CN115173928B

CN115173928B - Method and equipment for determining orbit parameters in satellite laser communication

Info

Publication number: CN115173928B
Application number: CN202210856477.4A
Authority: CN
Inventors: 潘云强
Original assignee: Beijing Rongwei Technology Co ltd
Current assignee: Beijing Rongwei Technology Co ltd
Priority date: 2022-07-21
Filing date: 2022-07-21
Publication date: 2023-03-28
Anticipated expiration: 2042-07-21
Also published as: CN115173928A

Abstract

The invention discloses a method and a device for determining orbit parameters in satellite laser communication, wherein the method comprises the following steps: when the timer is detected to finish timing, acquiring the current time according to the timing finishing moment; if a first orbit parameter corresponding to the first structure variable and a second orbit parameter conforming to a preset validity check rule exist in the current time, performing orbit extrapolation on the first orbit parameter according to the current time to obtain a first extrapolated orbit parameter corresponding to the second structure variable; performing orbit extrapolation on the second orbit parameter according to the current time and the type of the coordinate system of the second orbit parameter to obtain a second extrapolated orbit parameter corresponding to the third structure variable; and performing weighted average processing on the first extrapolation orbit parameter and the second extrapolation orbit parameter based on a preset smoothing factor to determine a third orbit parameter, so that the real-time orbit parameters of the satellite and the target can be accurately determined, and the reliability of capturing, tracking and chain building of laser communication can be effectively improved.

Description

Method and equipment for determining orbit parameters in satellite laser communication

Technical Field

The present application relates to the field of satellite laser communication technologies, and in particular, to a method and an apparatus for determining an orbit parameter in satellite laser communication.

Background

With the rapid development of remote sensing technology, the number of satellite loads and the resolution of the loads are greatly improved, and the generated data volume is increased in a geometric grade, so that the demand for high-speed satellite-ground data transmission is increasingly urgent. At present, data transmission based on microwave is limited by frequency band bandwidth and power consumption, volume, weight, heat dissipation and other limitations of a data transmission terminal, and the high-speed transmission requirement of mass data is difficult to meet no matter a microwave frequency band with higher frequency such as ka or modulation technologies such as high-order modulation and VCM are adopted. Therefore, the demand of satellite for high-speed data transmission is increasingly contradictory to the data transmission capability of the existing system. The laser communication can break through a plurality of problems of microwave data transmission, has the advantages of large available bandwidth, high cost efficiency, small platform load, good confidentiality and the like, more and more satellites select laser communication to carry out high-speed data transmission, and the laser communication is expected to be an important way for high-speed data transmission between satellites and between satellites in the future.

The laser wavelength of the optical communication which is used in large amount at present is 0.8-1.55μm, which is 3-5 orders of magnitude smaller than the wavelength of the traditional microwave communication, and the maximum beam divergence angle of the light wave diffraction is in direct proportion to the wavelength, so the beam divergence angle of a laser beam is much smaller than the beam divergence angle of a microwave beam, the smaller the beam divergence angle is, under the same transmitting power, the higher the energy density at the same transmission distance is, namely, the higher the light intensity is at a receiving terminal, and the power of a laser source of the transmitting terminal can be reduced. Because the beam divergence angle of the laser beam is small, the processes of capturing, aiming, tracking and the like are needed to finish the laser link between two points. In these processes, the spatial orientation of the target in the laser load coordinate system needs to be calculated according to the orbit parameters, the attitude parameters and the like. In the initial chain building (capturing) stage, in order to enable the emission light beam to fall into the visual field or the vicinity of the visual field of the target detector, the laser load is required to be capable of accurately calculating the target space direction, and high-precision direction is completed. In the tracking stage, the high-precision space pointing can provide a feed-forward quantity for target tracking, and the tracking precision is improved.

In order to realize high-precision spatial pointing calculation, real-time orbit parameters of the satellite and the target (the satellite or the laser ground station) need to be accurately calculated.

Therefore, how to accurately determine the real-time orbit parameters of the satellite and the target is a technical problem to be solved at present.

Disclosure of Invention

The invention provides a method for determining orbit parameters in satellite laser communication, which is used for accurately determining real-time orbit parameters of a satellite and a target.

Presetting a first structure variable, a second structure variable and a third structure variable which accord with a preset coordinate system, wherein structure elements in the first structure variable, the second structure variable and the third structure variable all comprise data validity marks, and the method comprises the following steps:

repeatedly running a timer according to a preset timing duration, and acquiring the current time according to the timing ending moment when the timing ending of the timer is detected;

if a first track parameter corresponding to the first structure variable and a second track parameter conforming to a preset validity check rule exist in the current time, performing track extrapolation on the first track parameter according to the current time to obtain a first extrapolated track parameter corresponding to the second structure variable, and marking a first data validity flag corresponding to the first extrapolated track parameter as valid;

performing track extrapolation on the second track parameter according to the current time and the type of the coordinate system of the second track parameter to obtain a second extrapolation track parameter corresponding to the third structure variable, and marking a second data validity flag corresponding to the second extrapolation track parameter as valid;

carrying out weighted average processing on the first extrapolation orbit parameter and the second extrapolation orbit parameter based on a preset smoothing factor, and determining a third orbit parameter according to the result of the weighted average processing;

outputting the third track parameter and updating the first track parameter based on the third track parameter;

the first orbit parameter is a real-time orbit parameter of the satellite at the previous timing end time, the second orbit parameter is an orbit parameter of the satellite broadcasted by the navigation receiver, and the third orbit parameter is a real-time orbit parameter of the satellite at the current time, or the first orbit parameter is a real-time orbit parameter of a target satellite at the previous timing end time, the second orbit parameter is an orbit parameter of a target satellite noted on the ground station, and the third orbit parameter is a real-time orbit parameter of the target satellite at the current time.

