Novel global satellite navigation system architecture

Abstract

The invention provides a novel global satellite navigation system architecture which provides various services through an integrated mixed constellation comprising GEO, IGSO, MEO and LEO satellites. A space-based communication and measurement network is constructed through an inter-satellite link, so that ground operation management and observation resources are simplified; under the support of a measuring part, the building and maintaining capability of a space-based space-time reference is enhanced based on an inter-satellite link, so that the dependence on the ground is reduced; based on a low-orbit navigation signal, signal availability and anti-interference and anti-cheating capabilities are improved through communication assistance. The system analyzes the characteristics and physical limits of the existing GNSS architecture, and defines the constraint factors for further improving the GNSS performance. On the basis, a GNSS architecture combining a measurement communication network, a high-orbit mixed constellation, a medium-orbit mixed constellation and a low-orbit mixed constellation is provided based on inter-satellite link construction. The global decimeter-level high-precision and high-credibility PNT service can be realized under the support of the extremely simple ground, and the user experience is stably upgraded.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation technology, and in particular to a novel global satellite navigation system architecture. Background Art

[0002] GNSS (Global Navigation Satellite System) is the main provider of positioning, navigation and timing (PNT) needs in today's human society. It is the core support for the modern production, life and governance of human society. Accuracy, reliability, convenience and efficiency are its unremitting pursuit. However, after decades of development and iteration, the performance of GNSS services in the current architecture has approached the limits of theory and engineering, and cannot fully meet the growing demand for global decimeter-level navigation and high-reliability services. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a new global satellite navigation system architecture, systematically analyze the characteristics and physical limits of the existing GNSS architecture, and clarify the constraints for further improving the performance of GNSS. On this basis, a GNSS architecture that combines a hybrid constellation of high orbit (GEO / IGSO), medium orbit (MEO) and low orbit (LEO) with a measurement communication network based on intersatellite links is proposed. The simulation and analysis results show that the new global satellite navigation system provided in this embodiment can achieve global decimeter-level high-precision and high-reliability PNT services with minimal ground support, is compatible and interoperable with the existing GNSS, and can evolve on its basis, with a smooth upgrade of user experience.

[0004] In the first aspect, an embodiment of the present invention provides a new global satellite navigation system architecture, including: providing multiple services through an integrated hybrid constellation; the integrated hybrid constellation includes GEO, IGSO, MEO, and LEO satellites; building a space-based communication and measurement network through inter-satellite links to simplify ground operation and observation resources; with the support of measurement components, strengthening the ability to establish and maintain space-based time and space references based on inter-satellite links to reduce dependence on the ground; based on low-orbit navigation signals, improving signal availability, anti-interference and anti-deception capabilities through communication assistance.

[0005] In an optional embodiment of the present application, based on the existing architecture, the new global satellite navigation system architecture adds new elements including: inter-satellite links, communication assistance and low-orbit constellations.

[0006] In an optional embodiment of the present application, the above-mentioned communication auxiliary is deployed in various communication facilities, and the low-orbit constellation is deployed in the LEO navigation constellation and its ground facilities.

[0007] In an optional embodiment of the present application, the above-mentioned inter-satellite links include: high-speed laser links, Ka links, and medium-speed laser links; the elements of the global satellite navigation system architecture also include: ground links; high-speed laser links are deployed on GEO, IGSO, and MEO satellites; Ka links are deployed on GEO, IGSO, and MEO satellites; medium-speed laser links are deployed on LEO satellites; and ground links are deployed on GEO and IGSO satellites.

[0008] In an optional embodiment of the present application, the above-mentioned Ka link is also deployed on a LEO satellite; the medium-speed laser link is deployed on a GEO, IGSO, and MEO satellite; and the ground link is also deployed on a LEO satellite.

[0009] In an optional embodiment of the present application, the above-mentioned measurement components include: an atomic clock group and a stellar camera; the atomic clock group is deployed on GEO, IGSO, and some MEO satellites; and the stellar camera is deployed on an IGSO satellite.

