When you enter a city, you will see the elevation, that is, the elevation relative to sea level, on the sign. Likewise, if you are on an airplane, the pilots will tell you the average altitude. Of course, many different technologies are used today for such measurements, but the underlying and uniform The system that is actively used is the altimeter. Nearly a hundred years have passed since the altimeter was invented.

Although there are different types of altimeters, the most commonly used version has a similar working system to the barometer, that is, it measures the pressure in the air. The pressure in the air decreases as you rise above the ground, allowing this device to almost determine how high you are relative to sea level or a predetermined level. Bride What is an altimeter, what is it for, what are its types? Let’s see all the details.

What is an altimeter?

Altimeter, relative to sea level or a fixed point level It is a device that measures height. The height above sea level is called altitude and the height measured relative to a fixed level is called altitude. Borametric altimeters measure mercury in mmHg and generally give results in feet, but they can also use different readings from place to place.

What does the altimeter do?

The primary and ultimate purpose of the altimeter is relative to sea level or a fixed point. height measurement. In simpler terms, we can say that the altimeter shows how high it is from the ground, but the height of the starting point relative to the sea level is the main factor that changes this definition.

Even if you have a simple map in your hand as you move around the Earth, you can more or less figure out where you are by reading it carefully, but how high are you off the ground? It is not possible to measure the eye resolution. For this reason, the first altimeter device was invented about a hundred years ago.

Altimeter History:

After the First World War, aviation studies gained momentum and many new inventions were made for this sector. One of these inventions First flight with altimeter It was performed in the United States in 1929 by James “Jimmy” Doolittle. The patent for the modern altimeter, which is still in use today, was taken out in 1936 by Paul Kollsman.

How does the altimeter work?

We will go into detail when describing the types of altimeters, but in answer to the question of how the altimeter works, we can explain the type of pressure gauge. This type of device, called a barometric altimeter, It consists of a sealed field, spring, mercury and pointer. The height is determined by the response of mercury to pressure change.

The working system of the barometric altimeter, one of the most widely used altimeter types, It is based on the principle that the pressure in the air decreases as it rises from the ground. A pressure change of 1 mmHg is observed every 10.5 meters (30 feet) above sea level. Since the pressure value changes with an average margin of error of 0.1 percent depending on weather conditions, it must be manually adjusted by the user depending on the situation.

What are the types of altimeters?

Barometric Altimeter:

The barometric altimeter, which is one of the most widely used altimeter types today, works on the principle of decreasing pressure as you rise above sea level. By comparing the internal pressure of the device with the external pressure Since a measurement is being taken, the internal pressure of the device is fixed at 1.

The barometric altimeter compares its internal pressure with the pressure reading it receives from the parts called static ports that transmit the external pressure. By making this comparison, are disks called aneroids in the device. Depending on the expansion and contraction of the disks, the pressure of the respective location relative to the sea level, i.e. the altitude, is revealed.

Radio altimeter:

Radio altimeter, also called radar altimeter, is used to measure altitude, as the name suggests. It is a kind of altimeter that uses radio frequencies. Like a radio, it has a system consisting of a receiver and a transmitter. The main difference between them and the barometric altimeter is that the radio altimeter determines the altitude level relative to the ground directly below the vehicle in the sky.

The radio altimeter transmits an FM radio frequency to the ground from one or more points. The transmitted frequency bounces and returns to the device. Here’s how high you are off the ground at that point in the time of going and coming of this frequency. It is a system widely used in automatic navigation and blind landing systems.

Since a radio altimeter type device transmits FM radio frequency, it is expected to receive FM radio frequency again, but the frequency range of the return signal is often higher. For this reason, the device’s receiver and transmitter systems are designed to measure different frequency ranges. The accuracy of the design is an important factor in the accuracy of the measurement.

Optical Altimeter:

The most modern type of altimeter, the optical altimeter works just like a radio altimeter, but the main difference is that the optical altimeter is not a radio wave. using laser pulses. The laser pulse is sent, bounces, returns and the height is determined by measuring this time.

Optical altimeter is used in conjunction with modern GPS and inertial navigation systems, abbreviated as INS. Laser pulses sent by the optical altimeter not only measure the height of the aircraft, it also detects surfaces such as mountains and buildings around and below them.

The optical altimeter, also known as a laser altimeter, was developed by NASA. It is also used in creating topographic maps by measuring ocean and land surfaces. The French space agency CNE made measurements with a very small margin of error of 2 cm using an optical altimeter on the TOPEX/Poseidon satellite. For example, the effect of global climate change on sea levels has been observed.

Where is the altimeter used?

The most commonly used area of ​​the altimeter, which in our language is also called an altimeter, is of course the aviation industry. Now there are even versions that fit in a watch It is also used by paratroopers and mountaineers. The modern altimeters, of which we have given an example, have now become an integral part of the aerospace industry.

It measures the height of our location relative to sea level. What is an altimeter, what is it for, how does it work, what are the types We’ve covered the details you need to know about this device by answering frequently asked questions. The fact that a device invented a hundred years ago is still in use, albeit with several changes, is the greatest proof of the timelessness of science.