How Pilots Use to Navigate Before GPS


In the recent time, GPS has turned into an essential and major method for navigation for pilots. Be that as it may, there were times when GPS was not in use. How did pilots manage to find their way before GPS? In addition, which navigation systems are still in use? Few methods used by pilots before the advent of GPS are being described below. As each basic method is described below, it should be noted that rarely did a pilot navigate by using just one method. Most pilots relied on two or more of the following basic techniques to navigate an aeroplane from departure to the desired destination.

Pilotage (Following the Landmark)
Pilotage is one of the main navigation systems taught to new pilots in the early days of air transportation. This is due to the fact that it’s simple and it’s secure. Pilotage just implies that a pilot watches out the window to discover points of interest, for example, urban communities, towers, waterways, mountains and lakes, and compares this with the printed sectional map he has close by. Indeed, even during the evening, pilotage can be proficient effortlessly by discovering city lights, parkways and air terminals. While pilotage is not difficult to do, it’s not the most productive method for navigation and is constrained to VFR (Visual Flight Rules) climate conditions, when the pilot can easily sight the ground.

Dead Reckoning
Dead reckoning isn’t as terrible as it sounds. Firstly, there’s nothing dead about it—the term alludes to effectively plotting and figuring the pilot’s course heading and keeping time in mind to record distance covered and use that to determine the current position. Substitute spellings, “ded reckoning” or “de’d reckoning,” uncover the term’s etymology: “found reckoning.” Reckoning is simply one more word for ascertaining, so dead reckoning (or concluded ascertaining) alludes to the way toward evaluating the position by calculations in light of velocity, course, heading, wind bearing, elapsed time, velocity and ground speed. Basically, the pilot utilized this to find out where he is and where he will be at a particular time provided that he holds the compass course and ground speed he travels. The fundamental instruments behind the operation of Dead Reckoning are the clock and the compass.

Non-Directional Beacons (NDBs) are radio signals that transmit radio waves to a recipient in the aircraft. The NDB flag, combined with the programmed course discoverer, also known as Automatic Direction Finder (ADF) gear in the aeroplane, will decipher the flag. The related instrument in the cockpit incorporates an arrow that focuses toward the NDB ground station, telling the pilot where he is in connection to the NDB station. Perhaps, a pilot needs to know where he will be; he can point his flying machine toward the needle and “follow” it specifically to the station. NDBs are winding up and are becoming obsolete as GPS assumes control as the prevalent technique for navigation, yet some pilots still utilize them.

VORs (Radio Navigation)
A VOR, which means VHF omnidirectional range, is a sort of radio navigation which is one of the advanced means of navigating before GPS. The framework incorporates a ground station, a reception apparatus (Antenna) on the aircraft, and an instrument in the cockpit that translates and shows the air ship’s position in connection with the signals transmitted from the VOR ground station. A VOR station transmits two signals simultaneously – one in all direction (omnidirectional) and the second, pivoting signal. The phase difference between the line of position from the station and the signals can be determined between 0 and 360 degrees. (360 degrees means north, 090 degrees means east, 180 degrees means south and 270 degrees means west. Coupled with various distance measuring tools, a pilot can decide his or her exact position in respect to a specific VOR station. There are around 1000 VOR stations in the U.S. today, and they are usually used with VFR and IFR aviation routes, or courses, in the sky.

Cross-country Air Mail Route Beacon 37A
In the good ‘old days, pilots needed to navigate by watching out the window and finding visual landmarks, or by divine route. In the 1920s, when the U.S. airmail transporters flew, pilots would navigate during the night with the guide of blazes (bonfires) deliberately put on the ground. While during the day, very large concrete arrows were placed strategically on the ground. The concretes were literally pointing the direction to the pilot and were noticeable to pilots in the air, truly pointing the way.

These arrows and bonfires were used in conjunction with dead reckoning and pilotage, after which a more advanced Radio Navigation Systems came to the scene. Combined with upgrades in flight instruments, the presentation of radio navigational guides, for example, VORs implied that pilots could navigate without visual references on the ground. The improvement brought about by these navigational guides implied that pilots had the capacity to navigate at higher heights, through and over mists, and without following streets or milestones. Finally, navigation was made significantly simpler and easier with the presentation of the Global Positioning System, or GPS.

The LORAN is a framework, which is fundamentally the same as GPS. All through the world, they are radio guides that communicate a signal. The plane has a framework which records the time distinction between various incoming signals and triangulates pilot’s position. All that it requires is that the pilot input the information about his or her destination, LORAN will show the details of the navigation such as distance, the time required for certain speed and route. Suppose the pilot realized that he had to fly at 185º for 60 miles. He would set his heading at 185º, and turn on autopilot. After 10 minutes, his LORAN discloses to him that he was 5 miles east of his planned way. When he gets close, he will search for VOR signals from a nearby airport to affirm he is in the correct zone. Inevitably he would detect the aeroplane terminal, and after that, he would set.

There are a group of other tools that were used by pilots to navigate as well, such tools like clock and sextant were used by pilots to figure out their positions. However, these tools were not used for long and probably not in use again.


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