An Analysis of the Positioning Accuracy of Horizontal Sextant Angles.

摘要

The paper presents a method for determining the positioning accuracy which may be obtained from horizontal sextant angle fixes. A system model for a three-object,two-line-of-position (LOP) fix is developed from which the independent and dependent component instrument and human factors errors for both the sextant and the three-arm protractor can be identified and analyzed. The conversion of these angular measurement errors into distance units is accomplished by a function termed the Geometric Multiplication of Precision (GMOP) which is derived from the gradient of beta (beta is defined as the exact angular measurement of a horizontal sextant angle). The LOP errors in distance units are used with the LOP crossing angle to determine the positioning accuracy,expressed as the radius from the exact position within which the actual position may be expected to lie for a particular accuracy probability. (Modified author abstract)