Single-satellite positioning method, user equipment and satellite equipment

Abstract

This application discloses a single-satellite positioning method, user equipment, and satellite equipment. The method includes: receiving multiple downlink synchronization signals transmitted by a satellite in multiple cycles, and receiving ephemeris information broadcast by the satellite; acquiring distance differences corresponding to multiple time periods, and acquiring first and second positions corresponding to the multiple time periods based on the ephemeris information; and locating the user equipment based on the first and second positions and distance differences corresponding to the multiple time periods to obtain a positioning result. This application solves the technical problem of low positioning accuracy in single-satellite positioning methods provided in related technologies.

Description

Technical Field

[0001] This application relates to the field of satellite communication technology, and more specifically, to a single satellite positioning method, user equipment, and satellite equipment. Background Technology

[0002] In related technologies, when the Global Navigation Satellite System (GNSS) is temporarily unavailable, user equipment (UE) positioning is typically performed based on the Time Difference of Arrival (TDOA) positioning method for single / multiple satellites. This then allows for the calculation of uplink timing advance (TA) and frequency offset pre-compensation values ​​to enable Physical Random Access Channel (PRACH) access. However, these methods are limited by the measurement accuracy of satellite signal arrival times and the time synchronization requirements between satellites. The positioning error amplifies linearly with the time difference measurement error. Furthermore, in single-satellite scenarios, multiple measurements over long time sequences are required to simulate the geometric distribution of multiple satellites, resulting in slow positioning convergence and poor real-time performance. Consequently, these methods struggle to meet the uplink access requirements of satellite communication systems, which demand fast, high-precision, and low-latency uplink access.

[0003] There is currently no effective solution to the above problems. Summary of the Invention

[0004] This application provides a single-satellite positioning method, user equipment, and satellite equipment to at least solve the technical problem of low positioning accuracy in the single-satellite positioning methods provided in related technologies.

[0005] According to one aspect of the embodiments of this application, a single satellite positioning method is provided, comprising: receiving multiple downlink synchronization signals transmitted by a satellite in multiple cycles, and receiving ephemeris information broadcast by the satellite; obtaining distance differences corresponding to multiple time periods, and obtaining first and second positions corresponding to multiple time periods based on the ephemeris information, wherein each of the multiple time periods contains a portion of multiple cycles, the first position is the satellite position corresponding to the start time of each time period, the second position is the satellite position corresponding to the end time of each time period, the distance difference is the difference between a first distance and a second distance of each time period, the first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period; and positioning the user equipment based on the first position, the second position, and the distance difference corresponding to the multiple time periods to obtain a positioning result.

[0006] Optionally, receiving multiple downlink synchronization signals transmitted by the satellite in multiple cycles includes receiving multiple synchronization signal block signals transmitted by the satellite in multiple cycles.

[0007] Optionally, receiving ephemeris information broadcast by the satellite includes receiving system messages sent by the satellite, wherein the information carried in the system messages includes ephemeris information.

[0008] Optionally, obtaining the distance difference corresponding to multiple time periods includes: obtaining the downlink signal frequency offset corresponding to multiple time periods; and obtaining the distance difference corresponding to multiple time periods based on the downlink signal frequency offset.

[0009] Optionally, obtaining the downlink signal frequency offset corresponding to multiple time periods includes: obtaining a first frequency point corresponding to multiple time periods, wherein the first frequency point is the frequency point at which the satellite transmits each downlink synchronization signal in each time period; and calculating the downlink signal frequency offset corresponding to multiple time periods using the first frequency point and a second frequency point, wherein the second frequency point is the frequency point at which the user equipment receives each downlink synchronization signal in each time period.

[0010] Optionally, obtaining the first frequency point corresponding to multiple time periods includes: determining the first frequency point based on the second frequency point in response to the maximum Doppler frequency offset satisfying a preset relationship with the frequency interval of the downlink synchronization signal in each time period.

[0011] Optionally, obtaining the first frequency point corresponding to multiple time periods includes: in response to the fact that the maximum Doppler frequency offset and the frequency interval of the downlink synchronization signal in each time period do not satisfy a preset relationship, determining the first frequency point based on the indication information and the second frequency point sent by the satellite, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, and N is an integer greater than or equal to 1.

[0012] Optionally, obtaining the distance difference corresponding to multiple time periods based on the downlink signal frequency offset includes: calculating the radial velocity between the user equipment and the satellite in each time period based on the downlink signal frequency offset; integrating or summing the radial velocity in each time period to obtain the distance difference corresponding to multiple time periods.

[0013] Optionally, the user device is located based on the first location, second location, and distance difference corresponding to multiple time periods. The location result includes: establishing multiple hyperboloid equations based on the first location, second location, and distance difference corresponding to multiple time periods; and obtaining the location result by analyzing the multiple hyperboloid equations.

[0014] Optionally, the above-mentioned single-satellite positioning method further includes: obtaining the uplink timing advance and frequency offset pre-compensation value based on the positioning result and ephemeris information; and accessing the satellite based on the timing advance and frequency offset pre-compensation value.

[0015] According to another aspect of the embodiments of this application, another single-satellite positioning method is also provided, including: sending multiple downlink synchronization signals to a user equipment in multiple periods, and broadcasting ephemeris information, wherein the user equipment is used to obtain the positioning result of the user equipment according to any one of the single-satellite positioning methods in the embodiments of this application; receiving an access request from the user equipment, wherein the access request is initiated by the user equipment based on the uplink timing advance and frequency offset pre-compensation value, the timing advance and frequency offset pre-compensation value being obtained based on the positioning result and ephemeris information.

[0016] Optionally, the above-mentioned single-satellite positioning method further includes: sending indication information to the user equipment, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, where N is an integer greater than or equal to 1.

[0017] According to another aspect of the embodiments of this application, a single satellite positioning device is also provided, comprising: a first receiving module, configured to receive multiple downlink synchronization signals transmitted by the satellite in multiple cycles, and to receive ephemeris information broadcast by the satellite; a first acquiring module, configured to acquire distance differences corresponding to multiple time periods, and to acquire first and second positions corresponding to multiple time periods based on the ephemeris information, wherein each of the multiple time periods contains a portion of multiple cycles, the first position is the satellite position corresponding to the start time of each time period, the second position is the satellite position corresponding to the end time of each time period, the distance difference is the difference between the first distance and the second distance of each time period, the first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period; and a positioning module, configured to position the user equipment based on the first position, the second position, and the distance difference corresponding to the multiple time periods, and to obtain a positioning result.

[0018] Optionally, the first receiving module is also used to receive multiple synchronization signal blocks transmitted by the satellite in multiple cycles.

[0019] Optionally, the first receiving module is further configured to: receive system messages transmitted by the satellite, wherein the information carried in the system messages includes: ephemeris information.

[0020] Optionally, the first acquisition module is further configured to: acquire downlink signal frequency offsets corresponding to multiple time periods respectively; and acquire distance differences corresponding to multiple time periods based on downlink signal frequency offsets.

[0021] Optionally, the first acquisition module is further configured to: acquire first frequency points corresponding to multiple time periods, wherein the first frequency point is the frequency point at which the satellite transmits each downlink synchronization signal in each time period; and calculate the downlink signal frequency offset corresponding to multiple time periods using the first frequency point and the second frequency point, wherein the second frequency point is the frequency point at which the user equipment receives each downlink synchronization signal in each time period.

[0022] Optionally, the first acquisition module is further configured to: determine the first frequency point based on the second frequency point in response to a preset relationship between the maximum Doppler frequency offset and the frequency interval of the downlink synchronization signal in each time period.

[0023] Optionally, the first acquisition module is further configured to: in response to the failure to satisfy a preset relationship between the maximum Doppler frequency offset and the frequency interval of the downlink synchronization signal in each time period, determine a first frequency point based on the indication information and the second frequency point transmitted by the satellite, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, and N is an integer greater than or equal to 1.

[0024] Optionally, the first acquisition module is further configured to: calculate the radial velocity between the user equipment and the satellite in each time period based on the downlink signal frequency offset; and integrate or accumulate the radial velocity in each time period to obtain the distance difference corresponding to multiple time periods.

