systems is considered, an additional constant bias parameter needs to be introduced at this time, which together with the DCB parameter will constitute an Inter-System Bias (ISB) parameter. For a navigation system using code division multiple access, all satellites correspond to the same ISB parameters, and because the GLONASS system uses frequency division multiple access technology, different satellites (frequency) correspond to different ISB parameters, and the ISB parameters are actually different at this time. Combination of inter-system code bias, time reference bias and inter-frequency bias (Inter-Frequency Bias, IFB) of different satellites within the GLONASS system.

Linearize equation (8) at the initial values of the given satellite orbit, clock error and other parameters. The unknown parameters mainly include: GNSS satellite orbit parameters, ground station position parameters, ground tracking station receiver clock errors, GNSS satellite clock errors, Parameters such as carrier phase ambiguity, zenith tropospheric delay, ISB/IFB, etc.

为GNSS卫星位置r^S,s和监测站位置r_a初值计算的星地距离，

可以表示为：in,

The satellite-to-earth distance calculated for the initial value of the GNSS satellite position r ^S,s and the monitoring station position _ra ,

It can be expressed as:

和

为观测信号的方向余弦值，而

通过求解变分方程得到。此外，观测模型对接收机钟差、卫星钟差、ISB/IFB的偏导数为1；观测模型对模糊度参数的偏导数为载波波长λ；观测模型对天顶对流层延迟参数偏导为

In the formula, r ^S,s is the function of the satellite orbit parameter x ^S,s in the orbit determination arc. In formula (9)

and

is the direction cosine of the observed signal, and

obtained by solving the variational equation. In addition, the partial derivative of the observation model to the receiver clock error, satellite clock error, and ISB/IFB is 1; the partial derivative of the observation model to the ambiguity parameter is the carrier wavelength λ; the partial derivative of the observation model to the zenith troposphere delay parameter is

The joint linearized observation model constructs the normal equation and solves the relevant parameters under the least squares criterion. Since the receiver clock error, satellite clock error, ISB and other parameters are related, reference constraints need to be added when solving. After solving the satellite orbit parameters x ^S,s , the continuous orbit product is obtained by dynamic integration.

In the embodiment of the present invention, after the Beidou-3 satellite in step S14 receives the differential correction information of the satellite navigation system, it uses the short message communication function of the Beidou-3 satellite to broadcast and broadcast the differential correction information of the satellite navigation system, It mainly includes the following two situations:

First, after the Beidou-3 satellite receives the differential correction information of the satellite navigation system, it uses the regional short message communication function of the Beidou-3 satellite to broadcast and broadcast the differential correction information of the satellite navigation system of the entire constellation in the territory and surrounding areas;

The second is that after the Beidou-3 satellite receives the differential correction information of the satellite navigation system, it uses the global short message communication function of the Beidou-3 satellite to broadcast and broadcast the visual satellite of the low-orbit satellite on a global scale. Satellite navigation system differential correction information.

Further, after the Beidou-3 satellite receives the differential correction information of the satellite navigation system, it uses the global short message communication function of the Beidou-3 satellite to broadcast and broadcast the differential correction information of the satellite navigation system on a global scale. The following steps are implemented:

The Beidou-3 satellite determines the visible satellite condition of the low-orbit satellite according to the low-orbit satellite forecast orbit and the satellite navigation system forecast orbit; the Beidou-3 satellite uses the Beidou-3 satellite according to the low-orbit satellite visible satellite condition. The satellite global short message communication function broadcasts and broadcasts the tracked differential correction information of the satellite navigation system on a global scale.

