484 results about "Multipath effect" patented technology

A method and apparatus for conducting a pilot signal search in a wireless communications network. The location of a mobile is determined within the network. This location is then used in determining search window sizes and other search parameter information that is used to search all pilot signals identified in a designated pilot signal set. Search window size is also determined based upon the location of the mobile and another component related to multipath effects for a transmitted pilot signal.

Location information provided by multiple positioning systems is combined to provide an estimated user location. In performing the combination, location information provided by the positioning system that is currently deemed more reliable is provided greater weight than the location information provided from the other positioning system(s). Alternatively, one of multiple positioning systems is selected to calculate an estimated user location. The selected system is the one that is currently deemed more reliable based on some indicia of reliability. Using either approach, an accurate estimate of a user's location can be provided both in rural areas or other sparsely-populated areas as well as in urban areas or other areas prone to high multipath effects.

One or more median filter circuits are used to filter radio link control measurements corresponding to one or more radio link parameters of interest, such as received signal quality or round trip delay measurements, such as might be used by a base station to trigger mobile station handoff. As such measurements are particularly susceptible to measurement outliers arising from rapid but short-lived changes in radio link propagation paths, for example, the application of median filtering to such measurements is particularly advantageous. That is, by operation of median filtering, which is a non-linear filtering process, outliers in a stream of control measurements, such as are caused by instantaneous changes in channel fading or other propagation phenomena, are discarded rather than averaged in with the other measurements. Non-linear filtering as implemented by exemplary median filtering does not impair or otherwise limit the bandwidth of the underlying control measurements.

A hybrid beamforming apparatus and method are proposed for a communication system. The hybrid beamforming apparatus includes a plurality of antennas, a plurality of FFT, a plurality of hybrid weight-coefficient generators and a plurality of adders. In each of the hybrid weight-coefficient generators, the weight coefficient for each subcarrier is calculated by a time-domain correlation matrix and a cross-correlation vector, which is calculated by a frequency domain signal and a training signal. The hybrid beamforming apparatus and method according to the present invention can enhance immunity for multipath effect with lower system complexity.

The invention discloses an electronic device and a signal processing method thereof. The method includes that a first signal pathway module in the electronic device receives radiofrequency signals through a main set of antennas and transmits the received radiofrequency signals to at least one radio frequency module for processing, or transmits at least one radiofrequency signals sent by the at least one radio frequency module and sends the radiofrequency signals through the main set of antennas; a second signal pathway module receives radiofrequency signals through a diversity antenna used by the second signal pathway module and sends the radiofrequency signals to at least one radio frequency module for processing; a GPS signal pathway module receives GPS signals through a GPS antenna used by the GPS signal pathway module and sends the GPS signals to at least one radio frequency module for processing; and at least one radio frequency module receives GPS signals through the GPS signal pathway module and at least one signal pathway module in the second signal pathway module. The influence of multipath effect of GPS signals on reception performance of the GPS signals on reception performance of GPS signals during reception of GPS signals.

A method and system of generating an indoor radio map. In order to reduce the influence of multipath effect on indoor localization and improve the accuracy of indoor localization, a technique of processing data for indoor target locating and a technique of locating an indoor target based on the above technique is proposed. The method for generating an indoor radio map performs a smoothing process on the wireless signal strength measured in at least one position by a mobile node based on wireless signal strengths measured by the mobile node at adjacent positions, so as to reduce the influence of multipath effect.

The invention provides a wireless and ultrasonic composite location system and a location method for the wireless and ultrasonic composite location system, wherein the wireless and ultrasonic composite location system comprises a plurality of beacon modules with fixed positions, at least one mobile location module and an electronic location platform; each of the beacon modules comprises a first wireless receiving and sending module, an ultrasonic transmitting module and a first intelligent processing module; the mobile location module is arranged on a mobile object, and comprises a second wireless receiving and sending module, an ultrasonic receiving array, an array processing module and a central processer; the electronic location platform is used for building an electronic map and sending the electronic map to the mobile location module, and is also used for coordinating the synchronization of the beacon modules and the mobile location module. The invention also comprises the location method for the wireless and ultrasonic composite location system. By adopting the system and the method, the problems of multipath effect and none-line-of-sight are solved, the measurement precision is improved, and the theoretical precision of less than 0.1mm can be reached.

The invention discloses a single-difference filtering-based deformation monitoring GNSS (global navigation satellite system) signal multi-path correction method. On the basis of the spatial correlation characteristics of inter-receiver single-difference observation residuals, a single-difference filtering method is adopted to fix ambiguity and extract a carrier pseudo-range observation residual; fast Fourier transform analysis and wavelet de-noising are performed on the data residual, so that a discrete multi-path correction map and a reflection multi-path spatial correction map are established; and therefore, influence on GNSS carriers and pseudo-range observation values caused by a multipath effect in a bridge deformation monitoring environment can be decreased. According to the method of the invention, the spatiotemporal repetition characteristics of multiple paths are utilized. With the single-difference filtering-based deformation monitoring GNSS signal multi-path correction method adopted, the reliability and success rate of ambiguity fixation can be effectively improved, and single-epoch calculation accuracy of dynamic monitoring can be improved.