[0025] Optionally, the positioning module is also used to: establish multiple hyperboloid equations based on the first position, the second position, and the distance difference corresponding to multiple time periods; and obtain the positioning result by analyzing the multiple hyperboloid equations.

[0026] Optionally, the above-mentioned single-satellite positioning device further includes: a second acquisition module, used to acquire the uplink timing advance and frequency offset pre-compensation value based on the positioning result and ephemeris information; and an access module, used to access the satellite based on the timing advance and frequency offset pre-compensation value.

[0027] According to another aspect of the embodiments of this application, another single-satellite positioning device is also provided, comprising: a first transmitting module, configured to transmit multiple downlink synchronization signals to a user equipment in multiple cycles, and broadcast ephemeris information, wherein the user equipment is configured to obtain the positioning result of the user equipment according to any one of the single-satellite positioning methods in the embodiments of this application; and a second receiving module, configured to receive an access request from the user equipment, wherein the access request is initiated by the user equipment based on the uplink timing advance and frequency offset pre-compensation value, the timing advance and frequency offset pre-compensation value being obtained based on the positioning result and ephemeris information.

[0028] Optionally, the above-mentioned single-satellite positioning device further includes: a second transmitting module, used to transmit indication information to the user equipment, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, where N is an integer greater than or equal to 1.

[0029] According to another aspect of the embodiments of this application, a user equipment is also provided, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the above-described single-satellite positioning method when it runs.

[0030] According to another aspect of the embodiments of this application, a satellite device is also provided, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the other single-satellite positioning method described above when it runs.

[0031] According to another aspect of the embodiments of this application, a single satellite positioning system is also provided, including: user equipment and satellite equipment.

[0032] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored executable program, wherein, when the executable program is running, it controls the device where the storage medium is located to execute any of the single satellite positioning methods in the embodiments of this application.

[0033] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program that, when executed by a processor, implements a single satellite positioning method according to any one of the embodiments of this application.

[0034] According to another aspect of the embodiments of this application, a chip system is also provided, including: a processor for calling and running a computer program from a memory, such that a communication device equipped with the chip system performs any of the single-satellite positioning methods in the embodiments of this application.

[0035] In this embodiment, by receiving multiple downlink synchronization signals transmitted by the satellite in multiple cycles and receiving ephemeris information broadcast by the satellite, the distance difference corresponding to multiple time periods is obtained, and based on the ephemeris information, the first position and second position corresponding to multiple time periods are obtained. Then, based on the first position, second position and distance difference corresponding to multiple time periods, the user equipment is located and the positioning result is obtained. This achieves the goal of autonomously completing the positioning of the user equipment before the establishment of the non-access layer without relying on the global navigation satellite system, thereby achieving the technical effect of improving the positioning accuracy of the user equipment under single-satellite conditions, and thus solving the technical problem of low positioning accuracy of the single-satellite positioning method provided in related technologies. Attached Figure Description

[0036] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0037] Figure 1 This is a schematic diagram of a 5G positioning network architecture based on relevant technologies;

[0038] Figure 2 This is a schematic diagram of a positioning signaling transmission process based on relevant technologies;

[0039] Figure 3 This is a schematic diagram of a multi-satellite positioning method based on related technologies;

[0040] Figure 4 This is a schematic diagram of a single-satellite positioning method based on related technologies;

[0041] Figure 5 This is a flowchart of a single satellite positioning method according to one embodiment of this application;

[0042] Figure 6 This is a flowchart of another single-satellite positioning method according to one embodiment of this application;

[0043] Figure 7 This is a structural block diagram of a single satellite positioning device according to one embodiment of this application;

[0044] Figure 8 This is a structural block diagram of another single-satellite positioning device according to one embodiment of this application. Detailed Implementation

[0045] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0047] In related technologies, when GNSS is temporarily unavailable, UE positioning is typically performed using a single-satellite / multi-satellite TDOA positioning method. This is followed by calculating the uplink TA and frequency offset pre-compensation values ​​to complete PRACH access. However, these methods are limited by the measurement accuracy of satellite signal arrival time and the time synchronization requirements between satellites. The positioning error amplifies linearly with the time difference measurement error. Furthermore, in single-satellite scenarios, multiple measurements over long time sequences are required to simulate the geometric distribution of multiple satellites, resulting in slow positioning convergence and poor real-time performance. Consequently, these methods struggle to meet the uplink access requirements of satellite communication systems, which demand fast, high-precision, and low-latency uplink access.

[0048] Specifically, in the field of satellite communication technology, cellular communication systems have evolved from 1G, 2G, 3G, 4G to 5G. Early cellular mobile communication systems (such as 1G and 2G) did not explicitly standardize specific positioning technologies. The first version (Release 99) of the 3G Wideband Code Division Multiple Access (WCDMA) system standardized two basic positioning methods: cell ID-based positioning and Observed Time Difference of Arrival (OTDOA) positioning. In subsequent evolutions, WCDMA Release 7 introduced Uplink Time Difference of Arrival (UTDOA) positioning. The 4G Long Term Evolution (LTE) system retained the positioning mechanism (OTDOA) of the 3G system and introduced a dedicated Position Reference Signal (PRS) and the LTE Positioning Protocol (LPP).

[0049] The 5G New Radio (NR) system began research and standardization of positioning technologies in its second release (R16). NR R16 comprehensively standardized various existing positioning methods, including: 1. Enhanced Cell ID (E-CID); 2. Downlink Time Difference of Arrival (DL-TDOA); 3. Uplink Time Difference of Arrival (UL-TDOA); 4. Multi-Round Trip Time (Multi-RTT); 5. Downlink Angle-of-Departure (DL-AoD); and 6. Uplink Angle-of-Arrival (UL-AoA). All of these positioning methods are based on the reception and measurement of NR signals, and are therefore called Radio Access Technology dependent (RAT-dependent) positioning technologies.

[0050] In 5G Non-Terrestrial Networks (NTNs), the UE obtains its own location information using its onboard GNSS receiver. It then receives system messages (such as System Information Block 19, SIB19) from the satellite to obtain satellite ephemeris information. This allows it to calculate the distance and relative velocity between the UE and the satellite, obtain the timing advance (TA) and frequency offset pre-compensation value for transmitting the PRACH signal, and subsequently initiate uplink access. With the continuous evolution of satellite communication technology, several companies have proposed supporting GNSS-independent NTN positioning functionality in 6G. This would enable the UE to locate itself using satellite signals even when it lacks GNSS functionality or cannot receive GNSS signals, and subsequently calculate the uplink timing advance (TA) and frequency offset pre-compensation value.

[0051] In related technologies, when positioning based on terrestrial cellular networks, the main feature of the 5G RAT-dependent positioning network architecture is that it performs location service operations through multiple network elements such as Location Management Function (LMF) and Access and Mobility Management Function (AMF). Figure 1This is a schematic diagram of a 5G positioning network architecture based on related technologies, such as... Figure 1 As shown, the AMF receives a location service request for a target UE initiated by another entity, and then sends the location service request to the LMF. The LMF processes the location service request, including sending relevant auxiliary data to the target UE and performing location calculations. The LMF then returns the location service result (e.g., an estimate of the target UE's location) to the AMF. Each NG-RAN node may control multiple Transmission / Reception Points (TRPs) for transmitting downlink positioning signals and / or receiving uplink positioning signals.

[0052] Specifically, Figure 1 In this context, the eNB (Evolved Node B) is a base station in a 4G LTE network, responsible for transmitting and receiving radio signals with the UE and connecting to the core network. The gNB (next-generation Node B) is a 5G base station, the base station entity in the 5G radio access network, responsible for wireless communication with the UE, sending / receiving positioning reference signals (such as PRS), and participating in positioning measurements. Xn is the interconnection interface between the eNB and gNB, used to support inter-base station handover, coordinated scheduling, and load balancing.

