What is a GPS Antenna?

A GPS antenna is a device that helps boost the reception signal to a GPS unit, whether it is a standalone unit or an embedded unit. Often a GPS antenna is used in a situation where the GPS unit itself is somehow removed from a line of sight to the sky, as in a car, to help the GPS “see” the sky without having to be moved. GPS antennae may be purchased for a range of budgets, or cheaper home versions can be made with fairly common components.

 

GPS, or the Global Positioning System, is a satellite system originally developed by the United States Department of Defense. It utilizes more than two dozen satellites orbiting the Earth to allow receivers on the ground or in the sky to tell exactly where they are, by receiving heads off of multiple satellites. Using this location, devices can detect not just latitude and longitude, but also altitude, and even heading and speed. For years, GPS was reserved for military use in the United States, but following a directive by President Reagan in 1983 it became open for civilian use.

 

Civilian GPS contains certain restrictions, imposed by the US government to make sure hostile forces don’t use the technology in missiles. As a result, consumer GPS isn’t capable of operating when moving at more than 515 m/s at more than 60,000 feet (18 km). Throughout the eighties and early nineties GPS was used primarily in commercial avenues, such as on fishing boats, in airplanes, or for geographic surveying. In the late nineties it began gaining popularity for consumers for hiking or for driving, and by the new millennium cars were being equipped with built-in GPS to give driving directions, and cell phones began having included GPS for directions and location.

 

A GPS unit has a built in antenna, which is usually quite small and located inside of the unit. While this will likely function in ideal circumstances, such as when in a desert moving at slow speeds or staying still, it may not work as well as one would like in more trying circumstances. A GPS unit likes to have a clear, unobstructed view of the sky, to best receive the microwave signals that allow it to communicate with satellites. For GPS units inside of cars, this can be problematic, so often an external GPS antenna will be used, mounted to the outside of the car with a magnet, and connected to the unit itself by a cable.

 

In situations such as heavy canopy cover while hiking, the small GPS antennas built into a consumer unit also may not be able to ideally communicate with the satellites. In this case, a larger, more advanced GPS antenna helps the unit overcome the environmental challenges, to give a clear signal. Similarly, moving at high velocities can overwhelm a smaller, less sophisticated antenna, and an external device can boost the signal.

 

There are a number of different types of GPS antenna, with the patch and Quad Helix styles being the most popular. Both are roughly equal in efficacy, although many people find the quad helix to have a slight bit more sensitivity. Other types of antennae include microstrips, of which the patch is one configuration, planar rings, and spiral helices.

 

Established in 1996, Cirocomm is an outstanding manufacturer of GPS antenna in the industry. We also provide various antenna series, including dielectric filter, Glonass, WIFI, GSM, NFC antenna series and more. If you are interested in and need more details about GPS antennas, welcome to visit our website and send inquiry to Cirocomm!

 

Article Source: http://www.wisegeek.com/what-is-a-gps-antenna.htm

Basic Information of CNC Rotary Table

A CNC rotary table is a disc-shaped metalworking device used to obtain precise workpiece positioning. It enables a metalworker to cut or drill a workpiece at precise intervals around a vertically or horizontally fixed axis. A rotary table can be both manually or computer numerical controlled. Certain types of rotary tables are designed to be used with indexing plates or dividing plates for specialized operations. A rotary table used together with one of these positioning plates is generally referred to as a dividing or indexing head.

 

The CNC rotary table device typically has a solid base that can be attached to a separate fixture or table using clamps. This device is basically a rotating disc which holds the workpiece in place during cutting or drilling operations. The disc portion of a rotary table can be freely rotated for indexing procedures or turned by an attached control arm known as a worm wheel. Tables used in high precision operations are typically turned by a duplex-type worm wheel to compensate for backlash. Rotary tables used in automated metal working processes are turned by computer numerical controlled machinery.

 

CNC rotary tables are most often used in a flat position with the table’s axis having a vertical orientation. They are sometimes mounted with the axis oriented in a horizontal fashion so that a tailstock can be used to support the free end of the workpiece. When this device is attached to a secondary table, the workpiece can be centered on the rotary table’s axis which is then centered on the cutting tool’s axis. In this configuration, the axes of the rotary table, secondary table, and cutting tool are coaxial to facilitate concentric cutting operations. This configuration also permits the secondary table to be offset for drilling equidistant holes in a workpiece.

 

It is also a necessary component for many different types of machining and milling procedures. This versatile device can be utilized to perform specialized tasks such as machining spanner flats on bolts and drilling holes in flanges. In certain other configurations, a rotary table can also be used cut complex curves, arcs, and round pieces with protruding tangs. Rotary tables are sometimes used to produce a large-diameter hole in a workpiece by cutting in a tight circular path. This device can also use in place of a lathe when it is operated by a stepper motor combined with a computer numerical controlled milling machine and tailstock.

 

Founded in 2000, OCEAN is the professional manufacturer of CNC rotary table and EDM machines. We provide high quality products and services for you. If you need more information about rotary tables, welcome to visit our website and feel free to contact OCEAN!

 

Article Source: http://www.wisegeek.com/what-is-a-rotary-table.htm