Research On Time Delay Estimation Method Of Lfm Signals

Due to the rapid development and popularization of the Internet of Things,the Internet of Things has in-depth applications in medical,transportation,environment and other fields,and the large-scale interconnection of all things may become a reality in the near future.However,with the gradual increase in the application of Io T scenarios,some traditional Io T algorithms will lose their practicality in some special application scenarios.Therefore,in terms of communication,how to choose new algorithms so that communication signals can make up for the shortcomings of traditional communication systems in the field of Internet of Things has become a hot topic at the moment.Thanks to the low-power transmission characteristics of chirp signals and strong anti-Doppler frequency deviation characteristics,the new communication system represented by Lora signals uses chirp signals as the carrier of signal transmission,bringing the chirp signals into In the daily communication system.Since then,some scholars have tried to apply chirp signals to the field of satellite communications.In terms of radar,chirp signals have good pulse compression characteristics,so the integration of communication and radar combined with radar signals also allows radar signals to have a wider range of uses.Because the chirp signal is not a single-frequency signal,the problem is that the traditional delay estimation method cannot be directly applied.In this system,how to use the characteristics of the chirp to redesign the delay estimation scheme is the research of this article.The main content of the subject is as follows:1.This article first introduces chirp technology and its development status in the field of communication at home and abroad in the introduction,and introduces the domestic and foreign development status of Fractional Fourier Transform,which is very practical for processing chirp signals.In the second chapter,the model of the linear frequency modulation signal is established and the basic mathematical principles of the fractional Fourier transform are introduced.The signal processed is a discretized signal,so the commonly used ones derived from the fractional Fourier transform are also introduced.The basic principle of discrete fractional Fourier transform.2.Analyzed the linear frequency modulation signal as the main body of signal transmission in the absence of frequency offset,the receiver's delay estimation algorithm for the signal in the synchronization process,and comprehensively considered the accuracy and calculation amount for different algorithms through simulation,and selected Develop the best algorithm based on matching,use Vivado for hardware design,and verify the correctness of the algorithm on the FPGA platform.3.Propose a joint estimation algorithm of time delay and frequency offset when the receiver is synchronized when the time delay and frequency offset will affect the instantaneous frequency in a scenario where the frequency offset cannot be ignored,and the estimation accuracy is obtained by software simulation.Time delay estimation has always been a very important link in the communication field,and it is the basis of carrier synchronization.The chirp signal is used as the carrier,and the characteristics of the chirp signal are used to estimate the time delay and frequency offset,so that the chirp signal can also complete the estimation of the time delay and frequency offset in the scene with low signal-to-noise ratio.