[0053] As mentioned earlier, to support downlink-dependent positioning methods (methods 2, 4, 5) and uplink-dependent positioning methods (methods 3, 6), the 5G NR protocol introduces a downlink positioning reference signal (DL Positioning Reference Signal, DL PRS) and an uplink positioning reference signal (SRS for Positioning). The NR PRS signal reuses the Gold sequence transmitter used by the NR Channel State Information-Reference Signal (CSI-RS), but its initial seed differs from that of the NR CSI-RS, and its resource mapping adopts a comb structure. The comb structure allows DL PRS signals from different nodes (TRPs) to be multiplexed onto the same Orthogonal Frequency Division Multiplexing (OFDM) symbol. Different frequency offset values ​​can be configured for the DL PRS signals of different TRPs. The configuration information for NR DL PRS is provided to the UE by the LMF via LPP protocol signaling. The parameter configuration of DL PRS adopts a 4-layer signaling structure, represented from top to bottom as: (1) Positioning Frequency Layer (PFL); (2) TRP; (3) DL PRS resource set; (4) DL PRS resource. The UE calculates the frequency, TRP ID, and PRS time-frequency domain information of the PRS sent by each TRP based on the above 4-layer signaling, thereby calculating the UE location result. The configuration information for the positioning SRS signal is provided to the user UE by the serving cell's gNB via Radio Resource Control (RRC) signaling. A UE can be configured with one or more positioning SRS signal resource sets. A positioning SRS signal resource set can contain one or more positioning SRS signal resources.

[0054] Figure 2 This is a schematic diagram of a positioning signaling transmission process based on related technologies, such as... Figure 2The diagram illustrates a typical positioning signaling transmission process in a 5G system. The core flow is as follows: The Local Positioning Provider (LMF) initiates a positioning capability request to the UE. The UE responds, providing its supported positioning capabilities and requesting positioning assistance information. Subsequently, the LMF provides corresponding positioning assistance information based on the positioning capabilities provided by the UE and requests location information from the UE. The UE completes positioning measurements based on the received positioning assistance information and provides its location information to the LMF. Finally, the LMF returns the target location calculated based on the location information provided by the UE to the UE, completing the entire positioning interaction process.

[0055] However, applying the above-mentioned terrestrial cellular network positioning method to satellite communication systems will have the following problems: (1) The positioning-related reference signals (PRS, SRS) are configured by the LMF. The UE needs to complete the establishment of the Non-Access Stratum (NAS) before it can complete the configuration of positioning signals, report measurement results and obtain location information. However, in the satellite communication scenario, before the NAS is established, the UE needs to determine its own location information to calculate the uplink timing advance (TA) and frequency offset pre-compensation value for uplink signal transmission such as PRACH signal, and complete the establishment of the Access Stratum (AS). The determination of the UE's uplink timing advance (TA) and frequency offset pre-compensation value needs to be completed before the NAS layer is established. (2) The UE's location information is calculated by the core network element LMF, which exposes the UE's location information to the core network, posing a challenge to the UE's security.

[0056] Furthermore, in related technologies, when GNSS is temporarily unavailable, the UE can use the satellite network to maintain uplink synchronization.

[0057] Figure 3 This is a schematic diagram of a multi-satellite positioning method based on related technologies, such as... Figure 3 The figure shows a TDOA positioning method based on multi-satellite synchronization signal block (SSB) signals, where T1 and T2 are the SSB signal transmission times of satellite 1 and satellite 2, respectively, and t arrive The time when the UE receives the SSB signal is defined by Tref1 and Tref2, which are the system reference times broadcast by satellite 1 and satellite 2, respectively. Specifically, when two or more satellites send SSB signals to the UE, the UE measures the Time of Arrival (ToA) of the SSB signal from each satellite and calculates the Time of Arrival (TDoA) between the satellite pairs. Using the TDoA, the UE can deduce the difference in propagation distance between the two satellites. The set of all UE locations that produce the same propagation distance difference forms a hyperbola in two-dimensional space and a hyperboloid in three-dimensional space. When more than two satellites are involved, the number of hyperbolas increases, and their intersection points correspond to the UE's location.

[0058] Figure 4 This is a schematic diagram of a single-satellite positioning method based on related technologies, such as... Figure 4 As shown, this is a TDOA positioning method based on a single-satellite reference signal, which uses multiple measurements at different times to locate the UE. The satellite moves to different positions at different times, and the satellite located at different positions at different times can simulate multiple satellites.

[0059] However, the above-mentioned TDOA positioning methods based on single / multi-satellite positioning have the following problems: (1) The positioning accuracy is greatly affected by the accuracy of TDOA measurement. Δd=Δt c, where c=3 10 8 m / s is the speed of light. Assuming the measurement error of Δt is 1us, a distance error of 300m will be introduced for Δd. (2) In the multi-satellite positioning scenario, multiple satellites are required to send signals at the same time. The time synchronization accuracy between satellites is extremely high. In order to avoid interference between satellites, the coverage overlap area between satellites is generally small. The UE can usually only receive the signal sent by one satellite.

[0060] According to embodiments of this application, a method embodiment for single-satellite positioning is provided. The method embodiment provided in this application can be executed in a terminal device (the terminal device may include, but is not limited to, a satellite terminal, a mobile terminal), or a similar network device. Taking operation on a user equipment as an example, the user equipment may include one or more processors (processors may include, but are not limited to, processing devices such as microprocessors (MCUs) or field-programmable gate arrays (FPGAs),) a memory for storing data, and a transmission device for communication functions. Those skilled in the art will understand that the above structure is merely exemplary and does not limit the structure of the user equipment. For example, the user equipment may also include more or fewer components, or have different configurations.

[0061] The memory can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the single-satellite positioning method in this embodiment. The processor executes various functional applications and data processing by running the computer program stored in the memory, thus implementing the aforementioned method. The memory may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory may further include memory remotely located relative to the processor.

[0062] The transmission device is used to receive or send data via a network. Specific examples of the network mentioned above may include, but are not limited to, satellite communication links, terrestrial cellular networks, the Internet, local area networks, Wi-Fi, Bluetooth networks, or any combination thereof, to enable two-way information exchange between user equipment and satellites, as well as connection and data transmission with other network nodes.

[0063] Figure 5 This is a flowchart of a single satellite positioning method according to one embodiment of this application, such as... Figure 5 As shown, the method includes the following steps:

[0064] Step S51: Receive multiple downlink synchronization signals transmitted by the satellite in multiple cycles, and receive ephemeris information broadcast by the satellite.

[0065] The aforementioned downlink synchronization signal is a periodic broadcast signal used in wireless communication systems to achieve time and frequency synchronization between the UE and the satellite.

[0066] The ephemeris information described above is broadcast data describing the satellite's orbital parameters and dynamic motion status. Specifically, the ephemeris information may include, but is not limited to, the satellite's semi-major axis, eccentricity, orbital inclination, right ascension of the ascending node, argument of perigee, mean perigee, perturbation correction terms for orbital elements, satellite clock bias parameters, clock drift rate, time reference system identifier, satellite health status, and valid timestamp.

[0067] Step S52: Obtain the distance difference corresponding to multiple time periods, and obtain the first position and second position corresponding to multiple time periods based on ephemeris information. Each time period contains a part of multiple cycles. The first position is the satellite position corresponding to the start time of each time period, the second position is the satellite position corresponding to the end time of each time period, the distance difference is the difference between the first distance and the second distance of each time period, the first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period.

[0068] The distance differences corresponding to the aforementioned multiple time periods represent the cumulative change in radial distance between the UE and the satellite between the start and end times of each time period. Specifically, the distance differences corresponding to the aforementioned multiple time periods can be obtained by integrating or summing the product of the radial velocity measured at each sampling point within that time period and the time interval. This reflects the net displacement effect of the satellite relative to the UE along the line-of-sight direction within that time period, rather than the absolute distance value.

[0069] For example, the distance difference corresponding to the above multiple time periods can be expressed as:

[0070]

[0071] in, for[ , The radial distance difference within the time period, i.e., the difference in the radial distance within the time period. Downlink synchronization signal transmission time To the Downlink synchronization signal transmission time The net change in radial distance between the UE and the satellite.

