Time synchronization method, apparatus, system, and computer storage medium

Abstract

The application discloses a time synchronization method, device, system and computer storage medium, comprising: setting a data link payload on a navigation satellite to control the time of the data link payload and the time of the navigation satellite to be synchronized; and the data link payload sending current time information to a data link terminal, so that the data link terminal realizes time synchronization with the data link payload according to the current time information. In this way, by synchronizing the time reference of the data link payload set on the navigation satellite with the time reference of the navigation satellite, then synchronizing the time of the data link payload and the data link terminal, and finally time-synchronizing a user receiver, the time uncertainty is compressed, and the time for long code direct acquisition / reacquisition is shortened.

Description

Technical Field

[0001] This invention relates to the field of navigation satellite technology, and in particular to a time synchronization method, apparatus, system, and computer storage medium. Background Technology

[0002] Satellite navigation systems, as an indispensable tool in people's work and life, have been widely used. However, satellite navigation systems are susceptible to interference, and signal reception performance gradually deteriorates with increasing interference intensity. Strong interference environments make civilian code acquisition extremely difficult, making it hard for civilian codes to support long-term acquisition. Therefore, how to shorten the acquisition time of long codes has been a subject of ongoing research. Summary of the Invention

[0003] The purpose of this application is to provide a time synchronization method, apparatus, system, and computer storage medium that can reduce time uncertainty and shorten the time for direct acquisition / reacquisition of long codes.

[0004] To achieve the above objectives:

[0005] In a first aspect, embodiments of this application provide a time synchronization method applied to a data link payload configured on a navigation satellite, the method comprising the following steps:

[0006] The timing of the data link payload is synchronized with the timing of the navigation satellites.

[0007] The current time information is sent to the data link terminal so that the data link terminal can synchronize with the data link payload according to the current time information.

[0008] Optionally, sending current time information to the data link terminal so that the data link terminal can synchronize time with the data link payload according to the current time information includes:

[0009] Receive the time synchronization request sent by the data link terminal;

[0010] In response to the time synchronization request, the current time information is sent to the data link terminal based on a preset time synchronization algorithm, so that the data link terminal can synchronize its time with the data link payload according to the current time information.

[0011] Optionally, the data link payload includes a baseband signal processing unit, an RF transmission channel unit, a first power amplification unit, and a first transceiver antenna. Sending the current time information to the data link terminal includes:

[0012] The current time information acquired and processed by the baseband signal processing unit is transmitted sequentially through the radio frequency transmission channel unit and the first power amplification unit to the first transceiver antenna, and then sent to the data link terminal through the first transceiver antenna.

[0013] Optionally, the data link payload further includes a first low-noise amplification unit and an RF receiving channel unit, wherein receiving the time synchronization request sent by the data link terminal includes:

[0014] The time synchronization request sent by the data link terminal is received through the first transceiver antenna, and the time synchronization request is transmitted to the baseband signal processing unit through the first low noise amplification unit and the radio frequency receiving channel unit in sequence.

[0015] Secondly, this application provides a time synchronization method applied to a data link terminal, the method comprising the following steps:

[0016] Receive current time information transmitted by the data link payload set on the navigation satellite;

[0017] Perform time synchronization processing based on the current time information to achieve time synchronization with the data link payload;

[0018] The synchronized time information of the data link terminal is sent to the user receiver to provide time synchronization for the user receiver.

[0019] Optionally, the receiving of the current time information transmitted by the data link payload of the navigation satellite before the receiving of the current time information further includes:

[0020] Send a time synchronization request to the data link payload.

[0021] Optionally, the data link terminal includes a digital signal processing unit, a receiving channel unit, a second low-noise amplification unit, and a second transceiver antenna. Receiving the current time information transmitted by the data link payload located on the navigation satellite includes:

[0022] The second transceiver antenna receives the current time information transmitted by the data link payload set on the navigation satellite;

[0023] The step of performing time synchronization processing based on the current time information to achieve time synchronization with the data link payload includes:

[0024] The current time information is transmitted sequentially through the second low-noise amplification unit and the receiving channel unit to the digital signal processing unit, and the digital signal processing unit performs time synchronization processing based on the current time information.

[0025] Optionally, the data link terminal further includes a transmit channel unit and a second power amplifier unit, and the step of sending a time synchronization request to the data link payload includes:

[0026] The time synchronization request generated by the digital signal processing unit according to the preset rules is transmitted sequentially through the transmission channel unit and the second power amplifier unit to the second transceiver antenna, and the time synchronization request is sent to the data link payload through the second transceiver antenna.

[0027] Thirdly, embodiments of this application provide a time synchronization system, the system comprising at least one navigation satellite configured with a data link payload, at least one data link terminal, and at least one user receiver; the data link payload is communicatively connected to the data link terminal, and the data link terminal is communicatively connected to the user receiver; wherein...

[0028] The data link payload is used to control the time of the data link payload to be synchronized with the time of the navigation satellite; and to send current time information to the data link terminal.

