1. Today Discuss articles Primary / secondary data GPS ArcGIS demo Talk about homework: due next week Collect a waypoint, write it on board NO LAB DUE MONDAY BUT HOMEWORK DUE BEGINNING OF CLASS TUESDAY 1

2. Primary data sources –Original: survey, interview, census, GPS –New findings (FACTS) from a project –Collected for a SPECIFIC STUDY and DURING a specific study Secondary data sources –Archive data (Census, USGS, Google Earth, a history textbook, a review article) –The interpretation of primary data –Biography, movie review 2

3. Primary / secondary data sources 3 http://lib1.bmcc.cuny.edu/help/sources.html

4. 4 Global Positioning System For navigation, projectile guidance, search and rescue, survey, communications, time, recreation, tectonics

5. 5 The GPS Master Control Station, operated by the 50th Space Wing's 2nd Space Operations Squadron at Schriever AFB is responsible for monitoring and controlling the GPS satellite constellation.

6. 6 Segments User segment (10s of millions) Control segment (master control station(s)) Space segment (satellites) Global Positioning System

7. 7 Control segment (master control station(s))

8. 8 Space Segment: US GPS satellites 63 in orbit ~31 ‘healthy’ and available (9 in view from any point) Non-uniform arrangement of orbits Global Positioning System

9. 9 US GPS satellites Medium Earth Orbit 20,200 km (12,552 mi.) 12 hr. orbit 6 orbits; 4 satellites each

10. 10 ISS = 93 minutes

11. 11 What’s next: ^ life expectancy, ^ accuracy –GPS Block IIF – #11 of #12 launched 2/5/16 –GPS Block III (under development; Lockheed Martin; 2014 launch delayed to 2017, 3x more accurate) $115M / satellite – 36 to be purchased (4.6B total) –Much more: http://www.gps.gov/http://www.gps.gov/ Global Positioning System

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13. 13 GLONASS – Russia’s GPS (2010) –with GPS, allows 14 – 20 satellites! BEIDOU – China’s GPS (2012) IRNSS – India’s GPS (2015) Galileo – Europe’s GPS (2020) France, Japan under development Access to US GPS not guaranteed in hostile situations. Access to US GPS not guaranteed in hostile situations.

14. 14 THE WHITE HOUSE Office of the Press Secretary For Immediate Release May 1, 2000 STATEMENT BY THE PRESIDENT REGARDING THE UNITED STATES' DECISION TO STOP DEGRADING GLOBAL POSITIONING SYSTEM ACCURACY Bill: Today, I am pleased to announce that the United States will stop the intentional degradation of the Global Positioning System (GPS) signals available to the public beginning at midnight tonight. We call this degradation feature Selective Availability. This means that civilian users of GPS will be able to pinpoint locations up to ten times more accurately than they do now.

15. 15 MAY 1, 2000 MAY 3, 2000 Q: What happened? A: Selective Availability was removed

16. Augmentation systems improve positioning 16 CORS 19,000 stations, mostly in U.S. For post-processing to cm accuracy. Free. WAAS 50 ref. stations in N. America & HI. correct GPS precision errors. Free.

17. A CORS tracking station 17

18. 18 This is why you average waypoints

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20. NEXT ArcMap demo Hand out homework GPS practice – write lat./long. On board Work on homework 20

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