Research Of Baseband Algorithm For Rescue Detection Station Based On Mobile Communication

So far,natural disasters are still one of the important issues that hinder social development.How to obtain the number and location of the trapped people in the disaster area is a key step in the rescue work in the limited time.Unfortunately,the existing search and rescue equipment cannot meet this large-scale search and rescue task.With the rapid development of mobile communication technology,the mobile station signal can be used as an effective indirect search and rescue resources.Researchers have done a lot of research about GSM under the post-disaster environment,and achieved considerable results.However,due to the high degree of confidentiality of CDMA,there is little research about it in the post-disaster environment at home and abroad.In this thesis,a system scheme for post-disaster search and rescue is designed according to the research status of less post-disaster search technology based on CDMA mobile communication.Based on this system,this thesis focuses on the base-band processing algorithm of post-disaster search and rescue station.The specific research results are as follows:(1)Aiming at the problem that the trapped people cannot answer the call in the complicated environment after the disaster,the scheme of using R-ACH as the detection station is proposed.According to the long pseudo-code periodicity and high burstiness of R-ACH,and the difference between the local carrier and the received carrier,this thesis proposes a method of parallel frequency acquisition with base station signals assisting,completing the design of pseudo-code and the estimation of acquisition time and reducing the signal leakage rate of detection station by continuously monitoring the synchronization channel and paging channel.The signal acquisition scheme is designed for both known and unknown mobile station numbers,and the performance analysis and the test of the actual signals are carried out.(2)Due to the small symbol spreading factor of the access message body of R-ACH with poor signal spreading performance in the post-disaster environment,this thesis proposes a new EKF tracking loop based on access prefix of R-ACH,which has conducted its performance analysis and the actual signal experiment.(3)In order to validate the validity of the baseband algorithm,the architecture of the test system and the construction process of the physical structure are designed,and the data acquisition and algorithm verification are carried out in the simulated disaster environment.Aiming at the process of the baseband processing algorithm,the base station hardware implementation scheme of the detecting station is designed at the end.