Welcome to the NavList Message Boards.

NavList:

A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding

Compose Your Message

Message:αβγ
Message:abc
Add Images & Files
    Name or NavList Code:
    Email:
       
    Reply
    Re: Infrared sextant
    From: Paul Dolkas
    Date: 2014 Aug 24, 14:57 -0700

    Back in the early days of the SR71 reconnaissance plane, there was a star tracking system that could pick up stars while sitting on a runway on an overcast day. It was a very expensive system, and they no  longer use it (replace by GPS). I wonder if it was also IR based?

     

    In any event, here’s the text from Wikipedia:

     

    Astro-Inertial Navigation System[edit]

    The USAF sought a precision navigation system for maintaining route accuracy and target tracking at very high speeds.[citation needed] Nortronics, Northrop's electronics development division, had developed an astro-inertial navigation system (ANS), which could correct navigation errors with celestial observations, for the SM-62 Snark missile, and a separate system for the ill-fated AGM-48 Skybolt missile, the latter of which was adapted for the SR-71.[52][verification needed]

    Before takeoff, a primary alignment brought the ANS's inertial components to a high degree of accuracy. In flight, the ANS, which sat behind the Reconnaissance Systems Officer (RSO)'s position, tracked stars through a circular quartz glass window on the upper fuselage.[38] Its "blue light" source star tracker, which could see stars during both day and night, would continuously track a variety of stars as the aircraft's changing position brought them into view. The system's digital computer ephemeris contained data on 56 (later 61) stars.[53] The ANS could supply altitude and position to flight controls and other systems, including the Mission Data Recorder, Auto-Nav steering to preset destination points, automatic pointing and control of cameras and sensors, and optical or SLR sighting of fix points loaded into the ANS before takeoff. According to Richard Graham, a former SR-71 pilot, the navigation system was good enough to limit drift to 1,000 feet off the direction of travel at Mach 3.[54]

     

     

    Paul Dolkas

     

    From: NavList@fer3.com [mailto:NavList@fer3.com] On Behalf Of Brad Morris
    Sent: Sunday, August 24, 2014 1:11 PM
    To: paul@dolkas.net
    Subject: [NavList] Re: Infrared sextant

     

    Note: The seller's published town "Melville" is right up the road (literally) from the town of the inventor "Huntington". It is likely that this item was the inventor's model.

       
    Reply
    Browse Files

    Drop Files

    NavList

    What is NavList?

    Get a NavList ID Code

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

    A NavList ID Code guarantees your identity in NavList posts and allows faster posting of messages.

    Retrieve a NavList ID Code

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

    Email Settings

    NavList ID 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