First, GPS navigation service is charged?
Thankfully, there is no extra charge for this service. Only need to purchase a navigation product can, such as GPS mobile phone, GPS PDA, or car GPS products, and even GPS module can be free to enjoy the satellite positioning service.
Second, GPS products, whether global?
Yes, the GPS product is actually a satellite signal receiver that can be used anywhere it receives a signal. Just to do for us to use, but also coupled with the local map software.
Third, what factors will affect the GPS receive signal?
(1) US Department of Defense SA Satellite Signal Interference (For the sake of its own safety, the U.S. government conducted a civil code called "Selective Availability" interference to ensure that its military system has the best The effectiveness of SA SA satellite via satellites randomly added error information, making civilian C / A code positioning accuracy down to about 100 meters.But using differential GPS technology, the system error can be reduced to 10 to 15 meters within.)
(2) weather factors (including sunspots, bad weather, etc. to reduce the intensity of the received signal)
(3) Under the shield of buildings, vehicles, heat insulation paper or metal components, GPS signals will be reduced or completely lost. In the open space, GPS devices receive the best signal.
Fourth, GPS how to complete positioning?
Because GPS is based on the principle of triangulation, it is necessary to receive more than three satellite signals to locate successfully, and when there are four satellite signals, the corresponding altitude values can be obtained. However, the error of altitude values is usually large. After all, Not a simple sphere.
Five, GPS equipment can not locate what is the reason?
(1) GPS signals are easily blocked by buildings and metal, so be sure to use your GPS outdoors.
(2) If you are unable to locate in the car, then GPS first placed on the roof of the GPS cold start and try it again, until the normal after the car.
(3) Please check if your GPS is connected to your device.
Sixth, GPS products appear "delayed" phenomenon?
(1) the receiver's connection performance;
(2) PDA or PC CPU speed and memory card read speed;
(3) PDA's RAM should have more than 20MB of space, allowing navigation software to work;
(4) GPS signal is transmitted once a second, more or less also has a relationship.
Seven, why GPS navigation "drift"?
The earlier GPS always had a broken message because of its weak ability to collect stars, especially when it was used for navigation in the city. This caused a lot of inconvenience to the user. Later developed some civilian GPS chip, the signal is not strong GPS signal income, resulting in the phenomenon of drift. But if, under the same circumstances, the older GPS product is completely broken, it is not until the signal is found that the satellite with enough signal will begin to accept it. So this is a more ambivalent choice, but with the continuous development and upgrading of software and hardware, I believe this situation will be less and less.