Navigation

Posted by P RUSKIN on June 28, 2005, 11:36 am

Hi Guys,

I'm not qualified to contribute anything significant to your musings but I
thought you might like the following. It may solve your positioning
requirements.

INERTIAL NAVIGATION SYSTEM

The following- explanation, in simplified terms, is typical of all Inertial
Navigation Systems*
First, the aircraft knows where it is at all times. It knows this because
it knows where it isn't. By subtracting where it is from where it isn't, or
where it isn't from where it is (whichever is greater), it obtains a
difference of deviation.
The inertial system uses deviations to generate corrective commands to drive
the system from a position where it is, to a position where it isn't,
arriving at the position where it wasn't, it now is. Consequently the
position where it is, is now the position where it wasn't, and it follows
the position where it was is the position where it isn't.
In the event that the position where it now is, is not the position where it
wasn't, the system has acquired a variation (variations are caused by
external factors, and the discussion of these factors is not considered to
be within the scope of this explanation), the variation being the difference
between where the aircraft is and where the aircraft wasn't. If variation
is considered to be a significant factor, it too may be corrected for by the
use of the Doppler system; however the aircraft must know where it was also.
The "thought process" of the system is as follows; because a variation has
modified some of the information which the aircraft has obtained, it is not
sure where it is. However, it is sure where it isn't (within reason), and it
knows where it was. It now subtracts where it should be from where it
wasn't (or vice versa) and by differentiating this from the algebraic
difference between its deviation and its variation, which is called error,
it computes the correct information to compensate for all factors, supplying
accurate navigation information.

N. A. Mwobbn

Note: The above explanation of the Inertial System is a variation of the
original published in "Electronics" magazine March 1959.

Posted by Padu on June 28, 2005, 2:43 pm

"P RUSKIN"

> I'm not qualified to contribute anything significant to your musings but I
> thought you might like the following. It may solve your positioning
> requirements.

Was that supposed to be funny?

Posted by on June 28, 2005, 6:16 pm

>Was that supposed to be funny?

is isn't where it was, it is where
it is funny. But funny isn't where
it can't be, but a place where it
cannot be in the future.

Rich

Posted by Andy P on June 29, 2005, 12:37 pm

Yeah but...Where you are is only your perception of where you are and is
actually where you have been a very short time ago. Where you will be a
very short time from now is where you are right now, given constant
speed and direction factors. Should either of these factors change
between where you were and are percieving you are now and where you will
be which is where you are right now, you wont be where you are when you
perceive where you were only moments ago.

Posted by JohnK on June 29, 2005, 5:07 pm

> Hi Guys,
> I'm not qualified to contribute anything significant to your musings but I
> thought you might like the following. It may solve your positioning
> requirements.
> INERTIAL NAVIGATION SYSTEM
> The following- explanation, in simplified terms, is typical of all
> Inertial Navigation Systems*
> First, the aircraft knows where it is at all times. It knows this because
> it knows where it isn't. By subtracting where it is from where it isn't,
> or where it isn't from where it is (whichever is greater), it obtains a
> difference of deviation.
> The inertial system uses deviations to generate corrective commands to
> drive the system from a position where it is, to a position where it
> isn't, arriving at the position where it wasn't, it now is. Consequently
> the position where it is, is now the position where it wasn't, and it
> follows the position where it was is the position where it isn't.
> In the event that the position where it now is, is not the position where
> it wasn't, the system has acquired a variation (variations are caused by
> external factors, and the discussion of these factors is not considered to
> be within the scope of this explanation), the variation being the
> difference between where the aircraft is and where the aircraft wasn't.
> If variation is considered to be a significant factor, it too may be
> corrected for by the use of the Doppler system; however the aircraft must
> know where it was also.
> The "thought process" of the system is as follows; because a variation
> has modified some of the information which the aircraft has obtained, it
> is not sure where it is. However, it is sure where it isn't (within
> reason), and it knows where it was. It now subtracts where it should be
> from where it wasn't (or vice versa) and by differentiating this from the
> algebraic difference between its deviation and its variation, which is
> called error, it computes the correct information to compensate for all
> factors, supplying accurate navigation information.
> N. A. Mwobbn
> Note: The above explanation of the Inertial System is a variation of the
> original published in "Electronics" magazine March 1959.

Hi
Could you kindly write that formula - preferable in C, since I think I have
the right application for such requirement/calculation

plzzz ....

rg,
johnk

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