Method, device, equipment and product for tracking multiple satellites in phased array ground station

Abstract

The invention discloses a phased array ground station multi-satellite tracking method, device, equipment and product, and relates to the technical field of satellite communication, and the method comprises the steps: obtaining the ephemeris information of each satellite, and correspondingly calculating the satellite initial state of each satellite according to the ephemeris information of each satellite; and based on the satellite initial states of the satellites, the motion trails of the satellites are correspondingly calculated according to the satellite trajectory prediction model, the angles of the satellites relative to the phased array ground station are calculated according to the motion trails of the satellites and the corresponding satellite estimation angles, the direction to which an antenna should point is accurately calculated, and it is ensured that beams are always aligned with the satellites. According to the angle of each satellite relative to the phased array ground station, the antenna beam of the phased array ground station is correspondingly adjusted, the phased array antenna can track multiple satellites at the same time by flexibly adjusting the beam, and by accurately adjusting the beam direction and the beam width, the direction error is reduced, the resource waste is avoided, and the resource utilization rate of the ground station is improved.

Description

Technical Field

[0001] The present application relates to the field of satellite communication technology, and in particular to a method, device, equipment and product for tracking multiple satellites in a phased array ground station. Background Art

[0002] With the development of low-orbit satellite constellations, their applications in remote sensing, communication, observation and other fields are becoming increasingly widespread, and the number of low-orbit satellites is increasing dramatically, which also requires ground stations to flexibly support communications among multiple satellites.

[0003] At present, traditional ground stations use parabolic antennas to track satellites, but parabolic antennas can only track one satellite at a time, and the mechanical rotation is not flexible enough to effectively switch tracking targets and track multiple targets simultaneously.

[0004] Therefore, when the ground station communicates with multiple satellites at the same time, how to track multiple satellites is a problem that needs to be solved urgently. Summary of the invention

[0005] The main purpose of this application is to provide a phased array ground station multiple satellite tracking method, device, equipment and product, aiming to solve the technical problem that multiple satellite tracking is difficult to achieve.

[0006] To achieve the above purpose, the present application proposes a method for tracking multiple satellites by a phased array ground station, the method comprising:

[0007] Obtaining ephemeris information of each satellite, and calculating the initial state of each satellite according to the ephemeris information of each satellite;

[0008] Based on the initial state of each satellite, the motion trajectory of each satellite is calculated according to the satellite trajectory prediction model;

[0009] Calculate the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle;

[0010] According to the angles of the satellites relative to the phased array ground station, the antenna beam of the phased array ground station is adjusted accordingly.

[0011] In one embodiment, the step of calculating the motion trajectory of each satellite based on the initial state of each satellite according to the satellite trajectory prediction model includes:

[0012] Loading the satellite initial state of each satellite into the satellite trajectory prediction model, and calculating the satellite acceleration of each satellite;

[0013] The motion trajectory of each satellite is calculated according to the satellite acceleration of each satellite and the corresponding satellite initial state.

[0014] In one embodiment, the step of calculating the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle includes:

[0015] Acquire satellite signals of each satellite collected by a preset phased array ground station, and calculate corresponding satellite estimation angles according to the satellite signals of each satellite;

[0016] Based on the motion trajectory of each satellite and the corresponding satellite estimated angle, the angle of each satellite relative to the phased array ground station is calculated by updating the model through an extended Kalman filter.

[0017] In one embodiment, the step of acquiring satellite signals of each satellite collected by a preset phased array ground station and calculating the corresponding satellite estimation angle according to the satellite signals of each satellite includes:

[0018] Acquire satellite signals of each satellite collected by a preset phased array ground station, and calculate the path difference of the x-axis and the y-axis according to the satellite signals of each satellite;

[0019] The satellite estimated angle is calculated according to the path difference between the x-axis and the y-axis.

[0020] In one embodiment, the step of calculating the angle of each satellite relative to the phased array ground station by updating the model through an extended Kalman filter based on the motion trajectory of each satellite and the corresponding satellite estimated angle includes:

[0021] Based on the initial state of each satellite, the satellite acceleration, the motion trajectory of each satellite and the corresponding satellite estimated angle, a state matrix and a prediction equation of a Kalman filter are established;

[0022] Based on the state matrix and prediction equation of the Kalman filter, an update formula of the extended Kalman filter is constructed, and the angle of each satellite relative to the phased array ground station is calculated according to the update formula.

[0023] In one embodiment, the step of adjusting the antenna beam of the phased array ground station accordingly according to the angle of each satellite relative to the phased array ground station comprises:

[0024] Based on the angle of each satellite relative to the phased array ground station, the motion trajectory and angle error of each satellite are corrected in real time by updating the model through an extended Kalman filter to obtain a corrected motion trajectory and satellite angle;

[0025] According to the corrected motion trajectory and satellite angle, dynamically adjust the number of activated antennas of the phased array ground station to obtain an adjusted number of antenna activations, wherein the step of dynamically adjusting the number of activated antennas of the phased array ground station is used to meet gain requirements of different scenarios;

[0026] Based on the adjusted antenna activation quantity, the beam direction and width of the phased array antenna are controlled to ensure that the beam is aligned with the satellite.

[0027] In addition, to achieve the above-mentioned purpose, the present application also proposes a phased array ground station multiple satellite tracking device, the phased array ground station multiple satellite tracking device comprising:

[0028] A state calculation module is used to obtain the ephemeris information of each satellite and calculate the initial state of each satellite according to the ephemeris information of each satellite;

[0029] A trajectory calculation module, used to calculate the motion trajectory of each satellite according to the satellite trajectory prediction model based on the initial state of each satellite;

[0030] An angle calculation module, used to calculate the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle;

[0031] The antenna adjustment module is used to adjust the antenna beam of the phased array ground station according to the angle of each satellite relative to the phased array ground station.