Specifically, in actual work, taking into account the differences and limitations of the communication bandwidth between the global short message and the regional short message of the Beidou-3 system, only the tracked specific satellite differential correction information can be broadcast on a global scale. Different numerical resolutions can be flexibly formulated for different systems and types, and the subcontracting strategy can also be adopted in the broadcasting method, and the complete differential correction information of the whole constellation can be broadcasted through at least two short messages; The regional short message communication function can be used to broadcast the differential correction information of the whole constellation. At the same time, a higher numerical resolution should be set to minimize the precision loss of orbit and clock errors caused by computer truncation errors. It is worth noting that low-orbit satellites in and around the territory should preferentially use the full-constellation differential correction information broadcast by regional short messages.

FIG. 3 schematically shows a schematic structural diagram of a real-time precise orbit determination system for low-orbit satellites based on Beidou short messages according to an embodiment of the present invention. 3 , the real-time precise orbit determination system for low-orbit satellites based on Beidou short messages according to an embodiment of the present invention specifically includes a ground monitoring station 301, a ground master control station 302, an uplink injection station 303, a Beidou-3 satellite 304 and a low-orbit satellite 305. The low-orbit satellite is configured with an on-board receiver;

The ground monitoring station 301 is used to collect the basic navigation and positioning information of the satellite navigation system, obtain the basic navigation and positioning information of the ground monitoring station, and send the basic navigation and positioning information of the ground monitoring station to the ground master control station 302;

The ground master control station 302 is configured to generate satellite navigation system differential correction information according to its own physical location information and the ground monitoring station basic navigation and positioning information, and send the satellite navigation system differential correction information to the uplink injection station 303 ;

The uplink injection station 303 is used to send the differential correction information of the satellite navigation system to the Beidou-3 satellite 304;

The Beidou-3 satellite 304 is used to broadcast the differential correction information of the satellite navigation system by using the short message communication function of the Beidou-3 satellite after receiving the differential correction information of the satellite navigation system;

The low-orbit satellite 305 is used to combine the basic navigation and positioning information of the low-orbit satellite received by the onboard receiver of the low-orbit satellite after receiving the differential correction information of the satellite navigation system to perform real-time precise orbit determination.

In this embodiment of the present invention, as shown in FIG. 4 , the ground master control station 302 specifically includes a computing unit 3021 and a processing unit 3022, wherein:

The computing unit 3021 is used to generate the precise orbit and clock error products of the satellite navigation system according to its own physical location information and the basic navigation and positioning information of the ground monitoring station;

The processing unit 3022 is configured to calculate the differential correction information of the satellite navigation system according to the precise orbit of the satellite navigation system, the clock error product and the satellite navigation system broadcast ephemeris in the basic navigation and positioning information of the ground monitoring station, and convert the satellite navigation system to the satellite navigation system. The satellite navigation system differential correction information is sent to the uplink injection station.

Further, the computing unit 3021 is specifically used to construct an observation model of the satellite navigation system; linearize the observation model according to its own physical location information and the basic navigation and positioning information of the ground monitoring station; adopt the least squares method The linearized observation model is calculated to obtain the precise orbit and clock error products of the satellite navigation system.

In another optional embodiment, the calculating unit 3021 is further configured to preconfigure a reference constraint condition; under the reference constraint condition, a least square method is used to calculate the linearized observation model.

Further, the Beidou-3 satellite 304 specifically includes:

The GEO satellite is used to broadcast and broadcast the differential correction information of the satellite navigation system of the whole constellation in the territory and surrounding areas by using the short message communication function of the Beidou-3 satellite after receiving the differential correction information of the satellite navigation system;

The MEO satellite is used to broadcast and broadcast the satellite navigation of the visible satellite of the low-orbit satellite on a global scale by using the global short message communication function of the Beidou-3 satellite after receiving the differential correction information of the satellite navigation system. System differential correction information.

As for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and for related parts, please refer to the partial description of the method embodiment.

