Uncertainty Evaluation on Arm Length Correction of GNSS/A Combined Observation

Objectives When global navigation satellite system/acoustic（GNSS/A） technology is applied in seafloor geodesy, GNSS antenna coordinates are converted to transducer position by arm length parameters and platform attitude observations. The conversion involves not only the error propagation of GNSS positioning error, but also the propagation of arm length error and attitude measurement error, which is a typical nonlinear error propagation problem.

Methods In this paper, both the guide to the expression of uncertainty in measurement (GUM) based on linearized error propagation and Monte Carlo method (MCM) based on nonlinear error propagation are used to evaluate the uncertainty of transducer location.

Results and Conclusions The results show that GUM and MCM have a good consistency on the whole process, but with the increase of nonlinear strength and measurement uncertainty, these two methods have a significant difference. The uncertainty of transducer increases with the increase of arm length, and increases with the decreas of the accuracies of attitude measurement and arm length measurement. It means that the longer the arm length of GNSS/A combined observation, the higher the requirement for attitude measurement accuracy. Attitude measurement uncertainty has the least influence on the uncertainty of transducer location, GNSS positioning uncertainty has the most, and arm length parameter has the secondary.