[0072] The first position corresponding to the aforementioned multiple time periods can be the three-dimensional spatial coordinates of the satellite in the geocentric inertial coordinate system at the start of each time period. Specifically, the first position corresponding to the aforementioned multiple time periods can be calculated using Kepler orbital parameters by combining the ephemeris information broadcast by the satellite with the precise timestamp of the start of each time period.

[0073] For example, the first position corresponding to the above multiple time periods can be represented as .

[0074] The second position corresponding to the aforementioned multiple time periods can be the three-dimensional spatial coordinates of the satellite in the geocentric inertial coordinate system at the end of each time period. Specifically, the second position corresponding to the aforementioned multiple time periods can be calculated by combining the ephemeris information broadcast by the satellite with the precise timestamp at the end of each time period using Kepler orbital parameters.

[0075] For example, the second position corresponding to the above multiple time periods can be represented as .

[0076] For example, assume the UE's location coordinates are ,for 0, the first distance for each of the above time periods can be represented as:

[0077]

[0078] The second distance for each of the above time periods can be expressed as:

[0079]

[0080] Specifically, each of the multiple time periods contains a portion of the multiple cycles. This can be understood as follows: the UE does not independently measure and calculate a single downlink synchronization signal cycle, but rather groups and aggregates multiple consecutive downlink synchronization signal transmission cycles to form several time intervals (i.e., time periods). Each time period consists of several consecutive downlink synchronization signal transmission cycles, with its start and end times corresponding to the transmission time of a specific downlink synchronization signal.

[0081] For example, if the satellite periodically transmits downlink synchronization signals, the periodic =20ms (i.e., sent once every 20ms), then: the first time period can be composed of the 1st to the 12001st downlink synchronization signals, corresponding to the time interval as follows: =0ms to =240s. The second time period can be composed of the 12001st to the 19501st downlink synchronization signals, corresponding to the time interval of... =240s to =390s. The third time period can be composed of the 19501st to the 27001st downlink synchronization signals, corresponding to the time interval of... =390s to =540s.

[0082] Step S53: Based on the first location, second location, and distance difference corresponding to multiple time periods, the user equipment is located to obtain the location result.

[0083] The aforementioned user equipment (UE) may include, but is not limited to, mobile phones, tablets, vehicle-mounted terminals, Internet of Things terminals, portable communication devices, handheld satellite terminals, shipborne terminals, airborne terminals, drone terminals, emergency communication terminals, smart wearable devices, and fixed satellite access terminals.

[0084] Specifically, multiple hyperboloid equations can be constructed based on the first position, second position, and distance difference corresponding to multiple time periods, and then the positioning result can be determined based on the constructed multiple hyperboloid equations.

[0085] Based on the above steps S51 to S53, by receiving multiple downlink synchronization signals transmitted by the satellite in multiple cycles and receiving ephemeris information broadcast by the satellite, and obtaining the distance differences corresponding to multiple time periods, and obtaining the first and second positions corresponding to multiple time periods based on the ephemeris information, and then locating the user equipment according to the first and second positions and the distance differences corresponding to multiple time periods, the positioning result is obtained. This achieves the goal of autonomously completing the positioning of user equipment before the establishment of the non-access layer without relying on the global navigation satellite system, thereby realizing the technical effect of improving the positioning accuracy of user equipment under single-satellite conditions, and thus solving the technical problem of low positioning accuracy of single-satellite positioning methods provided in related technologies.

[0086] Optionally, in step S51, receiving multiple downlink synchronization signals transmitted by the satellite in multiple cycles includes receiving multiple synchronization signal block signals transmitted by the satellite in multiple cycles.

[0087] The aforementioned Synchronization Signal Block (SSB) consists of a Primary Synchronization Signal (PSS), a Secondary Synchronization Signal (SSS), and a Physical Broadcast Channel (PBCH). It is used to achieve initial synchronization between the UE and the satellite and to acquire system information in the NTN network. Specifically, the PSS is used for symbol-level time-domain synchronization and partial cell ID identification, the SSS is used for frame synchronization and remaining cell ID identification, and the PBCH carries the primary information block information.

[0088] Specifically, the SSB signal occupies 4 consecutive OFDM symbols in the time domain and 240 subcarriers (i.e., 20 resource blocks) in the frequency domain. Its frequency domain position is uniquely identified by the Global Synchronization Channel Number (GSCN).

[0089] For example, during the periodic transmission of multiple SSB signals by the satellite, the UE can detect the PSS in the SSB through cell search, and after detecting the PSS, demodulate the SSS to determine the physical layer cell identifier, thereby completing the time slot and frame boundary synchronization. After synchronization is completed, the UE can continuously receive multiple SSB signals transmitted by the satellite in subsequent periods.

[0090] It should be noted that the embodiments in this application use SSB signals as an example to introduce the user equipment positioning process, but this does not constitute a specific limitation on the downlink synchronization signal type.

[0091] Based on the above optional embodiments, receiving multiple synchronization signal block signals sent by the satellite in multiple cycles enables the UE to reuse the existing synchronization signal structure to complete high-frequency, low-overhead downlink signal reception and timestamp extraction without the need for additional positioning reference signals, thereby avoiding the increase in signaling complexity and resource occupancy due to the introduction of dedicated positioning signals.

[0092] Optionally, in step S51, receiving ephemeris information broadcast by the satellite includes receiving a system message sent by the satellite, wherein the information carried in the system message includes ephemeris information.

[0093] The aforementioned system messages are downlink control information used in satellite communication systems to broadcast critical network configuration and operational parameters to the UE. Their core function is to enable the UE to perform autonomous positioning, uplink access, and link synchronization even without GNSS support. Specifically, these system messages may include, but are not limited to, the Master Information Block (MIB), System Information Block Type 1 (SIB1), and multiple extended system information blocks (such as SIB2~SIB19). The MIB provides the most basic access parameters, such as the high-order bits of the System Frame Number (SFN), partial information of the Physical Cell Identity (PCI), and an indication of whether NTN mode is enabled. SIB1 contains basic criteria for cell selection and reselection, SIB scheduling information, and access control parameters.

[0094] Specifically, in NTN, the UE cannot use system information sent by the terrestrial base station (such as SIB1 in 4G / 5G), and must be broadcast directly by the satellite. SIB19 is a dedicated system information block defined for satellite communication in the 3GPP R17 / R18 NTN standard, which is dedicated to transmitting key information such as ephemeris information, Doppler compensation parameters, and time synchronization.

[0095] For example, after receiving the system message sent by the satellite, the UE can extract the satellite orbit parameters, clock error correction, time reference information and ephemeris carried in SIB19, and then calculate the three-dimensional position coordinates and velocity vector of the satellite at any time.

[0096] Based on the above optional embodiments, by receiving system messages sent by the satellite to obtain ephemeris information, the UE can obtain the precise orbital parameters of the satellite at different points in time without relying on an external GNSS system, thereby ensuring that the satellite coordinate data on which the positioning calculation depends matches the ephemeris status at the actual launch time.

[0097] Optionally, in step S52, obtaining the distance differences corresponding to multiple time periods includes:

[0098] Step S521: Obtain the downlink signal frequency offset corresponding to multiple time periods respectively;

[0099] Step S522: Based on the downlink signal frequency offset, obtain the distance difference corresponding to multiple time periods.

[0100] The aforementioned downlink signal frequency offset, also known as Doppler frequency offset, is the frequency difference between the received frequency of the SSB signal at the UE and the carrier frequency at which the satellite actually transmits the SSB signal. This difference is caused by the Doppler effect and represents the frequency shift caused by the relative radial motion of the satellite and the UE in the signal propagation direction. Specifically, the magnitude of the downlink signal frequency offset is proportional to the radial velocity of the satellite relative to the UE and changes continuously over time as the satellite's trajectory continues to change.

[0101] Specifically, when a satellite moves relative to the UE at a certain speed, its transmitted SSB signal will experience a frequency offset at the UE receiver. Therefore, by measuring the downlink signal frequency offset received at each moment, the instantaneous radial velocity at that moment can be calculated. The aforementioned distance difference is essentially the cumulative effect of radial velocity over time, i.e., the relative displacement between the satellite and the UE along the line-of-sight direction within a certain time interval. By integrating or discretely summing multiple instantaneous radial velocities within this time interval, the net change in distance between the UE and the satellite within that time interval, i.e., the distance difference, can be obtained. Since the SSB signal is transmitted periodically with a fixed time interval (e.g., 20ms), multiple frequency offset values ​​can be continuously sampled, the velocity calculated point by point, and then accumulated segment by segment, thereby obtaining the distance change between any two time points.

