Based on Chinese Beidou Satellite Navigation and Positioning
Beidou Vessel Network is compatible with GPS satellite navigation
system and has lots of functions including all-dimensional and
all-day communication contacts with fishing boats and mastering of
accurate fishing boat location. Its scope of communication covers
the whole state and other countries and regions nearby. It can also
effectively make up the dead zones that cannot be monitored by
overseas vessels, and effectively protect the life and property
safety of numerous fishermen.
Besides, it also sets up an effective communication and information
interaction means for different fishery competent departments and
oversea fishing boats, with which the fishery competent departments
can catch fish cross borders in sensitive waters through system
alert and warning, and the fishermen can seek help in time if
disturbed, making it convenient for promptly mastering the offshore
conditions, and composing a dispute.
The following three items shall be constructed for the Project:
Beidou shipborne terminal, Beidou vessel data center & relevant
network platforms, and application system.
1. Beidou shipborne terminal
According to the Project’s background and demands, the shipborne
terminal shall be designed according to different functional unit
(i.e. display control unit, Beidou communication unit, and maritime
affairs unit) modules, including positioning, Beidou short message
communication, voice communication, management, alarming, display,
electronic chart, etc.
2. Beidou vessel data center & relevant network platforms
It is necessary for Beidou Vessel Network to construct Beidou
vessel data center, provincial monitoring & command center,
first-class fishing ports at the municipal, district, county level,
monitor terminals in townships, towns and villages, and relevant
network links, so as to offer direct services to administrative
departments at different levels, relevant government sectors,
maritime search and rescue centers and other institutions.
3. Application system
Beidou Public Location Service Platform shall be utilized for
relevant positioning service capabilities necessary for the
application system of Beidou Vessel Network. The business functions
shall be customized and developed based on specific demands.
According to the investigation and analysis, application demands of
the system include basic display of electronic chart, vessel data
management, vessel supervision, accident investigation, vessel
service, receive-disposal alarm function, remote terminal settings,
system expansion, etc.
1. Terminal control frequency variation technology
As the vessel is moving, the satellite system will arrive at the
ground through the ionized layer, and generate Doppler effect,
causing certain deviation to the satellite frequency received by
the terminal. In the base band algorithm, the clock frequency of
radio frequency module is controlled by figuring out the frequency
deviation between the local oscillator clock and the received
satellite signal, and controlling AFC voltage through digit
circuit, so as to maintain the clock frequency of the terminal
consistent with the deviation to the received satellite frequency.
2. Open data exchange technology
Besides system operation, a complex system sharing one data
interface with several business systems shall be capable of
integrating with other business systems. The system provides a data
exchange mode based on XML technology as well as the integration
capability based on WEB embedded technology and the business