Quiz Questions: 


1. 
FGCC is currently known as ________________. 







FGCS 



USCG 



USGS 




2. 
Global Positioning System (GPS) surveying produces a set of XYZ coordinates which can be transformed into geodetic latitude, longitude, and ellipsoidal height by using an reference ellipsoid to model the earth. 







True 



False 




3. 
A determination of a NAVD88 elevation using GPS measurements at a given point requires transformation between ellipsoid and geoid based height systems. 







True 



False 




4. 
________ is the reference system most frequently used with offtheshelf GPS equipment. 







WGS74 



WGS84 



WGS94 




5. 
The orthometric height of a point is the distance from the reference surface to the point, measured along the line perpendicular to every equipotential surface in between. 





True 


False 




6. 
The NAVD88 datum is the product of a horizontal adjustment of leveled height difference measurements made across North America. 







True 



False 




7. 
Geoidal heights or (geoid height values) represent the geoidellipsoid separation distance measured along the ellipsoid normal and are obtained by taking the difference between ellipsoidal and orthometric height values. 







True 



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 equipotential surfaces which are normal to gravity do not remain geometrically parallel over a given vertical distance. 







True 



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. 







True 



False 




10. 
The World Geodetic System of 1984 reference ellipsoid is 







Geocentric 



Biaxial 



An ellipsoid of revolution 



All of the above 




11. 
The GRS80 ellipsoid is ______________________. 







Exactly geocentric 



Not exactly geocentric 




12. 
The geoid model is constructed ____________________. 







From a truncated functional series approximation 



Using a spherical harmonics expansion 



Using an extensive set of globally available gravity data 



All of the above 




13. 
Most recent geoid models have an absolute accuracy for _________________. 







Geoid heights of one centimeter 



Geoid heights of a few centimeters 



Geoid heights of a few decimeters 



Geoid heights of one meter 




14. 
The lowest geoid heights in the US NGS GEOID96 model are 







7.2 meters 



21.5 meters 



39.8 meters 



51.6 meters 




15. 
The geoid model GEOID96 is based on 







NAD27 



NAVD29 



NAD83 




16. 
HPGN is abbreviated as _______________________. 







High Precision Geodetic Networ 



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. 







True 



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 __________________. 







Hi = hi − NI 



Hi = Ni − hI 




19. 
GPS baselines are not observed to determine ellipsoidal height differences across a network of stations. 







True 



False 




20. 
GPS reference stations for accurate vertical adjustment should include at least __________ NAVD first order benchmarks. 







Two 



Three 



Four 




21. 
An error estimate of ______________ is commonly seen as the minimum baseline error produced from static type surveys. 







10 mm 



20 mm 



30 mm 




22. 
Relative geoidal height precision from geoid modeling can have an expected standard deviation of __________. 







1020 mm 



1030 mm 



2030 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. 







True 



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. 







True 



False 




25. 
GPS relative positioning accuracy depends in part on the length of the measured baseline. 







True 



False 







