questions, I know NOTHING about this , and understand it is available on the c6. can it be used for global position? and altitudes, and directions? or, Do you need to ''subscribe'' to something?, has anyone used this, and is it easy to use, and does it work in a way that is easy to understand, and operate while driving? if anyone can answer, thanks very much, ahead of time.

 

The NAV system is very easy to use. It uses global positioning and tracks, I believe 11 satellites but only 3 at a time. There is no fee to get GPS signal at all, its free.
The answer to all of your questions is yes, with the exception of altitude. Some GPS systems can track altitude, like the one in my airplane, but the automotive GPS units don't because they don't require it I guess.
It's way cool, and once you have one, you will never want another car unless it has one.
You simply enter in your street name, pick a city from a list and select guidance and the system will give you turn by turn instructions that are both verbal as well as on the moving full color map. The HUD will also display information such as the name of the next street and which direction to turn etc....
I hope this helps.

 

My favorite way to use it is to put in a phone number. It does have to be a listed number.

 

Just to show how bored I am tonight...

The global positioning system consists of 24 satellites that broadcast a high-frequency radio signals that contain time and distance data that is picked up by a receiver. These satellites orbit the earth in 12 hours periods. The satellite orbits repeat almost the same ground track (as the earth turns beneath them) once each day. The orbit altitude is such that the satellites repeat the same track and configuration over any point approximately each 24 hours (4 minutes earlier each day). (The Russians have their own system, called GLONASS.) The GPS is controlled by the US Department of Defense.

The receiver notes the time that the signals were transmitted by the satellite, and compares this time stamp with the time the receiver actually received the signal. With this information, the receiver calculates how far away the satellite is, and by comparing this distance, with the distance calculated from two other satellites, the receiver can determine where on the earth it is at that time. With these measurements, the receiver can also calculate speed, bearing, distance for trips, and if the computer contains mapping data, it can also determine distance to your destination. To compute altitude (3D mode), four satellites are required.

Normal accuracy is 15 meters (50 feet) or less, however, if the receiver is WAAS enabled, accuracy increases to 3 meters. WAAS (Wide Area Augmentation System) enabled receivers; provide satellite navigation correction and validation, making WAAS-enabled receivers at least five times more accurate than standard devices. WAAS relay stations have been set at known positions throughout North America. Accuracy with a WAAS system is 3 meters (9.8 feet) or less.

Sometimes, the receiver will have problems due to atmospheric conditions, but this is quite seldom. Also, a good receiver has to not only locate satellites, calculate their distance, but also must make corrections within their own internal clock. The satellites are equipped with atomic clocks, with accuracy within one second every million years; therefore, the receiver must also calculate how far off its own clock is, and make changes to allow calculations to be as accurate as possible.

To demonstrate how accurate a WAAS led global positioning system is, last year when off-roading and hiking in the desert, my Topographical Magellan GPS unit, pinpointed our accuracy to a landmark, as designated on the TOPO map to within three feet by our measurement. I started using GPS for off-roading and desert hiking and was so sold on it; I purchased a Garmin iQue3600 for traveling in a car. If a person gets lost using a GPS, they deserve to be lost.

NOTE: The original design of the system prevented civilian users from having receivers that were as accurate as military receivers. At this time, the civilian system was known as SPS or standard positioning system. I believe it was in the 1990’s when the US President signed an order allowing the civilian system to use military data that allowed the accuracy to increase notably.

 

My new Garmin Street pilot 2610 has altitude. It is very close. A great unit for 610 dollars but not built in. Can move from car to car

 

A GPS receiver needs to track at least 4 satellites to get altitude information. 3 is the minimum to determine your position without altitude.


All the satellites do, in essence, it transmit a clock signal. The GPS receiver does all the calculating by comparing the differences in clock signals received from various satellites, and can triangulate the position.

 

Garmin 2610 shows alt. and speed and hold max speed in memory. That said the build in NAV system blows it away. One of the CDs or DVDs says it has to use 4 sats, I have always thought it was three. I did not intend to get it in mine but I am really glad I did. putting it in the HUD is fantastic. This is the best one I have ever seen, and I have had three and sold GM cars for 20 plus years. the early ones used buttons and a joystick and I was a nightmare. Touch screen is fantastic.

 

Whitec5vette said it best. The CD that comes with the C6 explains it well... There are as an earlier post said, 24 satelites in orbit. The nav system utilizes 4 at a time to get the job done. I've been amazed at how well it works, and how accurate it is. It's a great feature..

 

Obtaining four satellites will lead to greater accuracy, but four should not be required for 2D information; only for 3D information (altitude). However, if the NAV system in the GM is programmed to require four, that is how it will work. However, that could lead to a problem driving through the mountains, canyons, even heavy forests. The receiver to satellite link is direct line of sight, and in the mountain areas of the west, you will drop some satellites due to obstructions.
In reality, a GPS receiver will actually be tracking six + satellites at one time. My Magellan and Garmin both display the number of satellites being tracked, and in an open area, devoid of any sight obstructions, they both track around 8 - 10 satellites at one time; including one or two WAAS satellites.

 

Sounds like we have a few experts here. Do those satellites rotate around the earth in such a way that the system can be used in Europe if I buy European DVDs for the Nav?

 

Further reading on this topic:

http://www.navcen.uscg.gov/faq/gpsfaq.htm

http://www.garmin.com/aboutGPS/

http://electronics.howstuffworks.com/gps.htm

Have fun! Remember, you don't have to know how it works to use the NAV (Navigation) unit in the C6... but it is fun to know!