Clinometer
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A clinometer also known as an inclinometer is an instrument for measuring angles of slope (or tilt), elevation or inclination of an object with respect to gravity. Also known as a tilt meter, tilt indicator, slope meter, slope gauge, gradient meter, gradiometer, level gauge, level meter, pitch & roll indicator.
Early clinometers include examples such as Well's Clinometer, the essential parts of which are a flat side, or base, on which it stands, and a hollow disk just half filled with some heavy liquid. The glass face of the disk is surrounded by a graduated scale that marks the angle at which the surface of the liquid stands, with reference to the flat base. The line 0.——0. being parallel to the base, when the liquid stands on that line, the flat side is horizontal; the line 90.——90. being perpendicular to the base, when the liquid stands on that line, the flat side is perpendicular or plumb. Intervening angles are marked, and, by the aid of simple conversion tables, the instrument indicates the rate of fall per set distance of horizontal measurement, and set distance of the sloping line.
The earliest electronic clinometers used a weight, an extension, and a potentiometer. Early in the 1900's (circa 1917) precision curved glass tubes filled with a damping liquid and steel ball were introduced to provide accurate visual angle indication. Common sensor technologies for electronic tilt sensors and inclinometers are accelerometer, liquid capacitive, electrolytic, gas bubble in liquid, and pendulum. Moving forward, MEMs (Micro-Electro-Mechanical Systems) technology is becoming the newest type due to their tiny size and low cost.
Certain highly sensitive electronic inclinometer sensors can achieve an output accurate to .001 degrees. However, an inclinometer sensor's true or absolute accuracy (which is the combined total error) is a combination of initial sets of sensor zero offset and sensitivity, sensor linearity, hysteresis, repeatability, and the temperature drifts of zero and sensitivity - electronic clinometers accuracy can typically range from .01º to ±2º depending on the sensor and situation. Typically in room ambient conditions the accuracy is limited to the sensor linearity specification.
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[edit] Usages
Clinometers are used for:
- indicating pitch and roll of vehicles, sail boats, and aircraft.
- Monitoring boom angle of cranes and material handlers.
- Measuring the "look angle" of a satellite antenna towards a satellite.
- Measuring the slope angle of a tape or chain during distance measurement.
- Estimating the height of a building, tree, or other feature using a vertical angle and a distance (determined by taping or pacing).
- Measuring the angle of drilling in well-logging applications.
- Measuring the height of trees or other poles
- Measuring steepness of a ski slope. (<10 deg for beginners, 10-20 "green", 15-25 "blue", 25-35 "black", 35-45 "double black")
[edit] Factors which influence the use of clinometers
(Overall accuracy varies depending on the type of inclinometer and technology utilized)
- Gravity
- temperature (drift), zero offset, linearity, vibration, shock, cross-axis sensitivity, acceleration/deceleration
- A clear line of sight between the user and the measured point is needed.
- A well defined object is required to obtain the maximum precison.
- The angle measurement precision and accuracy is limited to slightly better than one degree of arc .
[edit] Survey methods used for
- Clinometers are used for the measurement of angles in reference to gravity.
- The USDA Forest Service uses clinometers to measure tree height in its Forest Inventory and Analysis program.
