978-0134604657 Chapter 13

13 GLOBAL NAVIGATION SATELLITE SYSTEMS—

INTRODUCTION AND PRINCIPLES OF OPERATION

Asterisks indicate problems that have partial answers given in Appendix G.

13.1 What does the GNSS receiver provide the user?

13.2 What are the three segments in GPS?

13.3 What is the frequency of the L1 signal and its relationship to the fundamental frequency

of the satellite clock?

*13.4 Discuss the purpose of the pseudorandom noise codes.

See Section 13.2, paragraphs 3 thru 8. “The individual satellites are normally identified

13.5 What type of information is broadcast in the GPS signal?

13.6 How is the line of apsides defined?

13.7 What new signals were added to the Block IIF satellites?

(*)

civilian codes along with a codeless component.”

13.8 What is the purpose of anti-spoofing?

13.9 Describe the geocentric coordinate system.

From Section 13.4.1, paragraph 2: “This three-dimensional rectangular coordinate

13.10 Define the terms “geodetic height,” “geoid height,” and “orthometric height.” Include

their relationship to each other.

13.11 Define PDOP, HDOP, and VDOP.

From Section 13.6.4:

2 2 2

X Y Z

 Horizontal dilution of precision:

22

ne

  

 Vertical dilution of precision:

2

Z



13.12 What reference ellipsoid is used in the broadcast message of GPS?

13.13 Why was the P code encrypted with the W code?

13.14 Why is it important to check the reference frame of previously determined coordinates

for a station?

13.15 Approximately how far from a GPS satellite will a signal travel in 0.07 sec?

13.16 What are the unknowns in Equation (13.13)?

13.17 What is integer ambiguity?

13.18 What are the major sources of error in a GPS pseudorange?

13.19 What errors can single differencing of phase-shift observations remove?

*13.20 What errors can double differencing of phase-shift observations remove?

*13.21 What are the geocentric coordinates in meters of a station in meters that has a latitude

of 49°27’32.20144” N longitude of 122°46’53.56027” W and height of 303.436 m.

13.22 Same as Problem 13.21 except with geodetic coordinates of 44°53’52.1918” N,

longitude of 68°40’07.3487” W and height of 38.405 m?

13.23 Same as Problem 13.21 except with geodetic coordinates of 27°42’45.18186” N

longitude of 97°19’27.98983” W and height of 4.267 m?

*13.24 What are the geodetic coordinates in meters of a station with geocentric coordinates of

(136,153.995,

4,859,278.535,

4,115,642.695)?

13.25 Same as Problem 13.24, except with geocentric coordinates in meters are (738,640.328,

−5,498,206.005, 3,136,724.170)?

13.26 Same as Problem 13.24, except with geocentric coordinates in meters are

(−1,556,234.893, −5,169,323.859, 3,387,440.832)?

13.27 The GNSS determined height of a station is 288.038 m. The geoid height at the point is

−31.068 m.

*13.28 The GNSS determined height of a station is 84.097 m. The geoid height at the point is

30.025 m.

What is the elevation of the point?

13.29 Same as Problem 13.28, except the height is 414.805 m and the geoid height is −28.968

m.

*13.30 The orthometric height of a point is 124.886 m. The geoid height of the point is −28.998

m. What is the geodetic height of the point?

13.31 Same as Problem 13.30, except the orthometric height is 1350.984 m, and the geoid

height is

22.232 m.

13.32 The geodetic heights of two stations are 324.685 m and 309.879 m, and their orthometric

heights are 356.496 m and 341.707 m, respectively. These stations have model-derived

geoid heights of −31.827 and −31.835 respectively. What is the orthometric height of a

station with a GNSS measured height of 305.645 m and a model-derived geoid height

of −31.802 m?

13.33 Why are satellites at an elevation below 10° from the horizon eliminated from the

positioning solution?

13.34 Why should NOAA’s space weather center be consulted at the beginning of any day

where a GNSS survey is planned?