On-board communication system, and portable device
First Claim
1. An on-board communication system, comprising:
- (i) an on-board device that transmits detection signals from a plurality of antennas disposed in a vehicle and (ii) a plurality of portable devices that each receive the detection signals transmitted from the on-board device and transmit response signals corresponding to the received detection signals, the on-board device performing position detection of each of the portable devices based on the response signals transmitted from each of the portable devices, wherein;
the detection signals are signals received in common by the plurality of portable devices,the on-board device comprises;
an on-board transmission unit that, prior to transmission of the detection signals, transmits from the antennas a processing start signal for causing reception processing of the detection signals by each of the portable devices to start, and then transmits the detection signals from the antennas, andan on-board reception unit that receives the response signals transmitted from each of the portable devices, andeach of the portable devices comprises;
a portable reception unit that receives the processing start signal and the detection signals transmitted from the on-board device,a timer unit that measures an elapsed time from when the portable reception unit receives the processing start signal, anda portable transmission unit that (i) when the portable reception unit has received the detection signals, transmits a first response signal that includes information corresponding to the received detection signals, and (ii) when a specified time has elapsed from when the portable reception unit received the processing start signal, transmits a second response signal including the same information as the information included in the first response signal, the specified time being different for each of the plurality of portable devices, whereineach portable device uses the same processing start signal as the basis of the start of timing.
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Accused Products
Abstract
In an on-board communication system, an on-board device transmits detection signals from a plurality of antennas disposed in a vehicle, and a plurality of portable devices each receive the detection signals and transmit response signals corresponding to the received detection signals. Each portable device measures an elapsed time from when the processing start signal is received, and (i) transmits a first response signal that includes information corresponding to the received detection signals, and (ii) when a specified time has elapsed from receipt of the processing start signal, transmits a second response signal including the same information as the information included in the first response signal. Position detection of the portable devices is performed based on the response signals.
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Citations
10 Claims
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1. An on-board communication system, comprising:
- (i) an on-board device that transmits detection signals from a plurality of antennas disposed in a vehicle and (ii) a plurality of portable devices that each receive the detection signals transmitted from the on-board device and transmit response signals corresponding to the received detection signals, the on-board device performing position detection of each of the portable devices based on the response signals transmitted from each of the portable devices, wherein;
the detection signals are signals received in common by the plurality of portable devices, the on-board device comprises; an on-board transmission unit that, prior to transmission of the detection signals, transmits from the antennas a processing start signal for causing reception processing of the detection signals by each of the portable devices to start, and then transmits the detection signals from the antennas, and an on-board reception unit that receives the response signals transmitted from each of the portable devices, and each of the portable devices comprises; a portable reception unit that receives the processing start signal and the detection signals transmitted from the on-board device, a timer unit that measures an elapsed time from when the portable reception unit receives the processing start signal, and a portable transmission unit that (i) when the portable reception unit has received the detection signals, transmits a first response signal that includes information corresponding to the received detection signals, and (ii) when a specified time has elapsed from when the portable reception unit received the processing start signal, transmits a second response signal including the same information as the information included in the first response signal, the specified time being different for each of the plurality of portable devices, wherein each portable device uses the same processing start signal as the basis of the start of timing. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- (i) an on-board device that transmits detection signals from a plurality of antennas disposed in a vehicle and (ii) a plurality of portable devices that each receive the detection signals transmitted from the on-board device and transmit response signals corresponding to the received detection signals, the on-board device performing position detection of each of the portable devices based on the response signals transmitted from each of the portable devices, wherein;
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9. A portable device that constitutes an on-board communication system in which (i) an on-board device transmits detection signals from a plurality of antennas disposed in a vehicle and (ii) a plurality of portable devices receive the detection signal transmitted from the on-board device and each transmit response signals corresponding to the received detection signal, the on-board device performing position detection of each of the portable devices by receiving the response signals transmitted from each of the portable devices, the portable device comprising:
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a portable reception unit that (i) receives a processing start signal, transmitted from the on-board device, for causing reception processing of the detection signals to start prior to receiving the detection signals, and (ii) receives the detection signals transmitted from the on-board device; a timer unit that measures an elapsed time from when the portable reception unit receives the processing start signal transmitted from the on-board device, and a portable transmission unit that (i) when the portable reception unit has received the detection signals, transmits a first response signal that includes information corresponding to the received detection signals, and (ii) when a specified time has elapsed from when the portable reception unit received the processing start signal, transmits a second response signal including the same information as the information included in the first response signal, the specified time being different for each of the plurality of portable devices, wherein each portable device uses the same processing start signal as the basis of the start of timing. - View Dependent Claims (10)
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Specification