[0032] In addition, to achieve the above-mentioned purpose, the present application also proposes a phased array ground station multi-satellite tracking device, the device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, the computer program being configured to implement the steps of the phased array ground station multi-satellite tracking method as described above.

[0033] In addition, to achieve the above-mentioned purpose, the present application also proposes a storage medium, which is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by the processor, the steps of the phased array ground station multi-satellite tracking method as described above are implemented.

[0034] In addition, to achieve the above-mentioned purpose, the present application also provides a computer program product, which includes a computer program, and when the computer program is executed by a processor, it implements the steps of the phased array ground station multi-satellite tracking method as described above.

[0035] One or more technical solutions proposed in this application have at least the following technical effects:

[0036] Obtain the ephemeris information of each satellite, and calculate the initial state of each satellite according to the ephemeris information of each satellite. Accurate calculation of satellite trajectory and position can be ensured through accurate ephemeris data. Based on the initial state of each satellite, the motion trajectory of each satellite is calculated according to the satellite trajectory prediction model, and the angle of each satellite relative to the phased array ground station is calculated according to the motion trajectory of each satellite and the corresponding satellite estimated angle. The direction in which the antenna should point is accurately calculated to ensure that the beam is always aimed at the satellite. According to the angle of each satellite relative to the phased array ground station, the antenna beam of the phased array ground station is adjusted accordingly. The phased array antenna can track multiple satellites simultaneously by flexibly adjusting the beam. By accurately adjusting the beam pointing and beam width, the pointing error can be reduced, resource waste can be avoided, and the resource utilization rate of the ground station can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0038] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0039] Figure 1 A schematic diagram of the flow chart of the first embodiment of the phased array ground station multi-satellite tracking method of the present application;

[0040] Figure 2 A schematic diagram of the flow chart of the second embodiment of the phased array ground station multi-satellite tracking method of the present application;

[0041] Figure 3 A schematic diagram of the flow chart of the third embodiment of the phased array ground station multi-satellite tracking method of the present application;

[0042] Figure 4 This is a schematic diagram of a measurement model for an embodiment of the present application;

[0043] Figure 5 This is a flow chart of a fourth embodiment of the phased array ground station multi-satellite tracking method of the present application;

[0044] Figure 6 This is a schematic diagram of the low-orbit satellite tracking method in an embodiment of the present application;

[0045] Figure 7 A schematic diagram of the communication between the phased array and multiple satellites in an embodiment of the present application;

[0046] Figure 8This is a schematic diagram of the module structure of a multi-satellite tracking device of a phased array ground station according to an embodiment of the present application;

[0047] Fig. 9 Schematic diagram of the equipment structure of the hardware operating environment involved in the phased array ground station multi-satellite tracking method in the embodiment of the present application.

[0048] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0049] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.

[0050] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.

[0051] With the development of low-orbit satellite constellations, low-orbit satellite constellations are increasingly widely used in remote sensing, communication, and observation. Due to the rapid increase in the number of low-orbit satellites, ground stations are required to flexibly support multi-satellite communications. Traditional ground stations use parabolic antennas to track satellites, but parabolic antennas can only track one satellite at a time, and the mechanical rotation is not flexible enough to effectively switch tracking targets and track multiple targets at the same time. Phased array antennas are a strong candidate for future ground stations. Phased array antennas can generate multiple beams to communicate with multiple satellites at the same time, and have the advantages of flexible steering and interference suppression. Ground stations not only need to provide telemetry, tracking, and command services for satellites, but also need to use narrow beams to provide high-speed services for high-throughput satellites. In this scenario, high beam pointing accuracy is required. When a phased array ground station communicates with multiple satellites at the same time, it is difficult to track multiple satellites at the same time due to the high-speed movement of LEO.

[0052] At present, the commonly used tracking methods are mainly open-loop tracking and closed-loop tracking. The open-loop tracking scheme is to track according to the satellite's ephemeris information. The usual way to obtain ephemeris is through the TLE (Two-Line Elements) file, which is generally updated once a day. The ephemeris information usually contains the satellite's six Kepler elements, indicating the satellite's position and velocity information in orbit, and then predicts the satellite's future trajectory through the SGP4 model. However, the SGP4 model does not consider the unmodeled forces, dynamic atmosphere, third-body gravity and other effects, which will cause orbit errors. The SGP4 propagation scheme has been proven to have an error of about 3 to 10 kilometers after updating the TLE file 24 hours later. Considering the impact of ephemeris errors, research is being conducted to improve the orbit determination accuracy of satellites, such as carrying a satellite-borne GPS module on the satellite, using GNSS satellites or Beidou and other navigation satellites to locate LEO satellites, and improving the position accuracy of LEO satellites. However, satellite-borne GPS will increase the burden on satellites. Not all satellites have the conditions to carry satellite-borne GPS, especially some small cubic satellites, and satellites carrying satellite-borne GPS usually do not disclose ephemeris information.

[0053] The closed-loop tracking scheme uses ephemeris information to obtain a priori angle information, and then uses the receiver to obtain angle error information to adjust the beam pointing. Common methods include single pulse tracking scheme, conical scanning, step tracking and other methods. The single pulse tracking scheme divides the array into 4 sub-arrays to generate multiple receiving beams, and obtains the angle error through the sum and difference signals of the single pulse signal sent by the satellite on the four beams. This method has high accuracy, but the array design and calculation are relatively complex, and each satellite requires multiple beams to obtain the angle error, which is not suitable for multi-satellite tracking scenarios. Other tracking methods such as conical scanning tracking and step tracking require scanning the error signal generated within a certain period of time, which is inefficient and not very accurate.

