Furuno Electric Company Limited

Kentaro Tsudaka

Akira Ninomiya

Suenobu Hase

There is provided a synchronization device capable of, even when transmission timings of a plurality of other ships are different, almost reliably synchronizing with the other ships during a transmission of a ship concerned and is also provided a synchronization method. The synchronization device, when the ship concerned performs a transmission, obtains timing differences DTi occurring over the past one minute from the transmission timing of the ship concerned (S) and creates a histogram of the timing differences DTi (S). The synchronization deviceselects a class with the highest frequency from classes of the timing differences DTi (S) and obtains a corrected timing DT' associated with the selected class (S). The synchronization devicecorrects a reference timing of the transmission of the ship concerned using the corrected timing DT&#x2032; and performs the transmission of the ship concerned (S).

Synchronization device and synchronization method

A TDMA communication apparatus is configured for transmitting DSC response signals while preventing overlapping with AIS. A CPUcomputes the DSC transmission time length Tof a DSC response command (S) and detects the present time t(S). CPUcomputes an AIS transmission standby time length Tand compares it with the DSC transmission time length T(Sto S). Next, if the DSC transmission time length Tis shorter, CPUcomputes an AIS reception standby time length Tand compares it with the DSC transmission time length T(Sto S). If the DSC transmission time length Tis shorter, CPUeffectuates transmission control (S).

TDMA communication apparatus

A network system where vessel instruments including sensors are connected through a communication network is provided. The sensors generate the same type of navigation data. The system includes a first network for realizing one-to-many communication, a first group instruments connected with each other through the first network, and a second group instruments connected to the first network with a different protocol from the first network. The first group instrument is an input/output gate between the second group instruments and the first network. At least one of the first group instruments has a server function. The first group instruments obtain identification information and types of navigation data of the second group instruments using the first group instruments as the gates, and the server-function instrument obtains identification information and types of navigation data of the instruments. The server function instrument selects one of the sensors generating the same type of navigation data, and outputs a sharing instruction of the data of the selected sensor, through the first network. The first group instrument provides the sharing instruction to the second group instruments using the first group instrument as the gate.

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Nishinomiya, Japan

Kentaro Tsudaka