[0010] In an optional embodiment of the present application, the above-mentioned integrated hybrid constellation includes: 24-30 MEO satellites, 150-200 LEO satellites, 3-6 GEO satellites, and 3-6 IGSO satellites; among them, 24-30 MEO satellites are the core constellation, 3-6 GEO satellites and 3-6 IGSO satellites are the node constellations, and 150-200 LEO satellites are the enhanced constellation; the core constellation provides global meter-level PNT services and SSV below 3000km, the node constellation provides regional diversified services, SSV, and navigation coverage enhancement, and the enhanced constellation provides global decimeter-level high-precision and high-reliability services below 30km.

[0011] In an optional embodiment of the present application, the service types of the above-mentioned high-speed laser link include: constellation management, communication relay, time and space measurement, external relay, the rate of the high-speed laser link is Gbps, and the accuracy is ps; the service types of the Ka link include: constellation management, time and space measurement, flexible access, the rate of the Ka link is Mbps, and the accuracy is ps; the service types of the medium-speed laser link include: constellation management, communication relay, time and space measurement, the rate of the medium-speed laser link is Mbps, and the accuracy is ps; the service types of the ground link include: ground data transmission and time and space reference fixed connection, the rate of the ground link is Gbps, and the accuracy is ps.

[0012] In an optional embodiment of the present application, the above-mentioned mercury ion clock, integrating sphere clock, inter-satellite measurement equipment, and satellite-to-ground measurement equipment are deployed on GEO satellites and IGSO satellites to establish a space-based time reference; the inter-satellite and satellite-to-ground measurement equipment of the large-array stargazing camera are deployed on the IGSO satellite to establish a space-based space reference; the inter-satellite and satellite-to-ground measurement equipment are deployed on the MEO satellite to support the construction of a space-based time and space reference; the navigation monitoring receiver is deployed on the LEO satellite to obtain the time and space reference established in the medium and high orbits; the satellite-to-ground measurement equipment is deployed on the ground anchor station to establish the connection between the space-based time and space reference and the earth's time and space reference.

[0013] In an optional embodiment of the present application, the frequency bands used for the above-mentioned LEO downlink navigation signal include: L1 frequency band and L5 frequency band, and the LEO downlink navigation signal is compatible with the GNSS navigation signal or a suitable communication signal.

[0014] The embodiments of the present invention bring the following beneficial effects:

[0015] The embodiment of the present invention provides a new global satellite navigation system architecture, which systematically analyzes the characteristics and physical limits of the existing GNSS architecture, and clarifies the constraints for further improving the performance of GNSS. On this basis, a GNSS architecture is proposed that builds a measurement communication network based on inter-satellite links, and combines a high orbit (GEO / IGSO), medium orbit (MEO), and low orbit (LEO) hybrid constellation. Simulation and analysis results show that the new global satellite navigation system provided by this embodiment can achieve global decimeter-level high-precision and high-reliability PNT services with minimal ground support, is compatible and interoperable with the existing GNSS, and can evolve on its basis, with a smooth upgrade of user experience.

[0016] Other features and advantages of the present disclosure will be set forth in the following description, or some features and advantages may be inferred or unambiguously determined from the description, or may be learned by implementing the above-mentioned technology of the present disclosure.

[0017] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1A mind map of a novel global satellite navigation system provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of the architecture of a novel global satellite navigation system provided by an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of establishing an intersatellite link provided by an embodiment of the present invention;

[0022] Figure 4 A schematic diagram of a space-based architecture of a time reference provided by an embodiment of the present invention;

[0023] Figure 5 A schematic diagram of a space-based architecture of a space reference provided by an embodiment of the present invention;

[0024] Figure 6 A schematic diagram of capture sensitivity corresponding to different coherent integration times provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] At present, GNSS is the main provider of positioning, navigation and timing (PNT) needs in today's human society, and is the core support for the modern production, life and governance of human society. Accuracy, reliability, convenience and efficiency are its unremitting pursuit of development. However, after decades of development and iteration, the performance of GNSS services in the current architecture has approached the limits of theory and engineering, and cannot fully meet the growing global decimeter-level navigation and high-reliability service needs.

