Classification Of Knowledge--GPS Antenna And The Important Role
The role of GPS receiver antenna, is the satellite radio signal receiver of electromagnetic energy is transformed into electronic devices can ingest application current. The size and shape of the antenna is very important, because these characteristics determine the antenna can get weak GPS signals. As needed, the antenna can be designed to work in a single on the L1 frequency, also can work on both L1 and L2 frequencies. Since GPS signals are circularly polarized wave, all receiving antennas were circularly polarized ways. Although there are a wide variety of conditions, there are still many different antenna types exist, such as unipolar, bipolar, spiral, four-arm spiral, and microstrip antennas.
We see in the market of GPS receiver antenna typically has two--flat-plate antenna and a four-arm spiral antenna, what advantages and disadvantages do exactly two types of antenna have let to answer it for you.
Flat-plate antenna (Patch Antenna)
Flat-plate antenna due to their durability and relatively easy to make and so became the most common type of antenna. Its shape can be round or square or rectangular, like a deposited copper printed circuit boards. It is made up of one or more pieces of metal, so the GPS antenna is the most common shape is a massive knot, like a pancake. Due to the small antenna can do it, so suitable for aerospace applications and handheld applications.
Another major characteristic of antenna, is the gain of the graphics, directional. Use directional antenna can improve their resistance and anti-multipath capability. In the precise positioning of antenna phase Center is a very important indicator of the stability. However, general navigation applications, it is desirable to use Omni-directional antenna, receiving antenna at least five degrees over the horizon in sight all visible satellites in the sky signal, but flat-plate antenna for satellite antenna was above the line, signal gain is the biggest, this has two problems:
1, above the reception range of the tablet in tablet, tablet to look to the sky, for handheld and in-car trouble, we can see more and more CF sink angle (collapsible SDGPS Li-9551), because flat-plate antenna this makes manufacturers in order to receive better reception result came up.
2, we know that while we are overhead satellite signal is better, easier to lock, but in fact are overhead satellite is the most useless, if there is no satellite at low angle, error will be relatively high precision will be very poor. So based on these shortcomings, GPS also began to use a four-arm spiral antenna on the receiver.