Long-term elastic space-based maintenance of inertial space reference for constellation navigation

Abstract

The application relates to a long-term elastic space-based maintenance method for a navigation constellation inertial space reference, and the method comprises the following steps: S1, correction of optical properties and thermal radiation factors of a navigation satellite; S2, solution of ECOM light pressure model parameters; S3, construction of an ECOM light pressure parameter prediction model; S4, correction of elastic upper injection optical properties and thermal radiation factors of a multi-carrier based on ECOM parameter prediction model coefficients; and S5, satellite on-orbit precise orientation prediction and satellite-borne orbit filtering determination. According to the application, constellation inertial rotation errors can be eliminated, the operation and maintenance cost and communication pressure of a ground operation and injection system can be maximally increased, and a ground injection station can be kept silent for a long time.

Description

Technical Field

[0001] This invention relates to the field of satellite technology, and specifically to a method for long-term elastic space-based maintenance of an inertial space reference for a navigation constellation. Background Technology

[0002] The long-term maintenance of a highly reliable space-based constellation reference is a crucial prerequisite for constructing an integrated space-ground spatiotemporal reference network and realizing intelligent and resilient operation and maintenance of satellite systems. Theoretically, navigation satellites can generate navigation messages and maintain constellation configuration in real time simply through inter-satellite two-way ranging, data exchange, and orbit determination filtering by onboard processors. This ensures the long-term normal operation of the constellation, effectively moving the space reference maintenance equipment from the ground to space and improving the system's resilience and survivability.

[0003] However, maintaining a satellite's space-based reference is inherently a rank-deficient free network adjustment problem, as there is no external reference. The constellation's orbit determination using inter-satellite ranging information is essentially a problem of adjusting the free network. Therefore, the constellation's true orientation in inertial space cannot be effectively determined using inter-satellite two-way ranging. It will inevitably be affected by errors in the onboard data processing model (mainly defects in radiation pressure modeling and neglect of seasonal thermal radiation from the Earth's shadow), causing the constellation to suffer significant rotational effects in inertial space. This gradually accumulates and leads to a rapid decline in the constellation's long-term space-based reference maintenance capability.

[0004] Conventional long-term satellite space reference maintenance algorithms, such as those used in the US GPS system, are limited by the performance of onboard processors and do not utilize methods like those used on the ground segment to accurately construct perturbations such as light pressure and thermal radiation based on complete dynamic parameter estimation to reduce constellation inertial space rotation errors. Instead, they use long-term ephemeris orientation prediction information of the entire constellation injected on the ground to constellate and correct the filtered orbit orientation information in real time, thereby achieving long-term reliable maintenance of the satellite inertial space orientation reference in orbit. Summary of the Invention

[0005] Conventional strategies for suppressing space-based inertial rotation errors and maintaining the space reference in constellations impose significant communication burdens and operational costs on ground systems and satellite-to-ground injection links, disrupting the silent state of ground injection stations and greatly increasing their vulnerability. To address these issues, this invention proposes a long-term, flexible space-based maintenance method for navigation constellations' inertial space references. This method suppresses constellation rotation effects, improves satellite-borne filtering and orbit determination accuracy, without increasing the operational costs and communication pressure on ground control and injection systems. Furthermore, it offers multiple injection modes, achieving long-term, reliable, flexible space-based inertial maintenance of the constellation.

[0006] To achieve the above-mentioned objectives of the present invention, the long-term elastic space-based maintenance method for the navigation constellation inertial space reference of the present invention includes:

[0007] S1, Correction of optical properties and thermal radiation factors of navigation satellites;

[0008] S2, ECOM photopressure model parameter solution;

[0009] S3, ECOM photopressure parameter prediction model construction;

[0010] S4, based on the optical properties of multi-carrier elastic injection, thermal radiation factor correction coefficient and ECOM parameter prediction model coefficient;

[0011] S5, precise on-orbit orientation prediction and onboard orbit filtering determination for satellites.

[0012] Furthermore, in step S1, an improved box-wing model is used to correct the optical properties and thermal emissivity. The improved box-wing model is expressed as:

[0013]

[0014] Where (a, δ, ρ) are the absorption, specular reflection, and diffuse emission optical coefficients of the satellite's illuminated surface, respectively; R and S are the thermal radiation scaling factors of the star and solar panels, respectively; A, m, Φ, and c are the illuminated surface area, satellite mass, solar radiation flux, and speed of light, respectively; when k is 0 or 1, the above formula is used to interpret the light pressure of the solar panels and the satellite body, respectively; e D e N S is the normal vector from the satellite to the sun and the illuminated surface. sh Here, θ is the star's self-occlusion factor, θ is the angle between the incident ray and the normal vector of the illuminated surface, and acc is the celestial self-occlusion factor. THM For the prior thermal radiation of solar panels.