[0027] Based on this, a new global satellite navigation system architecture provided by an embodiment of the present invention specifically provides a new global satellite navigation system architecture for more accurate and more reliable PNT services, systematically analyzes the characteristics and physical limits of the existing GNSS architecture, and clarifies the constraints for further improving GNSS performance. On this basis, a GNSS architecture is proposed that builds a measurement communication network based on inter-satellite links, and combines a high orbit (GEO / IGSO), medium orbit (MEO) and low orbit (LEO) hybrid constellation. Simulation and analysis results show that the new global satellite navigation system provided by this embodiment can achieve global decimeter-level high-precision and highly reliable PNT services with minimal ground support, is compatible and interoperable with the existing GNSS, and can evolve on its basis, with a smooth upgrade of user experience.

[0028] To facilitate understanding of this embodiment, a new type of global satellite navigation system disclosed in an embodiment of the present invention is first introduced in detail.

[0029] Embodiment 1:

[0030] An embodiment of the present invention provides a novel global satellite navigation system, which provides multiple services through an integrated hybrid constellation; the integrated hybrid constellation includes GEO, IGSO, MEO, and LEO satellites; a space-based communication and measurement network is constructed through inter-satellite links to simplify ground management and observation resources; with the support of measurement components, the ability to establish and maintain space-based time and space references is enhanced based on inter-satellite links to reduce dependence on the ground; based on low-orbit navigation signals, signal availability, anti-interference and anti-deception capabilities are improved through communication assistance.

[0031] See also Figure 1 A mind map of a new global satellite navigation system, and Figure 2 The schematic diagram of the architecture of a new global satellite navigation system is shown in Figure 1. From the perspective of system design, the "four more" are specifically defined as the following six goals:

[0032] (1) Integration realizes global decimeter-level real-time high-precision navigation and the integrity of Class I precision approach requirements of international civil aviation, meets the greatest common needs, and reduces dependence on various satellite-based and ground-based augmentation systems.

[0033] (2) Improve the availability and reliability of navigation signals in complex scenarios.

[0034] (3) Significantly improve space-based measurement, communication, and computing capabilities, simplify ground facilities, and reduce construction and operating costs.

[0035] (4) The user equipment hardware is compatible with existing GNSS terminals, and incremental capabilities can be achieved through software upgrades.

[0036] (5) Constellations and ground facilities can evolve based on existing GNSS infrastructure.

[0037] (6) Use communication systems to help improve user experience.

[0038] In some embodiments, based on the existing architecture, the new global satellite navigation system architecture of this embodiment includes: inter-satellite links, communication assistance and low-orbit constellations.

[0039] The new global satellite navigation system architecture in this embodiment is not a new one, but the result of integrating and reshaping the existing GNSS architecture by adding three core elements, namely low-orbit constellations, intersatellite links, and communication assistance. Compared with the existing GNSS, it can improve 11 capabilities, including accuracy, integrity, availability, and anti-interference, while greatly simplifying ground facilities, reducing construction and operation costs, and achieving the goal of "four more".

[0040] The new global satellite navigation system architecture in this embodiment does not change the basic properties of GNSS: Satellite Radio Determination System (RDSS). That is, using satellites as reference points and signal sources, it provides navigation, positioning, and timing services for users by transmitting radio signals. Whether it is satellite or user equipment, the time and space determination still adopts the time difference measurement system, and adopts or is compatible with the current navigation frequency band and signal structure. These ensure compatibility with existing user equipment. The existing GEO / IGSO / MEO constellations are still the core and backbone. Of course, with the addition of new elements, the appearance of GNSS has also changed significantly, presenting different characteristics from the past:

[0041] (1) GEO / IGSO / MEO / LEO integrated hybrid constellation, providing diversified services on demand.

[0042] (2) Intersatellite links build a space-based communication and measurement network, greatly simplifying ground operation and observation resources.

[0043] (3) With the support of high-performance satellite-borne measurement components, the ability to establish and maintain space-based time and space benchmarks is enhanced based on inter-satellite links and high-performance measurement components, and dependence on the ground is greatly reduced.

[0044] (4) Improved low-orbit navigation signals and the introduction of communication assistance to enhance signal availability, anti-interference and anti-spoofing capabilities.

