A Compact Optical Time Transfer Instrument for Ground-to-Space Synchronization of Clocks

Nydam, Seth; Anderson, Jeremy; Barnwell, Nathan; Peace, Jessie; Pistella, Frank; Ritz, Tyler; Roberts, Steven A.; Serra, Paul; Conklin, John; Attai, Watson; Clark, Ashley; Hanson, John; Nguyễn, Anh Ngọc; Priscal, Cedric; Stupl, Jan; Wolfe, J.A.; Jaroux, Belgacem

doi:10.2514/6.2017-5381

Cited by 1 publication

(2 citation statements)

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“…The CSAC will be flown on the NASA CubeSat Handling of Multisystem Precision Time Transfer (CHOMPTT) mission, slated for launch in Q1 of 2018 . This mission aims to demonstrate time transfer capability comparable to GPS via an optical link . Similar to what has been proposed here, CHOMPTT plans to employ an update interval of 100 min, once per its orbit.…”

Section: User Range Errormentioning

confidence: 99%

“…To determine orbit uncertainty requirements for the Broadband LEOs, we will stay with our running OneWeb example. As shown in Table , the SIS URE required to match the user performance of GPS with OneWeb's geometry is 3.3 m. If the CSAC were used with around twice the uncertainty of the GPS clocks, as shown in Table , the RMS clock error T would be 2 m. This is a conservative estimate as NASA expects the CSAC to achieve timing performance comparable to GPS on their CHOMPTT cubesat slated for launch in Q1 of 2018 . Furthermore, we will conservatively assume the clock T to be uncorrelated to the orbit radial component R .…”

Section: User Range Errormentioning

confidence: 99%

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Broadband LEO Constellations for Navigation

et al. 2018

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There has been resurgent interest in building low Earth orbiting (LEO) constellations of satellites on a new scale. Their aim is Internet for the world with plans for potentially thousands of satellites. Here, we explore how these LEO constellations can be utilized for navigation. Closer to Earth, LEO offers stronger signals, strengthening us against jamming and aiding in indoor and urban environments. Proximity is also its weakness, where satellites have a small Earth footprint requiring many to provide global coverage. We show that the strength of the Broadband LEO constellations is their numbers, where they offer threefold improvement in satellite geometry compared to navigation core-constellations today. This allows for relaxation of the signal-in-space user range error, while still matching the position accuracy of GPS. Coupled with the more benign radiation environment in LEO compared to GPS in medium Earth orbit, this enables a navigation payload designed using commercial-off-the-shelf components.

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Section: User Range Errormentioning

confidence: 99%

Section: User Range Errormentioning

confidence: 99%