Advancements in technology have facilitated the emergence of unmanned systems and vehicles utilized across aerial, terrestrial, and aquatic domains. The scope of applications for these systems is steadily expanding, prompting a plethora of studies and research endeavors. This research delves into the pivotal role of sensors and measurements in ensuring the optimal functionality of unmanned systems. It explores how these systems can meet the demands of diverse applications, enhance their navigation capabilities, and effectively monitor environmental variables. The discussion encompasses various types of unmanned systems and the key environmental factors influencing their performance. Additionally, it examines the array of measurements feasible with such vehicles, alongside an exploration of commonly employed onboard sensor technologies, including their strengths and limitations. The research also offers insights into sensor specifications pertinent to current applications and highlights recent advancements in the field of research, focusing the last few sections on a brief review of the advancement in the field of Quantum Sensing and Sensors.