[0045] The embodiment of the present invention provides a global satellite navigation system, which systematically analyzes the characteristics and physical limits of the existing GNSS architecture, and clarifies the constraints for further improving the performance of GNSS. On this basis, a GNSS architecture is proposed that builds a measurement communication network based on inter-satellite links, and combines a high orbit (GEO / IGSO), medium orbit (MEO), and low orbit (LEO) hybrid constellation. Simulation and analysis results show that the new global satellite navigation system provided by this embodiment can achieve global decimeter-level high-precision and high-reliability PNT services with minimal ground support, is compatible and interoperable with the existing GNSS, and can evolve on its basis, with a smooth upgrade of user experience.

[0046] In some embodiments, communication assistants are deployed in various communication facilities, and low-orbit constellations are deployed in LEO navigation constellations and their ground facilities.

[0047] Among them, communication assistance is implemented through software upgrade; the relationship with existing facilities is independent of each other; the service / function carried is GNSS performance enhancement; the capability increment is to shorten the cold start time of GNSS equipment, carry high-precision enhanced telegrams, and realize two-way authentication; the user equipment form is existing navigation equipment + related communication equipment.

[0048] Among them, the implementation method of low-orbit constellation is new construction / access; the relationship with existing facilities is mutual independence + deep integration; the business / function carried is global high precision / integrity; the incremental capability is global near-real-time decimeter-level high precision, greatly improved anti-interference capability, and higher information rate, realizing global monitoring of medium and high-orbit constellation navigation signals; the user equipment form is the software upgrade of existing navigation equipment.

[0049] In some embodiments, the inter-satellite links include: high-speed laser links, Ka links, and medium-speed laser links; the elements of the global satellite navigation system architecture also include: ground links; high-speed laser links are deployed on GEO, IGSO, and MEO satellites; Ka links are deployed on GEO, IGSO, and MEO satellites; medium-speed laser links are deployed on LEO satellites; and ground links are deployed on GEO and IGSO satellites.

[0050] Among them, the incremental capacity of inter-satellite links and ground links is to simplify ground facilities, reduce construction and operation costs, and support the establishment and maintenance of space-based space benchmarks; the user equipment form is existing navigation equipment.

[0051] In some embodiments, the Ka link is also deployed on LEO satellites; the medium-speed laser link is deployed on GEO, IGSO, and MEO satellites; and the ground link is also deployed on LEO satellites.

[0052] Among them, the implementation method of high-speed laser, Ka, and medium-speed laser is to add satellites, and the implementation method of the supporting ground links (including Ka / laser) is to add satellites + add master control stations / injection stations; the relationship between high-speed laser, Ka, and medium-speed laser and existing facilities is replacement of in-orbit satellites, and the relationship between the supporting ground links and existing facilities is replacement of in-orbit satellites + ground additions; the bearer services / functions of high-speed lasers are constellation management / space-time determination / communication relay, the bearer services / functions of Ka are space-time determination / flexible access, the bearer services / functions of medium-speed lasers are constellation management / space-time determination / communication relay, and the bearer services / functions of the supporting ground links are constellation management / ground space-time traceability / data landing.

[0053] In some embodiments, the measurement components include: an atomic clock group and a star camera; the atomic clock group is deployed on GEO, IGSO, and some MEO satellites; the star camera is deployed on an IGSO satellite.

[0054] Among them, the atomic clock group and stellar camera are realized by adding satellites; their relationship with existing facilities is the replacement of in-orbit satellites; the services / functions they carry are space-based time benchmarks; the incremental capabilities are to achieve the establishment and maintenance of space-based integrated atomic time; and the user equipment form is existing navigation equipment.

[0055] The above content gives the main information of the newly added elements, and their addition supports the realization of the aforementioned goals. From the perspective of the relationship between technology maturity and evolution, communication assistance technology is relatively mature, and incremental capabilities can be achieved by simply upgrading the software of the existing communication network, with almost no hardware changes involved. Its infrastructure and operation are independent of the existing GNSS and are the easiest to implement. Low-orbit constellations also have a high level of technical maturity. They can be built on their own or implemented by accessing related low-orbit navigation constellations. The infrastructure is independent of the existing GNSS. In terms of operation, interactive support is required through the connection, data exchange and fusion processing of satellite signals, and its implementation is relatively easy. However, the high-performance measurement components, intersatellite links and their supporting ground links on GEO / IGSO / MEO satellites have relatively low technical maturity, and need to be gradually deployed by replacing existing satellites. They will significantly change the measurement, control and operation methods of the existing GNSS. The implementation process will be subject to the evolution process of the existing GNSS, and the implementation is difficult and has a long period. Of course, this is actually a maximum envelope that can be tailored as needed.