[0015] Further, S2 includes:

[0016] The output optical properties and thermal emissivity factor are incorporated into the improved box-wing model as a priori model, and combined with the empirical ECOM light pressure model to solve the ECOM light pressure model parameters.

[0017] The ECOM light pressure model formula is as follows:

[0018] a D =D0

[0019] a Y =Y0

[0020] a D =B0+B c cosμ+B s sinμ

[0021] Where μ is the angle of the satellite relative to the ascending node of the inertial frame, and D0, Y0, and (B0, B... cB s The ECOM model radiation pressure parameters are along the satellite-sun, solar panel rotation axis, and the direction constituting the third axis of the right-hand system, respectively.

[0022] Further, S3 includes:

[0023] The long-term estimated ECOM model radiation pressure parameters D0, Y0, B0, and B from each satellite were obtained. c B s After timing, the analytical fitting is performed using a sine curve function of the solar elevation angle β relative to the satellite orbital plane for each parameter:

[0024]

[0025] Where n represents the number of terms in the Sine function, A i B i and C i For each Sine term, we define its amplitude, frequency, and phase.

[0026] Further, S4 includes:

[0027] The multi-carrier system includes ground-based fixed injection stations, vehicle-mounted and ship-mounted mobile injection systems, portable injection systems, and LEO or other relay satellite relays. The system utilizes minute-level elastic injection correction across the entire constellation to obtain the optical property coefficients (a, δ, ρ), the thermal radiation scaling factors R and S of the celestial body and solar panels, and the fitted estimated ECOM radiation pressure parameter prediction model coefficients n and A. i B i and C i .

[0028] Further, S5 includes:

[0029] After the navigation constellation's space-based baseline maintenance mode is activated, the onboard processor uses stored ground-based optical property coefficients (a, δ, ρ), body and solar panel thermal radiation scaling factors R, S, and fitted estimated ECOM radiation pressure parameter prediction model coefficients n, A. i B i and C i It analyzes the light pressure and thermal radiation perturbations experienced by the on-orbit satellite and solar panels, and predicts the satellite's orbital plane orientation and other status information in one step; further, it uses inter-satellite link bidirectional measurement to make real-time robust corrections to the satellite status information, thereby effectively suppressing the rotational effects of the constellation's inertial space and maintaining a long-term, highly reliable inertial space reference.

[0030] The long-term elastic space-based maintenance method for the navigation constellation inertial space reference in this invention uploads pre-constructed high-fidelity a priori optical pressure and thermal radiation model parameters to the satellite via a satellite-to-ground inter-satellite link within minutes. This allows for precise real-time interpretation of the optical pressure and thermal radiation perturbations experienced by the satellite in orbit, overcoming the defects of the onboard perturbation model and achieving effective suppression of the constellation's inertial space rotation effect and highly reliable long-term elastic space-based maintenance of the space reference. Considering that the optical and thermophysical properties of the satellite body and solar panels will not undergo qualitative changes within one to two years, frequent uploading as required for long-term ephemeris prediction is unnecessary. This invention can eliminate constellation inertial rotation errors while minimizing the increase in maintenance costs and communication pressure on the ground control and injection systems, maintaining long-term silence of the ground injection station. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a flowchart illustrating the long-term elastic space-based maintenance method for the navigation constellation inertial space reference according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram illustrating the principle of the long-term elastic space-based maintenance method for the navigation constellation inertial space reference according to an embodiment of the present invention.

[0034] Figure 3 This is a schematic diagram of the model coefficient technology for multi-carrier minute-level rapid elastic uploading and distribution of full constellation photopressure and thermal radiation in an embodiment of the present invention. Detailed Implementation

[0035] The description of the embodiments in this specification should be taken in conjunction with the accompanying drawings, which should form part of the complete specification. In the drawings, the shape or thickness of the embodiments may be exaggerated and may be indicated in a simplified or convenient manner. Furthermore, parts of the various structures in the drawings will be described separately; it is worth noting that elements not shown in the figures or not described in words are in a form known to those skilled in the art.

[0036] The descriptions of the embodiments herein, including any references to directions and orientations, are for ease of description only and should not be construed as limiting the scope of the invention. The following description of preferred embodiments involves combinations of features, which may exist independently or in combination; the invention is not particularly limited to the preferred embodiments. The scope of the invention is defined by the claims.

[0037] like Figure 1 and Figure 2 As shown, the long-term elastic space-based maintenance method for the navigation constellation inertial space reference in this embodiment of the invention includes:

[0038] S1, correction of navigation satellite optical properties and thermal radiation factor.

