Wireless distance measurement system and wireless terminal
First Claim
1. A wireless distance measurement system that comprises a wireless base station and a wireless terminal and that measures a distance between the wireless base station and the wireless terminal using a pulse signal, wherein:
- the wireless terminal comprises;
a receiving section that receives a pulse signal sequence transmitted from the wireless base station;
a detector that detects the received pulse signal sequence and outputs a detection signal;
a synchronization establishing section that comprises;
an integrator that integrates the detection signal per receiving timing candidate and outputs an integration result; and
a detecting section that detects a synchronization timing with the wireless base station based on the integration result; and
a distance measurement processing section that comprises;
a holding section that holds the integration result;
a comparator that outputs a binary signal matching an input signal using the integration result held in the holding section as reference data; and
a pulse generating section that generates a transmission pulse signal based on the binary signal outputted from the comparator;
the wireless base station comprises a calculating section that measures a time lag between a transmission timing for the pulse signal sequence and a receiving timing for a pulse signal sequence transmitted from the wireless terminal based on a pulse signal transmitted at the transmission timing, and calculates the distance based on the measured time lag; and
a route of signals varies between a distance measuring operation and a synchronization establishing operation in the wireless terminal, and, when the distance measuring operation is performed, the detection signal is inputted to the comparator without passing through the integrator.
1 Assignment
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Accused Products
Abstract
A wireless distance measurement system and wireless terminal improve the accuracy of distance measurement when the UWB communication scheme is used. In wireless terminal 200, a route of signals varies between a distance measuring operation and a synchronization establishing operation, and, when the distance measuring operation is performed, a detection result is inputted to comparator 208 without passing through integrator 204. By this means, the distance measuring operation of wireless terminal 200 does not involve integration processing, so that delay time due to integration processing is not produced and, consequently, it is possible to improve the accuracy of distance measurement. Further, the distance measuring operation uses the integration result acquired integrator 204 for a comparison reference voltage used in comparator 208. By this means, the integration result removing noise signal components from a detection signal is used for the comparison reference voltage, so that the comparison reference voltage is optimized. Consequently, it is possible to further improve the accuracy of distance measurement.
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Citations
10 Claims
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1. A wireless distance measurement system that comprises a wireless base station and a wireless terminal and that measures a distance between the wireless base station and the wireless terminal using a pulse signal, wherein:
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the wireless terminal comprises; a receiving section that receives a pulse signal sequence transmitted from the wireless base station; a detector that detects the received pulse signal sequence and outputs a detection signal; a synchronization establishing section that comprises; an integrator that integrates the detection signal per receiving timing candidate and outputs an integration result; and a detecting section that detects a synchronization timing with the wireless base station based on the integration result; and a distance measurement processing section that comprises; a holding section that holds the integration result; a comparator that outputs a binary signal matching an input signal using the integration result held in the holding section as reference data; and a pulse generating section that generates a transmission pulse signal based on the binary signal outputted from the comparator; the wireless base station comprises a calculating section that measures a time lag between a transmission timing for the pulse signal sequence and a receiving timing for a pulse signal sequence transmitted from the wireless terminal based on a pulse signal transmitted at the transmission timing, and calculates the distance based on the measured time lag; and a route of signals varies between a distance measuring operation and a synchronization establishing operation in the wireless terminal, and, when the distance measuring operation is performed, the detection signal is inputted to the comparator without passing through the integrator. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A wireless terminal comprising:
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a receiving section that receives a pulse signal sequence; a detector that detects the received pulse signal sequence and outputs a detection signal; a synchronization establishing section that comprises; an integrator that integrates the detection signal per receiving timing candidate and outputs an integration result; and a detecting section that detects a synchronization timing with a wireless base station based on the integration result; and a distance measurement processing section that comprises; a holding section that holds the integration result; a comparator that outputs a binary signal matching an input signal using the integration result held in the holding section as reference data; and a pulse generating section that generates a transmission pulse signal based on the binary signal outputted from the comparator, wherein a route of signals varies between a distance measuring operation and a synchronization establishing operation and, when the distance measuring operation is performed, the detection signal is inputted to the comparator without passing through the integrator. - View Dependent Claims (8, 9, 10)
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Specification