[0054] The present application provides a solution to obtain the ephemeris information of each satellite, and calculate the satellite initial state of each satellite according to the ephemeris information of each satellite. Accurate calculation of satellite trajectory and position can be ensured through accurate ephemeris data. Based on the satellite initial state of each satellite, the motion trajectory of each satellite is calculated according to the satellite trajectory prediction model, and the angle of each satellite relative to the phased array ground station is calculated according to the motion trajectory of each satellite and the corresponding satellite estimated angle. It is possible to accurately calculate the direction in which the antenna should point to ensure that the beam is always aimed at the satellite. According to the angle of each satellite relative to the phased array ground station, the antenna beam of the phased array ground station is adjusted accordingly. The phased array antenna can track multiple satellites simultaneously by flexibly adjusting the beam. By accurately adjusting the beam pointing and beam width, the pointing error can be reduced, resource waste can be avoided, and the resource utilization of the ground station can be improved.

[0055] Based on this, the present application embodiment provides a phased array ground station multiple satellite tracking method, referring to Figure 1 , Figure 1 This is a flow chart of a first embodiment of a method for tracking multiple satellites by a phased array ground station of the present application.

[0056] In this embodiment, the phased array ground station multiple satellite tracking method includes steps S10 to S40:

[0057] Step S10, obtaining the ephemeris information of each satellite, and calculating the initial state of each satellite according to the ephemeris information of each satellite.

[0058] It should be noted that ephemeris information is a set of parameters that describe the precise position and velocity of a satellite at a specific time in its orbit, such as the satellite's orbital parameters (such as semi-major axis, eccentricity, inclination, etc.), and the satellite initial state usually refers to the state of the satellite at a specific moment, such as the satellite's orbital position (usually expressed in three-dimensional coordinates) and velocity (which can also be expressed in orbital parameters). Exemplarily, the six satellite orbital numbers are obtained through an ephemeris data file such as a TLE file and the satellite initial state is calculated.

[0059] Step S20, based on the initial state of each satellite, the motion trajectory of each satellite is calculated according to the satellite trajectory prediction model.

[0060] It should be noted that the trajectory prediction model is a mathematical model that estimates the future position of the satellite based on the initial state of the satellite and physical principles (such as Newton's law of gravity, the earth's non-uniform gravity field, atmospheric resistance, etc.), such as the TWO-BODY model or the SGP4 model. Common orbit propagation methods include Kepler orbit propagation and numerical integration methods, which calculate the precise position of the satellite at each future moment to facilitate satellite tracking and communication planning.

[0061] Step S30, calculating the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle.

[0062] It should be noted that the angle relative to the ground station is the spatial azimuth information of the satellite relative to the ground station, which can include azimuth and elevation. The azimuth is the horizontal angle of the ground station relative to the ground reference point, and the elevation is the angle between the antenna and the ground plane.

[0063] Step S40: adjusting the antenna beam of the phased array ground station accordingly according to the angle of each satellite relative to the phased array ground station.

[0064] It should be noted that a phased array ground station is a ground communication station that uses phased array technology. Its antenna is composed of multiple units. By controlling the phase of the signal transmitted by each unit, the direction of the beam can be quickly adjusted. The antenna beam is the spatial area covered by the antenna when transmitting or receiving a signal. The phased array antenna can change the direction of the beam by adjusting the transmission phase of each antenna unit, thereby aiming at different targets. The directionality of the beam affects the communication quality and can be dynamically adjusted according to the position of the satellite relative to the ground station.

[0065] In this embodiment, the ephemeris information of each satellite is obtained, and the initial state of each satellite is calculated according to the ephemeris information of each satellite. Accurate calculation of the satellite trajectory and position can be ensured by accurate ephemeris data. Based on the initial state of each satellite, the motion trajectory of each satellite is calculated according to the satellite trajectory prediction model, and the angle of each satellite relative to the phased array ground station is calculated according to the motion trajectory of each satellite and the corresponding satellite estimated angle, and the direction in which the antenna should point is accurately calculated to ensure that the beam is always aimed at the satellite. According to the angle of each satellite relative to the phased array ground station, the antenna beam of the phased array ground station is adjusted accordingly. The phased array antenna can track multiple satellites simultaneously by flexibly adjusting the beam. By accurately adjusting the beam pointing and beam width, the pointing error can be reduced, resource waste can be avoided, and the resource utilization rate of the ground station can be improved.

[0066] Reference Figure 2 , Figure 2 This is a flow chart of the second embodiment of the phased array ground station multi-satellite tracking method of the present application. Figure 1 The first embodiment shown is a second embodiment of the phased array ground station multiple satellite tracking method of the present application.

[0067] In the second embodiment, the step S20 includes:

[0068] Step S201, loading the satellite initial state of each satellite into the satellite trajectory prediction model, and calculating the satellite acceleration of each satellite.

[0069] It should be noted that the satellite trajectory prediction model can predict the state information of the satellite in the future, including the satellite's position and speed information.

[0070] Exemplarily, the satellite trajectory prediction model can use the J2 perturbation model to predict the trajectory of the satellite, and the satellite acceleration expression is formula (1) to formula (3):

[0071]

[0072] In formula (1) to formula (3), They represent the satellite at x in the geocentric inertial coordinate system. S ,yS 、z S The acceleration in the direction, G represents the gravitational constant, M represents the mass of the earth, ‖r S ‖ represents the distance from the satellite to the center of the earth, x S ,y S 、z S are the x, y, and z coordinates of the satellite in the inertial reference system, J2 represents the second-order flattening coefficient of the earth, which represents the expansion effect of the earth near the equator, and R E represents the average radius of the Earth, w x 、w y 、w z Terms that represent additional acceleration in the x, y, and z directions in an inertial reference frame, such as atmospheric drag, light pressure, or other non-conservative forces.

