Provided herein are methods and systems for efficient communication between a server and a client in an assisted navigation system. In one or more embodiments, the server transmits a set of parameters for a satellite to the client, e.g., a GPS receiver, via a wireless or wired connection. The set of parameters includes a force parameter, initial condition parameters and time correction coefficients for the satellite. The receiver uses the received parameters in a numerical integration to compute the position of the satellite at a desired time. The set of parameters needed for the integration is small. To further reduce the amount of data transmitted, reference parameters may be subtracted from the original parameters before transmission from the server. The receiver is able to reconstruct the original parameters from the received parameters and the identically computed reference parameters. The parameters may be further compressed using data compression techniques.