[0102] Based on steps S521 to S522 above, downlink signal frequency offsets corresponding to multiple time periods are obtained respectively. Then, based on the downlink signal frequency offsets, distance differences corresponding to multiple time periods are obtained. This can transform the absolute distance, which is difficult to measure accurately in related technologies, into frequency offset changes that are easy to measure with high precision. And through time integration, it can be transformed into distance difference. This not only avoids the stringent requirements of microsecond-level time synchronization and simultaneous reception of multiple signals in traditional TDOA methods, but also takes advantage of the high resolution of frequency offset measurement in the frequency domain. This enables a single satellite to achieve a multi-satellite-like positioning effect through multiple samplings during its movement, thereby obtaining stable and reliable distance difference information.

[0103] Optionally, in step S521, obtaining the downlink signal frequency offset corresponding to multiple time periods includes:

[0104] Step S5211: Obtain the first frequency point corresponding to multiple time periods respectively, wherein the first frequency point is the frequency point at which the satellite transmits each downlink synchronization signal in each time period;

[0105] Step S5212: Calculate the downlink signal frequency offset corresponding to multiple time periods using the first frequency point and the second frequency point, where the second frequency point is the frequency point at which the user equipment receives each downlink synchronization signal in each time period.

[0106] The first frequency point mentioned above is the nominal transmission frequency used by the satellite when transmitting downlink synchronization signals, that is, the theoretical transmission frequency of the SSB signal at the satellite end, corresponding to the frequency point indicated by GSCN defined in the 3GPP standard.

[0107] The second frequency point mentioned above is the frequency of the downlink synchronization signal actually received by the UE, that is, the receiving frequency after Doppler shift caused by the relative motion between the satellite and the UE.

[0108] For example, based on the first frequency point and the second frequency point, the downlink signal frequency offset corresponding to multiple time periods can be calculated using the following formula:

[0109]

[0110] in, For the first The downlink signal frequency offset corresponding to each SSB signal For the second frequency point, This is the first frequency point.

[0111] For example, after the UE powers on, it first performs a cell search. When it detects a PSS in the SSB signal, the UE can measure the received frequency. If the UE knows the SSB's transmission frequency. Then the first Doppler frequency offset of the SSB signal .

[0112] Based on the above steps S5211 to S5212, the first frequency points corresponding to multiple time periods are obtained respectively. Then, the downlink signal frequency offset corresponding to multiple time periods is calculated using the first frequency points and the second frequency points. This can accurately restore the original carrier frequency point of the satellite transmitted signal and eliminate frequency position confusion caused by Doppler frequency shift. Thus, high-precision and time-continuous measurement of downlink signal frequency offset can be achieved without relying on GNSS or external auxiliary information.

[0113] Optionally, in step S5211, obtaining the first frequency points corresponding to multiple time periods includes:

[0114] In response to the preset relationship between the maximum Doppler frequency offset and the frequency interval of the downlink synchronization signal in each time period, the first frequency point is determined based on the second frequency point.

[0115] The frequency spacing of the aforementioned downlink synchronization signals is the minimum step size between the SSB transmission frequencies corresponding to the GSCN. Specifically, the frequency spacing of the aforementioned downlink synchronization signals is defined by the SSB frequency grid (Synchronization Raster) as defined in the 3GPP TS 38.101-5 standard, which is used to ensure that all UEs supporting satellite access can perform synchronization signal detection and frequency estimation based on a unified discrete set of frequency points. Under the SSB frequency grid structure, the transmission frequency of each SSB signal is limited to a specific frequency point mapped by the GSCN, and the frequency difference between adjacent GSCNs constitutes the aforementioned frequency spacing.

[0116] Table 1

[0117]

[0118] Table 1 shows the definitions for channel bandwidths above 3MHz. The mapping relationship between the GSCN parameters and the corresponding parameters.

[0119] Table 2

[0120]

[0121] Table 2 shows the definitions within the 3MHz channel bandwidth range. The mapping relationship between the GSCN parameters and the GSCN parameters.

[0122] Based on Tables 1 and 2 above, it can be seen that the SSB frequency location... The interval is 100kHz in the 0-3000MHz band and 1.4MHz in the 3000-24250MHz band.

[0123] The above preset relationship can be that the maximum Doppler frequency offset is less than half of the frequency interval of the downlink synchronization signal.

[0124] Specifically, when the maximum Doppler frequency offset is less than half the frequency interval of the SSB signal, the UE can determine the frequency of the received SSB signal. Determine the frequency point at which the satellite transmits the SSB signal. Specifically, assuming and For two adjacent SSB frequency positions, and lie in and Between, if Then UE determines The Doppler frequency offset of the SSB signal .

[0125] Based on the above optional embodiments, when the maximum Doppler frequency offset is less than half of the frequency interval of the SSB signal, the first frequency point is determined based on the second frequency point. By directly comparing the offset of the received frequency point with the adjacent frequency points in the predefined SSB frequency grid, the frequency point corresponding to the SSB signal actually transmitted by the satellite can be accurately identified, thereby achieving accurate calculation of the Doppler frequency offset without the need for additional indication information.

[0126] Optionally, in step S5211, obtaining the first frequency points corresponding to multiple time periods includes:

[0127] In response to the failure to satisfy the preset relationship between the maximum Doppler frequency offset and the frequency interval of the downlink synchronization signal in each time period, the first frequency point is determined based on the indication information and the second frequency point transmitted by the satellite. The indication information is used to indicate the N least significant bits of the global synchronization channel number, where N is an integer greater than or equal to 1.

[0128] Table 3

[0129]

[0130] Table 3 shows the Doppler frequency offset at different frequencies (3000MHz, 24250MHz) and different orbital altitudes (600km, 300km). It can be seen that when the Doppler frequency offset exceeds half the corresponding SSB frequency interval, it may cause SSB frequency position confusion on the UE side, preventing the UE from accurately determining the frequency of the received SSB signal. Determine the frequency point at which the satellite transmits the SSB signal. Therefore, it is impossible to determine the Doppler frequency offset. .

[0131] For example, the frequency location of the SSB (such as the GSCN) can be indicated by the network side in the MIB, SIB1, SIB19, or other System Information (OSI). Specifically, since the frequency offset caused by the NTN radio link is limited, it is not necessary to provide the complete GSCN value. For example, even if only the Least Significant Bit (GSCN LSB) is indicated to the UE, the transmission frequency of the SSB signal can be determined. It is still possible to match the receiving frequency of the SSB signal. The most recent value in the indicated GSCN LSB is used to determine the frequency. As shown in Table 3, the typical Doppler frequency offset does not exceed one SSB frequency interval; therefore, ≥1 GSCN LSB allows the UE to determine the transmission frequency of the SSB signal. .

[0132] Table 4

[0133]

[0134] For example, assume the transmission frequency of the SSB signal =2500.95MHz, corresponding to GSCN=6252 (binary "1100001101100"), the network side indicates GSCN LSB as "0" in the MIB, and the Doppler frequency offset is 54.6kHz. The frequency at which the UE receives the SSB signal is... =2500.95MHz + 54.6kHz = 2501.0046MHz, and receiving an indication that the GSCN LSB is "0", the SSB transmission frequency can be determined. The corresponding least significant bit of the GSCN is "0". According to Table 4, the distance from the SSB signal receiving frequency... The most recent GSCN with a least significant bit of 0 at 2501.0046MHz is 6252 (binary representation: "1100001101100"), corresponding to an SSB transmission frequency of 2500.95MHz. The UE can determine this. =2500.95MHz, thus the Doppler frequency offset can be determined. =2501.0046MHz-2500.95MHz=54.6kHz.