The method and system for real-time precise orbit determination of low-orbit satellites based on Beidou short messages provided by the embodiments of the present invention, by introducing the Beidou-3 satellite as a communication medium, solves the problems of small coverage, high cost, and relatively low security of general communication links. To solve the problems of poor and other disadvantages, the global short message communication function of my country's Beidou-3 system can be used to broadcast real-time high-precision satellite orbit, clock error and other correction information to achieve real-time precise orbit determination of low-orbit satellites around the world. Moreover, the invention takes full advantage of the wide coverage of short message communication of the Beidou No. 3 system, and has the advantages of not relying on external communication links, complete autonomy, high security and high cost performance.

In addition, the method and system for real-time precise orbit determination of low-orbit satellites based on Beidou short messages provided by the embodiments of the present invention configure an on-board receiver for the low-orbit satellite, and receive basic navigation information through it, plus the information broadcast by the Beidou-3 satellite. Differential correction information can realize real-time, autonomous and high-precision orbit determination of low-orbit satellites to meet high-precision requirements such as low-orbit enhancement.

Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be Modifications or equivalent substitutions without departing from the spirit and scope of the technical solutions of the present invention should be included in the scope of the claims of the present invention.

Claims (10)

1. a low-orbit satellite real-time precision orbit determination method based on Beidou short message, is characterized in that, for low-orbit satellite configuration on-board receiver, comprises the following steps: S11, the ground monitoring station obtains the basic navigation and positioning information of the ground monitoring station by collecting the basic navigation and positioning information of the satellite navigation system, and sends the basic navigation and positioning information of the ground monitoring station to the ground master control station; S12, the ground master control station generates satellite navigation system differential correction information according to its own physical location information and the ground monitoring station basic navigation and positioning information, and sends the satellite navigation system differential correction information to the uplink injection station; S13, the uplink injection station sends the satellite navigation system differential correction information to the Beidou-3 satellite; S14, the Beidou-3 satellite uses the short message communication function to broadcast the differential correction information of the satellite navigation system; S15. After receiving the differential correction information of the satellite navigation system, the low-orbit satellite combines the basic navigation and positioning information of the low-orbit satellite received by the onboard receiver of the low-orbit satellite to perform real-time precise orbit determination. 2. The real-time precise orbit determination method for low-orbit satellites based on Beidou short messages according to claim 1, wherein the step S12 comprises the following substeps: S121, the ground master control station generates the precise orbit and clock error products of the satellite navigation system according to its own physical location information and the basic navigation and positioning information of the ground monitoring station; S122. The ground master control station calculates and generates the satellite navigation system differential correction information according to the satellite navigation system precise orbit, clock error product and the satellite navigation system broadcast ephemeris in the basic navigation and positioning information of the ground monitoring station, and Sending the satellite navigation system differential correction information to the uplink injection station. 3. The real-time precise orbit determination method for low-orbit satellites based on Beidou short message according to claim 2, is characterized in that, the concrete implementation mode of described step S121 is: Build the observation model of the satellite navigation system; The ground main control station performs linearization processing on the observation model according to its own physical location information and the basic navigation and positioning information of the ground monitoring station; The least squares method is used to calculate the linearized observation model to generate the precise orbit and clock error products of the satellite navigation system. 4. The real-time precise orbit determination method for low-orbit satellites based on Beidou short message according to claim 3, is characterized in that, before adopting least squares method to calculate the observation model after linearization processing, pre-configure reference constraints; Under the above-mentioned benchmark constraints, the least squares method is used to calculate the linearized observation model. 