UAS Categgories and usage are as follows:
(1) High Altitude - Altitude Over 60,000 ft (above class A airspace), Endurance - Days/weeks, Typical Usage - Surveillance, data gathering, signal relay
(2) Medium Altitude - 18000- 60,000 ft (class B airspace), Endurance - Typical Usage - Surveillance, data gathering
(3) Low Altitude - - Altitude- Up to 18,000 ft (class E airspace), , Endurance - Up to 2 days, Typical Usage - Surveillance, data gathering
(4) Very Low Altitude - Below 1,000 ft, Endurance- A few hours, Typical Usage - Reconnaissance, inspection, surveillances.