Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Position-Finding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    or...
    Re: Latitude by Talcott-Horrebow Method
    From: Brad Morris
    Date: 2018 Nov 7, 17:19 -0500

    Peter wrote

    Geodetic latitude is a function of monuments anchored to bedrock (and then pointed out it is different then astronomic latitude)

    Paul wrote

    the rotation of the Earth and wandering of the pole have been absorbed into the ephemeris [ with regards to gps latitude ].

    +++++++++++++

    Okay, so now I am just a bit confused. The geoditic monuments that Peter mentioned must have their asigned latitude and longitude changed as they move about due to plate tectonics, or so it is stated. But are they also reassigned as a function of pole wander?

    If not, then how are the two systems aligned. Example of confusion. I take my GPS receiver to a geoditic monument. The GPS ephemeris updated to include pole wander, as per Paul. So the geoditic latitude will NOT match the GPS latitude.

    Maybe you fellows could clarify this for me


    Brad



    On Tue, Nov 6, 2018, 11:29 PM Peter Monta <NoReply_PeterMonta@fer3.com wrote:

    However, nowadays the polar motion is predicted and published a year in
    advance in IERS Bulletin A to .001″ precision. Bulletin B has more
    accurate values determined after the fact.

    The uncertainty of the pole a year in advance is quite a bit larger than 1 mas, though.  Bulletin A says the uncertainty is already 13 mas for 40 days out, and gives a little power-law formula that gives 75 mas for a year out.  But yes, the measured values are good to 90 uas (~3 mm).


    Cheers,
    Peter

    View and reply to this message

    Browse Files

    Drop Files

    NavList

    What is NavList?

    Join NavList

    Name:
    (please, no nicknames or handles)
    Email:
    Do you want to receive all group messages by email?
    Yes No

    You can also join by posting. Your first on-topic post automatically makes you a member.

    Posting Code

    Enter the email address associated with your NavList messages. Your posting code will be emailed to you immediately.
    Email:

    Email Settings

    Posting Code:

    Custom Index

    Subject:
    Author:
    Start date: (yyyymm dd)
    End date: (yyyymm dd)

    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site
    Visit this site