Enhanced Reception Technique Of ADS-B Signal

The recent and ever-increasing development of international air traffic is accompanied by many challenges,the major of them is to ensure the safety of people who use these activities in the air.Overtaken by the ever-increasing network,the traditional radars used to monitor air traffic will be,in recent years,replaced by a fully automatic monitoring technique called ADS-B.ADS-B defined here by Automatic Dependent Surveillance-Broadcast is an air traffic management and control surveillance system.This technology allows aircraft to constantly send their important information relating to position,altitude,longitude,ID,from transponders to earth stations using the Mode S as a signal transmission system.Mode S itself is a signaling scheme using squitters that are defined as a non-solicited message used in aviation radio systems.Basically,it is a Secondary Surveillance Radar(SSR)process that allows the selective interrogation of aircraft based on the unique 24-bit address assigned to each aircraft.It uses ground interrogators and transponders and operates at the radio frequencies(1030/1090 MHz).Mode S has been deployed because historical SSR systems have reached the limit of their operational capabilities.This takes the form of exceeding the maximum number of targets,Radio frequency pollution,lost targets,identity errors,and Mode A shortage.Mode S is therefore an essential development for both SSR and new air traffic management processes that will be essential in airspace with high traffic density or lack of air traffic control radar coverage.Although being automatic and ensuring a good Uplink and Downlink transmission between the ground station and the various aircraft information for their monitoring,the Mode S ADS-B remains vulnerable to many parasites present in the airspace such as noises,FRUIT(False Replies Unsynchronized to Interrogations Transmissions)and also the Garbling.These disruptive elements that can interfere with the basic signal transmitted by an aircraft are even capable of either completely destroying or seriously altering the basic information to be transmitted for good monitoring of the different aircraft.And a misinterpretation of a signal by the ground station can of course have serious consequences that are of course to be avoided with regard to exponentially increasing air traffic.Therefore,the need to ensure a check of all hours,a faithful reception of the basic signal sent by the planes,is essential.Our present work is based on the implementation of an Enhanced technique for receiving ADS-B signals from aircraft to ground stations in high interferences environments.The implementation of the said technique will be possible thanks to research carried out on the practical level by tests and simulations and theoretic level by a summary made of the previous research carried out in the field by different scientists.The proposed scheme will offer the faithful reception of signals sent by planes to ground stations thanks in particular to the various blocks that are included such as the Enhanced Preamble detection block,The Enhanced Bit and Confidence Declaration,The Error Detection,and Correction.Development and implementation of this block-based technique for an improved reception is generally carried out with the Matlab and Simulink software and the hardware RTL-SDR(Software Defined Radio)acting here as a receiving antenna for ADS-B signals in real-time and finally,the results achieved by using the system are presented as effective and allows a good reception of basics emitted signal.