5. The real-time precise orbit determination method for low-orbit satellites based on Beidou short message according to claim 2, is characterized in that, the concrete implementation mode of described step S122 is: Calculate the satellite position of the precise ephemeris and the satellite clock difference of the precise clock difference according to the precise orbit and clock difference product of the satellite navigation system, and calculate and obtain the satellite position and broadcast ephemeris of the broadcast ephemeris according to the broadcast ephemeris of the satellite navigation system satellite clock error; The satellite position of the precise ephemeris and the satellite position of the broadcast ephemeris are processed to make a difference, and the coordinate correction number in the XYZ direction of the fixed system of the agreement is generated, and the satellite clock difference of the precise clock difference is compared with the broadcast satellite. The satellite clock error of the calendar is processed to generate a clock error correction number; Convert the coordinate correction numbers in the XYZ directions of the ground-fixed system according to the protocol to the radial, tangential and normal directions of the satellites, respectively, to generate satellite navigation system orbit differential correction information; Performing averaging processing on the clock error correction number to obtain an average value of the clock error correction number, and subtracting the clock error correction number average value from the clock error correction number to obtain satellite navigation system clock error differential correction information; The satellite navigation system orbit differential correction information and the satellite navigation system clock differential correction information constitute the satellite navigation system differential correction information. 6. The real-time precise orbit determination method for low-orbit satellites based on Beidou short message according to claim 1, is characterized in that, the concrete implementation mode of described step S14 is: On a global scale, broadcast and broadcast the satellite navigation system differential correction information of the visible satellite of the low-orbit satellite through the global short message function of the Beidou-3 satellite; At the same time, in the domestic and surrounding areas, through the regional short message function of the Beidou-3 satellite, the differential correction information of the satellite navigation system of the entire constellation is broadcast and broadcast. 7. The real-time precise orbit determination method of low-orbit satellite based on Beidou short message according to claim 6, is characterized in that, in the global scope, described Beidou-3 satellite is based on the forecast orbit of described low-orbit satellite and all The visible satellite information of the low-orbit satellite is obtained from the forecast orbit of the satellite navigation system. 8. A low-orbit satellite real-time precision orbit determination system based on Beidou short message, is characterized in that, comprises: The ground monitoring station is used to collect the basic navigation and positioning information of the satellite navigation system, obtain the basic navigation and positioning information of the ground monitoring station, and send the basic navigation and positioning information of the ground monitoring station to the ground master control station; The ground master control station is used to generate satellite navigation system differential correction information according to its own physical location information and the basic navigation and positioning information of the ground monitoring station, and send the satellite navigation system differential correction information to the uplink injection station; an uplink injection station for sending the differential correction information of the satellite navigation system to the Beidou-3 satellite; The Beidou-3 satellite is used to broadcast the differential correction information of the satellite navigation system by using the short message communication function; The low-orbit satellite is used to perform real-time precise orbit determination in conjunction with the basic navigation and positioning information of the low-orbit satellite received by the onboard receiver of the low-orbit satellite after receiving the differential correction information of the satellite navigation system; The system for real-time precise orbit determination of low-orbit satellites based on Beidou short messages is used to implement the steps in the method for real-time precise orbit determination of low-orbit satellites based on Beidou short messages according to any one of claims 1-7. 9. The low-orbit satellite real-time precise orbit determination system based on Beidou short message according to claim 8, is characterized in that, described ground main control station comprises: a computing unit, configured to generate the precise orbit and clock error products of the satellite navigation system according to its own physical location information and the basic navigation and positioning information of the ground monitoring station; The processing unit is configured to calculate and generate the differential correction information of the satellite navigation system according to the precise orbit of the satellite navigation system, the clock error product and the broadcast ephemeris of the satellite navigation system in the basic navigation and positioning information of the ground monitoring station, and calculate the differential correction information of the satellite navigation system. The satellite navigation system differential correction information is sent to the upstream injection station. 10. The real-time precise orbit determination system for low-orbit satellites based on Beidou short messages according to claim 8, wherein the Beidou-3 satellite comprises: The GEO satellite is used to broadcast and broadcast the differential correction information of the satellite navigation system of the entire constellation in the territory and surrounding areas by using the Beidou-3 satellite regional short message communication function after receiving the differential correction information of the satellite navigation system; The MEO satellite is used to broadcast and broadcast the satellite navigation of the visible satellite of the low-orbit satellite on a global scale by using the global short message communication function of the Beidou-3 satellite after receiving the differential correction information of the satellite navigation system. System differential correction information.

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