[0029] The data link terminal is configured to receive current time information transmitted by the data link payload; perform time synchronization processing based on the current time information to achieve time synchronization with the data link payload; and send the time information synchronized by the data link terminal to the user receiver to provide time synchronization to the user receiver.

[0030] Fourthly, embodiments of this application provide a time synchronization apparatus for performing the above-described method, comprising: a processor and a memory storing a computer program, wherein when the processor runs the computer program, the steps of the above-described time synchronization method are implemented.

[0031] Fifthly, embodiments of this application provide a computer storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described time synchronization method.

[0032] This application provides a time synchronization method, apparatus, system, and computer storage medium. The method includes: controlling the time of a data link payload located on a navigation satellite to synchronize with the time of the navigation satellite; the data link payload sending current time information to a data link terminal, so that the data link terminal can synchronize with the data link payload according to the current time information. Thus, by synchronizing the time reference of the data link payload located on the navigation satellite with the time reference of the navigation satellite, then synchronizing the time of the data link payload with the time of the data link terminal, and finally providing time synchronization to the user receiver, time uncertainty is reduced, and the time for long code direct acquisition / reacquisition is shortened. Attached Figure Description

[0033] Figure 1 A schematic diagram of the structure of a time synchronization system provided in an embodiment of the present invention. Figure 1 ;

[0034] Figure 2 This is a schematic diagram of the data link payload in an embodiment of the present invention. Figure 1 ;

[0035] Figure 3 This is a schematic diagram of the data link terminal in an embodiment of the present invention. Figure 1 ;

[0036] Figure 4 A flowchart illustrating a time synchronization method provided in an embodiment of the present invention. Figure 1 ;

[0037] Figure 5 A flowchart illustrating a time synchronization method provided in an embodiment of the present invention. Figure 2 ;

[0038] Figure 6 A schematic diagram of the structure of a time synchronization system provided in an embodiment of the present invention. Figure 2 ;

[0039] Figure 7 This is a schematic diagram of the data link payload in an embodiment of the present invention. Figure 2 ;

[0040] Figure 8 This is a schematic diagram of the data link terminal in an embodiment of the present invention. Figure 2 ;

[0041] Figure 9 A flowchart illustrating a time synchronization method provided in an embodiment of the present invention. Figure 3 ;

[0042] Figure 10 This is a schematic diagram of the long code capture processing architecture in an embodiment of the present invention;

[0043] Figure 11 This is a schematic diagram of the capture timing in an embodiment of the present invention;

[0044] Figure 12 These are the capture sensitivities corresponding to different parameters in the embodiments of the present invention;

[0045] Figure 13 This is a schematic diagram of a time synchronization device provided in an embodiment of the present invention. Detailed Implementation

[0046] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0047] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, components, features, and elements with the same names in different embodiments of this application may have the same meaning or different meanings, the specific meaning of which must be determined by its interpretation in that specific embodiment or further in conjunction with the context of that specific embodiment.

[0048] It should be understood that although the terms first, second, third, etc., may be used herein to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this document, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if," as used herein, can be interpreted as "when," "when," or "in response to determination." Furthermore, as used herein, the singular forms "a," "an," and "the" are intended to also include the plural forms unless the context indicates otherwise. It should be further understood that the terms "comprising," "including," indicate the presence of the stated feature, step, operation, element, component, item, kind, and / or group, but do not exclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms "or" and "and / or" as used herein are to be interpreted as inclusive, or mean any one or any combination thereof. Therefore, "A, B, or C" or "A, B, and / or C" means "any one of the following: A; B; C; A and B; A and C; B and C; A, B, and C". Exceptions to this definition will only occur if the combination of elements, functions, steps, or operations is inherently mutually exclusive in some way.

[0049] It should be understood that although the steps in the flowcharts of this application's embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the figures may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily completed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be performed alternately or in turn with other steps or at least a portion of the sub-steps or stages of other steps.

[0050] It should be noted that step designations such as S101 and S102 are used in this document for the purpose of more clearly and concisely describing the corresponding content, and do not constitute a substantial limitation on the order. In specific implementation, those skilled in the art may execute S102 first and then S101, etc., but these should all be within the protection scope of this application.

[0051] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0052] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrative purposes and has no specific meaning in itself. Therefore, "module," "part," or "unit" may be used interchangeably.

[0053] See Figure 1 This application provides a time synchronization system comprising at least one navigation satellite equipped with a data link payload, at least one data link terminal, and at least one user receiver; the data link payload is communicatively connected to the data link terminal, and the data link terminal is communicatively connected to the user receiver; wherein,

[0054] The data link payload is used to control the time of the data link payload to be synchronized with the time of the navigation satellite; and to send current time information to the data link terminal.

[0055] The data link terminal is configured to receive current time information transmitted by the data link payload; perform time synchronization processing based on the current time information to achieve time synchronization with the data link payload; and send the time information synchronized by the data link terminal to the user receiver to provide time synchronization to the user receiver.

