As we all know, GPS is mainly a terminal product that receives satellite signals and then locates or navigates. During the process of receiving the antenna signal by GPS, the antenna must be used. GPS satellite signals are divided into L1 and L2, with frequencies of 1575.42MHZ and 1228MHZ, respectively, of which L1 is an open civil signal and the signal is circularly polarized. The signal strength is about -166dBW, which is a relatively weak signal. It is precisely because of these characteristics that GPS signal reception requires special antennas.

Introduction to the classification of GPS antennas

1. From the perspective of polarization mode, GPS antennas can be divided into vertical polarization and circular polarization.

Vertical polarization is not as effective as circular polarization. Therefore, except in special cases, GPS antennas will be circularly polarized and linearly polarized.

2. GPS antennas can be divided into internal antennas and external antennas according to the placement method.

The location of the antenna is also important. In early GPS handsets, flip antennas were mainly used. At this time, the antenna is basically isolated from the whole machine, EMI is almost not affected, and the satellite reception effect is very good. With the trend of miniaturization, GPS antennas are mostly built-in. At this time, the antenna must be on all metal devices, and the shell must be plated and well grounded, away from EMI interference sources, such as CPU, SDRAM, SD card, crystal oscillator, DC/DC, etc.

The application of automotive GPS will become more and more common. But car shells, especially car explosion-proof films, seriously hinder GPS signals. An external antenna with magnets, which can be attached to the roof of the car, is necessary for the vehicle's GPS system.

3. From the aspect of power supply, it is divided into active and passive.

External GPS is an active antenna,

such as the external antenna of da Gama GPS, which is basically an active antenna. The passive antenna does not contain an LNA amplifier, only the antenna body.

GPS antenna function

First: it is used to intercept satellites and receive satellite positioning information, that is, to radiate and receive electromagnetic waves; Any high-frequency circuit, as long as it is not completely shielded, can radiate electromagnetic waves into the space around it, or receive electromagnetic waves in the surrounding space. GPS antennas can be divided into flat panel antennas and spiral antennas, and spiral antennas have strong search capabilities. It does not transmit a cell phone signal.

Second: convert the electromagnetic wave energy from the radio signal from the satellite into the current that the receiver electronics can absorb, that is, energy conversion; Generally, for special equipment or vehicle-mounted equipment, because there is often a certain interval between the device and the GPS receiving module, a signal feeder of more than 1 meter may be used in the actual environment; However, since the feeder has considerable loss of the signal, only an active GPS antenna can be selected in this case.

Up to now, I believe that everyone should be familiar with GPS, in the signal receiving and transmitting device, GPS module antenna is an indispensable structure. For example, mobile phones that everyone uses most frequently every day, radios, TVs, drones and other devices have GPS module antennas.