The presently disclosed subject matter includes a Ux V system simulator. According to some examples synthetic images are display on the display device, the synthetic images showing an artificial representation of an environment in which operation of a Ux V is being simulated, the images are shown as if viewed from a vantage point of an imaging payload located onboard the Ux V; the images are processed to extract thereform values of one or more graphic image parameters; responsive to a command issued with respect to the synthetic images, the extracted values are compared with respective predefined reference values; A simulation of the issued command is executed only if the comparison between the extracted values and respective reference values complies with at least one predefined condition, thereby increasing similarity between the operation of the simulator and the operation of the real UAV system being simulated.