[0056] In the above scenario, the navigation satellite can be a navigation satellite included in the BeiDou Navigation Satellite System, Galileo System, GPS System, or GLONASS System. This embodiment uses a BeiDou navigation satellite as an example. Here, the data link payload can synchronize its time with the navigation satellite's time via an atomic clock within the navigation satellite after power-on or startup, ensuring that the data link payload and the navigation system use the same time. The data link payload located on the navigation satellite can send current time information to the data link terminal, allowing the data link terminal to synchronize its time based on the received current time information, thus achieving time synchronization with the data link payload. The operation of the data link payload sending current time information to the data link terminal can be proactive or based on a request from the data link terminal.

[0057] In one embodiment, see Figure 2 The data link payload includes a baseband signal processing unit, an RF transmission channel unit, a first power amplifier unit, and a first transceiver antenna. The data link payload sends current time information to the data link terminal, including: transmitting the current time information, acquired and processed by the baseband signal processing unit, sequentially through the RF transmission channel unit and the first power amplifier unit to the first transceiver antenna, and then transmitting the current time information to the data link terminal through the first transceiver antenna. Here, the baseband signal processing unit and the RF transmission channel unit are communicatively connected, the RF transmission channel unit and the first power amplifier unit are communicatively connected, and the first power amplifier unit and the first transceiver antenna are communicatively connected to form the transmission channel of the data link signal for the data link payload. After acquiring and processing the current time information, the baseband signal processing unit transmits the current time information sequentially through the RF transmission channel unit and the first power amplifier unit to the first transceiver antenna, and then transmits the current time information to the data link terminal through the first transceiver antenna. It should be noted that the output waveform of the baseband signal processing unit is configurable and can perform signal processing such as analog-to-digital conversion.

[0058] In one embodiment, see Figure 3 The data link terminal includes a digital signal processing unit, a receiving channel unit, a second low-noise amplification unit, and a second transceiver antenna. The data link terminal receives current time information transmitted by the data link payload set on the navigation satellite, including: receiving the current time information transmitted by the data link payload set on the navigation satellite through the second transceiver antenna.

[0059] The data link terminal performs time synchronization processing based on the current time information to achieve time synchronization with the data link payload, including:

[0060] The current time information is transmitted sequentially through the second low-noise amplification unit and the receiving channel unit to the digital signal processing unit, and the digital signal processing unit performs time synchronization processing based on the current time information.

[0061] Here, the digital signal processing unit is communicatively connected to the receiving channel unit, the receiving channel unit is communicatively connected to the second low-noise amplifier unit, and the second low-noise amplifier unit is communicatively connected to the second transceiver antenna to form a receiving channel for the data link signal of the data link terminal. After receiving the current time information sent by the data link payload set on the navigation satellite, the second transceiver antenna transmits the current time information sequentially through the second low-noise amplifier unit and the receiving channel unit to the digital signal processing unit.

[0062] In one embodiment, the data link payload is specifically configured to: receive a time synchronization request sent by the data link terminal; and, in response to the time synchronization request, send current time information to the data link terminal based on a preset time synchronization algorithm, so that the data link terminal can synchronize its time with the data link payload according to the current time information. It can be understood that when the data link payload receives a time synchronization request from the data link terminal, it indicates that the data link terminal wants to perform a time synchronization operation. Therefore, the data link payload sends current time information to the data link terminal based on the preset time synchronization algorithm, so that the data link terminal can synchronize its time with the data link payload according to the current time information. It should be noted that the preset time synchronization algorithm can be any existing time synchronization algorithm, and is not specifically limited here. The data link payload can send the current time information to the data link terminal in a preset format to facilitate data transmission.

[0063] In one embodiment, see further. Figure 2The data link payload further includes a first low-noise amplifier unit and an RF receiving channel unit. The data link payload receives a time synchronization request sent by the data link terminal, including: receiving the time synchronization request sent by the data link terminal through the first transceiver antenna, and transmitting the time synchronization request sequentially through the first low-noise amplifier unit and the RF receiving channel unit to the baseband signal processing unit. Here, the baseband signal processing unit and the RF receiving channel unit are communicatively connected, the RF receiving channel unit and the first low-noise amplifier unit are communicatively connected, and the first low-noise amplifier unit and the first transceiver antenna are communicatively connected to form the receiving channel for the data link signal of the data link payload. After receiving the time synchronization request sent by the data link terminal, the first transceiver antenna transmits the time synchronization request sequentially through the first low-noise amplifier unit and the RF receiving channel unit to the baseband signal processing unit. Furthermore, the data link payload also includes a first power supply unit for providing the voltage and / or current required for the operation of the data link payload.

[0064] In one embodiment, see further. Figure 3 The data link terminal further includes a transmit channel unit and a second power amplifier unit. The data link terminal sends a time synchronization request to the data link payload, including: transmitting the time synchronization request generated by the digital signal processing unit according to a preset rule sequentially through the transmit channel unit and the second power amplifier unit to the second transceiver antenna, and then sending the time synchronization request to the data link payload through the second transceiver antenna. Here, the digital signal processing unit is communicatively connected to the transmit channel unit, the transmit channel unit is communicatively connected to the second power amplifier unit, and the second power amplifier unit is communicatively connected to the second transceiver antenna, forming the transmit channel for the data link signal of the data link terminal. After generating the time synchronization request according to the preset rule, the digital signal processing unit transmits the time synchronization request sequentially through the transmit channel unit and the second power amplifier unit to the second transceiver antenna, and then sends the time synchronization request to the data link payload through the second transceiver antenna. The preset rule can be set according to actual needs, such as encoding format, modulation method, etc. In addition, the data link terminal also includes a second power supply unit for providing the voltage and / or current required for the operation of the data link terminal.

