However, both American and non-American forms of English agree that the spelling "meter" should be used as a suffix in the names of measuring devices such as chronometers and micrometers.
You can find metric conversion tables for SI units, as well as English units, currency, and other data. Type in unit symbols, abbreviations, or full names for units of length, area, mass, pressure, and other types.
Examples include mm, inch, kg, US fluid ounce, 6'3", 10 stone 4, cubic cm, metres squared, grams, moles, feet per second, and many more! You can do the reverse unit conversion from metre to foot , or enter any two units below:. A foot plural: feet is a non-SI unit of distance or length, measuring around a third of a metre. There are twelve inches in one foot and three feet in one yard. The metre, symbol: m, is the basic unit of distance or of "length", in the parlance of the physical sciences in the International System of Units.
Before measurement with an eyepiece reticle, a microscope must be calibrated with a stage micrometer a microscope slide with a ruler etched on it.
A measuring microscope is a highly precise measuring optical instrument with supporting software capable of measuring the length of small or large samples with sub-micron precision.
They are used for surface analysis and measurements in microelectronics, optoelectronics, telecommunication, and other industries. All medical imaging devices like fluoroscopes, projectional radiographs X-ray machines , magnetic resonance imaging MRI scanners, positron emission tomography PET scanners, ultrasound imaging devices can measure the size of internal organs with large precision.
Sonar is a device that can be used in many applications based on sound propagation underwater. It can be used for echo sounding, underwater navigation, communication, object detection, depth measuring to determine the distance to the ocean floor.
Sonars can be active or passive. Active sonars emit sound pulses and listen for their echoes. Passive sonars listen for the sounds made by vessels and their equipment and analyze them. They can be used to locate targets in the water. An ultrasonic rangefinder is a distance measuring device using the same principle as a sonar, only in the air. It detects a distance to an object by emitting an ultrasonic pulse, receiving a bouncing signal, and measuring the time it takes for the sound pulse to return to the rangefinder receiver.
They can measure the distance from several millimeters to several dozen meters. A stadimeter is an optical distance measuring instrument similar to a sextant used for estimating a range to an object of known height. It measures the angle between the top and the bottom of the object while it is observed from the stadimeter. A camera autofocus AF optical system is used not only to focus on an automatically or manually selected point or object but also as a distance-measuring device with the distance displayed in a focusing distance window.
Binoculars with a reticle and telescopic sights measure distances using a technique called stadiametric rangefinding. They use the same principle as a stadimeter described above. To measure the angle to a distant object of known height, they have a reticle with marks of a known angular spacing to estimate an angle to an object of know height, for example, a person or a tank.
Optical rangefinders use comparing two images obtained from two different optical systems spaced on different devices from several centimeters rangefinder cameras to several meters navy rangefinders. An operator rotates the optical prisms to achieve image coincidence and reads the distance from a dial. A laser rangefinder is an optoelectronic device for measuring a distance from an observer to an object. It measures the time of a laser ray travel from the observer to the object and back after reflection from the object.
Handheld laser rangefinders can measure distances up to 25 km. Lasers with optical telescopes were used to measure the distance between Earth and the Moon. This technique is also used in laser altimeters. A lidar is a tool used for surveying. It measures a distance to an object by illuminating it with a laser beam and measuring the time it takes for the beam to go to the object and back to the sensor. Lidars are used for making maps and to control autonomous cars.
Like in laser rangefinders, radar altimeters and rangefinders transmit a short pulse and measure the transit time for it to hit the target object or surface, reflect from it and return back. These devices can also measure speed. Radio navigation systems use radio frequencies to determine the position of a vessel or an aircraft on the Earth.
This includes, of course, measuring the distance from a receiver to the ground station transmitter. The radio navigation systems also measure angular directions and velocity by means of measuring the Doppler shift of radio waves. GPS technology made the majority of such systems obsolete. DME is a radio navigation equipment used by civil aircraft to measure the distance slant range between an aircraft and a DME ground station.
The measurement is achieved by timing the propagation delay of radio signals between an aircraft and the ground station. An airborne interrogator sends a signal to the ground station, which replies with its signal. This signal is received by the airborne interrogator and the distance is calculated from a known time delay and the speed of light. DME ground equipment is usually combined with the Very high frequency omni-directional range VOR equipment, which is used by aircraft to determine its position.
Inertial navigation systems use analog or digital computers, accelerometers linear acceleration sensors , and gyroscopes angular velocity sensors to continuously determine the position, orientation, and direction of movement and speed of a ship, a submarine, an aircraft, a missile, or spacecraft without the need to use external references. Of course, such systems can also measure distance. These systems are called inertial because they work by measuring and integrating inertial forces, which are forces arising due to acceleration of the reference frame, for example, of a spacecraft.
Older inertial navigations systems used gyrostabilized platforms with many precision mechanical moving parts that could wear out and were vulnerable to gimbal lock.
Newer systems do not use mechanical moving parts and their sensors are rigidly fixed to the structure of the moving object. Instead of mechanical rotating gyroscopes, ring laser gyroscopes are used. Unlike navigational systems based on radio waves from ground stations or satellites, the inertial navigation systems are immune to jamming and deception.
For example, in — GPS devices started going weird near the Kremlin showing users that they were at the center of Vnukovo airport, about 20 miles southwest of the Kremlin. Most probably this has happened because the government wanted to remove drones from the area. After all, many of them are preprogrammed to stop operating near major airports. If smartphones and drones were equipped with inertial navigation systems instead of satellite receivers, the smartphones would show the correct location and the drones would fly.
The square meter is one of many such units and is derived from the area of a square with sides of one meter. It is most often used to measure land area such as rooms, houses, and large plots of land. As with other SI units, the standard prefixes can be applied to the square meter to signify decimal multiples.
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