Timeline for Help understanding BepiColombo's weak capture at Mercury's L1 and need for delta-differential one-way range measurements
Current License: CC BY-SA 4.0
5 events
| when toggle format | what | by | license | comment | |
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| Nov 4, 2018 at 1:08 | vote | accept | uhoh | ||
| Oct 20, 2018 at 16:09 | history | edited | David Hammen | CC BY-SA 4.0 |
added 28 characters in body
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| Oct 20, 2018 at 16:08 | comment | added | David Hammen | @uhoh - The two ground stations receive signals from the spacecraft that are very slightly separated in time. The first thing is that whatever the errors are that originate in the spacecraft, so long as they're time correlated (which they are), the errors will nearly cancel. A spacecraft clock is a lot more stable than is (for example) the clock in your mobile device or in your laptop. | |
| Oct 20, 2018 at 14:55 | comment | added | uhoh | In "This, in theory, does two things..." re differential one-way ranging, I don't understand the first thing. I'm guessing that "mass be kept to a minimum... timing mechanisms" refers to something like an onboard oscillator with both low jitter and low drift not being also low mass. I see how using two ground station gives the additional DOF (which is the second thing), but I can't guess what the first thing is. (This is a high density answer, I'm taking on a bit at a time, this is where I've started.) | |
| Oct 20, 2018 at 13:55 | history | answered | David Hammen | CC BY-SA 4.0 |