@conference{62306, author = {Neil Ashby}, title = {The global positioning system, relativity, and extraterrestrial navigation}, year = {2009}, month = {2009-04-27}, publisher = {Proceedings IAU Symposium, No. 261, Virginia Beach, VA}, url = {https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=904814}, language = {en}, }