RAP opportunity at Air Force Science and Technology Fellowship Program AF STFP
Relativistic Time Synchronization for Satellite Crosslinks
Location
Space Vehicles Directorate, RV/Space and Planetary Sciences
| opportunity |
location |
|
| 13.40.01.C0064 |
Kirtland Air Force Base, NM 871175776 |
Advisers
| name |
email |
phone |
|
| Khanh Dai Pham |
khanh.pham.1@spaceforce.mil |
505.846.4823 |
Description
With an outlook towards flexible Global Positioning System (GPS)-surrogate technologies, this research opportunity focuses on time transfer and synchronization approaches for satellite constellations equipped with crosslink capabilities. Specifically, scientific breakthroughs are needed for time signals of onboard clocks to be transferred and synchronized through crosslinks, including gravitational effects such as Shapiro delays. The endpoints of these crosslinks are satellites with clocks in orbital motions (e.g., moving at 3 km per second for Geo-synchronous Orbits and 7 km per second for Low Earth Orbits). What follow are some technical challenges of interest, including (1) modeling, simulation, and analysis of relativistic time transfers in radio and/or optical clocks; (2) compensation of Shapiro delays and other propagation effects; (3) distributed time transfer mechanisms in radio and/or optical crosslinks; (4) stability and consensus in remote time dissemination; and (5) accurate processing of crosslink data for time synchronization accuracy and convergence.
References
Pham KD: “Stochastic Power Controls for Distributed Pulse-Coupled Synchronization”. IEEE Aerospace Conference, doi: 10.1109/AERO.2017.7943841, Big Sky, MT, 2017
Kirchner D: “Two-Way Time Transfer via Communication Satellites”. Proceedings of IEEE 79(7): 983-990, 1991
Miller J, et al: “NASA Architecture for Solar System Time Distribution”. Proceedings of IEEE Frequency Control Symposium: 1299-1303, 2007
Xie Y: “Relativistic Time Transfer for Inter-satellite Links”. Frontiers in Astronomy and Space Sciences 3: 2016
key words
GPS denied; Time synchronization; Distributed time transfer; Onboard processing; Crosslinks; Shapiro delay; Synchronization accuracy; Propagation effects;
Eligibility
Citizenship:
Open to U.S. citizens
Level:
Open to Postdoctoral and Senior applicants
Stipend
| Base Stipend |
Travel Allotment |
Supplementation |
|
| $95,000.00 |
$5,000.00 |
|
Experience Supplement
Postdoctoral and Senior awardees will receive an appropriately higher stipend based on the number of years of experience past their PhD.
|
Additional Benefits
Relocation
Awardees who reside more than 50 miles from their host laboratory and remain on tenure for at least six months are eligible for paid relocation to within the vicinity of their host laboratory.
Health insurance
A group health insurance program is available to awardees and their qualifying dependents in the United States.