[0073] Step S202, calculating the motion trajectory of each satellite according to the satellite acceleration of each satellite and the corresponding satellite initial state.

[0074] Exemplarily, the initial state of the satellite can be calculated through the ephemeris information. After the initial state of the satellite is known, the motion trajectory of the satellite can be further solved through the above acceleration model.

[0075] The satellite state equation can be expressed as the differential form of formula (4), and its state can be obtained by numerical integration. Formula (4) is:

[0076]

[0077] In formula (4), Represents the differential form of the satellite state, It represents the speed of the satellite in the x, y, and z directions in the inertial reference frame. It represents the acceleration of the satellite in the x, y, and z directions in the inertial reference frame.

[0078] In this embodiment, by introducing the initial state of the satellite and calculating the acceleration of the satellite in the earth's gravitational field, the satellite's motion trajectory can be predicted more accurately, which can effectively improve the efficiency of satellite navigation, control and scheduling, ensure that the satellite operates according to the predetermined orbit, maximize the satellite's service life and reduce operating costs.

[0079] Reference Figure 3 , Figure 3 This is a flow chart of the third embodiment of the phased array ground station multi-satellite tracking method of the present application. Figure 2 The second embodiment shown provides a third embodiment of the phased array ground station multiple satellite tracking method of the present application.

[0080] In the third embodiment, the step S30 includes:

[0081] Step S301, obtaining satellite signals of each satellite collected by a preset phased array ground station, and calculating corresponding satellite estimation angles according to the satellite signals of each satellite.

[0082] It should be noted that step S301 includes: obtaining satellite signals of each satellite collected by a preset phased array ground station, and calculating the path difference between the x-axis and the y-axis according to the satellite signals of each satellite; and calculating the satellite estimated angle according to the path difference between the x-axis and the y-axis.

[0083] For example, the phased array ground station collects satellite signals for DOA estimation to obtain the azimuth and elevation angle of the satellite. The satellite signal can be an opportunity signal or a beacon signal. Considering the real-time nature of DOA estimation, the 2-DESPRIT algorithm can be used for DOA estimation. The ESPRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) algorithm is based on the principle of subspace rotation invariance. For a two-dimensional array, the 2-D ESPRIT algorithm first calculates the path difference of the x-axis, which is expressed as formula (5):

[0084] u k =cos(El)sin(Az) (5)

[0085] In formula (5), u k It is expressed as the path difference of the x-axis, Az represents the azimuth angle, and El represents the elevation angle. The path difference of the y-axis can be expressed as formula (6):

[0086] v k =cos(El)cos(Az) (6)

[0087] In formula (4), u k It is expressed as the path difference of the y-axis. Further, the two-dimensional DOA estimation angle is obtained, which is expressed as formula (7) and formula (8):

[0088] Az = arctan(u k / v k ) (7)

[0089]

[0090] The meanings of the characters in formula (7) and formula (8) have been explained in the above formulas and will not be repeated here. Figure 4 Schematic diagram of the measurement model, showing the relationship between the satellite ECI coordinates and the azimuth and elevation angles of the satellite relative to the ground station. The conversion relationship is obtained by formula (9) to formula (13).

[0091] Specifically, firstly, the position of the satellite relative to the local coordinate system of the ground station is calculated according to the position of the satellite in the ECI coordinate system, which is expressed as formula (9):

[0092]

[0093] Among them, (x sm ,y sm , z sm ) T represents the position of the mth satellite in the ECI coordinates, (x G ,y G , z G ) T is the position of the ground station in the ECEF coordinate system, R is the transformation matrix from the ECI coordinate system to the ECEF coordinate system, and E represents the transformation matrix from the ECEF coordinate system to the local coordinate system ENZ of the ground station. The transformation matrices are shown in formulas (10) and (11):

[0094]

[0095] where θ represents the angle caused by the rotation of the Earth relative to the vernal equinox, λ, Indicates the latitude and longitude of the ground station. The calculation formulas for the azimuth and elevation angles in the ENZ coordinate system are expressed as formula (12) and formula (13):

[0096]

[0097] In formula (12) and formula (13), S E , S N ,s Z Expressed as values ​​in ENZ coordinates.

[0098] Step S302: Based on the motion trajectory of each satellite and the corresponding estimated satellite angle, the angle of each satellite relative to the phased array ground station is calculated by updating the model through an extended Kalman filter.

[0099] It should be noted that step S302 includes: establishing a state matrix and prediction equation of the Kalman filter based on the initial state of each satellite, the satellite acceleration, the motion trajectory of each satellite and the corresponding satellite estimated angle; constructing an update formula of the extended Kalman filter based on the state matrix and prediction equation of the Kalman filter, and calculating the angle of each satellite relative to the phased array ground station according to the update formula.

