Abstract: A technique that enables the sine and cosine branches within a PLL module to be obtained relatively easily and efficiently is described. According to the technique, the computation operations requiring a computation load, such as calculation of sine and cosine functions, are performed mostly once per a digital sampled signal, while relatively simple operations, such as multiplication and accumulations, are performed for every frame.

Abstract: A system for tracking and positioning a moving object, the system including a plurality of transmitters operative to transmit alternating electromagnetic fields within a three-dimensional space and at least one sensor arranged to be fixed to at least one corresponding portion of a moving object whose position it is sought to monitor. Each of said at least one sensors includes an electromagnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axis respectively, of the alternating electromagnetic fields, an accelerometer to independently measure at least one component of the acceleration of the moving object; and a digital signal processor.

Abstract: A method for coherent detection and demodulation of a FDMA signal, that is a superposition of amplitude modulated carriers, is provided. An array of special digital phase-locked loops (PLLs) is implemented in a digital signal processor (DSP) for processing the received signal after it is digitized, and for extracting the envelopes corresponding to each carrier. Each PLL is deliberately made to slowly respond to error signals in order to allow the loop to preserve its phase while the amplitude value of the envelope flips sign. A down-decimation technique is employed in order to reduce the computational load. This is achieved by applying a finite impulse-response filter (FIR) only once per each frame, thereby only a single multiplication of the frame by the vector of filter's taps is employed. A digital generation of sine and cosine sampled waveforms is employed inside a PLL by using a real-time solution of a difference equation.

Abstract: A device, communicative with a PDA and comprising a movable part, that inputs to the PDA information about all or some of the six spatial variables of the movable part within a space that may be appreciably larger that the PDA and its display screen. The device may serve to conveniently input graphical and symbolic information, in place of a touch-screen, as well as to control multi-dimensional position and orientation of virtual objects in a natural analogous-motion manner. It may also be used in conjunction with an external passive keyboard to input alphanumeric information and commands.

Abstract: A method for reducing a current crosstalk interference component from an oscillating multiplex electric current flowing through a magnetic coil of a given electrical circuit originated from an electromagnetic flux emanating from a magnetic coil of a certain neighboring electrical circuit and intercepted by the magnetic coil of the given electrical circuit. The oscillating multiplex electric current has a main current component, related to the given electrical circuit, which is superposed with the current crosstalk interference component. The reduction of the crosstalk interference is achieved by estimating the current crosstalk interference component induced by the certain neighboring electrical circuit, and subtracting this current crosstalk interference component from a multiplex electric current flowing through the magnetic coil of the given electrical circuit by using earlier obtained crosstalk interference estimates.

Abstract: A system for tracking and positioning a moving object, the system including a plurality of transmitters operative to transmit alternating electromagnetic fields within a three-dimensional space and at least one sensor arranged to be fixed to at least one corresponding portion of a moving object whose position it is sought to monitor. Each of said at least one sensors includes an electromagnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axis respectively, of the alternating electromagnetic fields, an accelerometer to independently measure at least one component of the acceleration of the moving object; and a digital signal processor.

Abstract: A device, communicative with a PDA and comprising a movable part, that inputs to the PDA information about all or some of the six spatial variables of the movable part within a space that may be appreciably larger that the PDA and its display screen. The device may serve to conveniently input graphical and symbolic information, in place of a touch-screen, as well as to control multi-dimensional position and orientation of virtual objects in a natural analogous-motion manner. It may also be used in conjunction with an external passive keyboard to input alphanumeric information and commands.

Abstract: A technique that enables the sine and cosine branches within a PLL module to be obtained relatively easily and efficiently is described. According to the technique, the computation operations requiring a computation load, such as calculation of sine and cosine functions, are performed mostly once per a digital sampled signal, while relatively simple operations, such as multiplication and accumulations, are performed for every frame.

Abstract: This invention discloses a tracking and positioning system including a plurality of transmitters distributed within a working space, and at least one sensors attached to at least one moving object and operative to sense transmissions arriving from the plurality of transmitters, a dynamic transmission activator operative to track at least one position parameters of at least one of said sensors and to selectively activate and deactivate individual sets of at least one transmitters from among the plurality of transmitters, at least partly responsively to at leas one position parameters of at least one of the sensors. A tracking method for tracking a moving object whose initial position is substantially unknown is also disclosed.

Abstract: This invention discloses a pose tracking apparatus operative to track the pose of a moving object based on magnetic flux measurements taken in the vicinity of the moving object. The pose tracking apparatus includes a non-linear Kalman filter-based tracker. The tracker is operated to receive magnetic flux measurements performed in the vicinity of the moving object, and to operate a non-linear Kalman-type filter on said measurements, thereby to generate information regarding the pose of the moving object. In addition, the pose tracking apparatus includes a pose indicator operative to provide an output indication of the information regarding the pose of the moving object.

Abstract: A three-dimensional position fixing system associated with the keyboard of a digital computer, the keyboard being provided with an array of passive keys which identify the numerals, letters, symbols and other values to be entered in binary code forms into the computer when the keys are touched by a finger of the operator. The system includes a responder mounted on the operator's finger and a transmitter-receiver assembly housed in the computer which cooperates with the responder to yield a signal indicative of the exact position of the finger when touching a particular key. Digitally stored in the data storage of the computer is a table listing the keyboard location of each key and the binary codes of the values identified by the keys.

Abstract: An apparatus for determining the relative height between two targets is disclosed. The present invention also discloses a method for determining the relative height between two targets; the method is substantially similar to the operational aspects of the device of the present invention. The method requires no angular measurements in order to determine the different height between the two targets, but rather only distance measurements that can be performed simply and accurately. The apparatus for determining the relative height between two targets a disclosed.

Abstract: A system for monitoring of the position of at least one portion of an object. The system includes a plurality of transmitters operative to transmit alternating magnetic fields within a three-dimensional space, and at least one positioning sensor arranged to be fixed to at least one corresponding portion of the object whose position it is sought to monitor. Each of the positioning sensors includes a magnetic field receiver having at least one active axis and operative to receive at least one component, lying along the at least one active axes respectively, of the alternating magnetic fields.

Abstract: A method of tracking an object within a surveillance area having a predetermined linear extent. One or more ultrasound transducers are fixed to the object. A plurality of background units are placed at known positions in the area, each unit including an ultrasound transducer. One or more ultrasound waves are transmitted between the object and the plurality of background units. The ultrasound waves are received if they have propagated between the object and the background units within a time window of a duration such that the product of the duration and the speed of sound is substantially less than the linear extent of the detection area. A characteristic of the received ultrasound waves is determined, and coordinates of the object are determined responsive to the characteristic.

Abstract: A method for the real time determination of the three dimensional position of a movable target with respect to a fixed coordinate system, the method utilizing a responder mounted on the target, at least one primary transmitter/receiver of known position and a plurality of secondary transmitter/receivers of known positions.