[0065] In summary, the time synchronization system provided in the above embodiments achieves reduced time uncertainty and shortened time for long code direct acquisition / reacquisition by synchronizing the time reference of the data link payload set on the navigation satellite with the time reference of the navigation satellite, synchronizing the time of the data link payload with the time of the data link terminal, and finally providing time synchronization to the user receiver.

[0066] See Figure 4This application provides a time synchronization method, which can be executed by a time synchronization device provided in this application. The device can be implemented in software and / or hardware. The time synchronization method provided in this embodiment can be applied to... Figure 1 The data link payload set up in the navigation satellite includes the following steps:

[0067] Step S101: Synchronize the time of the control data link payload with the time of the navigation satellite.

[0068] The navigation satellite can be a navigation satellite included in the BeiDou Navigation Satellite System, Galileo System, GPS System, or GLONASS System. This embodiment uses a BeiDou navigation satellite as an example. Here, the data link payload can synchronize its time with the navigation satellite's time via an atomic clock within the navigation satellite after power-on or startup, ensuring that the data link payload and the navigation system use the same time.

[0069] Step S102: Send the current time information to the data link terminal so that the data link terminal can synchronize with the data link payload according to the current time information.

[0070] Here, the data link payload deployed on the navigation satellite can send current time information to the data link terminal, so that the data link terminal, upon receiving the current time information, can synchronize its time with the data link payload. The operation of the data link payload sending the current time information to the data link terminal can be initiated actively or in response to a request from the data link terminal.

[0071] In one embodiment, sending current time information to the data link terminal so that the data link terminal can synchronize time with the data link payload according to the current time information includes:

[0072] Receive the time synchronization request sent by the data link terminal;

[0073] In response to the time synchronization request, the current time information is sent to the data link terminal based on a preset time synchronization algorithm, so that the data link terminal can synchronize its time with the data link payload according to the current time information.

[0074] It is understood that when the data link payload receives a time synchronization request from the data link terminal, it indicates that the data link terminal wants to perform a time synchronization operation. The data link payload then sends the current time information to the data link terminal based on a preset time synchronization algorithm, so that the data link terminal can synchronize its time with the data link payload according to the current time information. It should be noted that the preset time synchronization algorithm can be any existing time synchronization algorithm, and is not specifically limited here. The data link payload can send the current time information to the data link terminal in a preset format to facilitate data transmission.

[0075] In summary, the time synchronization method provided in the above embodiments achieves the reduction of time uncertainty and shortens the time for long code direct acquisition / reacquisition by synchronizing the time reference of the data link payload set on the navigation satellite with the time reference of the navigation satellite, synchronizing the time of the data link payload with the time of the data link terminal, and finally providing time synchronization to the user receiver.

[0076] In one embodiment, the data link payload includes a baseband signal processing unit, an RF transmission channel unit, a first power amplification unit, and a first transceiver antenna. Sending current time information to the data link terminal includes:

[0077] The current time information acquired and processed by the baseband signal processing unit is transmitted sequentially through the radio frequency transmission channel unit and the first power amplification unit to the first transceiver antenna, and then sent to the data link terminal through the first transceiver antenna.

[0078] Here, the baseband signal processing unit is communicatively connected to the RF transmission channel unit, the RF transmission channel unit is communicatively connected to the first power amplifier unit, and the first power amplifier unit is communicatively connected to the first transceiver antenna, forming the transmission channel for the data link signal of the data link payload. After acquiring and processing the current time information, the baseband signal processing unit transmits the current time information sequentially through the RF transmission channel unit and the first power amplifier unit to the first transceiver antenna, and then sends the current time information to the data link terminal through the first transceiver antenna. It should be noted that the output waveform of the baseband signal processing unit is configurable and can perform signal processing such as analog-to-digital conversion.

[0079] In one embodiment, the data link payload further includes a first low-noise amplification unit and an RF receiving channel unit, wherein receiving the time synchronization request sent by the data link terminal includes:

[0080] The first transceiver antenna receives the time synchronization request sent by the data link terminal and transmits the time synchronization request sequentially through the first low-noise amplifier unit and the radio frequency receiving channel unit to the baseband signal processing unit. Here, the baseband signal processing unit is communicatively connected to the radio frequency receiving channel unit, the radio frequency receiving channel unit is communicatively connected to the first low-noise amplifier unit, and the first low-noise amplifier unit is communicatively connected to the first transceiver antenna, forming the receiving channel for the data link signal of the data link payload. After receiving the time synchronization request from the data link terminal, the first transceiver antenna transmits the time synchronization request sequentially through the first low-noise amplifier unit and the radio frequency receiving channel unit to the baseband signal processing unit.

