It may be too long to fly from America to Asia on a direct flight, but you can reach the final destination comfortably and on schedule. It takes more than 15 hours for this flight to end without getting lost in the clouds. Ever wondered how without going off track or air route, airplanes hit their ultimate destination.
Pilots used optical landmarks or astronomical navigation to fly until the invention of airplanes. Postal carriers used bonfires early in 1900 to maneuver. Over the years, the bonfires, pilotage, dead reckoning, VOR, and the GPS are guides that the pilots have managed to navigate. The methods used for in-air navigation may depend on whether the aircraft is flying in compliance with Visual Flight Regulations (VFR) or Instrument Flight Regulations (IFR). In the case of IFR, radio navigation aids and flight instruments are used by the pilot.
If the pilot is using VFR, dead reckoning combined with pilotage concerning an appropriate map is used. Among them, RNAV is the method of IFR Navigation.
In aviation, RNAV stands for area navigation. It means the ability to navigate directly between any two points on earth. Today, the most common type of RNAV equipment is GPS, although many older systems have been used for decades on larger aircraft.
In 1970, the usage of RNAV began. Until GPS went into operation, two other RNAV devices achieved popularity. Avionics manufacturers developed devices that would use established VORs and DMEs in order to create simulated waypoints.
For instance, the pilot could schedule a waypoint 20 miles south of the VOR by programming. While these early VOR / DME RNAV systems are rare and far between these days, position coding is still used in aviation for phantom waypoints (geographical coordinates and distance between beacons).
Today, the RNAV umbrella covers many different technologies, from GPS / GNSS satellite systems to VOR or DME ground-based systems. Since various technologies have varying precision standards, some standardization to clarify what RNAV technology can be used while they are used has been introduced. For IFR operations, this is especially relevant.
RNAV specifications include some navigation function specifications. The following functional criteria are:
1. Continuous indications of the location of the aircraft relative to a pilot flying track in the principal field of view of the aircraft;
2. Show of the active waypoint distance and bearing
3.Show of the active waypoint ground speed or time;
4. Data storage navigation function;
5. RNAV device with its sensors Acceptable failure indication
The RNAV approach is a non-precision-based method, which implies an approach that uses a course deviation guidance method yet does not include details about the glide line. For orientation and spatial knowledge, the RNAV approach uses GPS or LORAN horizontal guidance. It flies much like a VOR or a VOR / DME approach. RNAV approaches are safer and also simpler to use and manage than standard navaids such as VOR’s and ILS’s, which must be checked for flight under such tolerances. Standard VOR and NDB approaches are removed at most airports in the US and substituted by RNAV approaches.
The RNAV approach uses area navigation (which typically means GPS but any system that helps the aircraft recognize where it is anytime, even away from radio navigation facilities). RNAV approaches do not require the airport to install ILS transmitters or any other facility, but only to track the approach and select arbitrary route points that keep the aircraft clear of obstacles.
ILS and RNAV Difference
RNAV is GPS and satellite-based, while ILS is just a landing system and is fully ground-based. ILS is just a landing system and is fully ground-based.
RNAV uses either the ground-based navigation support (VOR) electronic signal displacement or some other navigation mechanism (such as GPS or inertial navigation) to create a linear model to follow. A non-precision device approach (one and does not provide elevation guidance) can be made using RNAV.
ILS (Instrument Landing System) is a system that provides the direction of path (Localizer), the direction of altitude (glide slope), and horizontal orientation (marker beacons, such as external marker, center marker, and internal marker). A non-directional beacon can often include some of the markers with navigation assistance. A radar altimeter is needed in Category II ILS, and an auto-landing system is needed in Category III. Higher landing minimums are allocated if specific components are not available.