[0135] Based on the above optional embodiments, when the maximum Doppler frequency offset is greater than or equal to the frequency interval of the downlink synchronization signal in each time period, the first frequency point is determined according to the indication information and the second frequency point sent by the satellite. This can reduce the frequency point ambiguity range by transmitting only a small number of least significant bits of the GSCN, so that the UE can accurately identify the actual SSB signal frequency point sent by the satellite without the need for complete ephemeris information or frequency point mapping table, thereby realizing reliable calculation of Doppler frequency offset in high frequency offset environment.

[0136] Optionally, in step S522, based on the downlink signal frequency offset, obtaining the distance difference corresponding to multiple time periods includes:

[0137] Step S5221: Calculate the radial velocity between the user equipment and the satellite in each time period based on the downlink signal frequency offset;

[0138] Step S5222: Integrate or accumulate the radial velocity within each time period to obtain the distance difference corresponding to multiple time periods.

[0139] For example, assuming the satellite orbital altitude is 600km and the carrier frequency is... =2GHz (corresponding to a SSB signal frequency interval of 100kHz), the satellite periodically transmits SSB signals, periodically. =20ms. Assuming the UE is directly below the satellite's trajectory, the maximum Doppler frequency offset is 48kHz, which is less than half the frequency interval of the SSB signal (100kHz).

[0140] Assuming the satellite is The first SSB signal is sent at 0ms. The UE receives the first SSB signal and measures the Doppler frequency offset. =48kHz, then the radial velocity from the UE to the satellite 7.2 km / s.

[0141] Assuming the satellite is =4min=240s=240000ms The 12001st SSB signal is sent. The UE receives the 12001st SSB signal and measures the Doppler frequency offset. =40kHz, then the radial velocity from the UE to the satellite 6km / s.

[0142] Assuming the satellite is =6min30sec=390s=390000ms The 19501st SSB signal is transmitted. The UE receives the 19501st SSB signal and measures the Doppler frequency offset. =0kHz, then the radial velocity from the UE to the satellite 0km / s.

[0143] Assuming the satellite is =9min=540s=540000ms The 27001st SSB signal is sent. The UE receives the 27001st SSB signal and measures the Doppler frequency offset. =-40kHz, then the radial velocity from the UE to the satellite -6km / s.

[0144] Furthermore, by integrating or accumulating the radial velocity over the time interval [1, 12001], the resulting distance difference is: Integrating or summing the radial velocities over the time interval [12001, 19501] yields the distance difference. Integrating or summing the radial velocities over the time interval [19501, 27001] yields the distance difference. .

[0145] Based on steps S5221 to S5222 above, the radial velocity between the user equipment and the satellite is calculated based on the downlink signal frequency offset. Then, the radial velocity in each time period is integrated or accumulated to obtain the distance difference corresponding to multiple time periods. This can reduce the cumulative impact of single Doppler frequency offset measurement error on the distance difference calculation and improve the stability and reliability of the relative distance change based on time accumulation.

[0146] Optionally, in step S53, the user equipment is located based on the first location, the second location, and the distance difference corresponding to multiple time periods, and the location result includes:

[0147] Step S531: Based on the first position, second position, and distance difference corresponding to multiple time periods, establish multiple hyperboloid equations;

[0148] Step S532: The positioning result is obtained by analyzing multiple hyperboloid equations.

[0149] For example, suppose the satellite's position is determined based on ephemeris information in SIB19. The position coordinates at =0ms are , The position coordinates at 240000ms are , The position coordinates at 390000ms are , The position coordinates at 540000ms are Furthermore, based on the aforementioned location information and distance difference, the following three hyperboloid equations can be established:

[0150]

[0151]

[0152]

[0153] By solving the three hyperboloid equations together, the position coordinates of the UE can be obtained. .

[0154] Based on steps S531 to S532 above, multiple hyperboloid equations are established according to the first position, second position, and distance difference corresponding to multiple time periods. Then, by analyzing the multiple hyperboloid equations, the positioning result is obtained. This can effectively utilize the geometric constraints formed by the motion trajectory of a single satellite at different times. Under the condition that multiple satellites are not simultaneously visible or have high-precision time synchronization, the solvability and stability of the positioning equations are improved by accumulating multiple sets of distance difference observations, and the interference of single measurement errors on the positioning result is reduced. Thus, a highly robust three-dimensional position solution is achieved by relying only on the continuous signal of a single satellite.

[0155] Optionally, the above-mentioned single-satellite positioning method also includes:

[0156] Based on the positioning results and ephemeris information, the timing advance and frequency offset pre-compensation values ​​of the uplink are obtained.

[0157] Based on the timing advance and frequency offset pre-compensation values, the satellite is accessed.

[0158] The aforementioned timing advance (TA) is a timing adjustment parameter calculated by the UE based on its own location coordinates and satellite ephemeris information. It is used to compensate for the propagation delay experienced by the radio signal from the UE to the satellite. Based on the timing advance, it can be ensured that the PRACH signal transmitted by the UE arrives accurately within the expected reception window of the satellite, thereby meeting the satellite's time slot alignment requirements for uplink synchronization and avoiding the signal falling into the wrong time slot or conflicting with the uplink signals of other UEs due to propagation delay.

[0159] The aforementioned frequency offset pre-compensation value is a correction amount calculated by the UE based on its own position coordinates and satellite ephemeris information, used to compensate for the carrier frequency offset caused by the Doppler frequency shift due to relative motion. Specifically, the function of the aforementioned frequency offset pre-compensation value is to pre-adjust the output frequency of the local oscillator before the UE transmits the uplink signal, so that the center frequency of the transmitted signal is consistent with the expected receiving frequency of the satellite receiver, thereby eliminating the interference of frequency offset caused by high-speed orbital motion on signal demodulation performance, and ensuring that the uplink can maintain stable channel estimation and coherent demodulation capabilities even in a high-dynamic environment.

[0160] For example, the UE is based on its own three-dimensional position coordinates obtained by solving. After completing the positioning using the satellite ephemeris information decoded from SIB19, the geometric distance between the UE and the satellite can be calculated using this position information and the satellite's precise orbital parameters at the current moment. Specifically, the geometric distance between the UE and the satellite can be calculated using the following formula:

[0161]

[0162] in,( , , The position of the satellite is calculated based on ephemeris information. Subsequently, the UE can calculate the propagation delay of the uplink signal from the UE's transmission to the satellite's reception. The expected arrival time of the uplink signal at the satellite receiver can be calculated.

[0163] To ensure that the UE's PRACH preamble sequence is correctly aligned with the satellite, the UE needs to proactively advance its own transmission time by one bit. The corresponding time quantity, which is TA, is calculated using the following formula: ,in, This represents the inherent system delay of the UE's internal RF and baseband processing links, a value obtainable through factory calibration or historical measurement records. Simultaneously, the UE can calculate the frequency offset pre-compensation value based on its own location coordinates and satellite location / velocity information from SIB19. Finally, the UE can compare the calculated TA with... The physical layer access control unit is written to perform joint pre-adjustment in the time and frequency domains before the PRACH preamble is sent, so that even without establishing a NAS connection or obtaining the core network configuration, a high success rate of synchronization acquisition and channel access can be achieved during the first uplink access.

[0164] Based on the above optional embodiments, the timing advance and frequency offset pre-compensation values ​​of the uplink are obtained based on the positioning results and ephemeris information. Then, based on the timing advance and frequency offset pre-compensation values, the UE can access the satellite, enabling the UE to accurately complete the delay calibration and frequency compensation when transmitting uplink signals without GNSS support. This ensures the synchronization and reliability of PRACH channel access and avoids access failure or uplink interference caused by timing deviation or uncompensated frequency offset.

[0165] Figure 6 This is a flowchart of another single-satellite positioning method according to one embodiment of this application, such as... Figure 6 As shown, the method includes the following steps:

[0166] Step S61: Send multiple downlink synchronization signals and broadcast ephemeris information to the user equipment in multiple cycles, wherein the user equipment is used to obtain the positioning result of the user equipment according to any one of the single satellite positioning methods in the embodiments of this application.

[0167] Step S62: Receive an access request from the user equipment. The access request is initiated by the user equipment based on the uplink timing advance and frequency offset pre-compensation value, which are obtained based on the positioning result and ephemeris information.

