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Active and passive differences in using GPS antennas
Apr 07, 2017

Current GPS antenna in agriculture, aviation, environment, maritime transport, public security and disaster rescue, railways, space, surveying and mapping and other fields play a very important role; some friends don't know what the characteristics of GPS antennas are. It not only has high positioning accuracy, fast collecting star speed, but also can be divided into active and passive, so in the use of the time, what is the difference between the two? The following small series to explain:

Passive GPS antenna

Using passive GPS antennas, because only one ceramic slice receives the satellite signal of the sky, directly connected to the RF-IN feet of the module, this connection is simple, and the standard 25*25*4 of ceramic chips are inexpensive, mature technology, small footprint, suitable for emphasizing compact space GPS navigation products, Bluetooth GPS, mobile GPS and other small GPS consumer products.

This antenna layout is from the antenna's PIN to the module's RF-IN feet, this wire needs to carry on 50 euro impedance match, and in the vicinity of the antenna can not have electromagnetic interference, PCB design and the machine's EMI design requirements, but if the design of the excellent passive antenna GPS products have a very good performance, and power consumption of the province.

Active GPS antenna

Usually for the equipment or on-board machine, because the equipment and GPS receiver modules often have a distance, considering that the convenience of installation may have more than 1 meters of distance, in this case we can only choose the active GPS antenna, due to the antenna length signal attenuation needs to compensate, generally have two-level low-noise amplifier (LNA) antenna front-end signal amplification, amplified signal after the cable output, the cable synchronous supply LNA required DC voltage.

Due to the antenna received signal in the antenna receiver to complete the signal reception and antenna amplification, and away from the GPS equipment or other electrical equipment, the smallest interference source, and the installation location because the antenna distance to extend the installation can choose a very ideal environment, so the actual use of the signal is often strong.

The above is the GPS antenna has a source and passive distinction, in the purchase of the time not only from its stability to consider, but also need to pay attention to the level of the module, because the GPS antenna module can be divided into two levels, one is civil, one is industry, so everyone should see clearly.