Several commonly used modes of timing for GPS timing instruments

GPS timing meter is widely used in shooting range, weapon system, hospital, electric power, finance and other industries. In this paper, we will discuss several timing methods commonly used by GPS timing meter.

The GPS timing instrument consists of two parts: the satellite receiving antenna and the host. The host of the timing instrument can be divided into a standard time signal receiving unit, a time holding unit and a time frequency signal generating unit. In practical applications, these units are integrated on one device.

GPS timing meter provides users with accurate time and frequency signals to ensure that the whole system is highly accurate and unified. The time service methods of GPS timing instrument include NTP timing, IRIG-B code, IEEE588 and other time synchronization methods, including organic box type, board card type, module type and so on.

The timing meter acquires the standard time information by receiving satellite signals or various external reference time signals, synchronizes the local clock, maintains time by using the internal time base, and outputs NTP, PTP, B (DC) and other time signals externally. Next, we introduce these three commonly used modes of time service.

NTP network timing, commonly used network equipment, such as computers, servers, network cameras, etc., are suitable for NTP time service. The timing accuracy can reach the MS level time synchronization accuracy. The NTP protocol adopts client / server working mode. When the Beidou school receives the Beidou signal or uses the built-in atomic clock as the time benchmark of the system, the client regularly visits the server according to the set time interval to get accurate time information and adjusts its own system clock to synchronize its own time.

PTP timing requires hardware support, which is usually used by master slave. The exchange time synchronization message is continuously exchanged from the node to the master node to adjust the time from the calibration node.

In addition to the cabinet type master slave clock, the PTP device often requires less volume of equipment in the actual use environment, and the unit has 1588 clock module integration capability. This situation can choose to purchase various 1588ptp boards, small size, high cost performance, and can be used from the owner. For example, when using SYN2407C type timing module, it is recommended to use SYN2306C type receiver at the same time, otherwise debugging later will be more troublesome.

The B decoding device means that the device receives the IRIG-B (DC) /IRIG-B (AC) signal and demodulates it to generate the serial port time information and the 1PPS second signal synchronous pulse signal. This method has high precision and small transmission error.

The B code generator means that the device receives the GPS satellite signal, or accepts the serial port time information and the 1PPS signal to synchronize the B code product equipment (board or cabinet). It generates one or more channels IRIG-B (DC) or IRIG-B (AC) code signal to provide the B code time for the client in the clock system. There are portable chassis, standard 1U chassis and board module for users to choose to meet different application scenarios.

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