An Adaptive Designing Method of Broadcast Almanac Parameters

A model of the signal acquisition time influenced by the almanac was introduced to evaluate the almanac model. It shows that the six parameters almanac model outperforms the three parameters almanac model. The almanac truncation error was introduced to describe the error between the original data and the interface specification formatted terms. The parameter sen- sitivity and the truncation error were analyzed to validate the necessity to choose the proper definition of the almanac parameters, including the effective range and the scale factor. It demonstrates the parameter definition is the key designing element while the almanac representation is determined. Based on the research above, An Adaptive almanac designing method （AADM） of broadcast almanac parameters was presented. Simulation results reveal that the AADM can generate an optimum set of almanac parameters with the shortest signal acquisition time to a limited bit allocation.