Talk:Dilution of precision (navigation)

Untitled
what the main the PDOP = 3.40, HDOP = 1.70, VDOP = 2.90

"Football field" ?
Do you mean American or Soccer? Do you mean width or length?

American: 110m x 49m, Soccer 45m-90m x 90m-120m.


 * All of these linear measurements are within the same order of magnitudes (approx >10m and < 1000m) and as a cultural reference to rough size of "bigness" any would do. (However the offending reference to "Football field" appears to have been removed.) --BrianFennell (talk) 20:21, 19 April 2009 (UTC)

Optimal DOP value
The table shows 0; I had understood it to be 1, so I looked at the lone reference, in hopes of learning more. The reference indicates 1 as optimal, but perhaps it's wrong. Are there any more references for this? 129.74.64.45 (talk) 01:42, 9 September 2008 (UTC)

Optimal value was set to 1 and now <1. Should not be still 1 as ideal? It's unclear what the range [0,1[ means... 2A01:E35:8BAB:7050:5039:E67F:8B81:CCBD (talk) 14:41, 20 October 2015 (UTC)


 * By definition DOP continues to decrease as more rows are added to the design matrix. Early literature (from 1980s GPS) confused this because at the time the challenge was to select the best geometry given a limited number of channels. So as the number of satellites observed increases, the various DOP measures will continue to decrease. As the number of satellites tends to infinity, the corresponding matrix inverse will tend to zero.
 * A DOP (H,V, G, etc) lower than 1 means the geometry is strong enough that the computer position error is expected to be better than a single range error. Kpgokeef (talk) 21:55, 9 February 2023 (UTC)

c in matrix calculation
If (x - xi)/Ri is meant to be a component of a unit vector (with length of 1 unit) it would seem then the time difference has already been converted to spacial distance for Ri. If so, why does c (speed of light) appear in the matrix math? I could see if Ri/c was meant to be meters/(meters/second) giving seconds in the final column (making it a time component), but having c standing out there all on it's own seems inconsistent. (Or am I missing something more basic or more esoteric here?)

Also it would be helpful is a more authortative document was referenced - GPS is a standard, and there must be a standard document for it defining (among other things) GDOP, HDOP, VDOP and PDOP as defined for use in GPS calculations. --BrianFennell (talk) 20:21, 19 April 2009 (UTC)

Excellent points. I just ran a GDOP calculation using c in the last column and the inverse is not usable due to the singularity of A'A. Using 1 instead of c in the final column is the method defined in Per Enge's book on GPS. -- Steven Waslander —Preceding unsigned comment added by 129.97.68.181 (talk) 15:48, 20 May 2009 (UTC)

Possible Articles to cite
GPS GDOP metric - 2000 IEE Proceedings -
 * http://www.utdallas.edu/~nxa028000/GDOP.pdf

Dilution of Precision-Based Lunar Navigation Assessment for Dynamic Position Fixing
 * http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/38716/1/06-0023.pdf

B.W. Parkinson (Ed) Global Positioning System: Theory and Applications, Vols I and II 1996, AIAA Press.
 * ISBN 156347106X

Matrix Inversion - Ask Dr Math
 * http://mathforum.org/library/drmath/view/51680.html -- BrianFennell (talk) 21:23, 19 April 2009 (UTC)

Underlining of math expression
In section "Computation of DOP values", the first math expression is underlined. Does this have some meaning, that I am not aware of, or is it there by mistake?

Velle (talk) 01:11, 25 March 2010 (UTC)

Rendering of italic math style z
Have you noticed that the z letters (that are written in math style, and rendered) have lost their diagonal line? Now they look like the approximation symbol. I don't know if this could be fixed somehow, but it sure will confuse some people.

Velle (talk) 01:23, 25 March 2010 (UTC)

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Duplication
There's significant overlap between the present article and section Error analysis for the Global Positioning System. fgnievinski (talk) 20:54, 13 April 2021 (UTC)
 * I agree. Perhaps we could merge the content into this page, and replace that section with a summary and link to this page? TimSmit (talk) 01:13, 30 April 2021 (UTC)
 * Redirected that section; no unique, relevant, referenced content to merge. Klbrain (talk) 10:07, 22 October 2022 (UTC)