Did You Know… May 1st 2000 President Bill Clinton Opened up the GPS Signal that Enabled Navigation As We Know it Today. Some details about this provided to us via Navigon… President Bill Clinton changed the course of navigation possibilities with the push of a button that turned off the US GPS satellite dithering signal. Known as “selective availability”, this block was set up by the US government to prevent the military use of GPS by their enemies. Clinton’s decision to turn off the GPS interference signal helped mobile satellite navigation to finally make its breakthrough. See more details HERE
GPS, Did You Know?
1. Three satellites are needed to ascertain the position of a GPS receiver.
2. It takes 24 satellites and several backup satellites orbiting the Earth at a height of over 20,000 kilometers, to ensure that three satellites are available anywhere in the world and at any time.
3. Satellites transmit an uninterrupted signal detailing their current location and time, and it’s up to the GPS receiver to handle the signal delay with the help of an integrated clock to calculate its own position and speed.
4. Using distance measurements from three points, known as trilateration, exact positions are determined. The signal from the first satellite determines the receiver’s degree of longitude; the second identifies the degree of latitude. As the receiver’s integrated clock is not accurate enough to measure the exact signal delays, the clock error is calculated using a third satellite and thus identifying the exact position.