[0081] See Figure 5 This application provides a time synchronization method, which can be executed by a time synchronization device provided in this application. The device can be implemented in software and / or hardware. The time synchronization method provided in this embodiment can be applied to... Figure 1 The data link terminal in the middle includes the following steps:

[0082] Step S201: Receive the current time information sent by the data link payload set on the navigation satellite, wherein the time of the data link payload is synchronized with the time of the navigation satellite.

[0083] Here, the data link terminal can passively receive the current time information sent by the data link payload set on the navigation satellite, or it can actively receive the current time information sent by the data link payload based on its own request.

[0084] In one embodiment, before receiving the current time information transmitted by the data link payload of the navigation satellite, the method further includes sending a time synchronization request to the data link payload. Here, the data link terminal may send a time synchronization request to the data link payload periodically or irregularly to request the data link payload to perform a time synchronization operation on the data link terminal, that is, to request time synchronization processing with the data link payload.

[0085] Step S202: Perform time synchronization processing based on the current time information to achieve time synchronization with the data link payload.

[0086] Specifically, after receiving the current time information sent by the data link payload, the data link terminal performs time synchronization processing based on the current time information to achieve time synchronization with the data link payload. The specific operation process of the data link terminal performing the time synchronization processing can be found in existing technologies and will not be elaborated here.

[0087] Step S203: Send the synchronized time information of the data link terminal to the user receiver to provide time synchronization for the user receiver.

[0088] Specifically, after performing time synchronization processing based on the current time information to achieve time synchronization with the data link payload, the data link terminal can send the synchronized time information to the user receiver to provide time synchronization to the user receiver, thereby reducing time uncertainty.

[0089] In one embodiment, the data link terminal includes a digital signal processing unit, a receiving channel unit, a second low-noise amplifier unit, and a second transceiver antenna. Receiving the current time information transmitted by the data link payload located on the navigation satellite includes:

[0090] The second transceiver antenna receives the current time information transmitted by the data link payload set on the navigation satellite;

[0091] The step of performing time synchronization processing based on the current time information to achieve time synchronization with the data link payload includes:

[0092] The current time information is transmitted sequentially through the second low-noise amplification unit and the receiving channel unit to the digital signal processing unit, and the digital signal processing unit performs time synchronization processing based on the current time information.

[0093] Here, the digital signal processing unit is communicatively connected to the receiving channel unit, the receiving channel unit is communicatively connected to the second low-noise amplifier unit, and the second low-noise amplifier unit is communicatively connected to the second transceiver antenna to form a receiving channel for the data link signal of the data link terminal. After receiving the current time information sent by the data link payload set on the navigation satellite, the second transceiver antenna transmits the current time information sequentially through the second low-noise amplifier unit and the receiving channel unit to the digital signal processing unit.

[0094] In one embodiment, the data link terminal further includes a transmit channel unit and a second power amplifier unit. Sending a time synchronization request to the data link payload includes: transmitting the time synchronization request generated by the digital signal processing unit according to a preset rule sequentially through the transmit channel unit and the second power amplifier unit to the second transceiver antenna, and then sending the time synchronization request to the data link payload through the second transceiver antenna. Here, the digital signal processing unit is communicatively connected to the transmit channel unit, the transmit channel unit is communicatively connected to the second power amplifier unit, and the second power amplifier unit is communicatively connected to the second transceiver antenna, forming the transmit channel for the data link signal of the data link terminal. After generating the time synchronization request according to the preset rule, the digital signal processing unit transmits the time synchronization request sequentially through the transmit channel unit and the second power amplifier unit to the second transceiver antenna, and then sends the time synchronization request to the data link payload through the second transceiver antenna. The preset rule can be set according to actual needs, such as encoding format, modulation method, etc.

[0095] In summary, the time synchronization method provided in the above embodiments achieves the reduction of time uncertainty and shortens the time for long code direct acquisition / reacquisition by synchronizing the time reference of the data link payload set on the navigation satellite with the time reference of the navigation satellite, synchronizing the time of the data link payload with the time of the data link terminal, and finally providing time synchronization to the user receiver.

[0096] Based on the same inventive concept as the foregoing embodiments, the foregoing embodiments will be described in detail below through a specific example, in which the navigation satellite is the Beidou navigation satellite.

[0097] Currently, Assisted-GNSS technology in the civilian sector can shorten the initial positioning time of navigation receivers and improve positioning efficiency, and has been widely used in various types of smart terminals. However, for remote sea and ocean areas, coupled with the complex and ever-changing electromagnetic environment of the battlefield, Assisted-GNSS technology in the civilian sector is insufficient to support the rapid acquisition of BeiDou long codes under interference conditions. Furthermore, the ground-based assisted positioning wireless network has poor resilience and cannot be used to significantly shorten the initial positioning time of long-cycle long codes.

