Antenna: mainly refers to the position of the wire used when GPS receives signals, such as built-in antenna, external antenna, car antenna, etc.

　　Signal: is a kind of information resource that can be shared by countless users. For the majority of users on land, sea and space, as long as the user has a receiving device that can receive, track, transform and measure GPS signals, that is, a GPS signal receiver, you can use GPS signals for navigation and positioning measurement at any time. According to the different purpose of use, the GPS signal receiver required by the user is also different. At present, there are dozens of factories in the world to produce GPS receivers, and there are hundreds of products. These products can be classified according to principle, use, function, etc.

　　Installation position accuracy: mainly refers to a circle with the installation position of the GPS device as the center of the circle, when the GPS satellite positioning, the maximum error of the GPS receiving device will not be located outside this circle, so the radius of this circle is called the installation position accuracy. The accuracy error of the GPS positioning satellite system is only a few meters, but in order to avoid the misuse of the GPS system by terrorists to sabotage activities, the United States especially puts the GPS system plus a kind of error control called Selective Availability (SA), so that the general civilian GPS system error will reach about 100 meters. However, as of 2 May 2000, this control has been lifted. Existing GPS devices can be accurate to a few meters if the manufacturer wants.

　　Interface: The interface of GPS device can be divided into data interface, power interface and RF interface. The specific standards of various interfaces are as follows: Data/power interface: international standard 20-pin (2×10) plug, RTCM104/RS-232, NMEA0183; Rf interface: OSX (or MCX type, ultra-small, lock type).

　　Refresh speed: refers to how often after the GPS device is installed, it refreshes the information sent by the GPS satellite to obtain the latest positioning information. Generally, after installation, refresh once every 1 second, so that the positioning information obtained is almost real-time.

　　Track points: A route is a set of data stored in GPS memory, including coordinates for a starting point and an ending point. The start and end points here are called trajectory points.

　　Track: The route is a set of data stored in the GPS memory, including the coordinates of a starting point and an end point, and can also include the coordinates of several intermediate points, and the line segment between each two coordinate points is called a "track".

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