I am just learning about GPS and have been thinking about the timing aspects of GPS receiver navigation output. What is the relation between the time an output is produced and the time that output is a position/velocity estimate for? Is it always the case that the output is the estimate for the exact moment it is output, or was it the estimate for some (short) time in the past? And if it is the latter, is there a general method to figure out when that time was compared to the output instant?
One example of where this timing relation can be of great importance is when fusing GPS with other sensor data. For accurate fusion, being able to refer all input to the same time datum is relevant.