[0056] Embodiment 2:

[0057] This embodiment provides another new type of global satellite navigation system, which is implemented on the basis of the above embodiment. In this embodiment, global high-precision and high-reliability services can be provided through the integration of high, medium and low orbit hybrid constellations. In some embodiments, the integrated hybrid constellation includes: 24-30 MEO satellites, 150-200 LEO satellites, 3-6 GEO satellites, and 3-6 IGSO satellites; among them, 24-30 MEO satellites are core constellations, 3-6 GEO satellites and 3-6 IGSO satellites are node constellations, and 150-200 LEO satellites are enhanced constellations; the core constellation provides global meter-level PNT services and SSV below 3000km, the node constellation provides regional diversified services, SSV, and navigation coverage enhancement, and the enhanced constellation provides global decimeter-level high-precision and high-reliability services below 30km.

[0058] The constellation directly provides navigation signals and PNT services to users and is the core node of GNSS. The complete constellation framework consists of 24 to 30 MEO satellites, 150 to 200 LEO satellites, 3 to 6 GEO satellites, and 3 to 6 IGSO satellites. Depending on the needs, it can be cut and adjusted on this basis.

[0059] MEO is the core constellation, and its architectural contributions include: global four-fold or more RNSS signal coverage, support for ground stations and low-orbit constellations to maintain time and space benchmarks, and some satellites participating in establishing space-based time and space benchmarks; services provided include: global meter-level PNT service (below 3000km) / SSV.

[0060] GEO and IGSO are node constellations, and their architectural contributions include: improving regional visibility (high latitudes), establishing space-based space-time benchmarks, connecting ground data transmission with space-time benchmarks, and strengthening RNSS signal coverage in the region; the services provided include: regional diversified services / SSV / navigation coverage enhancement.

[0061] LEO is an enhanced constellation, and its architecture contributions include: real-time high-precision PNT, high-power navigation signals, improved PNT service availability and reliability, monitoring of GEO / IGSO / MEO constellation services and performance, and improved observation geometry for GEO / IGSO / MEO time and space determination; services provided include: global decimeter-level high-precision and high-reliability services (below 30 km).

[0062] Among them, MEO satellites, as the core constellation, provide meter-level positioning, navigation, timing and space service domain SSV services (3000km to 36000km or even higher) for the global space below 3000km, and some satellites serve as space-based space-time reference hubs.

[0063] GEO / IGSO satellites, as node constellations, are the central nodes of space-based time and space references, and realize fixed connection and data transmission with earth-based time and space references. They can also carry satellite-based augmentation, message communication and other regional diversified services on demand, and can strengthen RNSS signal coverage in specific areas.

[0064] The LEO constellation is the new member and the largest increment of the GNSS family. First, it provides decimeter-level high-precision and high-reliability services for the space below 30km around the world; second, it provides space-based monitoring capabilities for GEO / IGSO / MEO satellites, thereby getting rid of the dependence on large-scale global stations; third, it has higher signal power, which significantly improves the ranging accuracy, anti-multipath, anti-interference and anti-blocking capabilities of user equipment. Its time and space reference is provided by the MEO / GEO / IGSO constellation.

[0065] In order to achieve global coverage of LEO constellations, two Walker constellation combinations with inclinations of 55° and 85° are designed. The precession speeds of the two Walker constellations are consistent, and the overall configuration of the constellations is stable in the long term, with a total of 150 satellites. Among them, the 55° inclination constellation adopts a 120 / 12 / 0 configuration (120 satellites / 12 orbital planes / the phase difference between the corresponding satellites of two adjacent orbital planes is 0), with an orbital altitude of 975km, to achieve at least double coverage of the area between 72.5° north and south latitudes; the 85° inclination constellation adopts a 30 / 3 / 0 configuration (30 satellites / 3 orbital planes / the phase difference between the corresponding satellites of two adjacent orbital planes is 0), with an orbital altitude of 1248km, to achieve multiple coverage of high latitudes and polar regions.

