Abstract
Global Navigation Satellite Systems are foundational to timing, positioning, and navigation across consumer and professional applications. Their signals traverse long propagation paths and arrive at receivers that operate with constrained bandwidth, dynamic motion, and limited computational resources. In such conditions, the performance of a receiver is shaped by three dominant impairments: reflections that distort the code correlation shape, ionospheric plasma that induces group delay and rapid phase fluctuations, and man-made radiofrequency interference that raises noise floors or mimics authentic signals. This paper presents a comprehensive evaluation of receiver behavior under these concurrent stressors with emphasis on model fidelity, algorithmic robustness, and measurement repeatability. The study organizes a signal and observation framework that spans multi-constellation, multi-frequency operation and implements canonical estimators alongside modern robust and adaptive variants. Controlled channel emulation and field recordings are used to examine code and carrier tracking, time-transfer stability, integrity risk, and resilience to deceptive waveforms. Emphasis is placed on disentangling confounding effects so that degradations in positioning and timing are attributable to physically interpretable mechanisms rather than implementation details alone. The analysis highlights the relative contributions of specular and diffuse multipath, storm-time ionospheric disturbances, and narrowband as well as wideband interferers to the observed error budgets. The results are summarized in terms of practically relevant metrics including lock probability, protection levels, and outage likelihood across a range of dynamics and antenna configurations. The findings aim to support principled choices in receiver design and deployment without overstating the generality of the conclusions.