Mobile object identification device

Claim 2

A mobile object identification device for a communication area where information is exchanged between a mobile object and a station comprising: an antenna control unit having an antenna disposed at said station for repeatedly transmitting a communication signal-wave, which includes a pilot signal and an interrogatory signal in a portion of a cycle time of said communication signal-wave and an unmodulated carrier-radio-wave through said antenna toward said communication area, and for receiving a responding signal-wave from said communication area in another portion of said cycle time; and a responder unit mounted on said mobile object for transmitting said responding signal-wave when receiving said pilot signal and said unmodulated carrier-radio-wave subsequently, said responder unit including: a receiving circuit receiving said unmodulated carrier-radio-wave from said communication area, a control circuit generating a responding data-signal, and a transmitting circuit modulating said unmodulated carrier-radio-wave with said responding data-signal and transmitting a modulated carrier-radio-wave as said responding signal-wave; wherein said antenna control unit comprises: means for decreasing output power of said antenna to a prescribed level while said antenna control unit is transmitting said pilot signal of said communication signal-wave, said prescribed level being lower than the level of the output power of said antenna while said antenna control unit is transmitting said unmodulated carrier-radio-wave, to thereby decrease said communication area, and means for switching said pilot signal to said interrogatory signal when an acknowledgment of said pilot signal is received by said antenna control unit.

Claim 3

A mobile object identification device claimed in claim 1 further comprising a gate for toll collection, wherein said antenna is disposed on said gate.

Claim 4

A mobile object identification device claimed in claim 2, wherein said antenna control unit further comprises means for transmitting said unmodulated carrier-radio-wave subsequent to said interrogatory signal.

Claim 5

A mobile object identification device claimed in claim 3 further comprising a signal-processing-circuit for processing data for said toll collection when receiving said responding signal-wave.

Claim 6

A mobile object identification device claimed in claim 2, wherein said antenna control unit further comprises a plurality of antennas disposed on said gate.

Claim 7

A mobile object identification device claimed in claim 5, wherein said antenna control unit further comprises a means for generating a plurality of said carrier-radio-waves having different frequencies and respectively assigning said carrier-radio-waves to said plurality of antennas corresponding to said communication areas overlapping with one another.

Claim 8

A mobile object identification device claimed in claim 6, wherein said means for generating a plurality of carrier-radio-waves having different frequencies further comprises circuit means for supplying said communication signal-waves to said plurality of antennas at different times.

Claim 9

A mobile object identification device claimed in claim 4, wherein said responder unit includes a communication program which controls said responder unit to stop communication for a given period after said toll collection process has been completed.

Claim 10

A mobile object identification device claimed in claim 4, wherein said responder unit includes a communication program which controls said responder unit to stop communication until a given running distance after said toll collection process has been completed.

Claim 11

A mobile object identification device claimed in claim 3, wherein said responder unit includes a communication program which controls said responder unit to stop communication until it has received said pilot signal-wave.

Claim 12

A mobile object identification device claimed in claim 10, wherein said antenna control unit includes a plurality of antennas; and said responder unit includes a communication program which controls said responder unit to prohibit communication with other antennas when it has received a pilot signal-wave from one of said plurality of antennas.

Claim 13

A mobile object identification device claimed in claim 10, wherein: said antenna control unit comprises means for transmitting a pilot signal-wave and an unmodulated-carrier-radio-wave; and said means for transmitting said pilot signal-wave and interrogatory signal-wave transmit said pilot signal-wave at a power level lower than said interrogatory signal-wave.

Claim 14

A mobile object identification device claimed in claim 10, wherein: said antenna control unit comprises means for transmitting an unmodulated-carrier-radio-wave; and said means for transmitting said unmodulated-carrier-radio-wave transmits said unmodulated carrier-radio-wave at the same power level as said interrogatory signal-wave.

Claim 15

A mobile object identification device claimed in claim 1, wherein said antenna control unit further comprises a plurality of antennas disposed on a gate.

Claim 16

A mobile object identification device claimed in claim 14, wherein said antenna control unit further comprises means for generating a plurality of carrier-radio-waves having different frequencies, and respectively assigning said plurality of carrier-radio-waves to said plurality of antennas corresponding to said communication areas which overlap with one another.

Claim 17

A mobile object identification device claimed in claim 15, wherein said means for generating a plurality of said carrier-radio-waves having different frequencies further comprises circuit means for supplying said communication signal-waves to said antennas at different times.

Claim 18

A mobile object identification device claimed in claim 1, wherein said pilot signal indicates that said mobile object has entered said communication area.

Claim 19

A mobile object identification device claimed in claim 1, wherein said unmodulated carrier-radio-wave is transmitted after said pilot signal.

Claim 20

A mobile object identification device claimed in claim 1, wherein said mobile object is mounted on an automobile, and said station is disposed at a toll road for toll collection.

