GPS, and several other similar systems.
Orbiting satellites.
Venus has two artificial satellites orbiting it, radar-mapping the surface and gathering other useful information about its surface.
Mercury has no known moons (or natural satellites) and has no manmade satellites orbiting it either. It was visited in the 1970s buy a man made probe called mariner 10, which made three passes to observe and map it's surface.
GPSes, or Global Positioning Satellites combined with the WAAS (Wide Area Augmentation System) provide the signals GPS receivers use to determine a location on the Earth's surface
The US Department of Defense developed the satellite-based Global Positioning System (GPS) between 1973 and 1994. Accurate signals are sent by orbiting satellites to any receiver on the Earth's surface that is in their line-of-sight. With information from 4 or more satellites, the location of the receiver can be precisely determined.
No. Up to the present time (early-to-mid-2014), all successful satellite launch procedures have originated from the Earth's surface. (Plus perhaps the six Apollo launches from the lunar surface, which were actually navigated to rendezvous with the orbiting Command Module, and not to become satellites of anything.)
We see deep into space by using optical or radio telescopes, either from the Earth's surface, from satellites orbiting above us, or carried out into space on an unmanned spacecraft.
To determine latitude and longitude the minimum number of satellites that the receiver must lock onto is three. To also determine elevation the minimum number of satellites that the receiver must lock onto is four. If the receiver can lock onto more satellites then it can improve the calculations to get a more precise location.
The most widely-known use for geo-stationary satellites - is the GPS system. There are sixteen geo-stationary satellites spaced evenly around the globe, to provide the data required by the GPS network to enable motorists to navigate safely throughout their journey. Another use would be satellite TV. Satellites for TV broadcasting are usually orbiting in a fixed position, to provide a transmission 'footprint' on the surface of the earth.
GPS means Global Positioning System. This system includes 24 satellites that transmit microwave signals, allowing us to determine our location on the planet's surface with amazing accuracy. See link for details.
Mapping satellites.
For one thing, they make the clocks that go in GPS satellites advance a little bit slower than normal so that when the satellites are orbiting the earth at tens of thousands of miles per hour the clocks seem to be in sync with our clocks here on the earth's surface.