  Over the past two decades, Unmanned Aerial Vehicles (UAVs), more commonly
known as drones, have gained a lot of attention, and are rapidly becoming
ubiquitous because of their diverse applications such as surveillance, disaster
management, pollution monitoring, film-making, and military reconnaissance.
However, incidents such as fatal system failures, malicious attacks, and
disastrous misuses have raised concerns in the recent past. Security and
viability concerns in drone-based applications are growing at an alarming rate.
Besides, UAV networks (UAVNets) are distinctive from other ad-hoc networks.
Therefore, it is necessary to address these issues to ensure proper functioning
of these UAVs while keeping their uniqueness in mind. Furthermore, adequate
security and functionality require the consideration of many parameters that
may include an accurate cognizance of the working mechanism of vehicles,
geographical and weather conditions, and UAVNet communication. This is
achievable by creating a simulator that includes these aspects. A performance
evaluation through relevant drone simulator becomes indispensable procedure to
test features, configurations, and designs to demonstrate superiority to
comparative schemes and suitability. Thus, it becomes of paramount importance
to establish the credibility of simulation results by investigating the merits
and limitations of each simulator prior to selection. Based on this motivation,
we present a comprehensive survey of current drone simulators. In addition,
open research issues and research challenges are discussed and presented.
