Precise time and frequency distribution over a wireless network for A-GNSS users

Assisted-GNSS (A-GNSS) is an innovative technology intended to allow the use of GNSS (Global Navigation Satellite Systems) signals indoor or in environments in which the GNSS signal in space (SIS) is heavily attenuated or masked. Aiding is provided in the form of data that can be broadcast to the users via a variety of means, but primarily via the ubiquitous wireless telephone. ESA has tasked the DingPos project team to explore novel architectures to implement A-GNSS terminals using the SIS radiated by Galileo satellites to exploit the improved characteristics of the latter. In the framework of this project, ways are being explored to transfer precise time and frequency to the user terminal to aid in acquisition and tracking of Galileo signals. This is particularly important in the Galileo framework, where Local Elements have been sought as a way to improve the navigation system performance over limited areas.