1506 results about "Propagation time" patented technology

An object location monitoring system includes beacons that are spatially distributed throughout an area to be monitored. The beacons transmit interrogation signals that are received and echoed by transponders that attach to moveable objects. Each beacon retransmits its interrogation signal, and any transponder response thereto, to a receiver that measures a time difference between the two signals. This time difference reflects the signal propagation time, and thus the distance, between the beacon and the transponder. One such receiver preferably analyzes the retransmitted signals of multiple (e.g., 50 to 100) beacons. A triangulation method is used to determine the location of each transponder based on the transponder's distances from a set of beacons. In one embodiment, the transponders are provided as or within disposable ID bracelets worn by patients, and are used to track the locations of the patients within a hospital.

A system and method for deploying a network of wireless devices, including mobile terminals, wireless routers and a least one control console, within a three dimensional deployment area such as a building, so that communication, identification and position calculations of personnel, such as firefighters, using the mobile terminals can be achieved regardless of building structure. The wireless routers are deployed in a substantial vertical manner in staircases and elevator shafts of a building of interest, either in advance as part of a safety program or immediately upon arrival of firefighters or other team at the building during an emergency. The system and method according to the embodiment of the present invention described herein uses both TOF and RSSI between the mobile terminals and wireless routers to identify the floor numbers where firefighters are located and to track firefighter movements.

The position of a non-cooperating emitter is determined by detecting a signal from the emitter at three or more receiver communication devices positioned at different locations. The receiver communication devices determine respective detection times of the emitted signal in respective local time reference frames. To establish a common time reference frame for the emitted signal detections, each receiver communication device exchanges time synchronization signals with a reference communication device. Since any of the receiver communication devices and the reference communication device may be mobile, the signal exchange allows each receiver communication device to accurately determine the signal propagation time between itself and the reference communication device and factor the signal propagation time into an accurate adjustment of the local time reference frame. Using trilateration, the position of the emitter is determined from known positions of the receiver communication devices and the emitted signal detection times from the receiver communication devices.

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.

A high accuracy search and tracking system that uses a round-trip messaging scheme in which the time of arrive (TOA) of ranging signals is accurately determined to yield the range estimates between a target communications device and one or more search communications devices. Successive ranging estimates are used by a search device to home in upon the target device. The physical location pinpoint communications system can be used alone, or in combination with other location estimation systems that can be used initially, or throughout the search and tracking process to pinpoint the physical location of the target device. The search radio(s) transmits ranging signals to the target radio which responds by transmitting reply ranging signals. Upon reception of the reply ranging signal, the search radio determines the range to the reference radio from the signal propagation time. Errors in TOA estimates can be minimized using advanced processing techniques, if required.

A method and system for a Radio Frequency (RF)-based identification, tracking and locating of objects. The method and system use a narrow bandwidth signal in VHF of lower frequency range, which minimizes propagation loss and loss of accuracy of the RF locating signals. The signal is sent from a Master Unit(s) to a Tag. The signal traveling time is recorded and the distance between the Master(s) and the Tag is calculated. The method and system allow achieving a longer distance of the RF signal penetration and an increased accuracy by using VHF bands. The techniques of Digital Signal Processing and Software-Defined Radio are used. The actual waveforms transmitted and received by the radios are defined by the software. The roles of the Master Unit(s) and the Tag can be reversed.

A method and system for a long range Radio Frequency (RF)-based identification, tracking and locating of objects. The method and system use a narrow bandwidth ranging signal(s), including VHF of lower frequency bands, which minimizes propagation loss and loss of accuracy of the RF locating signals. The method and system includes narrow bandwidth ranging signal multi-path mitigations processor, which further improves the track-locate accuracy. The signal is sent from a Master Unit(s) to a Tag. The signal traveling time is recorded and the distance between the Master(s) and the Tag is calculated. The method and system allow achieving a longer distance of the RF narrow bandwidth ranging signal penetration and an increased accuracy by using VHF bands in conjunction with the narrow bandwidth ranging signal multi-path mitigations processor. The techniques of Digital Signal Processing and Software-Defined Radio are used. The actual waveforms transmitted and received by the radios are defined by the software. The roles of the Master Unit(s) and the Tag can be reversed.

A method and apparatus for determining a cardiovascular parameter including receiving an input signal corresponding to an arterial blood pressure measurement over an interval that covers at least one cardiac cycle, determining a propagation time of the input signal, determining at least one statistical moment of the input signal, and determining an estimate of the cardiovascular parameter using the propagation time and the at least one statistical moment.

A photoacoustic probe for port wine stain (PWS), burn and melanin depth measurements is comprised of optical fibers for laser light delivery and a piezoelectric element for acoustic detection. The probe induced and measured photoacoustic waves in acryl amide tissue phantoms and PWS skin in vivo. Acoustic waves were denoised using spline wavelet transforms, then deconvolved with the impulse response of the probe to yield initial subsurface pressure distributions in phantoms and skin. The waves were then analyzed for epidermal melanin concentration, using a photoacoustic melanin index (PAMI) related to the amount of laser energy absorbed by melanin. Propagation time of the photoacoustic wave was used to determine the depth of blood perfusion underlying necrotic, burned tissue. Thus, the photoacoustic probe can be used for determining PWS, burn and melanin depth for most patients receiving laser therapy.

