| 1. |
FGCC is currently known as___________________________. |
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FGCS |
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USCG |
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USGS |
| 2. |
Global Positioning System (GPS) surveying produces a set of X-Y-Z coordinates which can be transformed into geodetic latitude, longitude, and ellipsoidal height by using an reference ellipsoid to model the earth. |
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True |
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False |
| 3. |
A determination of a NAVD88 elevation using GPS measurements at a given point requires transformation between ellipsoid and geoid based height systems. |
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True |
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False |
| 4. |
_______________ is the reference system most frequently used with off-the-shelf GPS equipment. |
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WGS74 |
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WGS84 |
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WGS94 |
| 5. |
The ortho-metric height of a point is the distance from the reference surface to the point, measured along the line perpendicular to every equi-potential surface in between. |
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True |
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False |
| 6. |
The NAVD88 datum is the product of a horizontal adjustment of leveled height difference measurements made across North America. |
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True |
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False |
| 7. |
Geoidal heights or (geoid height values) represent the geoid-ellipsoid separation distance measured along the ellipsoid normal and are obtained by taking the difference between ellipsoidal and orthometric height values. |
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True |
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False |
| 8. |
The geoid itself is defined as a potential surface and natural variations in gravity induce a smooth, continuous, curvature to the plumb line and therefore physical equi-potential surfaces which are normal to gravity do not remain geometrically parallel over a given vertical distance. |
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True |
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False |
| 9. |
NAVD88 elevations are not ortho metric heights that represent the geometric distance from the geoid to the terrain measured along the plumb line. |
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True |
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False |
| 10. |
The World Geodetic System of 1984 reference ellipsoid is |
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Geocentric |
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Bi-axial |
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An ellipsoid of revolution |
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All of the above |
| 11. |
The GRS80 ellipsoid is ____________________________. |
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Exactly geocentric |
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Not exactly geocentric |
| 12. |
The geoid model is constructed ____________________. |
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From a truncated functional series approximation |
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Using a spherical harmonics expansion |
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Using an extensive set of globally available gravity data |
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All of the above |
| 13. |
Most recent geoid models have an absolute accuracy for _________________. |
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Geoid heights of one centimeter |
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Geoid heights of a few centimeters |
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Geoid heights of a few decimeters |
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Geoid heights of one meter |
| 14. |
The lowest geoid heights in the US NGS GEOID96 model are |
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-7.2 meters |
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-21.5 meters |
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-39.8 meters |
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-51.6 meters |
| 15. |
The geoid model GEOID96 is based on |
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NAD27 |
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NAVD29 |
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NAD83 |
| 16. |
HPGN is abbreviated as _______________________. |
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High Precision Geodetic Networ |
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High Probability Geodetic Network |
| 17. |
The geoid height is added to the published orthometric height at the GPS reference station to determine its ellipsoid height to the accuracy level of the geoid model. |
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True |
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False |
| 18. |
Once the reference stations’ ellipsoidal, orthometric and geoidal heights have been fully determined, elevations are transferred from the reference stations to the remaining points in the network according to the relation __________________. |
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Hi = hi − NI |
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Hi = Ni − hI |
| 19. |
GPS baselines are not observed to determine ellipsoidal height differences across a network of stations. |
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True |
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False |
| 20. |
GPS reference stations for accurate vertical adjustment should include at least __________ NAVD first order benchmarks. |
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Two |
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Three |
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Four |
| 21. |
An error estimate of ______________ is commonly seen as the minimum baseline error produced from static type surveys. |
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10 mm |
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20 mm |
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30 mm |
| 22. |
Relative geoidal height precision from geoid modeling can have an expected standard deviation of_____________. |
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10-20 mm |
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10-30 mm |
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20-30 mm |
| 23. |
In areas with obstructions, dense vegetation, or high relief between monuments or projects site, GPS cannot exceed leveling accuracy when time is critical to the project. |
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True |
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False |
| 24. |
It was determined that higher accuracy elevations are obtained by the transfer of ellipsoidal height differences and relative geoidal heights from a station with a known NAVD88 elevation, than is possible from the direct application of absolute geoid heights to GPS networks. |
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True |
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False |
| 25. |
GPS relative positioning accuracy depends in part on the length of the measured baseline. |
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True |
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False |
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