Base data extrapolator to operate with a navigation receiver in real-time kinematic (RTK) and differential global positioning system ( DGPS) modes

Base data received at a rover receiver is extrapolated to a rover measurement time referenced to a clock in the rover receiver. The base data comprises a plurality of base parameters, such as pseudo-ranges and full phases, calculated at base epochs from data received from navigation satellites. Base data is decomposed into a computed component, a common component, and an information component. Only the information component is extrapolated, thereby increasing the extrapolation time interval (during which base data are missing) over which an acceptable accuracy in determination of rover coordinates may be provided. The extrapolated base data is calculated by adding the computed component updated to the rover measurement time, the information component extrapolated to the rover measurement time, and the common component. A second-order recursive digital filter is used to generate the extrapolation function.