[0100] Exemplarily, a Kalman filter is used to update the satellite state angle information based on the satellite state of the prediction module and the measured satellite angle. The updated satellite state is used as the initial state of the prediction module, and the updated angle information is used for the phased array antenna to adjust the phase so that the beam is aligned with the satellite. The state matrix of the Kalman filter can be expressed as formula (14) and formula (15):

[0101]

[0102] In formula (14), represents the state matrix of the mth satellite. In formula (15), Expressed as the satellite's position in ECI coordinates, It is expressed as the speed of the satellite in the ECI coordinates, specifically expressed as formula (16) and formula (17):

[0103]

[0104] In formula (16), (x s ,y s , z s ) T represents the position of the mth satellite in the ECI coordinates. In formula (17), represents the speed of the mth satellite in the ECI coordinates. Az represents the azimuth of the mth satellite relative to the ground station, and El represents the elevation of the mth satellite relative to the ground station. The prediction equation of the Kalman filter can be expressed as formula (18) and formula (19):

[0105] X k+1|k =f(X k ) (18)

[0106]

[0107] In formula (18), f(X k ) is the satellite’s nonlinear motion equation, X k represents the state of the system at the previous moment, X k+1|k represents the predicted value of the system state at time k+1, which can be obtained by numerical integration of the J2 perturbation model. In formula (19), P k Expressed as the covariance of the system state at time k, P k+1|k It is expressed as the covariance prediction of the system state at time k+1, F k It is expressed as the linearized Jacobian matrix, describing the partial derivative of the system state with respect to the initial state, Q k It is expressed as the covariance matrix of the system noise, which usually represents the uncertainty in the prediction process. Since the satellite motion state is a nonlinear function and cannot be obtained directly, its differential form can be obtained first, and then the Runge-Kutta function can be used to integrate it.k It can be expressed as formula (20):

[0108]

[0109] The differential equation of the state transfer equation describes the relationship between the state transfer matrix and time, and its relationship is expressed as formula (21):

[0110]

[0111] In formula (21), A can be the system matrix, describing the dynamic behavior of the system, and A is expressed as formula (22):

[0112]

[0113] Let the initial state F(t,t k )=1 6×6 , the state transfer equation expression is obtained as formula (23):

[0114] F(t)=E+At+1 / 2AAt 2 +1 / 6AAAt 3 +1 / 24AAAAt 4 (twenty three)

[0115] In formula (23), E is the unit matrix and t represents the integration step.

[0116] The process error Q is expressed by continuous acceleration noise, as shown in formula (24):

[0117]

[0118] In formula (24), Represents a quantity related to gravity acceleration. Based on this, the typical update formula of the extended Kalman filter is obtained as formula (25) to formula (27):

[0119]

[0120] X k+1 =X k+1k +K k+1 (z k+1 -h(X k+1k )) (26)

[0121] P k+1 =(IK k+1 H k+1 ) k+1|k , (27)

[0122] Among them, z k+1represents the observed quantity. The azimuth and elevation angles of the satellite with respect to the ground station are obtained by measuring the DOA of the satellite signal through the phased array ground station. h is represented as the observation function, and H is represented as the observation state transfer matrix of the observation function. Since the angle is only related to the geometric position, the partial derivative with respect to the velocity is 0, and the observation state transfer matrix can be obtained as formula (28) to formula (30):

[0123]

[0124] In formula (29), R represents the observation noise, which is expressed as formula (31). The other variables have been explained in the above formula and will not be repeated here.

[0125]

[0126] It should be noted that the diagonal elements represent the azimuth variance and the pitch angle variance, respectively. When the observation noise is larger, the EKF result is more inclined to the predicted result, and when the observation noise is smaller, the EKF result is more inclined to the observed result. We note that the observation quantity is calculated by the DOA estimation algorithm. In some scenarios, there is a relatively small SNR. At this time, the estimation accuracy of DOA will decrease. For example, the SNR decreases at low elevation angles due to large road loss. The size of the observation noise R can be dynamically adjusted according to the SNR value to achieve better results.

[0127] In this embodiment, the satellite signals of each satellite collected by the pre-set phased array ground station are obtained, the corresponding satellite estimated angle is calculated according to the satellite signals of each satellite, and based on the motion trajectory of each satellite and the corresponding satellite estimated angle, the angle of each satellite relative to the phased array ground station is further calculated by updating the model through the extended Kalman filter. The satellite trajectory prediction adopts the J2 perturbation model, which is simple to calculate and can be well integrated into the extended Kalman filter to achieve the preliminary prediction of the satellite trajectory. The phased array ground station collects the signal sent by the satellite and uses a signal parameter estimation algorithm based on rotational invariance to estimate the satellite direction. The algorithm has high resolution and small calculation amount, and can meet the requirements of real-time estimation of the directions of multiple satellites. The extended Kalman filter combines the predicted data with the measured data, linearizes the state and observation model in the nonlinear system, minimizes the error covariance to provide the optimal satellite state estimation, and includes the state and observation process modeling related to the extended Kalman filter. The satellite tracking accuracy obtained can be within 0.1°, which effectively solves the higher tracking accuracy requirements in satellite communications.

[0128] Reference Figure 5 , Figure 5 This is a flow chart of a fourth embodiment of the phased array ground station multi-satellite tracking method of the present application. Figure 3 The third embodiment shown is a fourth embodiment of the phased array ground station multiple satellite tracking method of the present application.

[0129] In the fourth embodiment, the step S40 includes:

[0130] Step S401, based on the angle of each satellite relative to the phased array ground station, the motion trajectory and angle error of each satellite are corrected in real time by updating the model through an extended Kalman filter to obtain a corrected motion trajectory and satellite angle.

[0131] For example, Figure 6 The flowchart of a low-orbit satellite tracking method is shown in FIG. The prediction unit obtains the initial state of the satellite according to the initial ephemeris and predicts the state of the satellite using the satellite propagation model; the measurement unit receives the satellite signal through the phased array antenna and calculates the satellite direction using the DOA estimation algorithm; the extended Kalman filter combines the prediction data with the measurement data to calculate the accurate state of the satellite and the angle relative to the ground station, and uses the updated satellite state information as the initial state of the prediction unit. The beamforming unit adjusts the antenna beam pointing to the satellite according to the updated angle information. Furthermore, the initial state of the satellite can be updated according to the corrected motion trajectory, thereby improving the accuracy of the predicted state.

[0132] Step S402, dynamically adjusting the number of activated antennas of the phased array ground station according to the corrected motion trajectory and satellite angle to obtain an adjusted number of activated antennas.

