tranthuongbn
Posts : 316
Join date : 2011-03-04
 |  Subject: Global Positioning System  Sun Jun 19, 2011 2:48 am | |
| The Global Positioning System (GPS) is a space-based global navigation satellite system (GNSS) that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites. It is maintained by the United States government and is freely accessible by anyone with a GPS receiver. The GPS project was developed in 1973 to overcome the limitations of previous navigation systems,[1] integrating ideas from several predecessors, including a number of classified engineering design studies from the 1960s. GPS was created and realized by the U.S. Department of Defense (USDOD) and was originally run with 24 satellites. It became fully operation Philadelphia Car Accident LawyerMarketing Franchise | |
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