In this paper environmental imaging of an unknown indoor area is performed by an autonomous mobile security robot called CoLORbot which operates with UWB-Radar. The CoLORbot is fully equipped with professional motion units, UWB-Radar devices, antennas and a laptop for data processing. Solitary objects are randomly distributed. The robot maintains a collision avoiding chaotic track and records UWB pulses throughout his inspection tour. Environmental imaging by means of UWB-Radar is performed with a migration algorithm as well as with the novel revised Range Point Migration method. These partial and fusioned maps of the environment allow an independent and self-localising capability of the CoLORbot and enable an autonomous navigation in an unknown environment.