Abstract: In a system for measuring a time difference of arrival of signals for positioning, an accurate time difference is measured by a receiver which is reduced in power consumption, size, and cost. The system comprises a node (under measurement) for transmitting a positioning signal, a reference station for transmitting a reference signal, and a plurality of access points for receiving the positioning signal and reference signal, and a server connected to the plurality of access points through a network. Each of the plurality of access points measures a time difference between the reception of the positioning signal and the reception of the reference signal, and a frequency deviation from the reference station, using a clock signal and a signal for shifting the clock signal, and the server calculates the position of the node based on the measured time difference and frequency deviation.

Abstract: An invention for estimating the first path of an arrival signal by a method and device with a simple structure and lower power consumption. In this method, the nominal pulse repetition frequency or its integer multiple are A/D converted at a frequency less than the multiplicative inverse of the pulse width, the AD conversion timing is offset by time resolution ?t and the receive signal measured, data stored in a RAM, and the first path output time is estimated based on sequentially rearranging of the stored waveform data.

Abstract: In a system for measuring a time difference of arrival of signals for positioning, an accurate time difference is measured by a receiver which is reduced in power consumption, size, and cost. The system comprises a node (under measurement) for transmitting a positioning signal, a reference station for transmitting a reference signal, and a plurality of access points for receiving the positioning signal and reference signal, and a server connected to the plurality of access points through a network. Each of the plurality of access points measures a time difference between the reception of the positioning signal and the reception of the reference signal, and a frequency deviation from the reference station, using a clock signal and a signal for shifting the clock signal, and the server calculates the position of the node based on the measured time difference and frequency deviation.

Abstract: A sensor transmits and receives wireless signals at intervals. A sensor unit, a processor 130, a wireless transmitter circuit, and a wireless receiver circuit are activated in sequence only for a fixed time when the electric power generated by a generator circuit and charged in a capacitor reaches a preset level. Sensing information detected by the sensor unit is processed by the processor circuit and, information on the number of receivable bytes is added to the processing results in the wireless receiver circuit. This added information is sent as sensor information to the wireless host from the wireless transmitting circuit, and the wireless receiver circuit that activated after the wireless transmitter circuit was activated, receives a control information signal from the wireless host. This received information is processed in the processor circuit.

Abstract: A communications apparatus which ensures a predetermined communication quality even when an external environment changes dynamically, and enhances a throughput for overall system, thereby achieving favorable transmission efficiency. A communications apparatus having a receiver and a transmitter and carries out sending/receiving by use of a pulse train is provided with a communication environment measuring section to measure a communication status based on an output from the receiver. The transmitter is configured such that it transmits a transmission signal, in which the transmission rate of data to be transmitted and the pulse energy have been controlled in association with each other, according to a result of the measurement.

Abstract: To provide a method of measuring a position of a node by using a radio communication system which comprises the node to send a position measuring signal, and a plurality of base stations to receive radio signals from the node, the method including: the base stations watching signals from the node through a predetermined channel; at least one of the base stations sending a reference signal after receiving of the position measuring signal; at least two of the base stations measuring the reception timing of the position measuring signal and the reception timing of the reference signal; and calculating the position of the node by using the reception timing of the position measuring signal and the reference signal measured by the base stations which have received the reference signal, and position information of the base station which has received the position measuring signal.

Abstract: A node location system for detecting a node by receiving two or more access points. The node location system includes a node, a reference station, multiple access points, a server, and a network. After receiving a location signal, the reference station sends a reference signal, and the access points receive a position measurement signal and a reference signal, and detects a specified pattern from the received location signal and reference signal, and measures the time from detecting the specified pattern from the location signal until detecting the time from the reference signal, and sends the signal-receive-time information including that measured time to the server, and the server calculates the difference between the time the reference station received the location signal and the time that the access points received the location signal, and then calculates the node position based on this calculated differential.

Abstract: A positioning system having a node (subject to positioning) transmitting a positioning signal; a reference station transmitting a reference signal; at least three base stations having a receiving part receiving the aforementioned positioning signal and the aforementioned reference signal; and a server connected to the base stations by a network; wherein the aforementioned server measures, using a clock signal and a signal shifting the concerned clock signal, the time difference with which the aforementioned positioning signal and the aforementioned reference signal are received by the aforementioned plurality of base stations as well as the frequency deviation with the aforementioned base stations; decides whether to carry out a correction with respect to the aforementioned measured time difference, on the basis of the measurement result of the aforementioned positioning signal; and computes the position of the aforementioned node, based on the aforementioned time deviation for which appropriate processing

Abstract: An invention for estimating the first path of an arrival signal by a method and device with a simple structure and lower power consumption. In this method, the nominal pulse repetition frequency or its integer multiple are A/D converted at a frequency less than the multiplicative inverse of the pulse width, the AD conversion timing is offset by time resolution ?t and the receive signal measured, data stored in a RAM, and the first path output time is estimated based on sequentially rearranging of the stored waveform data.

Abstract: A sensor transmits and receives wireless signals at intervals. A sensor unit, a processor 130, a wireless transmitter circuit, and a wireless receiver circuit are activated in sequence only for a fixed time when the electric power generated by a generator circuit and charged in a capacitor reaches a preset level. Sensing information detected by the sensor unit is processed by the processor circuit and, information on the number of receivable bytes is added to the processing results in the wireless receiver circuit. This added information is sent as sensor information to the wireless host from the wireless transmitting circuit, and the wireless receiver circuit that activated after the wireless transmitter circuit was activated, receives a control information signal from the wireless host. This received information is processed in the processor circuit.