Correspondingly, the present invention further provides a device for determining an orbit parameter in satellite laser communication, in which a first structure variable, a second structure variable, and a third structure variable conforming to a preset coordinate system are preset, and structure elements in the first structure variable, the second structure variable, and the third structure variable all include data validity flags, and the device includes:

the timing module is used for repeatedly running a timer according to preset timing duration, and acquiring current time according to the timing ending moment when the timer is detected to end;

the first extrapolation module is used for carrying out orbit extrapolation on the first orbit parameter according to the current time to obtain a first extrapolated orbit parameter corresponding to the second structure variable if the first orbit parameter corresponding to the first structure variable and a second orbit parameter conforming to a preset validity check rule exist at the current time, and marking a first data validity flag corresponding to the first extrapolated orbit parameter as valid;

the second extrapolation module is used for performing track extrapolation on the second track parameter according to the current time and the type of the coordinate system of the second track parameter to obtain a second extrapolation track parameter corresponding to the third structure variable, and marking a second data validity flag corresponding to the second extrapolation track parameter as valid;

the smoothing processing module is used for carrying out weighted average processing on the first extrapolation track parameter and the second extrapolation track parameter based on a preset smoothing factor and determining a third track parameter according to the result of the weighted average processing;

an output module for outputting the third track parameter and updating the first track parameter based on the third track parameter;

By applying the technical scheme, the timer is repeatedly operated according to the preset timing duration, and when the timer is detected to finish timing, the current time is obtained according to the timing finishing moment; if a first track parameter corresponding to the first structure variable and a second track parameter conforming to a preset validity check rule exist in the current time, performing track extrapolation on the first track parameter according to the current time to obtain a first extrapolated track parameter corresponding to the second structure variable, and marking a first data validity flag corresponding to the first extrapolated track parameter as valid; performing track extrapolation on the second track parameter according to the current time and the type of the coordinate system of the second track parameter to obtain a second extrapolated track parameter corresponding to the third structure variable, and marking a second data validity flag corresponding to the second extrapolated track parameter as valid; carrying out weighted average processing on the first extrapolation orbit parameter and the second extrapolation orbit parameter based on a preset smoothing factor, and determining a third orbit parameter according to the result of the weighted average processing; outputting a third track parameter and updating the first track parameter based on the third track parameter; the first orbit parameter is a real-time orbit parameter of the satellite at the previous timing end time, the second orbit parameter is an orbit parameter of the satellite broadcasted by the navigation receiver, and the third orbit parameter is a real-time orbit parameter of the satellite at the current time, or the first orbit parameter is a real-time orbit parameter of a target satellite at the previous timing end time, the second orbit parameter is an orbit parameter of a target satellite injected on the ground station, and the third orbit parameter is a real-time orbit parameter of the target satellite at the current time, so that the real-time orbit parameters of the satellite and the target can be accurately determined, and the reliability of capturing, tracking and chain building of laser communication can be effectively improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic flowchart illustrating a method for determining an orbit parameter in satellite laser communication according to an embodiment of the present invention;

fig. 2 is a schematic flowchart illustrating a method for determining an orbit parameter in satellite laser communication according to another embodiment of the present invention;

fig. 3 is a flowchart illustrating a method for determining an orbit parameter in satellite laser communication according to another embodiment of the present invention;

fig. 4 is a flowchart illustrating a method for determining an orbit parameter in satellite laser communication according to another embodiment of the present invention;

fig. 5 is a flowchart illustrating a method for determining an orbit parameter in satellite laser communication according to another embodiment of the present invention;

fig. 6 is a flowchart illustrating a method for determining an orbit parameter in satellite laser communication according to another embodiment of the present invention;

fig. 7 is a flowchart illustrating a method for determining an orbit parameter in satellite laser communication according to another embodiment of the present invention;

FIG. 8 is a diagram illustrating extrapolated orbit position errors for different smoothing factors α for different GNSS broadcast periods;

fig. 9 shows a schematic structural diagram of an apparatus for determining an orbit parameter in satellite laser communication according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the embodiment of the present application, different orbit parameters to be determined are divided into two cases, where one case is determining a real-time orbit parameter of a local satellite, and in this case, a first orbit parameter is a real-time orbit parameter of the local satellite at a previous timing end time, a second orbit parameter is an orbit parameter of the local satellite broadcasted by a navigation receiver, and a third orbit parameter is a real-time orbit parameter of the local satellite at a current time; in another case, the real-time orbit parameter of the target satellite is determined, in this case, the first orbit parameter is the real-time orbit parameter of the target satellite at the previous timing end time, the second orbit parameter is the orbit parameter of the target satellite injected by the ground station, and the third orbit parameter is the real-time orbit parameter of the target satellite at the current time.

Presetting a first structure variable, a second structure variable and a third structure variable which accord with a preset coordinate system, wherein the first structure variable, the second structure variable and the third structure variable comprise a plurality of structure elements, the structure elements of each structure variable comprise a data validity mark, the data validity mark represents the validity of data, and the preset coordinate system is a coordinate system meeting the requirement of track extrapolation as the track extrapolation is involved, and as shown in figure 1, the method comprises the following steps:

and S101, repeatedly running a timer according to preset timing duration, and acquiring the current time according to the timing ending moment when the timer is detected to end.

In this embodiment, a timer is preset, the timer is repeatedly run according to a preset timing duration, and the current time is obtained when the timer is detected to end timing. The current time is provided by the satellite time system and may be the universal coordinated time (UTC) absolute time or UTC cumulative time in seconds.

The preset timing duration is determined by real-time requirements of satellite computing resources and laser communication target pointing computation, for example, in a specific application scenario of the present application, the preset timing duration is 20ms, that is, orbit parameter computation is performed every 20 ms. The skilled person can use different preset timing durations flexibly according to actual needs.

Step S102, if a first track parameter corresponding to the first structure variable and a second track parameter conforming to a preset validity check rule exist in the current time, track extrapolation is carried out on the first track parameter according to the current time to obtain a first extrapolated track parameter corresponding to the second structure variable, and a first data validity flag corresponding to the first extrapolated track parameter is marked as valid.

