Mobile Object Information Sharing System
First Claim
1. A mobile object information sharing system comprising a plurality of mobile stations, wherein the mobile station includes:
- a radio device for communicating mutually at one radio frequency;
a GPS receiver that obtains, by GPS radio waves, at least position information and moving speed information of its own station and shared time information;
a time division synchronous radio modem device that synchronizes mutually among the plurality of mobile stations using the shared time information, after this time synchronization, sets a fundamental transmission period by arranging continuously a plurality of transmission slots having a predetermined time width, transmits the position information of its own station to the radio device in an optional period of the plurality of transmission slots, and receives the position information of other mobile stations;
a transmission period determining unit for determining the optional period using the moving speed of the mobile station; and
an operation unit that determines a transmission timing among the plurality of transmission slots based on the optional period determined by the transmission period determining unit and transmits the position information of its own station.
1 Assignment
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Accused Products
Abstract
In a system where mobile stations use one frequency to transmit/receive and share position information data, synchronization has been made in a shared time resulting from GPS and the mobile stations transmit the data at mutually different timings that are predetermined, whereby overlapping of the transmissions is avoided. However, the transmission period of a station cannot be changed even if that station wants to change its transmission period. Transmission period determining units are disposed which determine transmission periods on the basis of the moving speeds of mobile stations. The mobile stations are time-synchronized by GPS. After the time synchronization, fundamental transmission periods comprising plural time slots are disposed. Transmission is done just in one time slot within one fundamental transmission period normally, and the number of transmissions is increased to two times or three times within one fundamental transmission period when the period is to be shortened.
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Citations
7 Claims
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1. A mobile object information sharing system comprising a plurality of mobile stations, wherein the mobile station includes:
a radio device for communicating mutually at one radio frequency;
a GPS receiver that obtains, by GPS radio waves, at least position information and moving speed information of its own station and shared time information;
a time division synchronous radio modem device that synchronizes mutually among the plurality of mobile stations using the shared time information, after this time synchronization, sets a fundamental transmission period by arranging continuously a plurality of transmission slots having a predetermined time width, transmits the position information of its own station to the radio device in an optional period of the plurality of transmission slots, and receives the position information of other mobile stations;
a transmission period determining unit for determining the optional period using the moving speed of the mobile station; and
an operation unit that determines a transmission timing among the plurality of transmission slots based on the optional period determined by the transmission period determining unit and transmits the position information of its own station. - View Dependent Claims (2, 6)
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3. A mobile object information sharing system comprising a base station and a plurality of mobile stations wherein the mobile station includes:
a radio device for communicating mutually at one radio frequency;
a GPS receiver that obtains, by GPS radio waves, at least position information and moving speed information of its own station and shared time information;
a time division synchronous radio modem device that synchronizes mutually among the plurality of mobile stations using the shared time information, after this time synchronization, sets a fundamental transmission period by arranging continuously a plurality of transmission slots with a predetermined time width, transmits the position information of its own station to the radio device in an optional period of the plurality of transmission slots, and receives the position information of other mobile stations;
a transmission period determining unit for determining the optional period using the moving speed of the mobile station; and
an operation unit that determines a transmission timing among the plurality of transmission slots based on the optional period determined by the transmission period determining unit and transmits the position information of its own station. - View Dependent Claims (4, 7)
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5. (canceled)
Specification