NavList:

   

Reply

I never practised navigation in the real world. But if I remember the Bowditch 
(1958 edition) well, in the context of CelNav the EP was defined as the spot 
on a LOP found by dropping the perpendicular to the LOP from 1) the DR 
position 2) from the DR position corrected for effects of current and wind, 
if reasonably judged. The text warned against using current and wind data too 
often. As it said (cited by memory), "in our time of powerful machines and 
great speeds, there is no great use guessing drifts and sets, it's better to 
proceed from one fix to another by DR."

Of course, Loran C, INS, Doppler logs, Omega, Transit, and lastly GPS shook 
this world to sherds step by step meanwhile.


Jan Kalivoda


----- Original Message -----
From: "Russell Sher" 
To: 
Sent: Sunday, September 26, 2004 6:45 PM
Subject: Definition of estimated position?


A navigational problem in the Jan/Febr. 2004 edition of Ocean Navigator 
Magazine (#135) posed a question which involved a navigator shooting the sun 
to obtain an LOP. Since there is only one LOP there is therefore no fix, but 
the one of questions asked is 'What is the Estimated Position?' I imagine 
that it is the position plotted on the LOP as being the closest from the DR. 
Does anyone agree?

Obviously in Coastal navigation, the estimated position is typically the 
position calculated from Course steered, log reading and taking tidal streams 
or current into account, but here the context is different.

(You can access the problem at -  www.oceannavigator.com (look under 'browse 
by issue'  - choose jan/feb 2004, select the nav problem )



regards

Russell



--------------------------------------------------------------------------------


Incoming mail is certified Virus Free.
Checked by AVG Anti-Virus (http://www.grisoft.com).
Version: 7.0.271 / Virus Database: 264.9.6 - Release Date: 24.9.2004

   

Reply