Calculation of Hydrographic Position Data by Least Squares Adjustment.

摘要

When redundant observations are available, hydrographic positioning problems require the application of a data adjustment method so that all information may be used for obtaining the most reliable fix. One of the oldest and best engineering techniques developed for the purpose is based on the least squares principle. The theoretical background is provided to explain that principle and the technique for its application. Also, the analytical solutions, and respective computer programs implementing them, are developed for the following hydrographic positioning methods: (a) fix by N azimuths; (b) fix by N sextant angles; and (c) fix by two range distances and one azimuth. For each method, an illustrative application of the respective computer program is presented. The least square adjustment method not only yields the most likely values for the fix coordinates but also statistically quantifies position accuracy. Relative accuracy achieved with conventional survey methods is elevated to absolute accuracy when redundant observations are made and adjusted using the method of least squares. (Author)