Getting direction and reaching your destination in a road journey is the easiest thing to consider. If at all, we are off the track and stumble over an unknown path, we can always look for a road sign, a gas station or may be a passer by to get some quick information. But imagine how difficult it would be for the air planes, when they travel in the sky, piercing through the riddle of clouds and trying to reach their destination without any physical path or road signs. It is where the aircraft navigation and waypoints come into play.
Air craft navigation is all about the journey of an aircraft from the point it takes off to the point of its flying and safe landing and the main concerns are its location, speed, direction and the weather condition. The previous aircrafts dated back to the era of early 20th century did not have any highly sophisticated technical assistance to navigate them through the air and land them safely. In 1929 U.S scientist Elmer Sperry came with his gyroscopic principle that could help the pilot in maintaining the proper attitude. The change in the orientation of the gyroscope caused due to specific factors could activate the electrical controls of the flight to maintain its proper flying.
The two-way radio navigation systems that were deployed during the same period could inform the pilot about the weather condition and the route of the plane from the ground. The first radio transmitted airport was built in Ohio in 1930. VOR or very high frequency Omni directional radio ranges followed the low frequency radio waves on which radio communication was held. A navigational chart was created to make the pilot aware of certain radio transmitter stations and their respective frequencies, so that he could identify his proper location in the sky. RDF or radio direction finders were used to allocate the exact source of radio waves. But Radio navigation systems could not provide accurate information on air traffic and safe landing.
Analog computers were used in aircrafts after world war two. In 1958, Canadian CF-105 arrow interceptor plane firstly used an analog computer to add to its flying capability. After that many aircrafts and spacecrafts like Apollo Lunar module, Gemini used analog flight control systems. Now a days computer is the most extensively used technology in aircraft helping it to know its position and displaying the data related to its altitude, speed and attitude.
Inertial Navigation system employed in the airplanes can keep track of the current location, attitude and the changes in air speed. Global positioning system, the milestone of current navigation system can exactly provide information regarding an aircraft's whereabouts in couple of seconds. A number of satellites orbiting around earth can transmit signal that can accurately tell about an aircraft's direction and location.
Waypoint may be the destination point or any reference point defined by latitude and longitude or any imaginary point in the sky that are to be followed on the flight course of a plane and are marked in the computer loaded in the plane. GPS systems use these points to properly navigate the flight. To follow a route GPS receiver gets to the waypoints one by one until it reaches the destination. These waypoints are generally fixed for a particular air route integrated with flight management system and the GPS receiver to lead an air plane on its distinct path without disturbing the path of other aircrafts. When radio navigation is considered waypoints are generally certain points that indicate the proximity to some radio beacons and for Visual Air Navigation they can be any signs like stadiums, big infrastructures, highways, which can be easily investigated through the cockpit.
Certain rules are also necessary to follow for the safe navigation of an aircraft, most importantly in places, where there is lot of air traffic. Instrument Flight Rules (IFR) keeps the plane safe, where a pilot has nothing to rely on except the instruments in the aircraft. For this reason, a pilot must be rated for IFR. Big aircrafts and most planes in high traffic zones have to abide by IFR rules for safe navigation. Visual flight rules or VFR are applied, when a pilot can take a visual advantage of the situation to avoid proximity with another aircrafts, controlling its attitude and avoiding hindrances like mountains and terrains. There is also Night VFR, which is prohibited in many countries, where flights go according to IFR rules at night. For Night VFR, landing light, illumination of every instrument in the plane and lighting in every compartment are necessary.
Though, there are ample numbers of regulations and precautions are to be taken, when a flight takes its journey. The advanced technology has led our current air navigation a long way as compared to the days, when pilots have to open their cockpit to manipulate their flying and landing. However, still there are uncertainties in a flight and experiments are still on the way to discover the safest and most accurate aircraft navigation.