[0098] For the above issues, please refer to Figure 6 The diagram below illustrates the structure of the time synchronization system provided in this embodiment, which includes: a BeiDou satellite, a military BeiDou receiver installed on the user side, and a data link terminal; wherein, the BeiDou satellite is equipped with a data link payload, and the data link payload is consistent with the navigation time reference. Figure 7This is a schematic diagram of the satellite data link payload structure. The satellite-to-ground time synchronization is achieved through bidirectional time synchronization between the data link payload and the user-side data link terminal. The data link payload includes a power supply unit, a baseband signal processing unit, an RF transmit channel unit, a power amplifier unit, a low-noise amplifier unit, an RF receive channel unit, and a transceiver antenna. The power supply unit includes a power-on / off control module, a short-circuit protection module, a surge suppression module, and a DC / DC conversion module. The signal generated by the baseband signal processing unit is transmitted sequentially through the RF transmit channel unit, the power amplifier unit, and the transceiver antenna to the user-side data link terminal. The transceiver antenna receives the data link signal from the user-side data link terminal. The received signal passes through the low-noise amplifier unit and the RF receive channel unit before entering the baseband signal processing unit for analog-to-digital conversion and digital signal processing. Furthermore, the transmission and reception switching of the satellite-side data link payload signal is achieved through a circulator or a switch.

[0099] Figure 8 This is a schematic diagram of the data link terminal. The data link terminal includes a digital signal processing module, a receiving channel, a low-noise amplifier module, a transceiver antenna, a transmitting channel, and a power amplifier module. The signal generated by the data link signal processing module is transmitted sequentially through the RF transmitting channel, the power amplifier module, and the transceiver antenna to the BeiDou satellite data link payload. The transceiver antenna receives the signal transmitted by the BeiDou satellite data link payload. The received signal passes sequentially through the low-noise amplifier module and the RF receiving channel module before entering the data link signal processing module for analog-to-digital conversion and digital signal processing. The user-side data link terminal switches between transmitting and receiving data link signals using a circulator or switch.

[0100] Based on the same inventive concept as the foregoing embodiments, see [link / reference]. Figure 9 The following is a schematic diagram of the specific process of the time synchronization method provided in this embodiment, including the following steps:

[0101] Step S301: Data link payload control. The data link payload time is synchronized with the BeiDou satellite time reference.

[0102] Here, the data link payload is configured within the BeiDou satellite. The data link payload achieves hard synchronization with the BeiDou satellite's second pulse, ensuring that the satellite data link system and the navigation system operate at the same time. Furthermore, the design must consider that the uplink and downlink signal frequencies of the data link should not interfere with the navigation signals.

[0103] Step S302: The data link terminal and the data link payload perform satellite-to-ground time synchronization.

[0104] Here, the data link terminal initiates a time synchronization request to the satellite-side data link payload. The time synchronization request information is encoded and modulated according to a prescribed format and then sent to the satellite-side data link payload. The satellite-side data link payload, in turn, returns time information to the ground terminal according to a predetermined time synchronization algorithm, thus completing the time synchronization of the data link's own system.

[0105] Step S303: The data link terminal calculates the time synchronization accuracy of the data link system.

[0106] The accuracy of satellite data link time synchronization between the satellite and the ground can be analyzed using an RTT-like synchronization algorithm, which will not be elaborated here.

[0107] If we disregard hardware channel delay errors, the timing error caused by position changes can be controlled within ±5µs (microseconds). For a BeiDou signal of 10.23 Mcps, this error is equivalent to an uncertainty range of only about 40 chips, significantly reducing the uncertainty of BeiDou time and demonstrating extremely high value in assisting long-code acquisition. Even if the onboard data link node time accuracy is only ±20ms, this is still a 50-fold reduction compared to the ±1s time uncertainty of direct long-code acquisition, resulting in significant benefits.

[0108] Step S304: The data link terminal transmits the data link time to the military Beidou receiver to assist in long code acquisition.

[0109] Here, the data link terminal transmits the data link time to the military Beidou receiver to assist the receiver in achieving 10µs precision time synchronization. Acquisition only requires searching for about 205 code phases to complete the rapid acquisition of long codes.

[0110] The specific process is as follows:

[0111] When the BeiDou receiver uses a PMF+DFT (Partially Matched Filter + Discrete Fourier Transform) processing method for long code acquisition, the PMF processing enables parallel search of the code phase, and the DFT enables parallel search of the frequency. (See also...) Figure 10 This is a schematic diagram of the processing architecture for long code capture, where PMF is implemented in the frequency domain.

[0112] The B3Q signal information rate is 500bps, limiting the coherent integration time to 2ms. The acquisition timing based on the 2ms coherent integration and post-accumulation is as follows: Figure 11 As shown. First, the signal data and local pseudocode need to be buffered. The signal sampling rate is 20.46MHz. The 2ms data is divided into 20 sub-blocks. Each sub-block contains 0.1ms of data and pseudocode. One DFT operation can complete the pseudocode search with a time uncertainty of 0.1ms.

