Timeline for Does XNAV (Pulsar navigation) give an absolute position, or a position in relation to the arbitrary inertial reference the system initiates with?
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| Nov 24 at 13:21 | comment | added | John Doty | @uhoh Note also that there was a dependency on GPS. NICER lacks a high stability clock oscillator. It emulates one by checking its seven low stability oscillators once per second against GPS time. In a real XNAV application, out of range of GPS, you'd need a high stability oscillator. | |
| Nov 24 at 13:09 | comment | added | John Doty | @uhoh It's not the same one, but it has what you want. See Figure 5. The "almanac" comes from radio observations. | |
| Nov 24 at 12:55 | comment | added | uhoh | Is this the same document? ntrs.nasa.gov/citations/20190031975 | |
| Nov 24 at 12:47 | comment | added | John Doty | @uhoh sciencedirect.com/science/article/abs/pii/…, but you have to pay for it. | |
| Nov 24 at 2:31 | comment | added | uhoh | Can you support this by linking to sources that confirm this? For example see Is NICER/SEXTANT the first civilian "spacecraft" to determine its own position in space without GPS or uplinked data? where I seem to assert (rightly or wrongly) that this demonstration was NOT tied to radio observations on Earth. "Help me Mr. Wizard!" | |
| Nov 23 at 14:30 | history | answered | John Doty | CC BY-SA 4.0 |