Research On UQPSK-DSSS Synchronization Technology

In recent years,Unmanned Aerial Vehicle(UAV)has been used widely in military and civilian fields,such as forest fire prevention,earthquake search and rescue,field investigation,battlefield information collection and so on.Data link plays an important role in UAV.UAV data link takes different mode to transmit information recording the characteristics of diverse Data and images.UQPSK-DSSS signals are widely used in the fields(such as the TDRSS satellite system)which require to transmit integrated services like video and data at the same time,as their can transmit two signals of different powers and different data rates simultaneously.In the field of civil UAV,the resource consumption of the transmission system,especially the signal receiving and processing module,needs to be constrained as the cost must be constrained.Based on this background,this paper studies the UQPSK-DSSS signal synchronization technology with low resource consumption.The main work of this paper includes two aspects.Firstly,we discuss the UQPSK-DSSS signal synchronization technology under the condition of limited hardware resources,and propose a synchronization scheme with low resource consumption.In the capture module,the scheme applies the sliding correlation method which consumes the least resources.To Avoid calculating complex multiply,the scheme applies the decision feedback loop in carrier phase synchronization module.In the timing synchronization module,the spread spectrum auxiliary code loop synchronization method is adopted to make the UQPSK-DSSS signal from in-phase and orthogonal branch achieve timing synchronization at the same time.In this way,the resources can be saved compared with the separated one.The effectiveness and feasibility of this scheme can be proved through simulation.The second point is to discuss the selection strategy of UQPSK-DSSS signal capture threshold,and a strategy based on Monte Carlo simulation is also proposed.This method starts from the two basic requirements of a signal transmission system,the bit error rate and the probability of false capturing.The capture threshold can be determined by simulating the false alarm probability under different thresholds.And at the final step,we use the simulation to verify the signal detection probability and confirm that the signal can be detected with a high probability under this threshold.