This article discusses the accuracy of the vessel’s position coordinates, calculated using the least squares method, in the presence of redundant line positions (LP) over time, assuming the LP error is normally distributed. It is stated that for a normal error distribution, the least squares method is the maximum likelihood method, thus the norm of the positional error covariance matrix is minimized, ensuring the highest accuracy of the vessel’s position coordinates. Field observation results are presented, where experimental data were obtained, demonstrating the possibility of altering navigational parameters. Following the adjustment of navigational parameters, a series of tests were conducted, exceeding 100 in total. The analysis of these results indicates that deviations in navigational parameterization, achieved over a limited time interval, conform to the normal law of variability distribution. Adjustments to the parameters over a larger interval are subject to changes in the laws of change, with the degree of power of some of the normal law proportional to the interval of the series value of the navigational parameter. It is demonstrated that the efficiency of observing the vessel’s coordinates, calculated by the least squares method during times of redundant LP, the errors of which can be calculated according to different laws, is less than one. To evaluate the efficiency of coordinate observation derived from overly large LP and gaps using the least squares method, a computer simulation was performed. During this simulation, efficiency values were compared with the highest theoretically achievable efficiency values, as outlined in the article, and the difference between them in the case of high-technological parameters was less than 22.0%. The simulations conducted showed good agreement between the efficiency assessments derived from analytical expressions and those obtained from the simulations, thereby confirming the validity of the analytical method for evaluating the efficiency of observed coordinates, calculated by the least squares method. Keywords: navigational safety, accuracy of coordinates assignment, change of law and subdivision, simulation modelling.
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