[0133] It should be noted that the step of dynamically adjusting the number of activated antennas of the phased array ground station is used to meet the gain requirements of different scenarios. For example, Figure 7 As shown in the figure, the ground station adopts a polyhedron structure, with a UPA (uniform plannar array) configured on each face. The planar array configuration N = N x ×N y antennas, where N x and N y Represents the number of antennas on the x-axis and y-axis respectively. The spacing between the antennas is half a wavelength. Using digital phased array antennas, each face can receive signals from multiple satellites at the same time. Phased arrays have the ability to flexibly adjust beams. A method for allocating beam resources on demand is proposed. By activating different numbers of antennas to adapt to the gain required for different tasks, the resource utilization efficiency of ground stations is improved. It can also generate wide beams in scenarios with low gain requirements and reduce tracking accuracy requirements. The number of activated antennas is flexibly adjusted according to the satellite's rate, orbital altitude, and elevation angle to meet gain requirements. In digital communications, E is often used. b / N0 is used to measure the bit error rate, and the expression is formula (32):

[0134]

[0135] In formula (32), EIRPt =P t ·G t , EIRP t Indicates the effective isotropic radiated power, G r is the gain of the receiving antenna, T sys represents the system noise, G r / T sys The G value is an indicator to measure the receiving performance of the phased array ground station. r / T sys The value is related to the number of antennas. Assuming that each antenna has the same performance, the G of the array antenna is r / T sys Value relative to the antenna unit G r / T sys The value can be increased by N times, L atm represents atmospheric loss, L path represents FSPL (Free Space Path Loss), which is calculated as shown in formula (33):

[0136]

[0137] In formula (33), λ is the wavelength of the signal, and d represents the distance between the satellite and the ground station. Since LEOs are mostly near-circular orbits, the distance d will vary with the elevation angle between the satellite and the ground station. Its calculation formula is approximately as follows:

[0138]

[0139] In formula (34), R represents the radius of the earth, h represents the satellite orbit height, and θ represents the elevation angle between the satellite and the ground station. r / T sys Value relative to the antenna unit G r / T sys The value can be increased by N times (expressed as formula (35)), so G can be achieved by increasing the performance of a single antenna unit or increasing the number of antennas. r / T sys For the given requirement, E b / N0 value, the expression of the number of activated antennas can be expressed as formula (34):

[0140]

[0141] From formula (36), we can see that the number of activated antennas is related to multiple factors such as satellite orbit height, elevation angle and speed. Usually the loss caused by antenna tracking error is defined as formula (37):

[0142]

[0143] In formula (37), θ er Indicates the angular deviation between the direction of the antenna pointing to the satellite and the direction of the antenna's maximum gain, θ BW represents the half-power beamwidth, usually expressed as formula (38):

[0144]

[0145] In formula (38), λ is the wavelength of the signal, N and d represent the number of antennas and the antenna spacing in the x-axis or y-axis direction respectively. If the gain loss does not exceed 0.5 dB, the tracking angle deviation is required to be less than 1 / 5 of the half-power beamwidth.

[0146] Step S403: Control the beam direction and width of the phased array antenna based on the adjusted antenna activation quantity.

[0147] It is understandable that the number of antenna activations is adjusted according to the corrected motion trajectory and satellite angle. Therefore, the beam direction and width of the phased array antenna can be controlled based on the adjusted number of antenna activations and satellite angle. For example, the phase of each antenna unit can be adjusted so that the signals emitted by all antennas are coherently superimposed in a specific direction. Static beamforming technology can be used to point the beam direction to the satellite direction. For a planar array, the phase adjustment weight is usually expressed as formula (39):

[0148]

[0149] In formula (39), W m,n represents the phase adjustment weights of the mth antenna on the x-axis and the nth antenna on the y-axis in the planar array, θ represents the azimuth angle of the satellite, represents the satellite's elevation angle, d x Respectively represent the array element spacing on the x-axis, d y Indicates the array element spacing on the y-axis. By monitoring the quality of the signal received from the satellite in real time, the beam direction and width are dynamically adjusted according to the actual signal strength and quality to ensure that the beam is aligned with the satellite.

[0150] In this embodiment, the satellite motion trajectory and angle error are corrected in real time by extending the Kalman filter, which can significantly improve the accuracy of signal reception, reduce signal attenuation or loss caused by errors, dynamically adjust the number of activated antennas, and flexibly configure resources according to the gain requirements of different scenarios, thereby providing stronger signal enhancement when needed and saving energy and resources when signal requirements are low. By precisely controlling the beam direction and width, the signal is always aimed at the satellite, thereby improving the reliability of communication and reducing the impact of signal interference and noise.

[0151] In one implementation, based on the above embodiments, the phased array ground station can also be composed of multiple planes, and can be extended to shipborne or airborne phased array antenna terminal scenarios. On this basis, based on the angle of each satellite relative to the phased array ground station, the motion trajectory and angle error of each satellite are corrected in real time by extending the Kalman filter update model to obtain the corrected motion trajectory and satellite angle; according to the corrected motion trajectory and satellite angle, the number of activated antennas of the phased array ground station is dynamically adjusted to obtain the adjusted number of antenna activations; based on the adjusted number of antenna activations, the beam direction and width of the phased array antenna are controlled, wherein beamforming can use static or adaptive beamforming algorithms to adjust beam pointing. Exemplarily, under known conditions, a fixed beam direction and width are set, or beam parameters are dynamically adjusted according to real-time signal feedback and environmental changes to ensure optimal signal reception and transmission.

