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Pacific Security Network News ]
GPS anti-theft device which is good GPS anti-theft device to buy
The GPS anti-theft device is the most advanced anti-theft device. In addition to the ordinary anti-theft, it can also quickly track the car position when the car is stolen, thus finding the car. However, the price of the GPS anti-theft device is more expensive than the ordinary burglar alarm, and it requires an additional service fee, so the popularity is not high. The GSM mobile anti-theft device relies on the GSM communication network, combined with the intelligent linkage anti-theft of the mobile phone and the car. The alarm of this type of anti-theft device is not limited by distance, covers a wide network, but needs to pay the monthly fee of the GSM number.
Shopping guide
When purchasing a GPS anti-theft device, you need to pay attention to the comparison of several common performances of GPS. The first is the positioning accuracy. Generally, the deviation of 5~10 meters in the positioning of GPS is a normal phenomenon. If the positioning deviation of the product is as many as several tens of meters or even hundreds of meters, such products can be ignored.
The second performance to be compared is the receiving capability. GPS is actually a receiver for satellite signals. When the GPS receiver receives three or more satellite signals, it can calculate the geodetic coordinates of the receiver. After receiving 4 satellites, you can also calculate the altitude.
The third thing to note is the satellite trajectory. There are a total of 24 GPS satellites orbiting the earth along six orbits. Each of the four satellites is a group. There are 12 satellites in the east and west hemispheres. There are not many and many satellites. Most GPS receivers can Track 8 to 12 satellites. At least three satellites are needed to calculate the coordinates. For a given location, the GPS receiver knows which satellites are nearby at this time because it constantly receives updates from the satellite.
The fourth point is the parallel channel. Generally, GPS devices have 2 to 5 parallel channels to receive satellite signals. Up to 12 satellites may be visible (average is 8). GPS receivers are mostly 12-channel type, which allows them to continuously track the information of each satellite. The advantages of the 12-channel receiver include fast cold start and initialization of satellite information, and better reception in forest areas. effect.
The last thing to notice is the positioning time. The positioning time is the time required to determine the current position when the GPS receiver is restarted. The closer to the last positioning position, the shorter the startup time and the cold start time is generally longer than the warm start time.