In this embodiment, the first track parameter corresponds to a first structure variable, and the validity thereof is determined according to a corresponding validity flag, for example, data is valid when the validity flag is 1, and data is invalid when the validity flag is 0. Judging whether a first effective orbit parameter and a second orbit parameter which accords with a preset validity check rule exist at the current time, if so, performing orbit extrapolation on the first orbit parameter according to the current time to obtain a first extrapolated orbit parameter corresponding to the second structure variable, specifically, determining a first difference value between the current time and the orbit time of the first orbit parameter, extrapolating the first orbit parameter to the first extrapolated orbit parameter according to the first difference value, and then marking a first data validity flag corresponding to the first extrapolated orbit parameter as valid.

The orbit extrapolation can be performed based on the longge-kutta method, or Adams method, or Cowell method, and the corresponding specific process is the prior art and is not described herein again.

Step S103, performing track extrapolation on the second track parameter according to the current time and the type of the coordinate system of the second track parameter to obtain a second extrapolated track parameter corresponding to the third structure variable, and marking a second data validity flag corresponding to the second extrapolated track parameter as valid.

In this embodiment, since the second orbit parameter is an orbit parameter of the satellite broadcasted by the navigation receiver or an orbit parameter of the target satellite injected by the ground station, the orbit parameter of the satellite or the target satellite changes in real time, and the second orbit parameter needs to be extrapolated to the current time, so as to determine a second extrapolated orbit parameter corresponding to the third structure variable at the current time. The type of the coordinate system of the second track parameter may be different from the preset coordinate system, and therefore, the second track parameter needs to be subjected to track extrapolation according to the current time and the type of the coordinate system of the second track parameter to obtain a second extrapolated track parameter, and then the second data validity flag corresponding to the second extrapolated track parameter is marked as valid.

And step S104, carrying out weighted average processing on the first extrapolation track parameter and the second extrapolation track parameter based on a preset smoothing factor, and determining a third track parameter according to the result of the weighted average processing.

In the embodiment, the value range of the preset smoothing factor is (0, 1), the weighted average processing, namely the smoothing filtering processing, has the effects that on one hand, as time goes on, the extrapolation accuracy of the first extrapolated orbit parameter gradually decreases, so that a new second orbit parameter needs to be adopted as a starting point for extrapolation, the second orbit parameter also has a orbit determination error, so that the estimation accuracy can be improved by adopting the weighted average processing, and on the other hand, if a new second orbit parameter is adopted for extrapolation at a certain moment and an old second orbit parameter is adopted for extrapolation for a longer time at the last moment, the track parameter extrapolated at the current moment can possibly have jump, so that the track parameter calculated by extrapolation can be prevented from jumping at a certain moment by adopting the weighted average processing.

In some embodiments of the present application, if the preset smoothing factor is α, then: third orbit parameter = (1- α) × first extrapolated orbit parameter + α × second extrapolated orbit parameter.

Optionally, in some embodiments of the present application, if the preset smoothing factor is α, then: third orbit parameter = (1- α) × second extrapolated orbit parameter + α × first extrapolated orbit parameter.

The skilled person can flexibly set different values of the preset smoothing factor according to actual needs.

In order to reliably obtain the third track parameter, in some embodiments of the present application, after obtaining the current time according to the end time of the current timing, the method further includes:

if the first track parameter which is valid exists at the current time and the second track parameter which meets a preset validity check rule does not exist, carrying out track extrapolation on the first track parameter according to the current time to obtain a first extrapolated track parameter, marking the first data validity flag as valid, marking the second data validity flag as invalid, and taking the first extrapolated track parameter as the third track parameter;

if the first track parameter which is valid does not exist at the current time and the second track parameter which accords with a preset validity check rule exists, track extrapolation is carried out on the second track parameter according to the current time and the type of a coordinate system of the second track parameter to obtain a second extrapolated track parameter, the first data validity mark is marked as invalid, the second data validity mark is marked as valid, and the second extrapolated track parameter is used as the third track parameter.

In this embodiment, if there is a valid first orbit parameter at the current time and there is no second orbit parameter that meets a preset validity check rule, the first orbit parameter is only required to be processed to obtain a first extrapolated orbit parameter, then the first data validity flag is marked as valid, the second data validity flag is marked as invalid, and the first extrapolated orbit parameter is used as a third orbit parameter; if the valid first track parameter does not exist at the current time and the second track parameter which accords with the preset validity check rule exists, the second track parameter is only required to be processed to obtain a second extrapolation track parameter, then the first data validity flag is marked to be invalid, the second data validity flag is marked to be valid, and the second extrapolation track parameter is used as a third track parameter.

In order to accurately obtain a second extrapolation orbit parameter, in some embodiments of the present application, the second extrapolation orbit parameter is obtained by performing orbit extrapolation on the second orbit parameter according to the current time and the type of the coordinate system of the second orbit parameter, which specifically includes:

if the type of the coordinate system is the preset coordinate system, performing track extrapolation on the second track parameter according to the current time to obtain a second extrapolated track parameter;

if the type of the coordinate system is not the preset coordinate system, converting the second track parameter into a fourth track parameter belonging to the preset coordinate system, and performing track extrapolation on the fourth track parameter according to the current time to obtain a second extrapolated track parameter.

In this embodiment, if the type of the coordinate system of the second orbit parameter is a preset coordinate system, it indicates that coordinate conversion is not required, and the second orbit parameter is subjected to orbit extrapolation according to the current time to obtain a second extrapolated orbit parameter, specifically, a second difference between the current time and the orbit time of the second orbit parameter is determined, and the second orbit parameter is subjected to orbit extrapolation according to the second difference to obtain a second extrapolated orbit parameter.

