Page 69 - Green - Maritime Archaeology: A Technical Handbook. 2nd ed
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Maritime Archaeology: A Technical Handbook, Second Edition
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3. GPS Errors
Figure 3.15 (Continued)
There are a number of sources of error in the GPS, which may in some way reduce the accuracy of position. These are listed below with a note in parenthesis indicating if it can be corrected:
1. Ionosphere and troposphere delays. The satellite signal slows as it passes through the atmosphere. The GPS system uses a built-in model that calculates an average amount of delay to partially correct for this type of error (possible to correct with DGPS).
2. Signal multipaths. This occurs when the GPS signal is reflected off objects such as tall buildings or large rock surfaces before it reaches