[0152] In the above implementation, the system can dynamically adjust according to environmental changes and needs to adapt to various complex conditions in ship-borne or airborne scenarios. Since the phased array ground station can be composed of multiple planes, the system design has good scalability, which is convenient for implementation and deployment on different platforms, and enhances the flexibility of the system. By correcting the satellite's motion trajectory and angle error in real time, the stability and clarity of signal reception are significantly improved. By accurately controlling the beam direction and width, it is ensured that the beam is always aimed at the target satellite, which improves the reliability of communication and reduces interference.

[0153] It should be noted that the above examples are only used to understand the present application and do not constitute a limitation on the phased array ground station multi-satellite tracking method of the present application. More simple transformations based on this technical concept are all within the scope of protection of the present application.

[0154] This application also provides a phased array ground station multiple satellite tracking device, please refer to Figure 8 , the phased array ground station multiple satellite tracking device comprises:

[0155] The state calculation module 10 is used to obtain the ephemeris information of each satellite and calculate the initial state of each satellite according to the ephemeris information of each satellite;

[0156] A trajectory calculation module 20, configured to calculate the motion trajectory of each satellite according to a satellite trajectory prediction model based on the initial state of each satellite;

[0157] An angle calculation module 30, used to calculate the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle;

[0158] The antenna adjustment module 40 is used to adjust the antenna beam of the phased array ground station according to the angle of each satellite relative to the phased array ground station.

[0159] The phased array ground station multi-satellite tracking device provided by the present application adopts the phased array ground station multi-satellite tracking method in the above embodiment, which can solve the technical problem that multi-satellite tracking is difficult to achieve. Compared with the prior art, the beneficial effects of the phased array ground station multi-satellite tracking device provided by the present application are the same as the beneficial effects of the phased array ground station multi-satellite tracking method provided by the above embodiment, and other technical features in the phased array ground station multi-satellite tracking device are the same as the features disclosed in the above embodiment method, which will not be repeated here.

[0160] The present application provides a phased array ground station multi-satellite tracking device, which includes: at least one processor; and a memory connected to the at least one processor in communication; wherein the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the phased array ground station multi-satellite tracking method in the above-mentioned embodiment 1.

[0161] Reference below Fig. 9 , which shows a schematic diagram of the structure of a phased array ground station multiple satellite tracking device suitable for implementing the embodiment of the present application. The phased array ground station multiple satellite tracking device in the embodiment of the present application may include but is not limited to mobile terminals such as mobile phones, laptop computers, digital broadcast receivers, PDAs (Personal Digital Assistants), PADs (Portable Application Descriptions), PMPs (Portable Media Players), vehicle terminals (such as vehicle navigation terminals), etc., and fixed terminals such as digital TVs, desktop computers, etc. Fig. 9 The phased array ground station multi-satellite tracking device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0162] like Fig. 9As shown, the phased array ground station multi-satellite tracking device may include a processing device 1001 (such as a central processing unit, a graphics processor, etc.), which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM: Read Only Memory) 1002 or a program loaded from a storage device 1003 to a random access memory (RAM: Random Access Memory) 1004. Various programs and data required for the operation of the phased array ground station multi-satellite tracking device are also stored in the RAM 1004. The processing device 1001, ROM 1002 and RAM 1004 are connected to each other through a bus 1005. An input / output (I / O) interface 1006 is also connected to the bus. Typically, the following systems can be connected to the I / O interface 1006: input devices 1007 including, for example, a touch screen, a touch pad, a keyboard, a mouse, an image sensor, a microphone, an accelerometer, a gyroscope, etc.; output devices 1008 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 1003 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 1009. The communication device 1009 can allow the phased array ground station multi-satellite tracking device to communicate with other devices wirelessly or by wire to exchange data. Although Fig. 9 A phased array ground station multiple satellite tracking device with various systems is shown, but it should be understood that it is not required to implement or have all of the systems shown. More or fewer systems may alternatively be implemented or have.

[0163] In particular, according to the embodiments disclosed in the present application, the process described above with reference to the flowchart can be implemented as a computer software program. For example, the embodiments disclosed in the present application include a computer program product, which includes a computer program carried on a computer-readable medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from a network through a communication device, or installed from a storage device 1003, or installed from a ROM 1002. When the computer program is executed by the processing device 1001, the above-mentioned functions defined in the method of the embodiment disclosed in the present application are executed.

[0164] The phased array ground station multi-satellite tracking device provided by the present application adopts the phased array ground station multi-satellite tracking method in the above embodiment, which can solve the technical problem that multi-satellite tracking is difficult to achieve. Compared with the prior art, the beneficial effects of the phased array ground station multi-satellite tracking device provided by the present application are the same as the beneficial effects of the phased array ground station multi-satellite tracking method provided by the above embodiment, and the other technical features of the phased array ground station multi-satellite tracking device are the same as the features disclosed in the method of the previous embodiment, which will not be repeated here.

[0165] It should be understood that the various parts disclosed in this application can be implemented by hardware, software, firmware or a combination thereof. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0166] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

[0167] The present application provides a computer-readable storage medium having computer-readable program instructions (ie, computer programs) stored thereon, and the computer-readable program instructions are used to execute the phased array ground station multi-satellite tracking method in the above-mentioned embodiment.

[0168] The computer-readable storage medium provided in the present application may be, for example, a USB flash drive, but is not limited to electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, systems or devices, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, system or device. The program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination of the above.

[0169] The computer-readable storage medium may be included in the phased array ground station multiple satellite tracking device; or may exist independently without being assembled into the phased array ground station multiple satellite tracking device.

[0170] The computer-readable storage medium carries one or more programs. When the one or more programs are executed by a phased array ground station multiple satellite tracking device, the phased array ground station multiple satellite tracking device: obtains ephemeris information of each satellite, and calculates the satellite initial state of each satellite according to the ephemeris information of each satellite; based on the satellite initial state of each satellite, calculates the motion trajectory of each satellite according to a satellite trajectory prediction model; calculates the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle; and adjusts the antenna beam of the phased array ground station according to the angle of each satellite relative to the phased array ground station.