If the type of the coordinate system of the second track parameter is not the preset coordinate system, it is indicated that the coordinate system conversion needs to be performed, the second track parameter is converted into a fourth track parameter belonging to the preset coordinate system, then the fourth track parameter is subjected to track extrapolation according to the current time to obtain a second extrapolated track parameter, specifically, a third difference value between the current time and the track time of the fourth track parameter is determined, and the fourth track parameter is subjected to track extrapolation according to the third difference value to obtain a second extrapolated track parameter.

if the first track parameter and the second track parameter which accord with a preset validity check rule do not exist in the current time, the first data validity flag mark and the second data validity flag mark are marked to be invalid, and a preset initialization track parameter corresponding to the first structure variable is used as the third track parameter.

In this embodiment, a preset initialization track parameter corresponding to the first structure variable is preset, and if the first track parameter and the second track parameter are both invalid, the first data validity flag and the second data validity flag are marked as invalid, and the preset initialization track parameter is used as the third track parameter.

In order to determine the track parameter more accurately, in some embodiments of the present application, the preset coordinate system is a J2000 coordinate system, the structural elements in the first structural variable, the second structural variable and the third structural variable further include three-dimensional coordinates, three-dimensional speed and track time, and before repeatedly running the timer for a preset time period, the method further includes:

and setting each structure element in the first structure variable, the second structure variable and the third structure variable to zero to complete initialization.

In this embodiment, the preset coordinate system is a J2000 coordinate system, and the structural elements include, in addition to the data validity flag Valid, a three-dimensional coordinate R of the satellite or the target satellite in the J2000 coordinate system: x, Y, Z; three-dimensional speed V: an X-direction velocity Vx, a Y-direction velocity Vy, and a Z-direction velocity Vz; track Time. And setting the structure elements in each structure variable to zero to complete initialization.

When the coordinate system type of the second track parameter is not the J2000 coordinate system, the coordinate system type of the second track parameter may be the WGS84 coordinate system, or the instantaneous six-number, or the first-type non-singular-point track flat number, or the second-type non-singular-point track flat number, etc.

In order to accurately determine the orbit parameter of the ground station, in some embodiments of the present application, after obtaining the current time according to the end time of the current timing, the method further includes:

if the position of the ground station injected by the ground station under the WGS84 coordinate system exists at the current time;

and converting the position into a fifth orbit parameter of the ground station in a J2000 coordinate system and outputting the fifth orbit parameter.

In this embodiment, when the target is the ground station, the position (i.e., three-dimensional coordinate R) of the ground station in the WGS84 coordinate system at the current time is converted into the fifth orbit parameter (i.e., three-dimensional coordinate R and three-dimensional velocity V) of the ground station in the J2000 coordinate system.

And step S105, outputting the third track parameter and updating the first track parameter based on the third track parameter.

In this embodiment, the third orbit parameter is output, that is, the real-time orbit parameter of the satellite at the current time or the real-time orbit parameter of the target satellite at the current time is output, and the first orbit parameter is updated based on the third orbit parameter, so that a new third orbit parameter is determined at the next timing end time.

In some embodiments of the present application, if the second orbit parameter is an orbit parameter of a target satellite annotated by a ground station, and the first orbit parameter includes an index value, after updating the first orbit parameter based on the third orbit parameter, the method further includes:

updating the index value in the first track parameter according to the next betting moment after the betting moment of the second track parameter;

the current time is not less than the betting time of the second orbit parameter, and the index value represents the position of the betting time of the second orbit parameter in a plurality of betting times under the one-time service duration of the ground station.

In this embodiment, if the second orbit parameter is an orbit parameter of a target satellite noted by the ground station, the ground station remotely notes N sets of target orbit parameters, which are uniformly distributed at N times within one service duration, that is, assuming that the service duration is T, then the target orbit parameters noted at time 0, time T/N, time 2T/N, and time 8230are remotely noted, and the target orbit parameters at time (N-1) T/N, for example, the service time (i.e., the service duration) when the satellite passes by is 10 minutes, and 10 sets of orbit parameters noted, that is, the orbit parameters at time 0, time 1, minute 2, time 8230, and time 9 are noted. When the satellite just starts service, reading the 1 st group of parameters; at minute 1, set 2 parameters, \8230;, were read.

The first orbit parameter comprises an index value, and the index value represents the position of the betting moment of the second orbit parameter in a plurality of betting moments under one service duration of the ground station. After updating the first track parameter based on the third track parameter, the index value in the first track parameter is updated according to a next betting moment after the betting moment of the second track parameter.

For example, the N groups of track parameters are noted, and RV _ tc [ ind _ tc ]. Time refers to the reporting time of the ind _ tc group of track parameters, i.e. the (ind _ tc-1) T/N time:

firstly, according to the current time _ now, when the time _ now is more than or equal to RV _ tc [0] time, adopting RV _ tc [0] to recur to the current time;

b: then, whether the time _ now is more than or equal to RV _ tc [1] time is judged, and as time goes on, when the time _ now is more than or equal to RV _ tc [1] time, the RV _ tc [1] is adopted to recur to the current time;

c: then, whether the time _ now is more than or equal to RV _ tc [2] time is met or not is judged, and the RV _ tc [2] is adopted to recur to the current time when the time _ now is more than or equal to RV _ tc [2] time along with the time;

therefore, after each time when time _ now ≧ RV _ tc [ ind _ tc ]. Time is satisfied, the next current time is compared with the next set of track parameter time RV _ tc [ ind _ tc +1]. Time, so the index value ind _ tc is updated to ind _ tc +1.

In order to further explain the technical idea of the present invention, the technical solution of the present invention is now described with reference to specific application scenarios.

Example one

The embodiment of the present application provides a method for determining an orbit parameter in satellite laser communication, which is used for determining a real-time orbit parameter of a satellite, where the orbit parameter broadcast by a navigation receiver belongs to a J2000 coordinate system, and as shown in fig. 2, the method includes the following steps:

step S201 starts.

Step S202, initializing the RV structure array, and setting the validity to 0.

