Informal Definition of Unmanned Systems

Firstly, I'm new to understanding Unmanned Systems and claim to be no expert on the subject as I am currently learning about it. That being said in my own words I would define unmanned systems in it's simplest terms as a unification of machine and software combined to give a product to reduce human workload and effort.The autonomy of Unmanned systems exist at two(2) different levels semi-autonomous and fully autonomous. Semi-autonomous means there is some sort of human interaction whether remotely or on standby with the system and fully autonomous is when there is no human input what so ever. There are also four(4) different domains at which unmanned systems operate: air, sea, land and space. Advancements in technology of Unmanned Systems are being discovered every day and the uses are boundless.Currently there are many semi-autonomous systems and the goal is for them to become fully autonomous but replicating human responses, emotions and reactions are proving to be more complex than anticipated. A fully autonomous system would be able to act and react as human being and operate as if it has a human brain. However advancements in understanding the biology behind the human brain is also not currently progressing at a fast paste further slowing the development of a fully autonomous system. But human curiosity, ingenuity and share will power will not deter mankind from attempting to do the impossible.