[0171] Computer program code for performing the operations of the present application may be written in one or more programming languages ​​or a combination thereof, including object-oriented programming languages ​​such as Java, Smalltalk, C++, and conventional procedural programming languages ​​such as "C" or similar programming languages. The program code may be executed entirely on the user's computer, partially on the user's computer, as a separate software package, partially on the user's computer and partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet service provider).

[0172] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0173] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0174] The readable storage medium provided by the present application is a computer-readable storage medium, which stores computer-readable program instructions (i.e., computer programs) for executing the above-mentioned phased array ground station multiple satellite tracking method, and can solve the technical problem that multiple satellite tracking is difficult to achieve. Compared with the prior art, the beneficial effects of the computer-readable storage medium provided by the present application are the same as the beneficial effects of the phased array ground station multiple satellite tracking method provided by the above-mentioned embodiment, and will not be repeated here.

[0175] The present application also provides a computer program product, including a computer program, which implements the steps of the above-mentioned phased array ground station multi-satellite tracking method when executed by a processor.

[0176] The computer program product provided by the present application can solve the technical problem that multiple satellite tracking is difficult to achieve. Compared with the prior art, the beneficial effects of the computer program product provided by the present application are the same as the beneficial effects of the phased array ground station multiple satellite tracking method provided by the above embodiment, which will not be repeated here.

[0177] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for tracking multiple satellites by a phased array ground station, characterized in that: The method includes: Obtaining ephemeris information of each satellite, and calculating the initial state of each satellite according to the ephemeris information of each satellite; Based on the initial state of each satellite, the motion trajectory of each satellite is calculated according to the satellite trajectory prediction model; Calculate the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle; According to the angles of the satellites relative to the phased array ground station, the antenna beam of the phased array ground station is adjusted accordingly.

2. The method according to claim 1, characterized in that The step of calculating the motion trajectory of each satellite based on the initial state of each satellite according to the satellite trajectory prediction model comprises: Loading the satellite initial state of each satellite into the satellite trajectory prediction model, and calculating the satellite acceleration of each satellite; The motion trajectory of each satellite is calculated according to the satellite acceleration of each satellite and the corresponding satellite initial state.

3. The method according to claim 1, characterized in that The step of calculating the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle comprises: Acquire satellite signals of each satellite collected by a preset phased array ground station, and calculate corresponding satellite estimation angles according to the satellite signals of each satellite; Based on the motion trajectory of each satellite and the corresponding satellite estimated angle, the angle of each satellite relative to the phased array ground station is calculated by updating the model through an extended Kalman filter.

4. The method according to claim 3, characterized in that The step of acquiring satellite signals of each satellite collected by a preset phased array ground station and calculating a corresponding satellite estimation angle according to the satellite signals of each satellite comprises: Acquire satellite signals of each satellite collected by a preset phased array ground station, and calculate the path difference of the x-axis and the y-axis according to the satellite signals of each satellite; The satellite estimated angle is calculated according to the path difference between the x-axis and the y-axis.

5. The method according to claim 4, characterized in that The step of calculating the angle of each satellite relative to the phased array ground station by updating the model through an extended Kalman filter based on the motion trajectory of each satellite and the corresponding satellite estimated angle comprises: Based on the initial state of each satellite, the satellite acceleration, the motion trajectory of each satellite and the corresponding satellite estimated angle, a state matrix and a prediction equation of a Kalman filter are established; Based on the state matrix and prediction equation of the Kalman filter, an update formula of the extended Kalman filter is constructed, and the angle of each satellite relative to the phased array ground station is calculated according to the update formula.

6. The method according to claim 5, characterized in that The step of adjusting the antenna beam of the phased array ground station accordingly according to the angle of each satellite relative to the phased array ground station comprises: Based on the angle of each satellite relative to the phased array ground station, the motion trajectory and angle error of each satellite are corrected in real time by updating the model through an extended Kalman filter to obtain a corrected motion trajectory and satellite angle; According to the corrected motion trajectory and satellite angle, dynamically adjust the number of activated antennas of the phased array ground station to obtain an adjusted number of antenna activations, wherein the step of dynamically adjusting the number of activated antennas of the phased array ground station is used to meet gain requirements of different scenarios; Based on the adjusted antenna activation quantity, the beam direction and width of the phased array antenna are controlled to ensure that the beam is aligned with the satellite.

7. A phased array ground station multiple satellite tracking device, characterized in that: The device comprises: A state calculation module is used to obtain the ephemeris information of each satellite and calculate the initial state of each satellite according to the ephemeris information of each satellite; A trajectory calculation module, used to calculate the motion trajectory of each satellite according to the satellite trajectory prediction model based on the initial state of each satellite; An angle calculation module, used to calculate the angle of each satellite relative to the phased array ground station according to the motion trajectory of each satellite and the corresponding satellite estimated angle; The antenna adjustment module is used to adjust the antenna beam of the phased array ground station according to the angle of each satellite relative to the phased array ground station.

8. A phased array ground station multi-satellite tracking device, characterized in that: The device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the computer program is configured to implement the steps of the phased array ground station multi-satellite tracking method according to any one of claims 1 to 6.

9. A storage medium, characterized in that: The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, the steps of the phased array ground station multi-satellite tracking method according to any one of claims 1 to 6 are implemented.

10. A computer program product, characterized in that The computer program product comprises a computer program, and when the computer program is executed by a processor, the steps of the phased array ground station multi-satellite tracking method according to any one of claims 1 to 6 are implemented.

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