Today, GPS is most commonly known for vehicle navigation solutions. However, the GPS system for many other useful purposes can be used. For example, many computer network time synchronization solutions, such as NTP time server, use the atomic clocks aboard the GPS satellites for accurate timing. The GPS system can be used as an accurate reference clock for synchronization of time-critical applications on computers and networks. This article describes how computer systems canusing GPS time and discussed what equipment is needed to represent a precision timing reference.
The GPS system is a U.S. military intended for global navigation. The GPS system is a space-based system, consisting of a network of 24 satellites in orbit. Precise navigation and positioning is achieved through the use of precision timing signals and triangulation between several satellites. In order to give exact time, each satellite has an integrated high-precisionAtomic clocks on board. Each satellite transmits timing information within a few nanoseconds the right time to deliver positioning with an accuracy of better than 10m. The exact timing will be information, it can by NTP servers and other computer timing devices as a very precise time reference used. The great thing about GPS is that it works anywhere in the world and is completely free to air service.
Each GPS satellite broadcasts a low-power radio signal into theSurface of the earth. Two separate frequencies are used, called L1 and L2. The L1 band is the civilian signal, transmitted at 1575.42 MHz. L2 is the military spectrum, designed for extremely high precision positioning. Transmission of radio signals through the air through the line of sight. The transmitted signal is easily powerful enough to pass through clouds, glass and most plastics, but also absorbs more substantial material such as bricks, roofing materials and metals. The ideal place fora GPS antenna tends to be outdoors and, ideally, on a rooftop with the best view of the sky.
To get this to GPS timing and position information, some relatively inexpensive equipment is not required. A GPS antenna can be used to enhance the GPS receiver and radio signals. While a GPS receiver decodes the information and presents it in a computer readable format. Many antennas are available with built-in receiver, but these have the disadvantage of only a few meters, the provision ofCabling to the host NTP server or computer system. Robust to install GPS marine antennas screw-down on a rigid threaded rod in a position to withstand the worst of the weather. These antennas offer the best solution for static timing applications.
The GPS receiver is usually in the NTP server, embedded or encapsulated in a housing. A GPS receiver is a small elecronic device that receives GPS signals amplified by an antenna via coaxial cable. The receiver decodes theseSignal and provides a computer readable output is usually via an RS232 or USB interface. Most receiver decodes information such as: location, visible satellites, the exact time and an accurate timing pulse output reference.
Coaxial cables are used to provide a connection between the GPS antenna and receiver. The cable distance can be critical. The antenna needs to step up the GPS signal enough to overcome all the losses used to run cable to the cable. Better qualityAntennas generally provide more amplification (gain) addition of a higher quality coax cables can be much smaller signal loss per meter used allows for a relatively long cable runs between the antenna and receiver. For longer cable runs, amplifiers can be used in order to encourage more GPS signals in order to overcome cable losses. Typically, a GPS sat-amp line on the coax cable and is powered by the receiver. Multiple amplifiers can be run for extremely long cable used.
A roof mountedGPS antenna can be vulnerable to lightning and power surges. It is recommended that surge arresters are utilized to protect expensive NTP server and timing systems from potential damage. A surge is essentially a barrier that is seated in-line on the coax cable between the antenna and receiver that the recipient protects from any potential damage from voltage surges.
In conclusion, the GPS system provides a very accurate timing reference for NTP servers and otherComputer timing equipment. It is a reliable service, free, can be used anywhere in the world air. In addition, with the boom in car navigation technology is required, get satellite channels constantly fall included.
0 ความคิดเห็น:
แสดงความคิดเห็น