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Improved viewshed analysis algorithms for avionics applications

Özkıdık, Mustafa
Viewshed analysis is a common GIS capability used in various domains with various requirements. In avionics, viewshed analysis is a part of accuracy critical applications and the real time operating systems in embedded devices use preemptive scheduling algorithms to satisfy performance requirements. Therefore, to effectively benefit from the viewshed analysis, a method should be both fast and accurate. Although R3 algorithm is accepted as an accuracy benchmark, R2 algorithm with lower accuracy is preferred in many cases due to its better execution time performance. This thesis prioritizes accuracy and presents an alternative approach to improve execution time performance of the R3 algorithm. Considering different execution environments, improved versions of R3 are implemented for CPU and GPU. The experiment results show that CPU implementation of improved algorithms achieve 1.23x to 13.51x speedup depending on the observer altitude, range and topology of the terrain. In GPU implementation experiments up to 2.27x speedup is recorded. In addition to execution time performance improvements, the analysis results prove that proposed algorithms are capable of providing higher accuracy like R3.