# NextGen ADS-B Software-Defined Reception with Enhanced Techniques
###### Abstract  
This paper provides research on the enhanced NextGen ADS-B reception method and its performance in laboratory and flight tests. It sheds the light on end-to-end reception techniques to comply with key requirements. ADS-B has emerged as among the most intriguing avionics for both researchers and companies since the launch of NextGen in 2009. ADS-B provides authorities with a mechanism for use in continuously monitoring the position and track of an airplane using periodic and independent broadcast messages that transmit Global Navigation Satellite System (GNSS) position information. The enhanced pulse detection technique is used to detect and validated preamble pulses. Besides the utilization of multiple amplitude samples technique not only improve bit and confidence declaration accuracy but also make it capable of deploying error detection/correction algorithms which are two aspects of enhanced Extended Squitter reception. In addition, applying a slow attack automatic gain control (AGC) algorithm improves system sensitivity and performance. The implementation is done in MATLAB Simulink and C++. Software Defined Radio (SDR) module, BladeRF, is used programable platform for the communication system. Subsequently, the lab experimental and flight test results show that when applying these strategies in a real environment, significant performance is achievable.  
ADS-B; NextGen; SDR; preamble detection; bit detection and confidence declaration; sensitivity; slow attack AGC; extended squitter +
Footnote †: journal:  
implementation of pulse detection schemes including cross-correlation and leading-edge and bit detecting techniques consists of central sampling and multiple sampling in a thorough simulation environment, as advised by RTCA. RF receptions are deployed in close accordance with the requirements of actual hardware (HW) devices.
* while the receiving methods are delineated in RTCA guidance, to our best understanding the evaluation of their doable performance with the realistic system functioning in real environments has not been addressed. Especially, when the system performance can be challenged in the presence of increasing air traffic volumes.  
Detection of the Mode-S 1090 MHz waveform preamble pulse, detection of the bits and declaration of each bit confidence value, and detection and correction of error are all included in extended Squitter reception. In this study, enhanced Extended Squitter reception methods are described and implemented in both MATLAB Simulink and C++ of SDAR. Enhanced Squitter reception takes the advantage of multiple amplitude samples to not only increase bit quality and declare precision but also be more competent algorithms for error detection and correction. The result of the simulation, and lab experimental shows better performance of mentioned scheme than other techniques. Preamble detection accuracy of interfered signal with mode A/C and additive gaussian white noise for received signals over \(-86\) is 100 percent. The packet Error Rate (PER) and Bit Error Rate (BER) of multiple sampling techniques are below 10 percent for signals above \(-82\) dBm. In addition, experimental result in the operational environment proves that deploying analog front-end SDR slow attach AGC brings about significant improvement in ADS-B sensitivity and performance.