Four-way signal processing carrier phase lock loop in ionosphere scintillation environment

A Kalman filter was proposed to solve loss of lock in ionosphere scintillation environment based on four-way signal processing carrier phase locked loop (quad-PLL). Extra two ways signal was added to correct phase discriminator's output with purpose of expanding phase pull-in range, while filter parameters were adjusted adoptively according to real-time carrier to signal ratio. Loss of lock was avoided effectively when amplitude fading and phase mutation were caused by ionosphere scintillation occurs. The simulation result shows that this proposed PLL can keep tracking in the high-intensity strength and instantaneous ionosphere scintillation.