#flight instrument

• Altimeter — A flight instrument or portable device used in aviation, mountaineering, and surveying to measure and display the altitude of a point or an aircraft relative to a predetermined reference level (usually sea level or ground level), operating on barometric, radio, or laser principles.
• Altitelemeter — A complex device or electronic instrument used to remotely measure the altitude of an object (aircraft, drone, rocket) and automatically transmit the obtained values via radio data streams to a control center.