Measuring devices are devices that are used when measuring physical quantities. An example of one of such devices is an altimeter. In this post we shall describe the uses and types of altimeters
What exactly is an Altimeter?
An altimeter, also called an altitude meter is an instrument used in the measurements of the altitude of objects above a fixed level. Before we go into the uses and types of altimeters, let’s first examine what an altitude is.
What is Altitude?
Altitude is defined as the height above a certain level especially above the sea level. It can also be defined as the distance measurement that usually occurs in the vertical or “up” direction between a reference datum and a point. Altitude is a scalar quantity because it has magnitude but no direction.
The measurements of altitude using the altimeter or any other measuring device is called Altimetery.
History and Development of Altimeters
The history of aviation changed for good after the development of altimeters. Paul Kollsman, a German-America inventor invented the the first barometric altimeter in 1928. His barometric altimeter was able to convert barometric pressure into the distance above sea level.
By introducing this instrument, the calculation of barometric pressure became possible.
Types of Altimeters
The different uses and types of altimeters and their application in the measurement of altitude as we have explained earlier is known as altimetry. There are four major types of altimeters used in aviation, these altimeters are;
1. Barometric Altimeter
2. Radio Altimeter
3. Laser Altimeter
4. GNS (GPS, Galileo etc)
A barometric altimeter is an altimeter consisting of a barometric capsule linked to a pointer by a suitable mechanical or electronic system.
Barometric altimeters are the most common type of altimeters used in the aviation industry. It helps in determining altitude by measuring air pressure.
Uses of Barometric Altimeters
Barometric altimeters are used for the following;
1. They are used to determine the changes in elevation.
2. They are used by sky divers and mountaineers to pinpoint locations in the sky or on the ground.
3. They are used in predicting the situation of the weather.
4. They are used in measuring a planes altitude at any given time.
Types of Barometric Altimeters
There are four types of barometric altimeters and they are;
1. Three Pointer Altimeters
2. Drum Point Altimeters
3. Counter-pointer Altimeters
4. Counter Drum-pointer Altimeters
Radio altimeters are air borne electronic devices used in the measurement of the height of an aircraft above terrain immediately below the aircraft.
Radio altimeters are also called the;
1. Radar Altimeters
2. Electronic Altimeters
3. Reflection Altimeters, and
4. Low Range Radio Altimeters
Uses of Radio Altimeters
Radio altimeters are used in aviation for the following reasons;
1. They are used in measuring the distance from an aircraft to the terrain directly beneath them.
2. They supply the primary altitude information for a landing decision height.
Types of Radio Altimeters
There are two types of radio altimeters and they are;
1. Pulsed-type Altimeters, and
2. Frequency Modulated Altimeters
Laser altimeters are altimeters used in learning about topography or the shape of any planet. Laser altimeters can be operated from a plane or a helicopter, or a satellite.
Laser altimeters are also called;
1. Light Detection and Ranging Altimeters
2. Laser Image Detection and Ranging Altimeters
Uses of Laser Altimeters
Laser altimeters are used in measuring the terrain of a planet.
Types of Laser Altimeters
There are three types of laser altimeters and they are ;
1. Light Detection Ranging (LiDAR)
2. Satellite Laser Altimeters
3. Terrestrial LiDAR Survey
Advantages and Disadvantages of Altimeters
Advantages of Altimeters
1. Altimeters are accurate
One of the advantage of using altimeters is to get an accurate precision. The accurate precision of altimeter is important because it provides an effective pressure measurement. Without the precise measurement of pressure, altitude can not be measured properly during a flight which can lead to a hazardous safety and a badly damaged aircraft.
2. Altimeters are cheap
4. Altimeters are easy to implement.
Disadvantages of Altimeters
Here are some of the disadvantages of using altimeters;
1. The barometric altimeters require recalibration with varying temperature.
2. The GPS is less accurate than the barometric altimeters.
3. The radio or radar altimeters require an extra licensing.
Frequently Asked Questions About Altimeters
1. What are altimeters used in measuring?
Altimeters are used in measuring altitude, the distance of a point above sea level.
2. What are the types of altimeters?
1. Barometric Altimeters
2. Radio Altimeters
3. Laser Altimeters
4. What are the uses of altimeters in aviation?
Altimeters are used in the measurements of aircrafts above a fixed level.