# Difference between revisions of "Effect of station angle on location errors"

(→Problem: added page) |
(add) |
||

Line 14: | Line 14: | ||

| isbn = ISBN 9781560801153 | | isbn = ISBN 9781560801153 | ||

}} | }} | ||

− | == Problem == | + | == Problem 7.2 == |

If the error in Shoran time measurements is <math>\pm 0.1 \mu s</math>, what is the the size of the parallelogram of error in Figure 7.2a when (a) <math>\theta=30^{\circ}</math> and (b) <math>\theta=150^{\circ}</math>? Take the velocity of radio waves as <math>3\times 10^{5}</math> km/s. | If the error in Shoran time measurements is <math>\pm 0.1 \mu s</math>, what is the the size of the parallelogram of error in Figure 7.2a when (a) <math>\theta=30^{\circ}</math> and (b) <math>\theta=150^{\circ}</math>? Take the velocity of radio waves as <math>3\times 10^{5}</math> km/s. | ||

## Latest revision as of 15:36, 8 November 2019

Series | Geophysical References Series |
---|---|

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 |

## Contents

## 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 .

## Continue reading

Previous section | Next section |
---|---|

Radiolocation errors because of velocity variations | Transit satellite navigation |

Previous chapter | Next chapter |

Characteristics of seismic events | Reflection field methods |

## Also in this chapter

- Radiolocation errors because of velocity variations
- Effect of station angle on location errors
- Transit satellite navigation
- Effective penetration of profiler sources
- Directivity of linear sources
- Sosie method
- Energy from an air-gun array
- Dominant frequencies of marine sources
- Effect of coil inductance on geophone equation
- Streamer feathering due to cross-currents
- Filtering effect of geophones and amplifiers
- Filter effects on waveshape
- Effect of filtering on event picking
- Binary numbers