Abstract: A target location inference apparatus includes a receiving section and an operation section. The receiving section receives a first radio signal from a first transmitter disposed on a target and a second radio signal from a second transmitter disposed in a reference location. The operation section infers a target presence range in which the target is present with respect to the reference location. The target presence range is inferred based on a first received radio signal strength, in the receiving section, of the first radio signal and a second received radio signal strength, in the receiving section, of the second radio signal.

Abstract: A target location inference apparatus includes a receiving section and an operation section. The receiving section receives a first radio signal from a first transmitter disposed on a target and a second radio signal from a second transmitter disposed in a reference location. The operation section infers a target presence range in which the target is present with respect to the reference location. The target presence range is inferred based on a first received radio signal strength, in the receiving section, of the first radio signal and a second received radio signal strength, in the receiving section, of the second radio signal.

Abstract: A location estimation system includes non-directional stationary devices having respective non-directional antennas configured to receive a radio signal transmitted by a mobile device; and directional stationary devices having respective directional antennas configured to receive a radio signal transmitted by the mobile device. The non-directional stationary devices output, as pieces of location estimation information for estimating a location of the mobile device, pieces of information indicating received signal strength indicators of the received radio signal. The directional stationary devices output, as pieces of complementary information for identifying a non-directional stationary device used for location estimation from among the non-directional stationary devices, pieces of information indicating received signal strength indicators of the received radio signal.

Abstract: A position detection system (10) includes receivers (20a to 20g) constituting a radio mesh network, and a gateway device (30). Each of the receivers (20a to 20g) includes a receiving unit (22), a sending unit (23), and a control unit (24). When the receiving unit (22) in each of the receivers (20a to 20f) receives the beacon, the control unit (24) generates first reception information containing information indicating signal strength of the received beacon and identification information of the relevant receiver, and sends the first reception information from the sending unit (23). When the receiving unit (22) receives second reception information, the control unit (24) sends the second reception information. When receiving the second reception information generated by the other receiver, the receiver (20g) connected to the gateway device (30) sends the received second reception information to the server device (34) through the gateway device (30).

Abstract: A position estimation apparatus includes receivers that are disposed at different known positions and are configured to measure a reception intensity of a radio wave emitted from a mobile object and a calculator configured to sequentially perform, for each target receiver that is one of the receivers, processing for updating an estimated position of the mobile object such that the estimated position is closer to a presence circle having a center at the target receiver and a radius based on a reception intensity measured by the target receiver.

Abstract: A lighting system serving as a wireless network system includes a plurality of lighting appliances, which are a plurality of wireless devices, that each have unique identifier and transmit/receive a radio signal. Under control performed by a lighting controller, an operation is sequentially performed with respect to each of the plurality of lighting appliances in which one lighting appliance from among the plurality of lighting appliances broadcasts a measurement signal that includes the identifier of that lighting appliance and the other lighting appliances receive the measurement signal and measure reception quality, which depends on the distance between the lighting appliances.

Abstract: A position detection system includes a transmitter that transmits a first beacon signal with a first strength and at a first incidence and that transmits a second beacon signal with a second strength, which is greater than the first strength, and at a second incidence, which is lower than the first incidence, a plurality of receivers that are installed at known positions different from each other and that measure signal strengths of the first beacon signal and the second beacon signal, and a calculator that performs first processing in which the position of the transmitter is detected on the basis of a signal strength of the first beacon signal measured by one of the receivers and second processing in which the position of the transmitter is detected on the basis of signal strengths of the second beacon signal measured by two or more of the receivers.

Abstract: A position detection system includes a transmitter that transmits a first beacon signal with a first strength and at a first incidence and that transmits a second beacon signal with a second strength, which is greater than the first strength, and at a second incidence, which is lower than the first incidence, a plurality of receivers that are installed at known positions different from each other and that measure signal strengths of the first beacon signal and the second beacon signal, and a calculator that performs first processing in which the position of the transmitter is detected on the basis of a signal strength of the first beacon signal measured by one of the receivers and second processing in which the position of the transmitter is detected on the basis of signal strengths of the second beacon signal measured by two or more of the receivers.

Abstract: A lighting system serving as a wireless network system includes a plurality of lighting appliances, which are a plurality of wireless devices, that each have unique identifier and transmit/receive a radio signal. Under control performed by a lighting controller, an operation is sequentially performed with respect to each of the plurality of lighting appliances in which one lighting appliance from among the plurality of lighting appliances broadcasts a measurement signal that includes the identifier of that lighting appliance and the other lighting appliances receive the measurement signal and measure reception quality, which depends on the distance between the lighting appliances.

Abstract: A position estimation device includes a calculator that calculates, in a mechanical system formed by connecting a hypothetical movable point and a plurality of receivers with a plurality of hypothetical springs, a position of the hypothetical movable point at which the plurality of hypothetical springs is in equilibrium as an estimated position of a mobile object, wherein the hypothetical spring corresponding to each of the plurality of receivers has a natural length that is a function of a distance from the receiver to the mobile object and has a smaller spring constant in contracted state than a spring constant in expanded state, the distance being based on the reception strength of a radio wave transmitted from the mobile object, the reception strength being measured by the receiver.

Abstract: A position estimation apparatus includes receivers that are disposed at different known positions and are configured to measure a reception intensity of a radio wave emitted from a mobile object and a calculator configured to sequentially perform, for each target receiver that is one of the receivers, processing for updating an estimated position of the mobile object such that the estimated position is closer to a presence circle having a center at the target receiver and a radius based on a reception intensity measured by the target receiver.

