Method for detecting satellite clock anomaly

Abstract

The invention discloses a method for detecting a satellite clock anomaly. After a satellite signal is decoded, message information is obtained and is sent to a CPU. The CPU judges whether an information stream read from the message information is accurate or not. If the information stream is accurate, a time processing module is controlled to tame PPS through utilization of a1PPS. Standard difference between the 1PPs and world standard time, and an accumulated error of the PPS are estimated through establishment of a weighted least square estimation model. The estimated standard difference iscompared with a standard difference set value of a GPS / BDS receiver. When the estimated standard difference is smaller than the set value, the time processing module carries out error correction on the PPS and carries out continuity and tendency judgment on a time interval error of the corrected PPS. If no error exists, a satellite clock is normal. Corrected PPS is output. According to the method,through multistep detection, whether the satellite clock is abnormal or not can be effectively identified, a high precision clock signal is output, and influence of satellite clock anomaly on outputtime of a time synchronization device is prevented.

Description

technical field [0001] The invention relates to a satellite timing system, in particular to a method for detecting abnormality of a satellite clock. Background technique [0002] In recent years, the hidden security flaws of the global satellite positioning system have become increasingly prominent. Taking advantage of the shortcomings of the civil global satellite navigation system that transmits navigation messages in clear text and lacks an encryption authentication mechanism for spoofing attacks, Iran issued a fictitious satellite navigation message in 2011 to trick it into landing and capture a U.S. military drone. Subsequent studies have shown that cruise ships and self-driving cars based on the GPS global positioning system can also launch fictitious navigation messages to carry out satellite clock synchronization attacks. In addition, power monitoring systems that must operate on a unified time reference may also suffer from satellite clock synchronization attacks. ...

AI Technical Summary

Problems solved by technology

The new specification can prevent clock attacks with a time error of more than 1us, but it cannot effectively prevent clock attacks with time errors within 1us, that is, if the deviation of each attack is within the allowable range, the system can be made Time error value accumulation is greater than its allowable value

Taking the WAMS wide-area measurement and control system as an example, if a continuous attack is carried out at a deviation of 0.2us per second (within the time deviation allowable range of the new specification), a continuous 600s synchronization time attack can cause a time deviation of 0.12ms, resulting in a power angle difference of 2.16° , which can lead to erroneous control decisions from

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