[0066] See Table 1 for an increment of low-orbit constellation added (compared with medium- and high-orbit). It should be noted that in this embodiment, the trusted capabilities include: availability, continuity, integrity, anti-interference and anti-spoofing, etc. It can be seen that, unlike various previous enhancement systems that mainly enhance accuracy and integrity, low-orbit constellations can comprehensively enhance trusted capabilities.

[0067]

[0068]

[0069] Table 1

[0070] Embodiment three:

[0071] This embodiment provides another novel global satellite navigation system, which is implemented on the basis of the above embodiment. For the establishment and operation management of space-based time and space reference supported by inter-satellite links, the space-based communication, measurement and operation control network based on inter-satellite links is first described:

[0072] As the "neural network" of GNSS, the intersatellite link is the cornerstone and core increment of the new architecture. It carries core services such as intersatellite communication, measurement, and operation control. First, it connects the constellation into a whole, realizing "one satellite, all networks", and realizing the operation and management of the entire constellation based on a small number of ground stations; second, it provides intersatellite pseudo-range measurement capabilities at the picosecond level, significantly improving the constellation's space-time measurement performance; third, it carries intersatellite exchanges related to global communication services, such as text messages, search and rescue, etc.

[0073] According to the types of services carried and the characteristics of the orbit, three types of intersatellite links are considered: high-speed laser link, medium-speed laser link, and Ka link. Figure 3 The schematic diagram of establishing an intersatellite link is shown. In order to realize the transmission of data to the ground and the transfer of time and space reference, a matching ground link is required.

[0074] In some embodiments, the service types of the high-speed laser link include: constellation management, communication relay, time and space determination, external relay, the rate of the high-speed laser link is Gbps, and the accuracy is ps; the service types of the Ka link include: constellation management, time and space determination, flexible access, the rate of the Ka link is Mbps, and the accuracy is ps; the service types of the medium-speed laser link include: constellation management, communication relay, time and space determination, the rate of the medium-speed laser link is Mbps, and the accuracy is ps; the service types of the ground link include: ground data transmission and time and space reference fixed connection, the rate of the ground link is Gbps, and the accuracy is ps.

[0075] Among them, the rate / accuracy of high-speed laser is Gbps / ps, the rate / accuracy of Ka is Mbps / ps, the rate / accuracy of medium-speed laser is Mbps / ps, and the rate / accuracy of the ground link (Ka / laser) is Gbps / ps.

[0076] As for establishing and maintaining space-based space-time benchmarks, building space-based space-time benchmarks with the support of intersatellite links is equivalent to giving the constellation the ability of a "brain", which can further reduce the operational support pressure of ground facilities and improve system resilience.

[0077] GEO / IGSO and some MEO satellites are equipped with high-performance onboard clock structures as backbone nodes, which realize constellation time synchronization through intersatellite link measurement and comparison, and establish space-based integrated atomic time. IGSO satellites are equipped with star observation equipment to establish and maintain the constellation inertial reference with the support of intersatellite measurement links. On this basis, through anchor measurement of a small number of ground stations, the traceability and conversion of space-based time and space references and earth time and space references can be achieved. At the same time, external space-based reference sources can also be accessed through intersatellite links for calibration and traceability.

[0078] See also Figure 4 A schematic diagram of a space-based architecture of a time reference is shown, and Figure 5A schematic diagram of a space-based benchmark architecture is shown. Figure 4 shows the time reference architecture, Figure 5 A spatial reference architecture is shown.

[0079] In some embodiments, mercury ion clocks, integrating sphere clocks, intersatellite measurement equipment, and satellite-to-ground measurement equipment are deployed on GEO satellites and IGSO satellites to establish a space-based time reference;

[0080] Large-array stargazing cameras, inter-satellite and satellite-to-ground measurement equipment are deployed on IGSO satellites to establish space-based space references. Inter-satellite and satellite-to-ground measurement equipment are deployed on MEO satellites to support the construction of space-based time and space references. Navigation monitoring receivers are deployed on LEO satellites to obtain time and space references established in medium and high orbits. Satellite-to-ground measurement equipment is deployed on ground anchor stations to establish the connection between space-based time and space references and Earth time and space references.