Abstract: A location estimation system includes non-directional stationary devices having respective non-directional antennas configured to receive a radio signal transmitted by a mobile device; and directional stationary devices having respective directional antennas configured to receive a radio signal transmitted by the mobile device. The non-directional stationary devices output, as pieces of location estimation information for estimating a location of the mobile device, pieces of information indicating received signal strength indicators of the received radio signal. The directional stationary devices output, as pieces of complementary information for identifying a non-directional stationary device used for location estimation from among the non-directional stationary devices, pieces of information indicating received signal strength indicators of the received radio signal.

Abstract: A position detection system (10) includes receivers (20a to 20g) constituting a radio mesh network, and a gateway device (30). Each of the receivers (20a to 20g) includes a receiving unit (22), a sending unit (23), and a control unit (24). When the receiving unit (22) in each of the receivers (20a to 20f) receives the beacon, the control unit (24) generates first reception information containing information indicating signal strength of the received beacon and identification information of the relevant receiver, and sends the first reception information from the sending unit (23). When the receiving unit (22) receives second reception information, the control unit (24) sends the second reception information. When receiving the second reception information generated by the other receiver, the receiver (20g) connected to the gateway device (30) sends the received second reception information to the server device (34) through the gateway device (30).

Abstract: A radar device includes a transmission antenna and a reception antenna having a plurality of antenna elements. The radar device switches the antenna elements in synchronization with a modulation cycle, thereby obtaining a reception signal. At this time, the radar device obtains the reception signal by switching the antenna elements using a first measurement phase and a second measurement phase having different switching cycles as one set. The radar device calculates an azimuth sine value sin ?1 from the reception signal in the first measurement phase and also calculates an azimuth sinusoidal value sin ?2 from the reception signal in the second measurement phase. Then, the radar device calculates a relative velocity V from the azimuth sine value sin ?1, the azimuth sine value sin ?2, an interval time difference ?t between switching cycles, and an inter-antenna element spacing d.

Abstract: A radar apparatus includes a transmitting antenna and a receiving antenna that has a plurality of antenna elements, and switches the plurality of antenna elements in synchronization with a modulation period to acquire receiving signals. At this time, the antenna elements are switched in accordance with a combination of a first sub-phase and a second sub-phase in which the antenna elements are sequentially switched in opposite directions to thereby acquire the receiving signals. The radar apparatus calculates an azimuth sine value sin ?1 from the acquired receiving signals of the first sub-phase and calculates an azimuth sine value sin ?2 from the receiving signals of the second sub-phase. Next, the radar apparatus calculates an actual azimuth ? through an averaging process of these azimuth sine values sin ?1 and sin ?2.

Abstract: A radar target detection method in which an azimuth at which a target is located is detected on the basis of reception signals obtained through antenna elements of an array antenna by detecting a change in levels of spectrum peaks in an azimuth spectrum of reception signal intensities, calculating a level of correlation between the level change of each spectrum peak and a directivity pattern of the array antenna in an azimuth range corresponding to the spectrum peak, and determining an azimuth corresponding to one of the spectrum peaks having the highest corresponding correlation level to be the azimuth at which the target is located.

Abstract: A radar apparatus includes a transmitting antenna and a receiving antenna that has a plurality of antenna elements, and switches the plurality of antenna elements in synchronization with a modulation period to acquire receiving signals. At this time, the antenna elements are switched in accordance with a combination of a first sub-phase and a second sub-phase in which the antenna elements are sequentially switched in opposite directions to thereby acquire the receiving signals. The radar apparatus calculates an azimuth sine value sin ?1 from the acquired receiving signals of the first sub-phase and calculates an azimuth sine value sin ?2 from the receiving signals of the second sub-phase. Next, the radar apparatus calculates an actual azimuth ? through an averaging process of these azimuth sine values sin ƒ1 and sin ?2.

Abstract: A radar device includes a transmission antenna and a reception antenna having a plurality of antenna elements. The radar device switches the antenna elements in synchronization with a modulation cycle, thereby obtaining a reception signal. At this time, the radar device obtains the reception signal by switching the antenna elements using a first measurement phase and a second measurement phase having different switching cycles as one set. The radar device calculates an azimuth sine value sin ?1 from the reception signal in the first measurement phase and also calculates an azimuth sinusoidal value sin ?2 from the reception signal in the second measurement phase. Then, the radar device calculates a relative velocity V from the azimuth sine value sin ?1, the azimuth sine value sin ?2, an interval time difference ?t between switching cycles, and an inter-antenna element spacing d.

Abstract: A radar target detection method in which an azimuth at which a target is located is detected on the basis of reception signals obtained through antenna elements of an array antenna by detecting a change in levels of spectrum peaks in an azimuth spectrum of reception signal intensities, calculating a level of correlation between the level change of each spectrum peak and a directivity pattern of the array antenna in an azimuth range corresponding to the spectrum peak, and determining an azimuth corresponding to one of the spectrum peaks having the highest corresponding correlation level to be the azimuth at which the target is located.

Abstract: A radar system in which a beat signal is generated by transmitting a transmission signal that is subjected to frequency modulation into a triangular wave and receiving a reflection signal from a target, the beat signal is sampled, and a window function is applied to yield a discrete frequency spectrum. When the window function is applied, a first window function having an amplitude that is gently attenuated from the center of the sampling period toward both sides thereof is applied in a lower frequency band in the frequency spectrum (at close range), and a second window function having an amplitude that is sharply attenuated from the center of the sampling period toward both sides thereof is applied in a higher frequency band in the frequency spectrum (at far range).