**Abstract**

Unmanned aerial vehicles (UAVs) are being used for commercial, scientific, agricultural and infrastructural enhancement to alleviate maladies. The objective of this chapter is to review existing capabilities and ongoing studies to overcome difficulties associated with the deployment of the agricultural unmanned aerial vehicle in obstacle-rich farms for pesticides and fertilizer application. By review of various literature, it is apparent that the potential for real-time and near real-time exists but the development of technology for quality imagery and rapid processing leading to real-time response is needed. The Infrared, time of flight and millimeter wavelength radar sensors for detecting farm and flight environment obstacles appear promising. The autonomous mental development algorithm, and the simultaneous localization and mapping technology are, however, ahead of others in achieving autonomous identification of obstacles and real-time obstacle avoidance. They are, therefore, found fit for further studies and development for deployment on agricultural unmanned aerial vehicles for obstacle-rich farms.

**Keywords:** unmanned aerial vehicle, obstacle avoidance, sensors, spraying, obstacle-rich farm
