Quick Answer
To check the accuracy of your altimeter, compare its reading to a reliable source, such as a GPS device or a physical barometer, at a known elevation. This can be done in a controlled environment, like a mountain with a marked elevation. The altimeter should match the known elevation within a reasonable margin.
Understanding Altitude Sources
When checking the accuracy of an altimeter, consider the available sources of altitude information. A GPS device, for instance, can provide a highly accurate reading of elevation. This is because GPS relies on a network of satellites orbiting the Earth, which can pinpoint a device’s location with great precision. In contrast, an altimeter measures atmospheric pressure to estimate altitude, which can be affected by weather conditions and temperature fluctuations.
Calibrating Your Altimeter
To ensure accuracy, calibrate your altimeter against a reliable source at a known elevation. For example, if you’re near a mountain with a marked elevation, take a reading from both the GPS device and the altimeter at the same location. Compare the two readings to see if they match within a reasonable margin, typically around 10-20 feet for a well-calibrated altimeter. If the readings differ significantly, re-calibrate the altimeter according to the manufacturer’s instructions.
Field Testing and Verification
In addition to calibration, field testing can help verify the accuracy of your altimeter. For instance, if you’re climbing a mountain, take readings at regular intervals to track changes in elevation. Compare these readings to the GPS device’s elevation data to ensure they match. If the altimeter consistently deviates from the GPS reading, it may indicate a calibration issue or the need for further adjustment.
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