[0081] Among them, the functions of ion clocks, integrating sphere clocks, intersatellite measurement equipment, and satellite-to-ground measurement equipment are to establish a space-based time reference; the functions of intersatellite and satellite-to-ground measurement equipment of large-array stargazing cameras are to establish a space-based space reference; the functions of configuring intersatellite, intersatellite, and satellite-to-ground measurement equipment are to support the construction of a space-based time and space reference; the function of configuring navigation and monitoring receivers is to obtain the time and space reference established in medium and high orbits; the function of configuring satellite-to-ground measurement equipment is to establish the connection between the space-based time and space reference and the earth's time and space reference.

[0082] Embodiment 4:

[0083] This embodiment provides another new type of global satellite navigation system, which is implemented on the basis of the above embodiments. For low-orbit constellation navigation signals that are compatible with existing user equipment hardware, in some embodiments, the frequency bands used for LEO downlink navigation signals include: L1 band and L5 band. The LEO downlink navigation signal is compatible with GNSS navigation signals or suitable communication signals.

[0084] See Table 2 for a table of LEO downlink navigation signal systems. The existing GNSS user devices have reached billions, and the navigation signals of medium and high orbit constellations need to remain stable. To ensure that user devices can obtain incremental capabilities through software upgrades, LEO constellation navigation signals are compatible with them and are an ideal choice. LEO constellation navigation signals should be kept consistent or close to the dual frequencies of L1 (1575.42MHz) and L5 (1176.42MHz) as much as possible.

[0085] Use frequency band L1, L5 (or other suitable frequency bands) Modulation BPSK Information Rate More than 1000bps Floor level -130dBW Anti-fraud Certification Information Broadcast ephemeris model 20 parameters compatibility Compatible with existing GNSS navigation signals (or with suitable communication signals) Interoperability Preferred interoperability with L1 and L5

[0086] Table 2

[0087] The modulation method considers BPSK to reduce the complexity of user equipment. The information rate is designed to be greater than 1000bps, which can support the rapid broadcast of multiple GNSS high-precision navigation messages; authentication information is added to the message, and the authenticated user equipment will have a certain anti-spoofing capability.

[0088] Due to the influence of the high-order terms of the earth's gravity field and atmospheric drag, the 16-parameter broadcast ephemeris model suitable for medium and high orbit constellations is not suitable for LEO constellations. Considering that there are large fitting residuals in the orbital tangent and there are certain periodic perturbations, it is considered to increase the major axis change rate and the average motion angular velocity change rate, and add two one-third cycle periodic perturbations in the ascending intersection angle direction to absorb the above errors. For this reason, the fitting parameters of low-orbit satellites are designed to be 20.

[0089] With the integration of communications and navigation, it is necessary to take appropriate communication frequency bands into consideration. For navigation signals deployed on the global low-orbit communication constellation, compatibility with corresponding communication signals such as C, Ka, and UHF bands, and sharing of related hardware is also a more cost-effective choice.

[0090] Embodiment five:

[0091] This embodiment provides another new type of global satellite navigation system, which is implemented on the basis of the above embodiment, and further improves the user experience for communication assistance, which is similar to A-GNSS in terrestrial mobile communication networks. All communication systems can deploy this capability, and the cost of hardware modification is not high, mainly the change of communication protocol and corresponding software upgrade. For the realization of global assistance capabilities, using the global low-orbit communication constellation is an ideal choice.

[0092] Based on the assistance of satellite navigation messages, approximate position and time broadcast by the communication system, the satellite navigation receiver can calculate the dynamics and Doppler frequency relative to the navigation satellite, and can adopt a longer coherent integration time, thereby improving the capture sensitivity.

[0093] See also Figure 6 The figure shows a schematic diagram of capture sensitivity corresponding to different coherent integration times. According to the signal capture sensitivity under different coherent integration times, the coherent integration time of the satellite navigation receiver in unassisted capture usually does not exceed 10ms; the coherent integration time can be significantly improved after communication assistance, typically by about 20 times (200ms), which is more than 10dB higher than unassisted capture.

[0094] Based on the high rate of the communication link, it can support the addition of two-way authentication information to achieve two-way interaction between the system and the user. It can provide authentication and anti-tampering capabilities from both the system and the user to prevent GNSS spoofing attacks.

