Altimeter is an instrument used to measure the height / altitude of an object above a certain level. It is also known as Altitude Meter.
It is used in aviation industry. It helps to measure the distance of aircraft from the ground by correcting the errors caused by temperature and local air pressure.
It is also capable of detecting dangerous currents like wind shear to facilitate automatic landing. Its unit of measurement is hectopascal (hPa).
Recently, the US Federal Aviation Administration (FAA) has warned that new 5G technology may hinder the use of devices such as altimeters.