|
|
|
|
|||||
|
||||||
Subject: Re: USNO celestial navigation algorithms
From: Stacy Hanna (jshanna@XXX.XXX)
Date: Mon Jun 02 2003 - 21:37:01 EDT
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@XXX.XXX] On Behalf Of Paul Hirose
Sent: Monday, June 02, 2003 1:49 PM
To: NAVIGATION-L@XXX.XXX
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.
|