Evaluation of N-RTK Interpolation with Location-Based Dependency

This paper presents an evaluation of interpolation methods, that commonly being used in Network-based Real-Time Kinematic (N-RTK) positioning. The interpolation methods attempt to estimate the network residuals of atmospheric and orbital errors for an N-RTK user, by calculating the so-called network coefficient. In this study, a network of GPS stations, known as ISKANDARnet was utilised to calculate the network coefficients at various locations of N-RTK users include inside and outside of the ISKANDARnet area. It was found that all the interpolation methods performed similarly when the user location is nearby to master station. However, the noise of correction terms for each interpolation method was different as the user is situated at various locations especially outside of the network. In addition, the coefficient value indicates more than one ( 1) as the user is located outside of the network area, except for the DIM interpolation method.