What do you need to test for GPS?
5.DGPS you know, differential GPS (DGPS) positioning accuracy is very high, some GPS equipment providers set up a DGPS transmitter in some areas, free of charge to its customers, if customers are buying GPS receivers with DGPS function. The DGPS transmitter is a fixed GPS receiver (in a 100km ~ 200km exploration scene in the radius setting) receive satellite signals, it knows exactly what is the exact time of transmitting satellite signal to the theory, and then compare it with the actual delivery time, then calculate the "difference", influence this is very close to the atmospheric refraction, it will send out the difference, usually with FM (FM) radio data transmission using subcarrier modulation signal in the baseband receiver, GPS and DGPS function can receive and use it more accurate positioning.
3 positioning time this means when you restart your GPS receiver, it determines the time required for the current position. For the 12 channel receiver, if you are in the last position near the location of the cold start time is 30 seconds to 5 minutes, hot start is usually 5 to 40 seconds, and for the 2 channel receiver, most of the cold start more than 15 minutes, hot start 2 to 5 minutes. The positioning accuracy of the positioning accuracy of 4 which is obtained in the case of no WAAS/EGNOS conclusion, rather than most of the GPS receiver specification of the positioning accuracy, can look at the test report of others so before the purchase of GPS, now on the market with 12 channel GPS receiver error level is generally not more than 30 meters, height error not more than 50 meters, the average error is about 15 meters. Due to the use of the module, our product positioning error is about 10 meters,
As a high-tech product, GPS has a very complex technical parameters. However, as people's living standards improved rapidly, more and more ordinary people began to pay attention to the positioning and navigation tools originated from the military. Because the convenience it brings is unprecedented. In order to let everyone out of all the technical parameters of GPS receiver, no longer confused at the time of purchase, the author selected six of the most important technical indicators, one by one to explain to you. 1 parallel channels on the market most of the GPS receiver is a 8 channel, 12 channel, the 16 channel, which allows them to continuously track the information of each satellite. Some GPS devices only have 2 to 5 parallel channel receiving satellite signals, because the average of 8 satellites are visible, which means that the GPS receiver must visit each of the satellites in order to obtain information about each satellite. All of our products are in Shenzhen channel 16 channel, multi-channel parallel GPS receiver, including the advantages of rapid cold start and initialization of satellite information, but also in the forest area can have a better reception. General 12 channel receiver does not require an external antenna, unless you are in a bad environment conditions such as closed space, such as the cabin, the car. 2 the sensitivity of the GPS satellite signal to the ground has been very weak, as well as ground wireless communication clutter interference. The lowest traceable signal strength of the GPS receiver determines how much useful signal is received. A GPS receiver with a lower minimum tracking signal strength has a higher sensitivity, and can receive more available satellites under bad conditions
6 antenna type to give you a good positioning, GPS receiver requires at least 3 ~ 5 satellites are visible. If you are in a canyon or on both sides of the street, or in the dense jungle, you may not be able to contact with enough satellites, so that you can not locate or only two-dimensional coordinates. Also, if you're in a building inside, you may not be able to update your location, some GPS receivers have a separate antenna can be attached to the windshield, or built-in active antenna, or an external active antenna can be placed on the roof, the receiver which helps you get more satellite signals the. 7 other indicators to buy GPS equipment, according to the needs and use of the environment, size, weight, waterproof, shockproof, dustproof performance, high temperature resistance, power consumption and other indicators should be taken into account.
