Chapter 9-10

Question 1

GPS

Answer 1

• consists of 24 satellites plus 6 in reserve that operate in 6 orbital planes and spaced at 55 degree intervals
• revolutionized surveying

Adv
precise locations can be instantly determined in minutes.
Does not require line of sight
not impacted by weather

Dis
- cant be used underground in tunnels
- verticle capabilities are limited
-

Question 2

Types of GPS

Answer 2

• Static
• rapid static
• kinematic/dynamic
• stop and go
• Real-Time Kinematic

Question 3

Rule of thumb in GPS surveying

Answer 3

keep it as simple as possible

Question 4

Most important field aspect of GPS

Answer 4

Consistency and Flexibility

Question 5

Choosing Base Station

Answer 5

• highest point on the project
• Ideal station has no obstruction 5 degrees above the horizon
• Solid permanent point

Question 6

Calibration Testing Schedule
- When new
- Daily
- weekly
- Monthly
- Yearly
- New job/high precision required

Answer 6

When New- chain, level rod, and ALL elements
Daily- Prism pole bubble
Weekly- Auto and Dumpy Level, and optical or laser plummets
Monthly - laser
Yearly - total station,transit/theodolite
New Job - ALL instruments

Question 7

Basic Principles

Answer 7

• Avoid the Hot Sun
• Avoid Inclement Weather
• Select a Flat Area
• select an open area

Question 8

Eliminating Parallax

Answer 8

• look through the instrument at light-colored object
• Adjust crosshairs so they are dark and crisp
• look at the level rod and move your head slightly looking at crosshair. If it stays on the same spot on the rod, parallax has been eliminated for now
• throughout day as eyes become tired and crosshairs fuzzy, re[eat procedurre

Question 9

Upper Clamp of instrument

Answer 9

The upper clamp sets the instrument to zero, and it secures the line of sight on to the foresight (right side of angle).

Question 10

Lower Clamp

Answer 10

secure the line of sight onto the back sight (left side of angle)

Question 11

The PDOP value should be less than

Answer 11

6

Question 12

The GDOP value should be less than

Answer 12

5

Question 13

When calibrating a chain, any chain measuring more than _________ from nominal should be discarded

Answer 13

.020 ft

Question 14

Of the several “dilution of precision” (DOP) values the two most important are

Answer 14

PDOP and GDOP

Question 15

How many people are required to properly calibrate a chain?

Answer 15

4

Question 16

How to Calibrate Chain

Question 17

The ideal base station location would have no physical obstructions more than ___ degrees above the horizon

Answer 17

5