Abstract: A radio signal receiving method grasps features of a propagation path at the start of communication and generates a template waveform corresponding to the features. A receiver examines a reception waveform of a propagation path condition judgment portion contained in a header portion of a packet, individually generates the template waveform in each communication session and performs correlation detection on the basis of the template waveform generated individually.

Abstract: A node position measuring system according to this invention includes a node, a reference station, base stations, a server that calculates a position of the node, and a network. The reference station includes a positioning signal reception module and a reference signal generation module that transmits a reference signal after the positioning signal reception module receives the positioning signal. Each of the base stations includes a signal reception module, a reception time measuring module that detects specific patterns from the positioning signal and the reference signal received by the signal reception module to measure a detection time, and a communication module that transmits time information, which is generated from the time measured by the reception time measuring module, to the server. The server includes a position calculation module that calculates the position of the node based on the time information transmitted from the base station.

Abstract: A sensor transmits and receives wireless signals at intervals. A sensor unit, a processor 130, a wireless transmitter circuit, and a wireless receiver circuit are activated in sequence only for a fixed time when the electric power generated by a generator circuit and charged in a capacitor reaches a preset level. Sensing information detected by the sensor unit is processed by the processor circuit and, information on the number of receivable bytes is added to the processing results in the wireless receiver circuit. This added information is sent as sensor information to the wireless host from the wireless transmitting circuit, and the wireless receiver circuit that activated after the wireless transmitter circuit was activated, receives a control information signal from the wireless host. This received information is processed in the processor circuit.

Abstract: A location system of a configuration that facilitates initial introduction, maintenance, and system expansion. A terminal location system basically has at least (N+1) base station (here, N=1 to 3) and a location server and finds a position of a terminal performing wireless communication in N-dimensional coordinates. Further, the terminal location system calculates distances among the at least (N+1) base stations, finds relative coordinates of the base stations, evaluates the obtained relative coordinates, determines switching to terminal location processing of finding the position of the terminal, and finds the position of the terminal using propagation times of radio signals transmitted/received among the terminal and the base stations and the obtained relative coordinates of the base stations.

Abstract: In a system for measuring a time difference of arrival of signals for positioning, an accurate time difference is measured by a receiver which is reduced in power consumption, size, and cost. The system comprises a node (under measurement) for transmitting a positioning signal, a reference station for transmitting a reference signal, and a plurality of access points for receiving the positioning signal and reference signal, and a server connected to the plurality of access points through a network. Each of the plurality of access points measures a time difference between the reception of the positioning signal and the reception of the reference signal, and a frequency deviation from the reference station, using a clock signal and a signal for shifting the clock signal, and the server calculates the position of the node based on the measured time difference and frequency deviation.

Abstract: In the conventional wireless location system that synchronizes base stations by wireless communication, waveforms of a signal used for synchronization and of a signal used for delay measurement are the same, and therefore if there is a reflected wave in an earlier-sent signal, it becomes difficult to distinguish two kinds of signals, and accordingly location accuracy suffers degradation. Moreover, when two different waveforms are allocated to the two signals, a matched filter that supports the two waveforms becomes necessary, which inevitably makes a circuit size large. The invention is characterized in that signals having the same waveform but having different polarities are allocated to the synchronizing signal and the signal for delay measurement, respectively. This enables the two kinds of signals to be detected with one matched filter and also to be distinguished by simple means using polarity difference.

Abstract: A node position measuring system according to this invention includes a node, a reference station, base stations, a server that calculates a position of the node, and a network. The reference station includes a positioning signal reception module and a reference signal generation module that transmits a reference signal after the positioning signal reception module receives the positioning signal. Each of the base stations includes a signal reception module, a reception time measuring module that detects specific patterns from the positioning signal and the reference signal received by the signal reception module to measure a detection time, and a communication module that transmits time information, which is generated from the time measured by the reception time measuring module, to the server. The server includes a position calculation module that calculates the position of the node based on the time information transmitted from the base station.

Abstract: The disclosed invention provides a wireless communications terminal apparatus that calculates its accurate position, eliminating the influence of a repeater on the calculation without using complicated processing. The terminal apparatus receives signals transmitted from a plurality of radio stations and calculates its position, using the received signals. The terminal apparatus comprises repeater detection means for detecting a signal from a repeater which transmits signals that are generated on the basis of signals transmitted from one of the radio stations and indistinguishable from the signals transmitted from that radio station from among the received signals and position calculation means for calculating its position. When the repeater detection means has detected a signal from a repeater, the position calculation means ignores the detected signal from the repeater and calculates the terminal position, using the received signals from other radio stations.

Abstract: A communications apparatus which ensures a predetermined communication quality even when an external environment changes dynamically, and enhances a throughput for overall system, thereby achieving favorable transmission efficiency. A communications apparatus having a receiver and a transmitter and carries out sending/receiving by use of a pulse train is provided with a communication environment measuring section to measure a communication status based on an output from the receiver. The transmitter is configured such that it transmits a transmission signal, in which the transmission rate of data to be transmitted and the pulse energy have been controlled in association with each other, according to a result of the measurement.

Abstract: To provide a method of measuring a position of a node by using a radio communication system which comprises the node to send a position measuring signal, and a plurality of base stations to receive radio signals from the node, the method including: the base stations watching signals from the node through a predetermined channel; at least one of the base stations sending a reference signal after receiving of the position measuring signal; at least two of the base stations measuring the reception timing of the position measuring signal and the reception timing of the reference signal; and calculating the position of the node by using the reception timing of the position measuring signal and the reference signal measured by the base stations which have received the reference signal, and position information of the base station which has received the position measuring signal.