Abstract:
A method and apparatus for computing a convolution between an input GPS signal and a C/A code reference by generating the convolution result in real time without storing unprocessed signal samples. The method and apparatus is capable of operating in multiple modes of resolution so as to enhance the sensitivity of the convolution processing.
Abstract:
A system and method for monitoring and displaying characteristics of one or more athletes, the system including a plurality of tag devices, at least one tag being located on each athlete and being capable of periodically transmitting a tag device signal in the form of a short burst, frequency-hopped spread spectrum radio frequency signal. At least three separately located wideband receivers are capable of receiving a tag device signal and processing the tag device signal to provide data representative of the time of arrival of the tag device signal at the receiver. A centralised processing means receives and processes the time of arrival data from each receiver to determine the position of the tag devices using differences in the time of arrival data from each receiver. The positions determined by the centralized processing means are stored on a data server and are able to be retrieved and processed so as to enable a graphical representation of at least one selected athlete characteristic to be displayed.
Abstract:
A system which allows a central control unit to track automatically the positions of a fleet of mobile units. Each mobile unit carries a position updating apparatus which includes means (2) to determine its position, and processing means (4) in the form of computing equipment in communication with the position determining means. The processing means (4) in turn controls a transmitting means (6), such as a radio transmitter of the private mobile radio system that the mobile unit uses for communication, for transmitting information to the central control. The position determining means (2) and processing means (4) are arranged to send the latest position of the mobile unit to the central control at intervals. The processing means (4) stores a number of rules for determining the interval between the transmission of position update messages to the central control. These rules are based upon the direction of travel of the mobile unit and other factors, such as its location.
Abstract:
An apparatus and method for generating an accumulated phase measurement (406) of a communication signal over a predetermined time interval. A frequency estimate of the signal is generate (402); the frequency estimate is then converted to a coarse phase measurement (404, 642). A phase error is generated based on the frequency estimate (644); the phase error is then converted to a fine phase measurement (646). The coarse and fine phase measurements are summed to yield an accumulated phase measurement (648).
Abstract:
A multifunction wristwear device includes a distance tracking device to calculate the total distance traveled by the wearer during an event by using GPS signals. The distance tracking device automatically adjusts the sampling rate to compensate for blockage of GPS satellites and changes in direction so as to provide the optimal accuracy given the available battery power. The device can provide useful information to the wearer during and after the event through a menu-driven interface on a matrix-type display screen.
Abstract:
The invention relates to determining the position of a mobile receiver (4) in a digital telephone network positioning system. A first receiver (3) is at a known location and others are mobile. The method involves transmitting signals from a plurality of sources (1), the transmission signals having a format at least a portion of which has predetermined values or a portion of which is repeated. The time offset of the transmission signals received at each receiver (4, 5) from a transmission source (1) relative to a reference clock of each receiver is determined by generating a reference signal locked to the reference clock. The reference signal has a similar format to the transmission signals and includes a portion identical to the predetermined values or repeated portion of the received signal and compares the received transmission signal and the reference signal. The time delay between the respective signals received at the receivers (4, 5) is determined from their relative time offset, to thereby determine the position of the other receivers (4).
Abstract:
A narrow field electromagnetic sensor system and method of sensing a characterisitc of an object such as density, thickness, or presence, for any desired coordinate position on the object. The sensor employs a transmitter (120) for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver (110) for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor (181) for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path.
Abstract:
A narrow field electromagnetic sensor system and method of sensing a characterisitc of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object. Usually, the electromagnetic signal is a short RF burst and the obstruction must provide a substantially complete eclipse of the direct RF path. By employing time-of-flight techniques, a timing circuit controls the receiver to sample only the initial direct RF path of the electromagnetic signal while not sampling indirect path electromagnetic signals. The sensor system also incorporates circuitry for ultra-wideband spread spectrum operation that reduces interference to and from other RF services while allowing co-location of multiple electronic sensors without the need for frequency assignments.
Abstract:
Presented is a proximity monitoring apparatus and method. The apparatus comprises: a transmitter adapted to transmit a electromagnetic signal in a periodic time slot defined with reference to a master clock signal; and a detector adapted to receive the electromagnetic signal transmitted by the transmitter, to determine the period of the received electromagnetic signal, and to determine that the received electromagnetic signal was transmitted by the transmitter of the proximity monitoring apparatus if the determined period is within a predetermined range of values