On 9/23/11 10:25 AM, Jim Lux wrote:
One aspect of why at least a standardized second order model would be nice is that it allows you to make smooth non-discontinuous changes in rate. the transformation from count to time would be discontinuous in rate of rate (i.e. it would go from zero, to something, to zero), but continuous in terms of rate.
The other thing that crops up all the time in the spacecraft world is that you're always taking into account the light time propagation delay between two ends of a link, which is varying fairly quickly. Since the problem of doing something like "I want my signal to arrive at a particular time over there" crops up a lot, as does the general "I want to measure my oscillator against the one on that other spacecraft", something that provides a consistent computational framework (as opposed to specifically designed for the application) might be useful.
For instance, GPS receivers have to do this calculation already, so the whole range/range rate estimation process is built in, in order to do the nav solution. Each implementation probably does it a different way, but at least the observables are reported in a standard way as RINEX (tailored to the needs of GPS, e.g carrier phase is measured in cycles)
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