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Re: navigation math

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Don - At this point just the basics are of need, but the various subleties
are worth looking at. Thanks.

Hul

Don Y <blockedofcourse@foo.invalid> wrote:
> On 11/19/2021 1:28 PM, Hul Tytus wrote:
> >     Anyone know the method for calculating a reciever's position from the time
> > difference between three rf pulse transmiters of known positions? This has
> > apparantly been in use since the second world war but a description of the
> > mathematics involved is hiding. Maybe a text on navagation methods?

> You will be dealing with families of "concentric" hyperbolae
> (as the equation for a hyperbola involves maintaining a constant
> difference between lengths of vectors to foci).

> LORAN was renowned for using this -- on a global scale.  It has
> since been decommissioned in the wild but there's an abundance
> of information regarding its use and deployment.

> Note, however, that there are many subtleties buried in the
> LORAN implementation that make it differ from a theoretical
> approach.  E.g., there are intentional delays introduced
> to make the numbers cleaner.

> If you are truly looking to navigate on a *large* scale
> (hundreds of miles), then you will have to consider things
> like changes in propagation delays over different types
> of terrain and the "shape" of that terrain (e.g., the Earth
> is an oblate sphere).  Again, LORAN has these covered but
> you'll have to dig for details.

> Similar problems exist "in the small" for position
> resolution within a structure!  (I use similar technology
> to determine where, in an "arena" -- home or office, in
> my case -- the user is sited)

> [If you look at a preprinted maritime map augmented with
> LORAN "lines of constant time difference", you'd see
> that they differ from what you would otherwise expect
> from a more naive mathematical/geometric treatment]

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navigation math Hul Tytus <ht@panix.com> - 2021-11-19 20:28 +0000
  Re: navigation math Dennis <dennis@none.none> - 2021-11-19 16:12 -0600
    Re: navigation math Hul Tytus <ht@panix.com> - 2021-11-20 20:45 +0000
  Re: navigation math Grant Edwards <invalid@invalid.invalid> - 2021-11-19 22:54 +0000
    Re: navigation math Grant Edwards <invalid@invalid.invalid> - 2021-11-19 23:03 +0000
    Re: navigation math Don Y <blockedofcourse@foo.invalid> - 2021-11-19 16:28 -0700
    Re: navigation math Hul Tytus <ht@panix.com> - 2021-11-20 20:50 +0000
  Re: navigation math Don Y <blockedofcourse@foo.invalid> - 2021-11-19 16:19 -0700
    Re: navigation math Hul Tytus <ht@panix.com> - 2021-11-20 20:55 +0000
      Re: navigation math Don Y <blockedofcourse@foo.invalid> - 2021-11-20 15:38 -0700
  Re: navigation math Paul Rubin <no.email@nospam.invalid> - 2021-11-19 18:17 -0800
    Re: navigation math Hul Tytus <ht@panix.com> - 2021-11-20 20:59 +0000
  Re: navigation math Robert Roland <fake@ddress.no> - 2021-11-20 14:27 +0100

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