57 results about "Multipath mitigation" patented technology

A method and system for identification, tracking and locating in wireless communications and wireless networks. The method and system use reference and / or pilot signals that are present in wireless communications and wireless networks. The method and system might also use RTT, TOA and time-stamping measurements / techniques to determine one or more reference signals traveling time between the Base Station (eNB) or its functional equivalent and mobile device (UE) and or network device. Other wireless networks that do not use reference and / or pilot signals may employ one or more of the following types of alternate embodiments of present invention: 1) where a portion of frame is dedicated to the ranging signal / ranging signal elements; 2) where the ranging signal elements are embedded into (spread across) transmit / receive signals frame(s); and 3) where the ranging signal elements are embedded with the data. The method and system includes multi-path mitigations processor and multi-path mitigations techniques and algorithms which improve the track-locate accuracy. The method and system allow achieving increased accuracy by using multi-path mitigations processor and multi-path mitigations techniques and algorithms. The techniques of Digital Signal Processing and Software-Defined Radio are used.

A demodulator used in a base band processor of the spread spectrum radio transceiver includes a demodulator circuit for spread spectrum phase shift keying (PSK) demodulating an information signal received from a radio circuit. The information signal includes data symbols formed from a plurality of high rate mode chips forming a spread spectrum information signal. At least one predetermined code function correlator is in line with a signal input for decoding the information signal according to a predetermined code. A carrier loop circuit allows phase and frequency tracking of the information signal and a chip decision circuit is operative with the carrier loop circuit for tracking high rate mode chips. A decision feedback equalizer formed from a feedback finite impulse response filter is operative with the chip decision circuit and the carrier loop circuit. It has a plurality of feedback taps. At least one feedback tap is selected for logical add / subtract operations to aid in canceling multipath signal echoes. A feed forward finite impulse response filter can also be positioned in line to the code function correlator and the signal input and has a plurality of feed forward taps that are selected for logical multiply operations to aid in reducing multipath signal echoes. A method aspect of the invention is also disclosed.

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 for mitigating the effects of multipath errors in GNSS devices is provided. Signals from GNSS satellites are received. Image data from an image sensor is received. Orientation data from an orientation sensor is received. The orientation data describes the orientation of the image sensor. Obstruction data is determined based on the image data. The obstruction data includes an obstruction region that indicates the sky in that region is obstructed by a structure. Based on the orientation data, obstruction data, and GNSS satellite location data, the position of GNSS satellites with respect to the obstruction region is determined. The location of the GNSS device is determined based on signals from some of the GNSS satellites and the position of GNSS satellites with respect to the obstruction region.

This invention is directed to a method for estimating and compensating for multipath errors in a pseudorandom noise ranging receiver. The method exploits the asymmetry of the correlation function and proportionately relates it to the magnitude of multipath error. In a pseudorandom noise ranging receiver, the correlation function is obtained by generating the local pseudorandom noise sequences at different programmed non-uniform phases resulting in non-uniformly spaced correlators. Numerically controlled oscillators, code generators and shift registers are programmed to determine the correlation values at non-uniformly distributed points on a correlation function. Curve fitting is undertaken to determine the code phase at which the correlation function peaks. A proportionality constant is applied to the measure of asymmetry of the correlation function to determine the multipath error in the pseudorandom noise signal. A filter is used to detect and eliminate outliers.

Systems, methods and devices for multipath mitigation are presented. Specifically, embodiments of the invention can advantageously use sensor inputs to mitigate the effect of multipath signals received at a receiver. The use of physical sensors in navigation systems is deemed particularly advantageous.

A receiver utilizes an array of complex accumulation registers to form an image of the average chip shape or, as appropriate, chip edge shape, of the received signal over a specified period of time as a time series of complex power measurements. The receiver divides the length of the chip into a plurality of ranges, or bins, and, as appropriate, extends the bins to cover additional chips or portions thereof. When a sample is taken, the receiver enables the respective registers that are associated with the corresponding bin or bins, and the respective registers then accumulates the associated power measurement. The receiver uses the accumulated measurements from selected registers and / or selected groups of registers, to produce the correlation values that are needed to perform one or more correlation techniques and / or one or more multipath mitigation techniques. As appropriate, the sizes and / or starting points of the bins, and / or the selections of the bins for the various groupings may be altered, to change the spacings, locations, and so forth to which correlation values correspond.

A quadrature multi-frequency ranging system applied to DSSS multipath mitigation problems is described. The QMFR techniques include taking the time-of-arrival measurements on the received signal at a time when the multipath component is at a 90 degree angle to the direct path. Further, the preferred embodiment of the present invention recognizes that when a signal is transmitted at a series of frequencies, and the spread of these frequencies is sufficient, a quadrature or near quadrature condition can be forced to occur, at which the TOA estimation gives the highest certainty of measurement.