ATC

Terminology: Controlled Airspace

Controlled airspace is airspace of defined dimensions within which ATC services are provided. The level of control varies with different classes of airspace.

As per the DESIGNATED AIRSPACE HANDBOOK – Nav Canada

Canadian Domestic Airspace has seven classifications (A, B, C, D, E, F, G). The application of any classification to an airspace structure determines the operating rules, the level of ATC service provided within the structure, and in some
instances, communications and equipment requirements.

Airspace classes A through E are controlled. Class F can be controlled or uncontrolled. Class G is always uncontrolled. Any airspace that is not designated is Class G airspace.

Terminology: ATC

ATC – Air Traffic Control.

For operations conducted in, or near, controlled airspace you may need to contact the ATC and often times have them issue a NOTAM for your UAV flights.

Wikipedia – ATC

is a service provided by ground-based controllers who direct aircraft on the ground and through controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purpose of ATC worldwide is to prevent collisions, organize and expedite the flow of traffic, and provide information and other support for pilots.[1] In some countries, ATC plays a security or defensive role, or is operated by the military.