[0168] The aforementioned access request is the transmission behavior of the PRACH preamble sequence. This behavior is the first synchronization access operation performed by the UE on the physical layer uplink access channel after completing the positioning calculation based on a single satellite and deriving the uplink TA and frequency offset pre-compensation value, based on the time and frequency synchronization parameters determined by the satellite orbit parameters and its own position calculation results.

[0169] For example, after completing the positioning calculation based on a single satellite, the UE can deduce the TA corresponding to the signal propagation delay at the current moment and the pre-compensation value of the Doppler frequency offset caused by relative motion based on its own three-dimensional position coordinates and satellite ephemeris information. At the first available PRACH resource opportunity, the UE sends the PRACH preamble sequence to the satellite with a pre-configured preamble sequence format, a precisely calibrated transmission time slot, and a frequency offset corrected carrier frequency. This enables the first reliable access for physical layer uplink synchronization without establishing any NAS layer connection, ensuring that the satellite base station can correctly receive and demodulate the preamble, triggering the Random Access Response (RAR) procedure.

[0170] Based on steps S61 to S62 above, multiple downlink synchronization signals and broadcast ephemeris information are sent to the user equipment in multiple cycles, and then access requests from the user equipment are received. This enables the UE to autonomously calculate its own position coordinates, radial velocity changes and relative motion parameters based on the received periodic downlink synchronization signals and ephemeris information without relying on GNSS. This allows the UE to derive the TA and frequency offset pre-compensation values ​​required for the uplink, ensuring the time and frequency synchronization accuracy of the access request and realizing reliable triggering and efficient response of the satellite access process.

[0171] Alternatively, the above-mentioned single-satellite positioning method also includes:

[0172] Send indication information to the user equipment, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, where N is an integer greater than or equal to 1.

[0173] The above indication information is the least significant bit information of GSCN, which is used to assist in determining the precise carrier frequency position of the satellite transmission synchronization signal block at the satellite signal receiving end.

[0174] Specifically, in an NTN network, the SSB signal received by the UE is prone to Doppler frequency shift due to the high-speed motion of satellites, causing the received frequency to deviate from the theoretical value in the standard SSB frequency sequence. When the Doppler frequency shift exceeds half of the frequency interval of the SSB signal, the receiver cannot directly match the correct SSB transmission frequency based solely on the received frequency, thus causing frequency position confusion. In this case, the network side can broadcast the N least significant bits of the GSCN to the UE through system message blocks (such as MIB, SIB1, SIB19, or OSI). Specifically, N is an integer greater than or equal to 1, which can be set according to the relationship between the maximum Doppler frequency shift and the frequency interval of the SSB signal, ensuring that only one GSCN conforms to the least significant bit pattern within the frequency shift range.

[0175] Based on the above optional embodiments, sending indication information to the UE enables the UE to uniquely determine the corresponding SSB signal transmission frequency from a finite candidate set by matching it with the least significant bit of the indication, given that the receiving frequency point is known, thereby accurately calculating the Doppler frequency offset.

[0176] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods according to the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the related technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0177] This application also provides a single-satellite positioning device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0178] Figure 7 This is a structural block diagram of a single-satellite positioning device according to one embodiment of this application, such as... Figure 7 As shown, the device includes:

[0179] The first receiving module 701 is used to receive multiple downlink synchronization signals transmitted by the satellite in multiple cycles, as well as to receive ephemeris information broadcast by the satellite.

[0180] The first acquisition module 702 is used to acquire the distance difference corresponding to multiple time periods, and to acquire the first position and second position corresponding to multiple time periods based on ephemeris information. Each time period contains a part of multiple cycles. The first position is the satellite position corresponding to the start time of each time period, the second position is the satellite position corresponding to the end time of each time period, the distance difference is the difference between the first distance and the second distance of each time period, the first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period.

[0181] The positioning module 703 is used to locate the user equipment based on the first position, the second position, and the distance difference corresponding to multiple time periods, and to obtain the positioning result.

[0182] Optionally, the first receiving module 701 is further configured to: receive multiple synchronization signal block signals transmitted by the satellite in multiple cycles.

[0183] Optionally, the first receiving module 701 is further configured to: receive system messages sent by the satellite, wherein the information carried in the system messages includes: ephemeris information.

[0184] Optionally, the first acquisition module 702 is further configured to: acquire downlink signal frequency offsets corresponding to multiple time periods respectively; and acquire distance differences corresponding to multiple time periods based on downlink signal frequency offsets.

[0185] Optionally, the first acquisition module 702 is further configured to: acquire first frequency points corresponding to multiple time periods respectively, wherein the first frequency point is the frequency point at which the satellite transmits each downlink synchronization signal in each time period; and calculate the downlink signal frequency offset corresponding to multiple time periods using the first frequency point and the second frequency point, wherein the second frequency point is the frequency point at which the user equipment receives each downlink synchronization signal in each time period.

[0186] Optionally, the first acquisition module 702 is further configured to: determine the first frequency point based on the second frequency point in response to the maximum Doppler frequency offset satisfying a preset relationship with the frequency interval of the downlink synchronization signal in each time period.

[0187] Optionally, the first acquisition module 702 is further configured to: in response to the failure to satisfy a preset relationship between the maximum Doppler frequency offset and the frequency interval of the downlink synchronization signal in each time period, determine a first frequency point based on the indication information and the second frequency point transmitted by the satellite, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, and N is an integer greater than or equal to 1.

[0188] Optionally, the first acquisition module 702 is further configured to: calculate the radial velocity between the user equipment and the satellite in each time period based on the downlink signal frequency offset; and integrate or accumulate the radial velocity in each time period to obtain the distance difference corresponding to multiple time periods.

[0189] Optionally, the positioning module 703 is also used to: establish multiple hyperboloid equations based on the first position, the second position, and the distance difference corresponding to multiple time periods; and obtain the positioning result by analyzing the multiple hyperboloid equations.

[0190] Optionally, the above-mentioned single-satellite positioning device further includes: a second acquisition module 704, used to acquire the uplink timing advance and frequency offset pre-compensation value based on the positioning result and ephemeris information; and an access module 705, used to access the satellite based on the timing advance and frequency offset pre-compensation value.

[0191] Figure 8 This is a structural block diagram of another single-satellite positioning device according to one embodiment of this application, such as... Figure 8 As shown, the device includes:

[0192] The first transmitting module 801 is used to transmit multiple downlink synchronization signals to the user equipment in multiple cycles, and to broadcast ephemeris information, wherein the user equipment is used to obtain the positioning result of the user equipment according to any one of the single satellite positioning methods in the embodiments of this application.

[0193] The second receiving module 802 is used to receive access requests from user equipment. The access request is initiated by the user equipment based on the uplink timing advance and frequency offset pre-compensation value, which are obtained based on the positioning result and ephemeris information.

[0194] Optionally, the above-mentioned single-satellite positioning device further includes: a second transmitting module 803, used to transmit indication information to user equipment, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, where N is an integer greater than or equal to 1.

[0195] It should be noted that the above modules can be implemented by software or hardware. For the latter, they can be implemented in the following ways, but are not limited to: all the above modules are located in the same processor; or, the above modules are located in different processors in any combination.

[0196] According to another aspect of the embodiments of this application, a user equipment is also provided, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the above-described single-satellite positioning method when it runs.

[0197] Optionally, in this embodiment, the processor can be configured to perform the following steps via a computer program:

[0198] Step S51: Receive multiple downlink synchronization signals transmitted by the satellite in multiple cycles, and receive ephemeris information broadcast by the satellite.

[0199] Step S52: Obtain the distance difference corresponding to multiple time periods, and obtain the first position and second position corresponding to multiple time periods based on ephemeris information. Each time period contains a part of multiple cycles. The first position is the satellite position corresponding to the start time of each time period, the second position is the satellite position corresponding to the end time of each time period, the distance difference is the difference between the first distance and the second distance of each time period, the first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period.

[0200] Step S53: Based on the first location, second location, and distance difference corresponding to multiple time periods, the user equipment is located to obtain the location result.