[0095] In addition, in the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0096] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0097] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A new global satellite navigation system architecture, characterized in that: include: Through integrated hybrid constellations to provide multiple services; The integrated hybrid constellation includes GEO, IGSO, MEO, and LEO satellites; Building space-based communication and measurement networks through intersatellite links to simplify ground operations and observation resources; Strengthen the ability to establish and maintain space-based time and space references based on the intersatellite links with the support of measurement components to reduce dependence on the ground; Based on low-orbit navigation signals, communication assistance is used to improve signal availability, anti-interference and anti-deception capabilities.

2. The novel global satellite navigation system architecture according to claim 1, characterized in that: Based on the existing architecture, the new global satellite navigation system architecture adds the following new elements: the intersatellite link, the communication assistance and the low-orbit constellation.

3. The novel global satellite navigation system architecture according to claim 2, characterized in that: The communication auxiliary is deployed in various communication facilities, and the low-orbit constellation is deployed in the LEO navigation constellation and its ground facilities.

4. The novel global satellite navigation system architecture according to claim 2, characterized in that: The intersatellite links include: high-speed laser links, Ka links, and medium-speed laser links; the elements of the global satellite navigation system architecture also include: ground links; The high-speed laser link is deployed on GEO, IGSO, and MEO satellites; the Ka link is deployed on GEO, IGSO, and MEO satellites; the medium-speed laser link is deployed on LEO satellites; and the ground-to-earth link is deployed on GEO and IGSO satellites.

5. The novel global satellite navigation system architecture according to claim 4, characterized in that: The Ka link is also deployed on LEO satellites; the medium-speed laser link is deployed on GEO, IGSO, and MEO satellites; and the ground link is also deployed on LEO satellites.

6. The novel global satellite navigation system architecture according to claim 1, characterized in that: The measuring components include: an atomic clock group and a star camera; The atomic clock group is deployed on GEO, IGSO, and some MEO satellites; the star camera is deployed on IGSO satellite.

7. The novel global satellite navigation system architecture according to claim 1, characterized in that: The integrated hybrid constellation includes: 24-30 MEO satellites, 150-200 LEO satellites, 3-6 GEO satellites, and 3-6 IGSO satellites; Among them, the 24-30 MEO satellites are the core constellation, the 3-6 GEO satellites and the 3-6 IGSO satellites are the node constellation, and the 150-200 LEO satellites are the enhanced constellation; the core constellation provides global meter-level PNT services and SSV below 3000km, the node constellation provides regional diversified services, SSV, and navigation coverage enhancement, and the enhanced constellation provides global decimeter-level high-precision and high-reliability services below 30km.

8. The novel global satellite navigation system architecture according to claim 4, characterized in that: The service types of the high-speed laser link include: constellation management, communication relay, time and space determination, external relay, the rate of the high-speed laser link is Gbps, and the accuracy is ps; The service types of the Ka link include: constellation operation management, time and space determination, and flexible access. The rate of the Ka link is Mbps and the accuracy is ps; The service types of the medium-speed laser link include: constellation management, communication relay, and time and space determination. The rate of the medium-speed laser link is Mbps and the accuracy is ps; The service types of the ground link include: ground data transmission and space-time reference fixed connection. The rate of the ground link is Gbps and the accuracy is ps.

9. The novel global satellite navigation system architecture according to claim 1, characterized in that: Mercury ion clocks, integrating sphere clocks, intersatellite measurement equipment, and satellite-to-ground measurement equipment are deployed on GEO and IGSO satellites to establish space-based time references; Large-array star-gazing camera intersatellite and satellite-to-ground measurement equipment are deployed on the IGSO satellite to establish a space-based space benchmark; Configure inter-satellite and satellite-to-ground measurement equipment and deploy them on MEO satellites to support the construction of space-based time and space benchmarks; Configure navigation monitoring receivers to be deployed on LEO satellites to obtain the time and space references established in medium and high orbits; Satellite-to-ground measurement equipment is deployed at ground anchor stations to establish the connection between the space-based time and space reference and the Earth's time and space reference.

10. The novel global satellite navigation system architecture according to claim 6, characterized in that: The frequency bands used for the LEO downlink navigation signal include: L1 band and L5 band. The LEO downlink navigation signal is compatible with the GNSS navigation signal or a suitable communication signal.

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