Method for carrying out IPPS signal control

Abstract

The invention discloses a method for carrying out IPPS signal control, and the method comprises the steps: inputting a satellite IPPS signal and a local IPPS signal into a phase discriminator; carrying out the floating point DSP data type conversion of a phase difference value outputted by the phase discriminator into a floating point type; carrying out second-order digital filtering modeling through matlab, achieving a filter structure with the adjustable coefficient in a second-order digital filter based an FPGA through the VHDL language, and carrying out the smoothing filtering of the phase difference value of the floating point type; carrying out the floating point DSP data type conversion of an output value of the second-order digital filter into an integral type through a floating point DSP; outputting the integral data to a digital voltage-controlled oscillator through the floating point DSP; adjusting the IPPS output phase through the voltage-controlled oscillator according to the input data; enabling the IPPS signal outputted by the voltage-controlled oscillator to serve as an input signal, and feeding back the signal to the phase discriminator.

Description

technical field [0001] The invention relates to a signal latch and a control method, in particular to a latch and a control method for IPPS signal comparison. Background technique [0002] Satellite navigation systems are mainly used for navigation, positioning and timing. Cesium atomic clocks are usually installed on satellites, which can provide high-precision synchronous pulse signals, including second pulse signals (IPPS for short). Because the satellite clock system has the characteristics of long-term stability and insensitivity to changes in external factors, various systems gradually adopt the time signal and frequency signal provided by the satellite as the clock reference of the system. [0003] Usually there is a local clock in the system. When the satellite signal is abnormal or unavailable, the system can automatically switch the time signal source, and rely on the built-in high-stable crystal oscillator to continue to provide high-reliability time and frequency...

AI Technical Summary

Problems solved by technology

Due to the long distance from the satellite transmitting signal to the receiving end, in the process of signal transmission, it is generally affected by different sources such as ephemeris error, wireless link transmission attenuation, multipath effect, external interference, bit error and delay jitter. Interference will cause the drift of the IPPS signal. If the IPPS phase cannot be accurately identified, it will directly affect the timing performance