Claim 21

A mobile object identification device as claimed in claim 1, wherein said antenna control unit transmits said pilot signal and said unmodulated carrier-radio-wave successively.

Claim 22

A mobile object identification device for exchanging information between a mobile object and a station comprising: an antenna control unit having an antenna disposed at said station for repeatedly transmitting a communication signal-wave, which includes a pilot signal and an interrogatory signal in a portion of a cycle time of said communication signal-wave, and an unmodulated carrier-radio-wave through said antenna toward a first communication area, and for receiving a responding signal-wave from a second communication area in another portion of said cycle time; and a responder unit mounted on said mobile object for transmitting said responding signal-wave when receiving said pilot signal and said unmodulated carrier-radio-wave subsequently, said responder unit including: a receiving circuit receiving said unmodulated carrier-radio-wave from said first communication area, a control circuit generating a responding data-signal, and a transmitting circuit modulating said unmodulated carrier-radio-wave with said responding data-signal and transmitting a modulated carrier-radio-wave as said responding signal-wave; wherein said antenna control unit comprises: means for decreasing output power of said antenna to a prescribed level lower than said unmodulated carrier-radio-wave while said antenna control unit is transmitting said pilot signal of said communication signal-wave, said prescribed level being lower than the level of the output power of said antenna while said antenna control unit is transmitting said unmodulated carrier-radio-wave, to thereby decrease said first communication area so that the first communication area of said pilot signal coincides with the second communication area of said responding signal-wave, and means for switching said pilot signal to said interrogatory signal when an acknowledgment of said pilot signal is received by said antenna control unit.

Claim 23

A mobile object identification device for exchanging information between a mobile object and a station comprising: an antenna control unit having an antenna disposed at said station for repeatedly transmitting a communication signal-wave, which includes a pilot signal and an interrogatory signal in a portion of a cycle time of said communication signal-wave, and an unmodulated carrier-radio-wave through said antenna toward a first communication area, and for receiving a responding signal-wave from a second communication area in another portion of said cycle time; and a responder unit mounted on said mobile object for transmitting said responding signal-wave when receiving said pilot signal and said unmodulated carrier-radio-wave subsequently, said responder unit including: a receiving circuit receiving said unmodulated carrier-radio-wave from said first communication area, a control circuit generating a responding data-signal, and a transmitting circuit modulating said unmodulated carrier-radio-wave with said responding data-signal and transmitting a modulated carrier-radio-wave as said responding signal-wave; wherein said antenna control unit comprises: means for decreasing output power of said antenna to a prescribed level lower than said unmodulated carrier-radio-wave while said antenna control unit is transmitting said pilot signal of said communication signal-wave, said prescribed level being lower than the level of the output power of said antenna while said antenna control unit is transmitting said unmodulated carrier-radio-wave, to thereby decrease said first communication area so that the first communication area of said pilot signal coincides with the second communication area of said responding signal-wave, and means for switching said pilot signal to said interrogatory signal when an acknowledgment of said pilot signal is received by said antenna control unit.

Claim 24

A mobile object identification device claimed in claim 21, further comprising a gate for toll collection, wherein said antenna is disposed on said gate.

Claim 25

A mobile object identification device claimed in claim 22, wherein said antenna control unit comprises means for transmitting said unmodulated carrier-radio-wave subsequent to said interrogatory signal-wave.

Claim 26

A mobile object identification device claimed in claim 23, further comprising a signal-processing-circuit for processing data for said toll collection when receiving said responding signal-wave.

Claim 27

A mobile object identification device claimed in claim 22, wherein said antenna control unit further comprises a plurality of antennas disposed on said gate.

Claim 28

A mobile object identification device claimed in claim 25, wherein said antenna control unit further comprises means for generating a plurality of carrier-radio-waves having different frequencies, and respectively assigning said carrier-radio-waves to said plurality of antennas corresponding to said communication areas which overlap with one another.

Claim 29

A mobile object identification device claimed in claim 26, wherein said means for generating a plurality of carrier-radio-waves having different frequencies further comprises circuit means for supplying said communication signal-waves to said plurality of antennas at different times.

Claim 30

A mobile object identification device claimed in claim 24, wherein said responder unit includes a communication program which controls said responder unit to stop communication for a given period after said toll collection process has been completed.

Claim 31

A mobile object identification device claimed in claim 24, wherein said responder unit includes a communication program which controls said responder unit to stop communication until a given running distance after said toll collection process has been completed.

Claim 32

A mobile object identification device claimed in claim 22, wherein said antenna control unit comprises means for transmitting said pilot signal and an unmodulated carrier-radio-wave successively, and an interrogatory signal-wave after receiving said responding signal-wave from said responder unit.

