Data Compression and Packaging to support delivery of Differential GPS corrections to Kinematic Users

The project’s primary technical objective is to devise a compression and formatting scheme for the transport of real time differential GPS correction information in standardized forms (RTCM 104 messages and other formats) such that it can be transmitted over limited bandwidth communications media to support requirements for high accuracy position determination in ground based transportation users. A process model of the information is developed and used to predict future message contents over a limited period of time. The resulting compression is a reversible process that removes as much entropy from the transmitted data as possible to produce the smallest practical message size. Upon receipt, mobile devices can expand this information back into standard formats for further use. Using this information to correct their own estimate of position, a high level of kinematic accuracy can be maintained by the user. Use is made of sets of real data to compare the developed model to actual data and to ensure that the developed compressed message can handle the expected variation in information as well as the established error budgets and divergence. In this way, the developed solution is fully validated and proven as a part of the development process.