[0113] Due to time constraints in coherent integration, incoherent accumulation methods are generally used to improve acquisition sensitivity. A 0.1ms pre-integration is equivalent to a 10kHz frequency search range; different frequency search accuracies f... dop The maximum total incoherent accumulation time is calculated using the following formula:

[0114] t×f dop ×f code / f r ≤0.5

[0115] Among them, f code It is the spreading code rate, f r This refers to the carrier frequency. Given a fixed total hardware resource, increasing the number of incoherent accumulations will increase the total search time, requiring a balance between sensitivity and acquisition speed. Table 1 shows the simulation table of acquisition probabilities for different sensitivities (i.e., signal power) and incoherent accumulation counts. Currently, the D2 code acquisition sensitivity of the BeiDou system is generally limited to -143 to -141 dBm.

[0116] Table 1

[0117]

[0118] The data link terminal can assist the BeiDou receiver in achieving 10µs accuracy time synchronization, greatly reducing time uncertainty and requiring only the search of approximately 205 code phases. Given that BD provides the B3A pilot channel, the sensitivity can be improved by extending the coherent integration time, significantly enhancing the acquisition performance of military BeiDou signals and narrowing the difference between the acquisition threshold and the tracking threshold.

[0119] With the significant reduction in time uncertainty, the dwell time for each code phase is increased. Based on the B3A pilot channel, a coherent integration time of over 10 ms can be used. (See [reference needed]). Figure 12 This indicates that the sensitivity can be improved to -145dBm.

[0120] In summary, this embodiment provides a time synchronization method with the following innovations: integrated design of BeiDou and satellite data link platforms; data link payload configured on BeiDou satellites; data link waveform designed as a high-speed variable frequency hopping system; leveraging the high anti-interference performance of the data link channel to enhance the anti-interference capability of the BeiDou navigation system; synchronization of the on-board data link payload time reference with the BeiDou time reference; and use of the data link terminal access synchronization to complete BeiDou receiver time synchronization, reducing BeiDou time uncertainty and accelerating the direct acquisition / reacquisition time of BeiDou long codes. Meanwhile, it has the following advantages: By constructing a fusion system of satellite navigation and satellite data link, it can provide users with an additional anti-interference timing channel. For users who already require navigation and data link to coexist, there is no need to rebuild the existing wireless network required by A-GNSS technology. They can use the satellite data link to assist in the acquisition of BeiDou long codes without affecting the functions and performance of BeiDou and the satellite data link itself. The satellite data link time is synchronized with BeiDou time. Assuming the timing accuracy of the satellite data link is ±20ms, it can be compressed by 50 times compared to the ±1s time uncertainty of BeiDou long code direct acquisition, greatly shortening the long code direct acquisition time. By optimizing the time synchronization algorithm of the satellite-ground data link, the timing accuracy is further improved, which is of great significance for reducing the time uncertainty of BeiDou.

[0121] Based on the same inventive concept as the foregoing embodiments, this invention provides a time synchronization device, such as... Figure 13 As shown, the device includes: a processor 310 and a memory 311 storing a computer program; wherein, Figure 13 The processor 310 shown in the diagram does not indicate that there is only one processor 310, but only indicates the positional relationship of the processor 310 relative to other devices. In practical applications, there can be one or more processors 310; similarly, Figure 13 The memory 311 illustrated in the diagram has the same meaning, that is, it is only used to indicate the positional relationship of memory 311 relative to other devices. In practical applications, there can be one or more memories 311. When the processor 310 runs the computer program, the time synchronization method applied to the above-described device is implemented.

[0122] The device may also include at least one network interface 312. The various components of the device are coupled together via a bus system 313. It is understood that the bus system 313 is used to implement communication between these components. In addition to a data bus, the bus system 313 also includes a power bus, a control bus, and a status signal bus. However, for clarity, in... Figure 13 The general designated all buses as Bus System 313.

[0123] The memory 311 can be volatile memory or non-volatile memory, or both. The non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), ferromagnetic random access memory (FRAM), flash memory, magnetic surface memory, optical disc, or compact disc read-only memory (CD-ROM); the magnetic surface memory can be disk storage or magnetic tape storage. The volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Synchronous Static Random Access Memory (SSRAM), Dynamic Random Access Memory (DRAM), Synchronous Dynamic Random Access Memory (SDRAM), Double Data Rate Synchronous Dynamic Random Access Memory (DDRSDRAM), Enhanced Synchronous Dynamic Random Access Memory (ESDRAM), SyncLink Dynamic Random Access Memory (SLDRAM), and Direct Rambus Random Access Memory (DRRAM).The memory 311 described in the embodiments of the present invention is intended to include, but is not limited to, these and any other suitable types of memory.

[0124] The memory 311 in this embodiment of the invention is used to store various types of data to support the operation of the device. Examples of such data include: any computer programs used to operate on the device, such as operating systems and applications; contact data; phonebook data; messages; pictures; videos, etc. The operating system includes various system programs, such as the framework layer, core library layer, driver layer, etc., used to implement various basic services and handle hardware-based tasks. Applications can include various applications, such as media players, browsers, etc., used to implement various application services. Here, the program implementing the method of this embodiment of the invention can be included in the application.

