Getting accurate time from GNSS receivers: Considerations to approach nanosecond time

A range of issues apply to getting time from GNSS receivers, depending strongly on what the user needs. The words "accurate time" mean very different things to different users. Accurate time from GNSS receivers becomes challenging as the required accuracy is better than a microsecond or so. While this paper discusses a broad range of issues related to accurate timing from GNSS, it focusses on issues in receivers that are perhaps less well understood and yet are required in order to attain the best possible accuracy and reliability for receiving time.