In this step, when a service is started, the processor of the satellite completes the definition of the three-dimensional coordinates and velocity (RV) structure of the satellite, which is denoted as RV _ local (orbit parameter structure variable 1, corresponding to a first structure variable), RV _ now (orbit parameter structure variable 2, corresponding to a second structure variable), and RV _ gnss (orbit parameter structure variable 3, corresponding to a third structure variable). The structural elements comprise three-dimensional coordinates R of the star under a J2000 coordinate system: x, Y, Z; three-dimensional velocity V: an X-direction velocity Vx, a Y-direction velocity Vy, and a Z-direction velocity Vz; track Time; the data validity flag Valid. And initializing the RV structure array, namely setting the values of all structure elements in each structure variable to be 0.

Step S203, query 20ms timer.

In step S204, if the timing end time is reached, step S205 is executed, otherwise step S203 is executed.

In step S205, the current time is read, and step S206 and step S210 are executed.

When the timing Time of 20ms arrives, the current Time _ now is read.

In step S206, if there is GNSS broadcast information, step S207 is executed, otherwise step S208 is executed.

In step S207, whether the data is valid is determined, if yes, step S209 is performed, otherwise, step S208 is performed.

Validity checks are performed on the GNSS broadcast information, and the validity checks include but are not limited to: checking the broadcast time, wherein the absolute value of the difference between the current time and the broadcast time needs to be less than a preset value (for example, 10 seconds); checking the orbit parameters, and calculating the distance from the satellite to the center of the earth according to the three-dimensional coordinates X, Y and Z of the broadcast satellite

Calculating the absolute speed (Vx, vy, vz) of the satellite based on the three-dimensional speeds (Vx, vy, vz) of the broadcast satellite>

Where R, V need to be within a predetermined range, which is related to the orbit of the satellite (the range of R, V of a satellite in a specific orbit).

In step S208, the flag RV _ gnss data is invalid.

Step S209, the GNSS broadcasts RV to extrapolate to the current time to obtain RV _ GNSS, and the marked data is valid.

If the GNSS broadcast information is valid, calculating the difference between the current time and the broadcast time, performing track recursion according to the GNSS broadcast information (track parameters) to obtain a track parameter RV _ GNSS of the current time, and setting the validity of the RV _ GNSS to be 1.

In step S210, whether the RV _ local data is valid is determined, if yes, step S211 is executed, otherwise, step S212 is executed.

And inquiring whether the data validity flag in the structure RV _ local is valid (whether RV _ local. Valid is 1). If the current Time is valid, calculating the difference (Time _ now-RV _ local. Time) between the current Time and the RV _ local data Time of the structure, performing track recursion according to the RV _ local to obtain a track parameter RV _ now of the current Time, and setting the RV _ now validity to be 1.

And S211, extrapolating the effective RV at the previous moment to the current time to obtain RV _ now, and marking the data to be effective.

For the track extrapolation of the satellite, the effective RV at the previous moment is the RV _ local at the last timing ending moment, and because the track forecast frequency is higher and is generally in the Hz magnitude, a first-order Runge-Kutta method can be adopted, and the implementation complexity is reduced.

In step S212, the flag RV _ now data is invalid.

In step S213, whether the RV _ gnss and RV _ now data are both valid is determined, if yes, step S214 is executed, otherwise, step S215 is executed.

Whether both are valid is determined by querying the validity flags of the structure RV _ now and the structure RV _ gnss.

In step S214, the RV is smoothed, output, and updated RV _ local.

If the current orbit parameter is valid, performing smooth filtering, outputting a smooth filtering result RV _ filter as the real-time orbit parameter of the satellite at the current time, and updating RV _ local.

In step S215, whether the RV _ now data is valid is determined, if yes, step S216 is performed, otherwise, step S217 is performed.

In step S216, RV _ now is output and RV _ local is updated.

And if the validity flag of the RV _ now is valid and the validity flag of the RV _ gnss is invalid, outputting the RV _ now as the real-time orbit parameter of the satellite at the current time, and updating the RV _ local.

In step S217, whether the RV _ gnss data is valid is determined, if yes, step S218 is performed, otherwise, step S219 is performed.

In step S218, RV _ gnss is output and RV _ local is updated.

And if the validity flag of the RV _ now is invalid and the validity flag of the RV _ gnss is valid, outputting the RV _ gnss as the real-time orbit parameter of the satellite at the current time, and updating the RV _ local.

In step S219, RV _ local is output.

If the validity flag of RV _ now is invalid and the validity flag of RV _ gnss is invalid, RV _ local is output.

Step S213 to step S219, i.e.

Wherein, the smoothing filtering process, i.e. the weighted average process, is the weighted average of the orbit parameters extrapolated from the GNSS broadcast information and the orbit parameters extrapolated from the real-time orbit parameters at the previous time (20 ms ago), and the process procedure is as follows:

RV_filter.X = (1-α)*RV_now.X + α*RV_gnss.X

RV_filter.Y = (1-α)*RV_now.Y + α*RV_gnss.Y

RV_filter.Z = (1-α)*RV_now.Z + α*RV_gnss.Z

RV_filter.Vx = (1-α)*RV_now.Vx + α*RV_gnss.Vx

RV_filter.Vy = (1-α)*RV_now.Vy + α*RV_gnss.Vy

RV_filter.Vz = (1-α)*RV_now.Vz + α*RV_gnss.Vz

RV_filter.Time = Time_now

RV_filter.Valid = 1

wherein alpha is a smoothing factor and has a value range of (0, 1).

When the GNSS orbit parameter prediction period is shorter, the extrapolation time is shorter (the longest is the GNSS broadcast prediction time interval), and the extrapolation error is smaller, so that the smoothing factor alpha needs to be reduced, the reliability of the GNSS orbit parameter is reduced, and the reliability of the extrapolation value RV _ now is increased; when the GNSS orbit parameter prediction period is large, the extrapolation time is long, and the extrapolation error is increased, so that the smoothing factor alpha needs to be increased, the reliability of the extrapolated value RV _ now is reduced, and the reliability of the GNSS orbit parameter is increased. The optimal smoothing factor a is therefore related to the orbit parameter prediction period.