[0039] Utilizing long-term global ground tracking station data (over three years), LEO onboard data, inter-satellite links, laser ranging (SLR), and satellite metadata provided by the manufacturer, an adjustable box-wing technique is employed to accurately estimate the satellite orbit while precisely correcting its optical properties and thermal emissivity. In addition to calculating the absorption, specular reflection, and diffuse emission optical coefficients (a, δ, ρ) of the satellite's illuminated surface along with its orbit, the self-shading effects of the satellite payload and the thermal radiation from the satellite and its solar panels are also considered to estimate the corresponding thermal emissivity scaling factors R and S. The specific model formula is as follows:

[0040]

[0041] Where A, m, Φ, and c represent the area of ​​the illuminated surface, the satellite mass, the solar radiation flux, and the speed of light, respectively; when k is 0 or 1, the above formula is used to interpret the light pressure of the solar panels and the satellite body, respectively; e D e N S is the normal vector from the satellite to the sun and the illuminated surface. sh Here, θ is the star's self-occlusion factor, θ is the angle between the incident ray and the normal vector of the illuminated surface, and acc is the celestial self-occlusion factor. THM For the prior thermal radiation of solar panels.

[0042] S2, ECOM photoelectric pressure model parameter solution.

[0043] The output optical and thermal radiation parameters are incorporated into the improved box-wing model, which is then used as a priori model. Using long-term satellite global ground tracking station data (three years or more), LEO onboard data, inter-satellite links, and laser ranging (SLR), the parameters of the empirical ECOM radiation pressure model developed by the traditional European Orbit Determination Centre are estimated. The ECOM radiation pressure model formula is as follows:

[0044] a D =D0

[0045] a Y =Y0

[0046] a D =B0+B c cosμ+B s sinμ (2)

[0047] Where μ is the angle of the satellite relative to the ascending node of the inertial frame, and D0, Y0, and (B0, B... c Bs The ECOM model radiation pressure parameters are along the satellite-sun, solar panel rotation axis, and the direction constituting the third axis of the right-hand system, respectively.

[0048] S3, ECOM photoelectric pressure parameter prediction model construction.

[0049] The long-term estimated ECOM model radiation pressure parameters D0, Y0, B0, and B from each satellite were obtained. c B s After time series analysis, each parameter is fitted as a sine curve function (sum of sine) of the solar elevation angle β relative to the satellite orbital plane:

[0050]

[0051] Where n represents the number of terms in the Sine function, A i B i and C i For each Sine term, we define its amplitude, frequency, and phase.

[0052] S4 is based on the optical properties of multi-carrier elastic upflow, thermal radiation factor correction coefficient, and ECOM parameter prediction model coefficient.

[0053] like Figure 3 As shown, the total number of optical property and thermal emissivity correction coefficients and ECOM parameter prediction model coefficients for each satellite does not exceed 30, which is a significant decrease compared to the data volume of long-term ephemeris prediction. Through dedicated multi-carrier (ground fixed injection station, vehicle-mounted and ship-mounted mobile injection, portable injection, and LEO and other relay satellite relay) inter-satellite links, the full constellation's optical property coefficients (a, δ, ρ), body and solar panel thermal emissivity scaling factors R, S, and fitted estimated ECOM radiation pressure parameter prediction model coefficients n, A are rapidly and elastically injected and corrected within minutes. i B i and C i .

[0054] S5, precise on-orbit orientation prediction and onboard orbit filtering determination for satellites.

[0055] After the navigation constellation's space-based baseline maintenance mode is activated, the onboard processor uses stored ground-based optical property coefficients (a, δ, ρ), the thermal radiation scaling factors R, S of the star and solar panels, and the fitted estimated ECOM radiation pressure parameter prediction model coefficients n, A. i B i and C iThe perturbations of light pressure and thermal radiation experienced by the on-orbit satellite and solar panels are analyzed in equations (1)-(3), and the satellite orbital plane orientation and other state information are accurately predicted in one step. Furthermore, bidirectional measurements via inter-satellite links are used to make real-time robust corrections to the satellite state information, thereby effectively suppressing the rotational effects of the constellation's inertial space and maintaining a long-term, highly reliable inertial space reference.

[0056] The present invention has the following beneficial effects:

[0057] (1) The conventional approach of using long-term predicted orientation information to constrain the overall rotation effect of the constellation is abandoned. Instead, a high-fidelity perturbation model is constructed using the light pressure and thermal radiation model coefficients rapidly uploaded from the ground. This model accurately predicts the orientation of the satellite orbital plane in inertial space, achieving long-term effective suppression of constellation rotation errors and high-reliability maintenance of the inertial space reference. The new method eliminates the need for frequent uploading of ground orientation prediction and other state information as in traditional schemes, and significantly reduces the amount of information required for uploading, greatly reducing engineering costs and improving the concealment and survivability of the uploading carrier. Furthermore, it eliminates the need for real-time inter-satellite transmission of information such as the orientation error of the filtered orbit of the entire constellation or a part of the constellation relative to the long-term predicted ephemeris, effectively reducing the communication burden of long-term maintenance of the constellation's space reference.

