On-vehicle DSRC apparatus
An on-vehicle DSRC apparatus capable of being operated with a battery power supply while decreasing power consumption includes a radio unit ( 1 ) for performing communication with an on-road radio equipment ( 30 ), a data processing unit ( 2 ) for processing data received from the radio unit ( 1 ), a battery ( 3 ) for supplying an electric power to the radio unit ( 1 ) and the data processing unit ( 2 ) and a first power switch ( 4 ) inserted in a power supply line extending between the battery ( 3 ) and a combination of the radio unit ( 1 ) and the data processing unit ( 2 ). The first power switch ( 4 ) is imparted with a function for controlling the power supply from the battery ( 3 ) so that the power can be saved. In case use of the on-vehicle apparatus is unnecessary, a power supply is interrupted for saving electric energy to prolong the battery life.
1. An on-vehicle DSRC apparatus employed for a dedicated short-range communication in an intelligent transport system, comprising:
a radio unit for performing communication with an on-road radio equipment installed at a location associated with a road;
a data processing unit for processing data received from said radio unit;
a battery for supplying an electric power to said radio unit and said data processing unit; and
a first power switch inserted in a power supply line extending between said battery on one hand and said radio unit and said data processing unit on the other hand,
wherein said first power switch is imparted with a function for effectuating a power save for control for the power supply from said battery so that electric energy of said battery can be saved,
said on-vehicle DSRC apparatus further comprising:
an electric field intensity detecting circuit for detecting a field intensity of radio wave transmitted from said on-road radio equipment;
an activating circuit for activating said first power switch when a detection output of said electric field intensity detecting circuit becomes higher than a predetermined level inclusive thereof;
a second power switch inserted in a power supply line extending between said battery and said electric field intensity detecting circuit for controlling the power supply to said electric field intensity detecting circuit from said battery; and
a first timer for intermittently driving said second power switch.
2. An on-vehicle DSRC apparatus according to claim 1 , further comprising:
a switch control unit for controlling the power supply through said second power switch and interruption thereof in response to an output signal of said data processing unit.
3. An on-vehicle DSRC apparatus according to claim 2 , further comprising:
a second timer for delaying starting of the power supply through of said second power switch in response to an output signal issued from said second switch control unit.