The smoothing factor a may be obtained by simulation. As shown in fig. 8. The GNSS orbit parameters forecast error is single axis 10m (1 sigma), and the orbit extrapolation step is 0.02 s. When the orbit prediction period is 1 second, the optimal smoothing factor value is 0.05, and when the smoothing factor alpha is greater than 0.05, the orbit output error is mainly influenced by the GNSS prediction error; when α <0.05, the orbit output error is mainly affected by the extrapolation error.

Example two

The embodiment of the application provides a method for determining orbit parameters in satellite laser communication, which is used for determining real-time orbit parameters of a satellite, wherein the orbit parameters broadcast by a navigation receiver belong to a WGS84 coordinate system, and when the broadcast orbit parameters are required to be effective, a satellite coordinate RV under the WGS84 coordinate system is firstly converted into a satellite coordinate RV under a J2000 coordinate system, and then the processes of extrapolation, smoothing and the like are performed. The transformation between the WGS84 coordinate system and the J2000 coordinate system is prior art and will not be described in detail. As shown in fig. 3, the method comprises the following steps:

step S301 starts.

Step S302, initializing the RV structure array, and setting the validity to 0.

Step S303, query 20ms timer.

In step S304, if the timing end time is reached, step S305 is executed, otherwise step S303 is executed.

In step S305, the current time is read, and step S306 and step S311 are performed.

Step S306, determine whether there is GNSS broadcast information, if yes, execute step S308, otherwise execute step S307.

Step S307, the mark RV _ gnss data is invalid.

In step S308, whether the data is valid or not is determined, if yes, step S309 is performed, otherwise, step S307 is performed.

In step S309, the RV in the WGS84 coordinate system is converted to the RV in the J2000 coordinate system.

Step S310, the GNSS broadcasts RV extrapolation to the current time to obtain RV _ GNSS, and the marked data is valid.

In step S311, whether the RV _ local data is valid is determined, if yes, step S312 is performed, otherwise, step S313 is performed.

And S312, extrapolating the effective RV at the previous moment to the current time to obtain RV _ now, and marking the data to be effective.

In step S313, the flag RV _ now data is invalid.

In step S314, whether the RV _ gnss and RV _ now data are both valid is determined, if yes, step S315 is performed, otherwise, step S316 is performed.

In step S315, the RV is smoothed, output, and RV _ local is updated.

In step S316, if the RV _ now data is valid, step S317 is executed, otherwise, step S318 is executed.

In step S317, RV _ now is output and RV _ local is updated.

In step S318, whether the RV _ gnss data is valid is determined, if yes, step S319 is executed, otherwise, step S320 is executed.

In step S319, RV _ gnss is output and RV _ local is updated.

In step S320, RV _ local is output.

EXAMPLE III

The embodiment of the application provides a method for determining an orbit parameter in satellite laser communication, which is used for determining a real-time orbit parameter of a satellite, wherein the orbit parameter broadcast by a navigation receiver belongs to six instantaneous numbers (specifically, a rising intersection declination, a near-location angular distance, an orbit inclination angle, an orbit long semi-axis, an orbit eccentricity ratio, a true near-point angle or a flat near-point angle), the range of the six instantaneous numbers needs to be determined according to a satellite orbit, the effectiveness of the six instantaneous numbers is judged according to a reasonable range, the six instantaneous numbers are converted into satellite coordinates RV under a J2000 coordinate system, and then the processing processes such as extrapolation and smoothing are carried out. The conversion of the instantaneous six numbers and the J2000 coordinate system into the prior art is not described in detail. As shown in fig. 4, the method comprises the following steps:

step S401 starts.

Step S402, initializing the RV structure array, and setting the validity to 0.

In step S403, the 20ms timer is queried.

Step S404 is executed if the timing end time is reached, if yes, step S405 is executed, otherwise, step S403 is executed.

In step S405, the current time is read, and step S406 and step S411 are executed.

In step S406, whether GNSS broadcast information exists is determined, if so, step S408 is performed, otherwise, step S407 is performed.

In step S407, the flag RV _ gnss data is invalid.

In step S408, whether the data is valid is determined, if yes, step S409 is performed, otherwise step S407 is performed.

Step S409, the instantaneous six numbers are converted into RV under a J2000 coordinate system.

Step S410, the GNSS broadcasts RV to extrapolate to the current time to obtain RV _ GNSS, and the marked data are valid.

In step S411, whether RV _ local data is valid is determined, if yes, step S412 is performed, otherwise, step S413 is performed.

And step S412, extrapolating the effective RV at the previous moment to the current time to obtain RV _ now, and marking the data to be effective.

In step S413, the flag RV _ now data is invalid.

In step S414, whether the RV _ gnss and RV _ now data are both valid is judged, if yes, step S415 is executed, otherwise, step S416 is executed.

In step S415, the RV is smoothed, output, and RV _ local is updated.

In step S416, whether the RV _ now data is valid is determined, if yes, step S417 is executed, otherwise, step S418 is executed.

In step S417, RV _ now is output and RV _ local is updated.

In step S418, whether the RV _ gnss data is valid is determined, if yes, step S419 is performed, otherwise, step S420 is performed.

In step S419, RV _ gnss is output and RV _ local is updated.

In step S420, RV _ local is output.

Example four

The embodiment of the application provides a method for determining an orbit parameter in satellite laser communication, which is used for determining a real-time orbit parameter of a target satellite, wherein the orbit parameter of the target satellite injected on a ground station is a J2000 coordinate system. As shown in fig. 5, the method comprises the following steps:

step S501 starts.

And step S502, acquiring and storing track parameters through remote control annotation.