An earth station receives a return signal via more than one satellite link from a mobile terminal using TDMA. The earth station selects one or more of the satellite links for transmitting a forward signal on the basis of the quality of signal received via each link. The earth section allocates frequency channels to the mobile terminals according to their location on the surface of the earth, so that the propagation time to and from those mobile terminals which share the same frequency channel is approximately the same. The satellite includes an antenna which generates an array of beams which are individually pointed to fixed regions of the earth, until the elevation of the satellite relative to a fixed region falls below a minimum value, in which case the corresponding beam is redirected to a new area, while the other beams remain pointed at the corresponding fixed areas. In this way, beam-to-beam handover is reduced, while maintaining the boresight of the antenna pointing at the nadir.

An optoelectronic distance measuring device is disclosed. The device has a transmitting unit with a driver stage for emitting optical pulses, a receiving unit for receiving a portion of the optical pulses, said portion being reflected from a target object, and converting it into an electrical reception signal, via a photosensitive electrical component. It also has an analog-digital converter for digitizing the reception signal, and an electronic evaluation unit to ascertain a distance from the target object on the basis of a signal propagation time using the digitized reception signal. The driver stage can be designed so that at least two pulse durations of different length for the optical pulses can be set.

The propagation time (1605) of signals between a terminal (1304) and a base station (1302) is calculated from the round-trip time (1601) of signals between the terminal (1304) and the base station (1302) and the turn-around time (1603) from the reception by terminal (1304) of a signal from base station (1302) until the transmission of the signal to the base station (1302). The propagation time (1606) of signals between the terminal (1304) and another base station (1303) is similarly calculated. The difference between the propagation times (1605 and 1606) and the arrival time difference (1607) that is calculated in the terminal (1304) are then compared to calculate the transmission time difference (1608) between the base stations (1302 and 1303).

Methods, apparatus, and systems for accurately estimating acoustic propagation velocity are described. One method comprises deploying in a marine environment a towed seismic spread comprising a plurality of acoustic positioning transmitters and a plurality of positioning point receivers, and using travel times for signals between at least some of the transmitters and point receivers to derive a mathematical model describing acoustic propagation velocity for the marine environment as a function of at least one spread spatial dimension, distances between transmitters and receivers, and any combination thereof. This abstract is provided to comply with the rules requiring an abstract, and allows a reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

A health management apparatus includes a first pulse wave measuring unit that measures a first pulse wave of a subject during sleep; and a second pulse wave measuring unit that measures a second pulse wave of the subject during sleep. The second pulse wave is different from the first pulse wave in propagation time from the heart of the subject. The apparatus also includes a pulse transmission time calculating unit that calculates a pulse transmission time indicating a time difference between the first and second pulse waves; a pulse interval calculating unit that calculates a pulse interval based on at least one of the first and second pulse waves; an autonomic nerve index calculating unit that calculates an autonomic nerve index based on the pulse transmission time and the pulse interval; and a health determining unit that determines the condition of health of the subject based on the autonomic nerve index.

The circuitry comprises successive stages, each comprising a combinatory logic circuit connected to the input of a first latch. Staggered clock signals are respectively associated with the first latches of the odd and even stages. Means for detecting a transient disturbance affecting the first latch of a stage and liable to propagate downstream, compare, in each stage, a value present on the output of the first latch of the stage considered at an observation time with a value present on the input of said first latch at a predetermined observation time taking account of the various propagation times.

A method and system for testing a Layer 2 tunnel in a data communication network including a network device and a network manager are described. According to the method, a test invocation is received from the network manager at the network device. In response to receipt of the test invocation at the network device, a Layer 2 tunnel within the data communication network is tested, and a result of the test is reported to the network manager. The tests that may be conducted include a connectivity test to determine if a Layer 2 tunnel can be established and a responsiveness test to determine the propagation time of a Layer 2 tunnel. Advantageously, both compulsory and voluntary Layer-2 tunnels can be tested, thereby enabling all Layer 2 protocols (e.g., L2TP, L2F, and PPTP) to be supported.

A method and a system for radar-based gauging of a filling level of a filling material is disclosed, wherein the tank has at least one interfering structure. The method comprises: transmitting at a first time moment a microwave signal towards the surface of the filling material; receiving microwave signals as reflected against the surface of the filling material and as reflected against said at least one interfering structure; calculating based on propagation times of the transmitted and reflected microwave signals at least two distances to reflective surfaces in the tank; and repeating at a second time moment the transmitting, the detecting and the calculating, wherein said first time moment is timely separated from said second time moment. Based on the several repeated measurements, the distance to the surface of the filling material is determiend as the calculated distance that exhibits the greatest change between said first and second time moments. Based on this time difference analysis, it is possible to discinguish moving surfaces very easy and acurate. The method is specifically advantageous in overfill or high level alarm systems.