Claim 33

A mobile object identification device claimed in claim 30, wherein said responder unit includes a communication program which controls said responder unit to stop communication until it has received said pilot signal-wave.

Claim 34

A mobile object identification device claimed in claim 31, wherein said responder unit includes a communication program which controls said responder unit to prohibit communication with other antennas when it has received a pilot signal-wave from one of said antennas.

Claim 35

A mobile object identification device claimed in claim 31, wherein said means for transmitting said pilot signal-wave and interrogatory signal wave transmit said pilot signal-wave at a power level lower than said interrogatory signal-wave.

Claim 36

A mobile object identification device claimed in claim 31, wherein said means for transmitting said unmodulated carrier-radio-wave transmits said unmodulated carrier-radio-wave at the same power level as said interrogatory signal-wave.

Claim 37

A mobile object identification device claimed in claim 21, wherein said pilot signal indicates that said mobile object has entered said communication area.

Claim 38

A mobile object identification device claimed in claim 21, wherein said unmodulated carrier-radio-wave is transmitted after said pilot signal.

Claim 39

A mobile object identification device claimed in claim 21, wherein said mobile object is mounted on an automobile, and said station is disposed at a toll road for toll collection.

Claim 40

A mobile object identification device as claimed in claim 21, wherein said antenna control unit transmits said pilot signal and said unmodulated carrier-radio-wave successively.

Claim 41

A mobile object identification device where information is exchanged between a mobile object and a station comprising: an antenna control unit having an antenna disposed at said station for repeatedly transmitting a communication signal-wave which includes a pilot signal and an interrogative signal in a portion of a cycle time of said communication signal-wave through said antenna toward a first communication area and receiving a responding signal-wave from a second communication area in another portion of said cycle time; and a responder unit mounted on said mobile object for transmitting said responding signal-wave when receiving said communication signal-wave, said responder unit including a circuit for transmitting said responding data-signal as said responding signal-wave; wherein said antenna control unit comprises: means for decreasing output power of said antenna to a prescribed level while said antenna control unit is transmitting said pilot signal of said communication signal-wave, said prescribed level being lower than the level of the output power of said antenna while said antenna control unit is transmitting said interrogative signal, to thereby decrease the first communication area, and means for switching said pilot signal to said interrogative signal when an acknowledgment of said pilot signal is received by said antenna control unit.

Claim 42

A mobile object identification device where information is exchanged between a mobile object and a station comprising: an antenna control unit having an antenna disposed at said station for repeatedly transmitting a communication signal-wave which includes a pilot signal and an interrogative signal in a portion of a cycle time of said communication signal-wave through said antenna toward a first communication area and receiving a responding signal-wave from a second communication area in another portion of said cycle time; and a responder unit mounted on said mobile object for transmitting said responding signal-wave when receiving said communication signal-wave, said responder unit including a circuit for transmitting said responding data-signal as said responding signal-wave; wherein said antenna control unit comprises: means for decreasing output power of said antenna to a prescribed level while said antenna control unit is transmitting said pilot signal of said communication signal-wave, said prescribed level being lower than the level of the output power of said antenna while said antenna control unit is transmitting said interrogative signal, to thereby decrease the first communication area, and means for switching said pilot signal to said interrogative signal when an acknowledgment of said pilot signal is received by said antenna control unit.

Claim 43

A mobile object identification device claimed in claim 39, wherein said means for decreasing output power of said antenna decreases said output power so that said first communication area of said pilot signal coincides with said second communication area of said responding signal-wave.

Claim 44

A mobile object identification device claimed in claim 39, wherein said antenna control unit further comprises a plurality of antennas disposed on a gate.

Claim 45

A mobile object identification device claimed in claim 41, wherein said antenna control unit further comprises means for generating a plurality of carrier-radio-waves having different frequencies, and respectively assigning said carrier-radio-waves to said plurality of antennas corresponding to said communication areas which overlap with one another.

Claim 46

A mobile object identification device claimed in claim 42, wherein said means for generating said carrier-radio-waves having different frequencies further comprises circuit means for supplying said communication signal-waves to said plurality of antennas at different times.

Claim 47

A mobile object identification device claimed in claim 39, wherein said pilot signal indicates that said mobile object has entered said communication area.

Claim 48

A mobile object identification device claimed in claim 39, wherein an unmodulated carrier-radio-wave is transmitted by said antenna control unit after said pilot signal is transmitted by said antenna control unit.

Claim 49

A mobile object identification device claimed in claim 39, wherein said interrogative signal causes said responder unit to read data stored therein and transmit said stored data.

Claim 50

A mobile object identification device claimed in claim 39, wherein said mobile object is mounted on an automobile, and said station is disposed at a toll road for toll collection.

Claim 51

A mobile object identification device as claimed in claim 39, wherein said antenna control unit transmits said pilot signal and an unmodulated carrier-radio-wave successively.