A clock adjustment method for low-orbit navigation satellites without interrupting navigation services

Abstract

The invention provides a low-orbit satellite clock adjustment method without interrupting the navigation service, comprising the following steps: the low-orbit satellite generates a first clock adjustment command before the clock difference exceeds the limit according to the clock difference monitoring result of the satellite-borne high-precision navigation receiver , wherein the first clock adjustment instruction includes adjusting the time t1 of the satellite clock and the amount of frequency that needs to be adjusted; and adjusting the frequency item of the satellite clock at the time t1 to change the drift direction of the satellite clock error; and the user receiver Use the satellite clock parameters, frequency modulation time, and frequency modulation parameters to calculate the satellite clock error. This method can reduce or even avoid the time when the satellite is out of service due to time adjustment, and at the same time provide sufficiently accurate satellite time, so as to provide users with navigation services more effectively, and improve service quality and user experience.

Description

technical field [0001] The present invention generally relates to a navigation satellite time adjustment technology, in particular to a low-orbit navigation satellite clock adjustment method without interrupting navigation services. Background technique [0002] The Global Navigation Satellite System (GNSS) is equipped with a high-precision spaceborne atomic clock to maintain the navigation satellite frequency reference, and the satellite time is generated by the time-frequency system. Navigation satellites generate navigation signals based on the time frequency generated by the time-frequency system to achieve positioning and timing services. The atomic clock and frequency system carried by the navigation satellite is the key to provide high-precision positioning and timing services for the navigation system. [0003] The traditional GNSS system belongs to the infrastructure of the national time-frequency system, and its navigation satellite platform is large, so the requi...

AI Technical Summary

Problems solved by technology

In order to meet the application requirements of miniaturization, low power consumption, low cost, and large capacity of low-orbit satellites, low-orbit satellites are generally equipped with low-cost small atomic clocks or chip atomic clocks, and their frequency stability is 10 -12 to 10 -13 The magnitude of s / d is two orders of magnitude lower than that of the satellite-borne atomic clock on navigation satellites, resulting in a relatively fast drift of the time reference of low-orbit navigation satellites, which increases the frequency of adjustment of the time reference of low-orbit satellites

According to the time-frequency adjustment strategy of the GNSS system, the chip atomic clock needs to be adjusted once every 1-2 days, which will inevitably cause frequent interruption of satellite navigation services

In addition, the low-orbit navigation augmentation constellation is generally large in scale, on the order of hundreds to thousands of satellites, which also greatly increases the probability of satellite clock adjustment in the navigation augmentation system

Therefore, the traditional time reference adjustment method will lead to frequent time adjustments and interruption of satellite navigation services in the low-orbit navigation constellation system, which is not suitable for low-orbit satellite navigation systems

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