[0125] Based on the same inventive concept as the foregoing embodiments, this embodiment also provides a computer storage medium storing a computer program. The computer storage medium can be a magnetic random access memory (FRAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD-ROM), etc.; it can also be various devices including one or any combination of the above-mentioned memories, such as mobile phones, computers, tablet devices, personal digital assistants, etc. When the computer program stored in the computer storage medium is executed by a processor, it implements the time synchronization method applied to the above-mentioned device. For the specific steps implemented when the computer program is executed by the processor, please refer to [link to relevant documentation]. Figure 4 The description of the illustrated embodiments will not be repeated here.

[0126] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] In this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0128] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A time synchronization method, characterized in that, The method, applied to a data link payload located on a navigation satellite, includes: The time of the data link payload is synchronized with the time of the navigation satellite by using the atomic clock in the navigation satellite, so that the time of the data link payload and the navigation satellite adopt the same time. The current time information is sent to the data link terminal so that the data link terminal can synchronize with the data link payload according to the current time information; wherein, the data link terminal sends the synchronized time information to the user receiver to assist the user receiver in long code acquisition.

2. The method according to claim 1, characterized in that, Sending current time information to the data link terminal so that the data link terminal can synchronize its time with the data link payload based on the current time information includes: Receive the time synchronization request sent by the data link terminal; In response to the time synchronization request, the current time information is sent to the data link terminal based on a preset time synchronization algorithm, so that the data link terminal can synchronize its time with the data link payload according to the current time information.

3. The method according to claim 1 or 2, characterized in that, The data link payload includes a baseband signal processing unit, an RF transmission channel unit, a first power amplification unit, and a first transceiver antenna. Sending current time information to the data link terminal includes: The current time information acquired and processed by the baseband signal processing unit is transmitted sequentially through the radio frequency transmission channel unit and the first power amplification unit to the first transceiver antenna, and then sent to the data link terminal through the first transceiver antenna.

4. The method according to claim 3, characterized in that, The data link payload further includes a first low-noise amplification unit and an RF receiving channel unit. Receiving the time synchronization request sent by the data link terminal includes: The time synchronization request sent by the data link terminal is received through the first transceiver antenna, and the time synchronization request is transmitted to the baseband signal processing unit through the first low noise amplification unit and the radio frequency receiving channel unit in sequence.

5. A time synchronization method, characterized in that, Applied to a data link terminal, the method includes: Receive current time information transmitted by the data link payload set on the navigation satellite, wherein the time of the data link payload is synchronized with the time of the navigation satellite through the atomic clock of the navigation satellite; Perform time synchronization processing based on the current time information to achieve time synchronization with the data link payload; The synchronized time information of the data link terminal is sent to the user receiver to provide time synchronization for the user receiver and assist the user receiver in long code acquisition.

6. The method according to claim 5, characterized in that, The process of receiving the current time information transmitted by the data link payload of the navigation satellite before the process of receiving the current time information also includes: Send a time synchronization request to the data link payload.

7. The method according to claim 5 or 6, characterized in that, The data link terminal includes a digital signal processing unit, a receiving channel unit, a second low-noise amplification unit, and a second transceiver antenna. Receiving the current time information transmitted by the data link payload located on the navigation satellite includes: The second transceiver antenna receives the current time information transmitted by the data link payload set on the navigation satellite; The step of performing time synchronization processing based on the current time information to achieve time synchronization with the data link payload includes: The current time information is transmitted sequentially through the second low-noise amplification unit and the receiving channel unit to the digital signal processing unit, and the digital signal processing unit performs time synchronization processing based on the current time information.

8. The method according to claim 7, characterized in that, The data link terminal further includes a transmit channel unit and a second power amplifier unit. Sending a time synchronization request to the data link payload includes: The time synchronization request generated by the digital signal processing unit according to the preset rules is transmitted sequentially through the transmission channel unit and the second power amplifier unit to the second transceiver antenna, and the time synchronization request is sent to the data link payload through the second transceiver antenna.

9. A time synchronization system, characterized in that, The system includes at least one navigation satellite equipped with a data link payload, at least one data link terminal, and at least one user receiver; the data link payload is communicatively connected to the data link terminal, and the data link terminal is communicatively connected to the user receiver; wherein... The data link payload is configured to synchronize its time with the time of the navigation satellite using an atomic clock in the navigation satellite, so that the time of the data link payload is the same as that of the navigation satellite; and to send current time information to the data link terminal. The data link terminal is configured to receive current time information transmitted by the data link payload; perform time synchronization processing based on the current time information to achieve time synchronization with the data link payload; and send the time information synchronized by the data link terminal to the user receiver to provide time synchronization for the user receiver and assist the user receiver in long code acquisition.

10. A time synchronization device, characterized in that, include: A processor and a memory storing a computer program, wherein, when the processor executes the computer program, the steps of the time synchronization method according to any one of claims 1 to 8 are implemented.

11. A computer storage medium, characterized in that, The device contains a computer program that, when executed by a processor, implements the steps of the time synchronization method according to any one of claims 1 to 8.

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