In the step, orbit parameters of N groups of target satellites are annotated through ground remote control and are uniformly distributed at N moments within the duration time of the laser communication service, namely, if the service duration time is T, orbit parameters of the target satellites at 0 th moment, T/N th moment, 2T/N th moment, \ 8230and (N-1) th T/N moment are annotated through the remote control. Defining a structure array RV _ tc [ 0N-1 ], and storing orbit parameters of the injected target satellite, wherein the orbit parameters comprise time, coordinates X, Y and Z and speeds Vx, vy and Vz of each orbit parameter group.

Step S503, initializing the RV structure array, and setting the validity flag to 0.

In this step, the index value of the orbit parameter of the target satellite is initialized, even if ind _ tc =0.

Step S504, query 20ms timer.

In step S505, if the timing end time is reached, step S506 is executed, otherwise step S504 is executed.

In step S506, the current time is read, and steps S507 and S511 are performed.

The current time _ now is acquired.

And step S507, inquiring the stored remote control upper note track parameters.

Step S508, whether new data is available, if yes, step S510 is executed, otherwise step S509 is executed.

In step S509, the flag RV _ gnss data is invalid.

And step S510, remotely controlling the upward injection RV to extrapolate to the current time to obtain RV _ gnss, and marking the data to be valid.

If time _ now is greater than or equal to RV _ tc [ ind _ tc ]. Time, the track parameter RV _ tc [ ind _ tc ] is available, and the current time is deduced according to the track parameter.

In step S511, if RV _ local data is valid, step S512 is executed, otherwise step S513 is executed.

Then, whether the data validity flag in the structure RV _ local is valid (is 1) is queried.

And S512, extrapolating the effective RV at the previous moment to the current time to obtain RV _ now, and marking the data to be effective.

And if the previous time effective RV is valid, namely RV _ local of the last timing end time, performing track extrapolation according to RV _ local to obtain a track parameter RV _ now of the current time. For the orbit extrapolation of the target satellite, because the orbit prediction frequency is low, generally several minutes, a second-order or fourth-order Runge-Kutta method can be adopted to improve the orbit extrapolation accuracy.

In step S513, the flag RV _ now data is invalid.

In step S514, whether the RV _ gnss and RV _ now data are both valid is determined, if yes, step S515 is performed, otherwise, step S516 is performed.

And querying validity flags of the structure RV _ now and the structure RV _ gnss.

In step S515, RV is smoothed, output, and RV _ local is updated.

And if the signals are valid, performing smooth filtering, outputting a smooth filtering result RV _ filter as a real-time orbit parameter of the target satellite at the current time, updating RV _ local, and adding 1 to ind _ tc.

In step S516, whether the RV _ now data is valid is determined, if yes, step S517 is performed, otherwise, step S518 is performed.

In step S517, RV _ now is output and RV _ local is updated.

And if the validity flag of the RV _ now is valid and the validity flag of the RV _ gnss is invalid, outputting the RV _ now as the real-time orbit parameter of the target satellite at the current time, and updating the RV _ local.

In step S518, whether the RV _ gnss data is valid is determined, if yes, step S519 is executed, otherwise, step S520 is executed.

In step S519, RV _ gnss is output and RV _ local is updated.

And if the validity flag of the RV _ now is invalid and the validity flag of the RV _ gnss is valid, outputting the RV _ gnss as the real-time orbit parameter of the target satellite at the current time, and updating the RV _ local.

In step S520, RV _ local is output.

EXAMPLE five

The embodiment of the application provides a method for determining orbit parameters in satellite laser communication, which is used for determining real-time orbit parameters of a target satellite, wherein the orbit parameters of the target satellite injected on a ground station are six instantaneous numbers. As shown in fig. 6, the method comprises the following steps:

step S601 starts.

And step S602, acquiring and storing track parameters through remote control annotation.

Step S603, initialize the RV structure array, and set the validity flag to 0.

Step S604, query 20ms timer.

In step S605, if the timing end time is reached, step S606 is executed, otherwise, step S604 is executed.

In step S606, the current time is read, and steps S607 and S612 are executed.

And step S607, inquiring the stored remote control annotation track parameters.

Step S608 is performed, if new data is available, step S610 is performed, otherwise step S609 is performed.

In step S609, the flag RV _ gnss data is invalid.

Step S610, the instantaneous six numbers are converted into RV under a J2000 coordinate system.

And step S611, remotely controlling the upward injection RV to extrapolate to the current time to obtain RV _ gnss, and marking the data to be valid.

In step S612, whether the RV _ local data is valid is determined, if yes, step S613 is executed, otherwise, step S614 is executed.

And step S613, extrapolating the effective RV at the previous moment to the current time to obtain RV _ now, and marking the data to be effective.

In step S614, the flag RV _ now data is invalid.

In step S615, whether the RV _ gnss and RV _ now data are both valid is judged, if yes, step S616 is executed, otherwise, step S617 is executed.

In step S616, RV is smoothed, output, and RV _ local is updated.

In step S617, if the RV _ now data is valid, step S618 is executed if the RV _ now data is valid, and step S619 is executed if the RV _ now data is not valid.

In step S618, RV _ now is output and RV _ local is updated.

Step S619, if RV _ gnss data is valid, if yes, step S620 is executed, otherwise, step S621 is executed.

In step S620, RV _ gnss is output and RV _ local is updated.

In step S621, RV _ local is output.

EXAMPLE six

The embodiment of the application provides a method for determining orbit parameters in satellite laser communication, which is used for determining real-time orbit parameters of a ground station, wherein the orbit parameters of the ground station injected by the ground station are a WGS84 coordinate system. As shown in fig. 7, the method comprises the following steps:

step S701 starts.

And step S702, acquiring and storing the position of the ground station through remote control injection.

Step S703 initializes the RV structure array, and sets the validity to 0.

The RV-structure array may include only RV _ local since no track extrapolation is required.

Step S704, query 20ms timer.

Step S705 is performed, if the timing end time is reached, step S706 is performed, otherwise step S704 is performed.

Step S706, reads the current time.

And step S707, calculating RV of the ground station in a J2000 coordinate system according to the position of the ground station in the WGS84 coordinate system.

And step S708, outputting.

