The locational delta between an unmanned aircraft and the Remote Pilot can be a matter of tens of meters or thousands of kilometres and, broadly speaking, these operating ‘ranges’ are termed either Visual Line Of Sight (VLOS) or Beyond Visual Line Of Sight (BVLOS) operations.
Visual Line Of Sight (VLOS) operations; means exactly that, keeping the unmanned aircraft in visual-line-of-sight at all times. This means not flying an unmanned aircraft into clouds or fog, not behind trees, buildings or other [even partial] obstructions. VLOS also means un-aided vision except for prescription glasses or sunglasses, and not having to use binoculars, telescopes or zoom lenses to see the unmanned aircraft.
In Europe, maximum VLOS is typically set at not more than 400ft AGL vertically and 500m horizontally. In Australia, CASA has not set a limit. Maximum VLOS will vary according to the size and ‘visibility’ of the unmanned aircraft at extreme range. VLOS range can vary from about 200-300m horizontally for the popular small 'Quadcopter' UAS, out to maybe 3-4kms if the unmanned aircraft is of a suitable size & colour and fitted with high-visibility lighting.
Extended Visual Line Of Sight (EVLOS) operations; relates to the operating method whereby the Remote Pilot in command (PIC) relies on one or more Remote Observers to keep the unmanned aircraft in visual sight at all times, relaying critical flight information via radio and assisting the Remote Pilot in maintaining safe separation from other aircraft [manned or unmanned].
In theory one could traverse the Australian continent with a UAS under EVLOS conditions, assuming you could deploy enough Remote Observers across the continent to keep it in visual line of sight at all times.
EVLOS operations require more advanced flight-crew experience, coordination, communications and communications infrastructure. EVLOS flight operations must be approved by CASA.
Beyond Visual Line Of Sight (BVLOS or BLOS) operations; means flying an unmanned aircraft without the Remote Pilot having to keep the unmanned aircraft in visual line of sight at all times. Instead, the Remote Pilot flies the aircraft by instruments from a Remote Pilot Station (RPS).
BVLOS operations require higher pilot/operator qualifications & experience to operate safely. BVLOS operations will only be approved by CASA in specific circumstances where safe separation standards can be ensured (ie remote or segregated airspace), or where traditional 'See &Avoid' methodologies or new 'Detect & Avoid' technologies are deployed. (ie Chase-Plane or approved ‘Detect & Avoid’ technologies)
First Person View (FPV); refers to a Remote Pilot operating an unmanned aircraft by reference to an onboard video camera, providing the Remote Pilot on the ground with a live ‘cockpit-view’ from the unmanned aircraft. FPV is very popular with recreational flyers but is not generally used in commercial small UAV operations to actually fly the aircraft. FPV type equipment is used extensively in commercial operations but this is usually only to monitor onboard payload sensors, or the data & imagery being collected from the aerial imaging system.
NOTE: FPV flying is not legal in Australia unless it is conducted in accordance with the Model Aeronautical Association of Australia (MAAA) - Policy No. MOP066 ‘FPV Flying’, or is otherwise approved by CASA.