Effect of station angle on location errors
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Series | Geophysical References Series |
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Title | Problems in Exploration Seismology and their Solutions |
Author | Lloyd P. Geldart and Robert E. Sheriff |
Chapter | 7 |
Pages | 221 - 252 |
DOI | http://dx.doi.org/10.1190/1.9781560801733 |
ISBN | ISBN 9781560801153 |
Store | SEG Online Store |
Problem 7.2
If the error in Shoran time measurements is , what is the the size of the parallelogram of error in Figure 7.2a when (a) and (b) ? Take the velocity of radio waves as km/s.
Background
Shoran is a radio-navigation device which measures the 2-way traveltime between the point of observation and a fixed station. Using two fixed stations, the point of observation can be located by swinging arcs centered at the two stations; for large distances the arcs become nearly straight lines.
The traveltimes are subject to error , so the ranges are , , 2. Swinging the four arcs corresponding to these time values, we get a parallelogram of error such as that in Figure 7.2a; the location lies somewhere inside this parallelogram.
Solution
In Figure 7.2a, the error in range
.
The long diagonal m.
The short diagonal m.
To get the figure for we merely reverse the arrow on or ; therefore the error values are the same as for .
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Radiolocation errors because of velocity variations | Transit satellite navigation |
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Characteristics of seismic events | Reflection field methods |
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- Effect of station angle on location errors
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