The embodiment of the present application further provides a device for determining an orbit parameter in satellite laser communication, in which a first structure variable, a second structure variable, and a third structure variable that conform to a preset coordinate system are preset, and all structure elements in the first structure variable, the second structure variable, and the third structure variable include data validity flags, as shown in fig. 9, the device includes:

the timing module 10 is configured to repeatedly run a timer according to a preset timing duration, and when the end of the timing of the timer is detected, obtain the current time according to the end time of the timing;

a first extrapolation module 20, configured to, if there are a first orbit parameter corresponding to the first structure variable and a second orbit parameter that meets a preset validity check rule that are valid at the current time, perform orbit extrapolation on the first orbit parameter according to the current time to obtain a first extrapolated orbit parameter corresponding to the second structure variable, and mark a first data validity flag corresponding to the first extrapolated orbit parameter as valid;

the second extrapolation module 30 is configured to perform track extrapolation on the second track parameter according to the current time and the type of the coordinate system of the second track parameter to obtain a second extrapolation track parameter corresponding to the third structure variable, and mark a second data validity flag corresponding to the second extrapolation track parameter as valid;

a smoothing processing module 40, configured to perform weighted average processing on the first extrapolated orbit parameter and the second extrapolated orbit parameter based on a preset smoothing factor, and determine a third orbit parameter according to a result of the weighted average processing;

an output module 50, configured to output the third track parameter and update the first track parameter based on the third track parameter;

In a specific application scenario, the first extrapolation module 20 is further configured to, if the valid first orbit parameter exists at the current time and the second orbit parameter that meets a preset validity check rule does not exist, perform orbit extrapolation on the first orbit parameter according to the current time to obtain the first extrapolated orbit parameter, mark the first data validity flag as valid, mark the second data validity flag as invalid, and use the first extrapolated orbit parameter as the third orbit parameter;

the second extrapolation module 30 is further configured to, if the valid first track parameter does not exist at the current time and the second track parameter that meets the preset validity check rule exists, perform track extrapolation on the second track parameter according to the current time and the type of the coordinate system of the second track parameter to obtain the second extrapolated track parameter, mark the first data validity flag as invalid, mark the second data validity flag as valid, and use the second extrapolated track parameter as the third track parameter.

In a specific application scenario, the second extrapolation module 30 is specifically configured to:

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit the same; although the present application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not necessarily depart from the spirit and scope of the corresponding technical solutions in the embodiments of the present application.

Claims

1. A method for determining orbital parameters in satellite laser communication is characterized in that a first structure variable, a second structure variable and a third structure variable which conform to a preset coordinate system are preset, and structure elements in the first structure variable, the second structure variable and the third structure variable all comprise data validity marks, and the method comprises the following steps:

repeatedly running a timer according to preset timing duration, and acquiring current time according to the timing ending moment when the timing ending of the timer is detected;

performing orbit extrapolation on the second orbit parameter according to the current time and the type of the coordinate system of the second orbit parameter to obtain a second extrapolated orbit parameter corresponding to the third structure variable, and marking a second data validity flag corresponding to the second extrapolated orbit parameter as valid;

the first orbit parameter is a real-time orbit parameter of the satellite at the previous timing end time, the second orbit parameter is an orbit parameter of the satellite broadcasted by the navigation receiver, and the third orbit parameter is a real-time orbit parameter of the satellite at the current time, or the first orbit parameter is a real-time orbit parameter of a target satellite at the previous timing end time, the second orbit parameter is an orbit parameter of a target satellite injected on the ground station, and the third orbit parameter is a real-time orbit parameter of the target satellite at the current time;

performing orbit extrapolation on the second orbit parameter according to the current time and the type of the coordinate system of the second orbit parameter to obtain the second extrapolated orbit parameter, which specifically comprises the following steps:

2. The method according to claim 1, wherein after acquiring the current time according to the current timing end time, the method further comprises:

3. The method according to claim 1, wherein after acquiring the current time according to the current timing end time, the method further comprises:

4. The method of claim 1, wherein the predetermined coordinate system is a J2000 coordinate system, the structure elements in the first, second, and third structure variables further comprise three-dimensional coordinates, three-dimensional speed, and orbital time, and before repeatedly running the timer for a predetermined timing duration, the method further comprises:

zeroing each structure element in the first, second, and third structure variables to complete initialization.

5. The method of claim 1, wherein if the second orbital parameter is an orbital parameter of a target satellite noted on a ground station, the first orbital parameter includes an index value, the method further comprising, after updating the first orbital parameter based on the third orbital parameter:

updating the index value in the first track parameter according to the next betting time after the betting time of the second track parameter;

6. The method according to claim 1, wherein after acquiring the current time according to the current timing end time, the method further comprises:

7. An apparatus for determining an orbital parameter in satellite laser communication, wherein a first structure variable, a second structure variable, and a third structure variable conforming to a preset coordinate system are preset, and structure elements in the first structure variable, the second structure variable, and the third structure variable each include a data validity flag, the apparatus comprising:

the timing module is used for repeatedly running the timer according to preset timing duration, and acquiring the current time according to the timing ending moment when the timing ending of the timer is detected;

the second extrapolation module is specifically configured to:

8. The apparatus of claim 7,

the first extrapolation module is further configured to perform, if the valid first orbit parameter exists at the current time and the second orbit parameter that meets a preset validity check rule does not exist, an orbit extrapolation on the first orbit parameter according to the current time to obtain a first extrapolated orbit parameter, mark the first data validity flag as valid, mark the second data validity flag as invalid, and use the first extrapolated orbit parameter as the third orbit parameter;

the second extrapolation module is further configured to perform, if the valid first track parameter does not exist at the current time and the second track parameter meeting a preset validity check rule exists, track extrapolation on the second track parameter according to the current time and the type of the coordinate system of the second track parameter to obtain the second extrapolated track parameter, mark the first data validity flag as invalid, mark the second data validity flag as valid, and use the second extrapolated track parameter as the third track parameter.