[0058] (2) In order to suppress the constellation space-based orientation error and achieve long-term high-reliability satellite orbit filtering determination, the information to be uploaded mainly includes the satellite body absorption, specular reflection and diffuse emission optical coefficients based on multi-source long-term data with precise correction, the thermal radiation ratio factor of the star body and the solar panel, and the ECOM light pressure parameter prediction model coefficients of the fitted estimate.

[0059] (3) The prediction model for ECOM radiation pressure parameters designed in this invention is expressed as: a sine curve fitting relative to the solar altitude angle.

[0060] (4) The flexible injection mode designed in this invention includes: ground injection station, mobile anchored injection, portable injection and LEO relay satellite transfer injection. This flexible multi-mode injection can apply all technologies of constellation space-based intelligent operation and maintenance for flexible processing, including long-term space-based time synchronization and timekeeping, and is not limited to the long-term maintenance of constellation inertial space reference space-based systems.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for long-term elastic space-based maintenance of an inertial space reference for a navigation constellation, characterized in that, The method includes: S1, correction of navigation satellite optical properties and thermal emissivity, specifically includes: The optical properties and thermal emissivity are corrected using an improved box-wing model, which is expressed as follows: in, These represent the absorption, specular reflection, and diffuse emission optical coefficients of the satellite's illuminated surface, respectively. These are the thermal radiation scaling factors for celestial bodies and solar panels, respectively. , , , These are the surface area exposed to sunlight, satellite mass, solar radiation flux, and speed of light, respectively. When the value is 0 or 1, the above formula is used to interpret the light pressure of the solar panels and the satellite body, respectively; , This is the normal vector of the satellite in the direction from the sun and the illuminated surface. As a celestial self-occlusion factor, Let be the angle between the incident ray and the normal vector of the illuminated surface. For the priori thermal radiation of solar panels; S2, ECOM photopressure model parameter solution; S3, ECOM photoelectric pressure parameter prediction model construction, specifically includes: After obtaining the long-term estimated ECOM model radiation pressure parameters for each satellite , , , , After time series analysis, each parameter is the solar elevation angle relative to the satellite orbital plane. Sine curve function: in, Represented as the number of terms in the Sine function. , and For each Sine term, define its amplitude, frequency, and phase; S4, based on the optical properties of multi-carrier elastic injection, thermal radiation factor correction coefficient and ECOM parameter prediction model coefficient; S5, precise on-orbit orientation prediction and onboard orbit filtering determination for satellites.

2. The method for long-term elastic space-based maintenance of a navigation constellation inertial space reference according to claim 1, characterized in that, S2 includes: The output optical properties and thermal emissivity factor are incorporated into the improved box-wing model as a priori model, and combined with the empirical ECOM light pressure model to solve the ECOM light pressure model parameters. The ECOM light pressure model formula is as follows: in, The angle of the satellite relative to the ascending node of the inertial frame. , and These are the ECOM model radiation pressure parameters along the satellite-sun, solar panel rotation axis, and the direction constituting the third axis of the right-hand system, respectively.

3. The method for long-term elastic space-based maintenance of a navigation constellation inertial space reference according to claim 2, characterized in that, S4 includes: The multi-carrier system includes ground-based fixed injection stations, vehicle-mounted and ship-based mobile injection systems, portable injection systems, and LEO or other relay satellite relays. The system utilizes minute-level elastic injection correction for the entire constellation's optical property coefficients. Scale factor of thermal radiation of stars and solar panels And the coefficients of the ECOM light pressure parameter prediction model that were fitted and estimated. , , and .

4. The method for long-term elastic space-based maintenance of a navigation constellation inertial space reference according to claim 3, characterized in that, S5 includes: After the space-based maintenance mode of the navigation constellation is activated, the onboard processor uses the stored ground-based optical attribute coefficients. Scale factor of thermal radiation of stars and solar panels And the coefficients of the ECOM light pressure parameter prediction model that were fitted and estimated. , , and It analyzes the light pressure and thermal radiation perturbations experienced by the on-orbit satellite and solar panels, and predicts the satellite's orbital plane orientation and other status information in one step; further, it uses inter-satellite link bidirectional measurement to make real-time robust corrections to the satellite status information, thereby effectively suppressing the rotational effect of the constellation's inertial space and maintaining a long-term, highly reliable inertial space reference.

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