GPS signal source is mainly through simulating the GPS satellite navigation signal, forming an accurate simulation GPS satellite navigation platform system under certain conditions, and applying it to various production and test simulation.Based on the comparison of the foreign GPS signal sources, this paper focuses on the functional characteristics of the domestic GPS signal source.

The GPS simulator abroad is relatively mature, such as Stanford Telecom and SPIRENT. The analog source is divided into single channel and multi-channel. The structure is mostly in the form of computer plus independent instrument cabinet or computer plus plug-in card. It has interactive graphical interface, and some analog sources can also simulate all kinds of environmental and human interference signals. It can not only simulate single point positioning satellite signals, but also simulate differential signals and attitude measurement signals. Some of them also have the function of satellite based augmentation system (such as WAAS).

However, the price of GPS signals abroad is very expensive. In practical applications, the budget of each unit is limited, so it can only be deterred. Moreover, at present, the international economic and trade wars are constantly upgrading, and high-end instruments and equipment, such as blindly relying on other countries, virtually push us to the passive and controlled situation. Under such circumstances, the development, use and iteration of homemade domestic simulator is particularly important.

The SYN5203 type domestic GPS satellite signal simulator is the best choice to replace the foreign signal source. The signal source standard product currently supports only GPS satellites, and can support GPS and Beidou satellite signals at the same time. To meet the needs of basic type and timing user equipment, we can finish the functions of precision test, navigation message test, lock out re capture test, location accuracy test, speed accuracy test, channel delay test, conformance test, bit error rate test and so on.

The domestic signal source has four main functions: real-time track recording, static trajectory production, dynamic track recording and track transmission. Support external track data entry and user defined trajectory input. Theoretically, all GPS receivers within a radius of 100 meters can be connected. If it is necessary to reduce the analog GPS signal strength and prevent the signal from overly affecting other devices, it is recommended that the device and simulator be connected directly, and the signal after direct connection is weak. Additionally, the signal attenuator can be added to the output interface of the simulator.

In terms of track duration, the default standard version is 32G support for 100 minutes, and can also be extended to 1T external hard disk. It can preset multiple trajectories or static trajectories, that is, fixed points. The track switch is convenient, and the track preset number is not limited, and the detailed data such as velocity and acceleration can be set.It has the functions of single run and infinite loop.

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