NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: USNO celestial navigation algorithms
From: Stacy Hanna
Date: 2003 Jun 2, 21:37 -0400
From: Stacy Hanna
Date: 2003 Jun 2, 21:37 -0400
According to the 2002 edition of Bowditch it does appear that those algorithms are used in STELLA. I will look at the documentation with STELLA at work tomorrow and see if I can find more information. "U.S. Naval navigators have access to a program called STELLA (System To Estimate Latitude and Longitude Astronomically; do not confuse with a commercial astronomy program with the same name). STELLA was developed by the Astronomical Applications Department of the U.S. Naval Observatory based on a Navy requirement. The algorithms used in STELLA provide an accuracy of one arc-second on the Earth's surface, a distance of about 30 meters. While this accuracy is far better than can be obtained using a sextant, it does support possible naval needs for automated navigation systems based on celestial objects. These algorithms take into account the oblateness of the Earth, movement of the vessel during sight-taking, and other factors not fully addressed by traditional methods. STELLA can perform almanac functions, position updating/ DR estimations, celestial body rise/set/transit calculations, compass error calculations, sight planning, and sight reduction. On-line help and user's guide are included, and it is a component of the Block III NAVSSI. Because STELLA logs all entered data for future reference, it is authorized to replace the Navy Navigation Workbook. STELLA is now an allowance list requirement for Naval ships, and is available from: Superintendent U.S. Naval Observatory Code: AA/STELLA 3450 Massachusetts Ave. NW Washington, DC, 20392-5420" -----Original Message----- From: Navigation Mailing List [mailto:NAVIGATION-L@LISTSERV.WEBKAHUNA.COM] On Behalf Of Paul Hirose Sent: Monday, June 02, 2003 1:49 PM To: NAVIGATION-L@LISTSERV.WEBKAHUNA.COM Subject: USNO celestial navigation algorithms Seen on the U.S. Naval Observatory Web site: "As part of a Navy software project, new algorithms for celestial navigation have been developed. These algorithms are based on a solution to a familiar astronomical problem - determining the orbit of a body from a series of observations. In this case, the body in question is a ship and its orbit is a rhumb-line track over the spheroidal surface of the Earth. Given suitably accurate observing systems, these algorithms would provide sight reduction and positional fixes at the one arcsecond (30 meter) level of precision." The algorithms were published in four papers by G.H. Kaplan, published 1995 - 1996. Two are available online. Reprints of all may be ordered from the USNO. http://aa.usno.navy.mil/research/celnav.html Several months ago I mentioned a whiz-bang celestial nav program called STELLA, which unfortunately is in the military-only area of the USNO site. I wonder if STELLA is based on the algorithms in these papers.