[0201] According to another aspect of the embodiments of this application, a satellite device is also provided, including: a memory storing an executable program; and a processor for running the program, wherein the program executes the other single-satellite positioning method described above when it runs.

[0202] According to another aspect of the embodiments of this application, a single satellite positioning system is also provided, including: user equipment and satellite equipment.

[0203] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, the computer-readable storage medium including a stored executable program, wherein, when the executable program is running, it controls the device where the storage medium is located to execute any of the single satellite positioning methods in the embodiments of this application.

[0204] Optionally, in this embodiment, the storage medium may be configured to store a computer program for performing the following steps:

[0205] Step S51: Receive multiple downlink synchronization signals transmitted by the satellite in multiple cycles, and receive ephemeris information broadcast by the satellite.

[0206] Step S52: Obtain the distance difference corresponding to multiple time periods, and obtain the first position and second position corresponding to multiple time periods based on ephemeris information. Each time period contains a part of multiple cycles. The first position is the satellite position corresponding to the start time of each time period, the second position is the satellite position corresponding to the end time of each time period, the distance difference is the difference between the first distance and the second distance of each time period, the first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period.

[0207] Step S53: Based on the first location, second location, and distance difference corresponding to multiple time periods, the user equipment is located to obtain the location result.

[0208] Optionally, in this embodiment, the storage medium may include, but is not limited to, various media capable of storing computer programs, such as USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks.

[0209] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program that, when executed by a processor, implements a single satellite positioning method according to any one of the embodiments of this application.

[0210] Optionally, in this embodiment, the above-mentioned computer program product can be configured as a computer program that performs the following steps:

[0211] Step S51: Receive multiple downlink synchronization signals transmitted by the satellite in multiple cycles, and receive ephemeris information broadcast by the satellite.

[0212] Step S52: Obtain the distance difference corresponding to multiple time periods, and obtain the first position and second position corresponding to multiple time periods based on ephemeris information. Each time period contains a part of multiple cycles. The first position is the satellite position corresponding to the start time of each time period, the second position is the satellite position corresponding to the end time of each time period, the distance difference is the difference between the first distance and the second distance of each time period, the first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period.

[0213] Step S53: Based on the first location, second location, and distance difference corresponding to multiple time periods, the user equipment is located to obtain the location result.

[0214] According to another aspect of the embodiments of this application, a chip system is also provided, including: a processor for calling and running a computer program from a memory, such that a communication device equipped with the chip system performs any of the single-satellite positioning methods in the embodiments of this application.

[0215] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0216] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0217] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0218] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0219] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0220] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to related technologies, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, ROM, RAM, portable hard drives, magnetic disks, or optical disks.

[0221] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A single satellite positioning method, characterized in that, include: Receive multiple downlink synchronization signals transmitted by the satellite in multiple cycles, and receive ephemeris information broadcast by the satellite; The distance difference corresponding to multiple time periods is obtained, and based on the ephemeris information, the first position and the second position corresponding to the multiple time periods are obtained respectively. Each of the multiple time periods contains a part of the multiple cycles. The first position is the satellite position corresponding to the start time of each time period, and the second position is the satellite position corresponding to the end time of each time period. The distance difference is the difference between the first distance and the second distance of each time period. The first distance is the distance between the user equipment and the satellite corresponding to the start time of each time period, and the second distance is the distance between the user equipment and the satellite corresponding to the end time of each time period. The user equipment is located based on the first location, the second location, and the distance difference corresponding to the multiple time periods, and a location result is obtained.

2. The single-satellite positioning method according to claim 1, characterized in that, Receiving the multiple downlink synchronization signals transmitted by the satellite in the multiple periods includes: Receive multiple synchronization signal blocks transmitted by the satellite in the multiple cycles.

3. The single-satellite positioning method according to claim 1, characterized in that, The ephemeris information received from the satellite broadcast includes: Receive system messages sent by the satellite, wherein the information carried in the system messages includes: the ephemeris information.

4. The single-satellite positioning method according to claim 1, characterized in that, Obtaining the distance difference corresponding to the multiple time periods includes: Obtain the downlink signal frequency offset corresponding to the multiple time periods respectively; Based on the downlink signal frequency offset, the distance difference corresponding to the multiple time periods is obtained.

5. The single-satellite positioning method according to claim 4, characterized in that, Obtaining the downlink signal frequency offset corresponding to the multiple time periods includes: The first frequency point corresponding to each of the multiple time periods is obtained respectively, wherein the first frequency point is the frequency point at which the satellite transmits each downlink synchronization signal in each time period; Using the first frequency point and the second frequency point, the downlink signal frequency offset corresponding to the multiple time periods is calculated, wherein the second frequency point is the frequency point at which the user equipment receives each downlink synchronization signal in each time period.

6. The single-satellite positioning method according to claim 5, characterized in that, Obtaining the first frequency point corresponding to the plurality of time periods includes: In response to the maximum Doppler frequency offset satisfying a preset relationship between the frequency interval of the downlink synchronization signal in each time period, the first frequency point is determined based on the second frequency point.

7. The single-satellite positioning method according to claim 5, characterized in that, Obtaining the first frequency point corresponding to the plurality of time periods includes: In response to the failure to satisfy a preset relationship between the maximum Doppler frequency offset and the frequency interval of the downlink synchronization signal in each time period, the first frequency point is determined based on the indication information transmitted by the satellite and the second frequency point, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, where N is an integer greater than or equal to 1.

8. The single-satellite positioning method according to claim 4, characterized in that, Based on the downlink signal frequency offset, obtaining the distance difference corresponding to the multiple time periods includes: Based on the downlink signal frequency offset, calculate the radial velocity between the user equipment and the satellite in each time period; The radial velocity within each time period is integrated or accumulated to obtain the distance difference corresponding to the multiple time periods.

9. The single-satellite positioning method according to claim 1, characterized in that, Based on the first location, the second location, and the distance difference corresponding to the multiple time periods, the user equipment is located, and the location result includes: Based on the first position, the second position, and the distance difference corresponding to the multiple time periods, multiple hyperboloid equations are established; The positioning result is obtained by analyzing the multiple hyperboloid equations.

10. The single-satellite positioning method according to claim 1, characterized in that, The single-satellite positioning method also includes: Based on the positioning results and the ephemeris information, the timing advance and frequency offset pre-compensation values ​​of the uplink are obtained. Based on the timing advance and the frequency offset pre-compensation value, the satellite is accessed.

11. A single satellite positioning method, characterized in that, include: Multiple downlink synchronization signals and broadcast ephemeris information are sent to the user equipment in multiple cycles, wherein the user equipment is used to obtain the positioning result of the user equipment according to the single satellite positioning method according to any one of claims 1 to 10; The system receives an access request from the user equipment, wherein the access request is initiated by the user equipment based on the uplink timing advance and frequency offset pre-compensation value, and the timing advance and frequency offset pre-compensation value are obtained based on the positioning result and the ephemeris information.

12. The single-satellite positioning method according to claim 11, characterized in that, The single-satellite positioning method also includes: Send indication information to the user equipment, wherein the indication information is used to indicate the N least significant bits of the global synchronization channel number, where N is an integer greater than or equal to 1.

13. A user equipment, characterized in that, include: Memory, which stores executable programs; A processor for running the program, wherein the program, when running, executes the single-satellite positioning method according to any one of claims 1 to 10.

14. A satellite device, characterized in that, include: Memory, which stores executable programs; A processor for running the program, wherein the program, when running, executes the single-satellite positioning method according to any one of claims 11 to 12.

15. A single-satellite positioning system, characterized in that, include: The user equipment as described in claim 13 and the satellite equipment as described in claim 14.

16. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored executable program, wherein, when the executable program is executed, it controls the device on which the storage medium is located to perform the single-satellite positioning method according to any one of claims 1 to 12.

17. A computer program product, characterized in that, It includes a computer program that, when executed by a processor, implements the single-satellite positioning method according to any one of claims 1 to 12.

18. A chip system, characterized in that, Includes: a processor for retrieving and running a computer program from memory, causing a communication device equipped with the chip system to perform the single-satellite positioning method as described in any one of claims 1 to 12.

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