Onboard high-accuracy time synchronization method for satellite

Abstract

The invention discloses an onboard high-accuracy time synchronization method for a satellite, which is used for effectively solving the problem of unavailability of meeting time synchronization in the sensitive acting process of the satellite due to low accuracy and poor stability of an onboard time system. By adopting the high-accuracy time synchronization method, the time accuracy (an error between the time accuracy and GPS (Global Positioning System) standard time is less than 25 mus) of a satellite central computer is enhanced, the time synchronization accuracy among subsystems of the entire satellite is higher than 0.1 ms (based on the GPS standard time), and the defect of unavailability of continuing working when a GPS receiver is not positioned existing in a design method in which only GPS second pulse is taken as time synchronization of each subsystem of the entire satellite is overcome. Once one of the GPS receiver and a satellite-to-ground observing and controlling channel exists at the in-orbit flying period of the satellite, time synchronization of the satellite can be realized, so that the risk of functional failure of the system is lowered effectively, the time synchronization mode can be changed in time as required or along with the change of environment, and the time synchronization flexibility, reliability and security of the satellite are enhanced remarkably.

Description

technical field

[0001] The invention relates to a high-precision time synchronization method on a satellite. Background technique

[0002] In the past, the clock on the satellite was the system clock. The system clock was generated by the telemetry interruption of the computer in the star affairs center. The telemetry interruption of the computer in the star affairs center was generated every 3.90625ms. The software accumulated time in the telemetry interruption service program. After 256 telemetry interruptions, the time Exactly 1 second. The on-board system clock is accumulated in seconds and milliseconds, and its time resolution is 1 millisecond. The system clock is cleared when the satellite-arrow separation signal is received. The star affairs center computer broadcasts the system clock to each subsystem on the star through the CAN bus, which can provide the day, hour, minute, second and millisecond. Its accuracy and stability are determined by the crystal oscillator i...

Examples

Embodiment Construction

[0022] Such as figure 1 Shown is a schematic structural diagram of the high-precision time synchronization method of the present invention. The satellite is equipped with a GPS receiver, a satellite center computer, a clock unit and various time users (subsystems on the satellite).

[0023] Among them, the GPS receiver receives the navigation signal of the GPS navigation satellite to calculate the GPS standard time, and sends a high-precision second pulse to the star service center computer.

[0024] The internal timing generated by the star center computer is accumulated based on the internal clock or clock unit, and the clock unit is used most of the time when it is in orbit. The clock unit provides a high-precision timing reference for the star center computer, and reduces the ground-to-satellite time correction. It adopts constant temperature control technology to ensure that the quartz crystal and oscillator circuit work at a stable temperature, to ensure the stability o...

technical field

[0001] The invention relates to a high-precision time synchronization method on a satellite. Background technique

[0002] In the past, the clock on the satellite was the system clock. The system clock was generated by the telemetry interruption of the computer in the star affairs center. The telemetry interruption of the computer in the star affairs center was generated every 3.90625ms. The software accumulated time in the telemetry interruption service program. After 256 telemetry interruptions, the time Exactly 1 second. The on-board system clock is accumulated in seconds and milliseconds, and its time resolution is 1 millisecond. The system clock is cleared when the satellite-arrow separation signal is received. The star affairs center computer broadcasts the system clock to each subsystem on the star through the CAN bus, which can provide the day, hour, minute, second and millisecond. Its accuracy and stability are determined by the crystal oscillator i...

Examples

Embodiment Construction

[0022] Such as figure 1 Shown is a schematic structural diagram of the high-precision time synchronization method of the present invention. The satellite is equipped with a GPS receiver, a satellite center computer, a clock unit and various time users (subsystems on the satellite).

[0023] Among them, the GPS receiver receives the navigation signal of the GPS navigation satellite to calculate the GPS standard time, and sends a high-precision second pulse to the star service center computer.

[0024] The internal timing generated by the star center computer is accumulated based on the internal clock or clock unit, and the clock unit is used most of the time when it is in orbit. The clock unit provides a high-precision timing reference for the star center computer, and reduces the ground-to-satellite time correction. It adopts constant temperature control technology to ensure that the quartz crystal and oscillator circuit work at a stable temperature, to ensure the stability o...

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