The invention discloses a wireless indoor positioning method and a device based on environmental backscattering. The method comprises steps: a radio frequency source RFs transmits signals; a label performs environmental backscattering; a mobile terminal Q detects the received label signals; and three-dimensional positioning on the mobile terminal is finally carried out. The device comprises the radio frequency source, the label and the mobile terminal. The environmental backscattering technology is used to be combined to multi-antenna label beam scanning, indoor and real-time three-dimensionalpositioning is realized, and the method and the device have the advantages of low power consumption, good anti-multipath effects are good; the safety is high; the system complexity is low; and the like.

This provides methods and systems for V2X applications, such as forward collision warning, electronic emergency brake light, left turn assist, work zone warning, signal phase timing, and others, mainly relying on a GNSS positioning solution transmitted via the Dedicated Short-Range Communications (DSRC) to / from the roadside units and onboard units in other V2X-enabled vehicles. However, the positioning solution from a GNSS may be deteriorated by noise and / or bias due to various error sources, e.g., time delay, atmospheric effect, ephemeris effect, and multipath effect. This offers a novel quality filter that can detect noise and the onset of drift in GNSS signals by evaluating up to four metrics that compare the qualities of kinematic variables, speed, heading angle change, curvature, and lateral displacement, obtained directly or derived from GNSS and onboard vehicle sensors. This is used for autonomous cars and vehicle safety, with various examples / variations.

This provides methods and systems for the global navigation satellite system (GNSS) combined with the dead-reckoning (DR) technique, which is expected to provide a vehicle positioning solution, but it may contain an unacceptable amount of error due to multiple causes, e.g., atmospheric effects, clock timing, and multipath effect. Particularly, the multipath effect is a major issue in the urban canyons. This invention overcomes these and other issues in the DR solution by a geofencing framework based on road geometry information and multiple supplemental kinematic filters. It guarantees a road-level accuracy and enables certain V2X applications which does not require sub-meter accuracy, e.g., signal phase timing, intersection movement assist, curve speed warning, reduced speed zone warning, and red-light violation warning. Automated vehicle is another use case. This is used for autonomous cars and vehicle safety, shown with various examples / variations.

A method and apparatus for improving the accuracy of a round trip time (RTT) estimate between a first device and a second device are disclosed. The method involves calculating an acknowledgement correction factor and a unicast correction factor. These correction factors are used to compensate for symbol boundary time errors resulting from multipath effects.

The invention relates to an indoor localization method based on clustering algorithm analytical data optimization, which is used for carrying out accurate localization on an unknown node in a complex index environment. The indoor localization method comprises the steps of: executing an RSSI (Received Signal Strength Indicator) signal processing optimization strategy, i.e., optimizing an RSSI value by using a clustering analysis Gaussian hybrid filtering model so as to eliminate the problems of dispersed intersection and serious jitter of the RSSI value, which exist due to factors of a multipath effect, a barrier and the like, and obtain one more reliable and reasonable RSSI value; adopting a fitting RSSI distance measurement model, i.e., according to an RSSI-distance conversion curve, carrying out fitting of the curve by adopting a least square method so as to obtain a logarithm path loss model suitable for a current environment; and then estimating out position information of the unknown node by using a weighted centroid localization algorithm. According to the indoor localization method disclosed by the invention, by an optimal RSSI distance measurement algorithm, accuracy of localization and distance measurement is improved, so that adaptability and localization accuracy of the localization algorithm are improved; and the indoor localization method is suitable to apply and popularize in the complex indoor environment.

Systems and Methods are described for determining proximity motion of a mobile wireless device around a fixed target node. The present invention provides a method of regressively analyzing the signal strength on a receiver node, which may be either the mobile wireless device or the fixed target node, as a function of time to determine the proximity of the sending node, which may be either the mobile wireless device or the fixed target node, to the receiving node. The method includes detecting motion of mobile wireless device with a fixed wireless device within a proximity range of less than about 15 cm, and more preferably within around 5 cm. The system provides accurate proximity motion sensing that is not susceptible to multipath effects, and which can be implemented in a wide variety of wireless applications.

The invention relates to a time modulation array antenna system with reconfigurable frequency and beam direction, which comprises a control circuit for changing the work state time sequence of two bit phase shifters in a period so as to change the beam direction to trace mobile objects and changing the time modulation period so as to change the beam frequency to complement Doppler frequency shift; two bit phase shifters for periodically maintaining or reversing signals so that the beam energy is concentrated for a primary harmonic component for communication. According to the invention, Doppler frequency shift generated by high speed movement is complemented by changing time modulation period, and the work time sequence of the two bit phase shifters is adjusted to adjust the beam direction and concentrate beam energy to reduce multipath effect. The invention is particularly applied to the field of communication in high-speed movement environments such as railway, airplane and the like.

The invention provides an accurate target positioning method based on channel state information. According to the method of the invention, channel state information (CSI in short) of a wireless target and a multi-antenna channel gain matrix are acquired. Firstly the channel state information with amplitude lower than a threshold is filtered. Then discontinuous subcarriers are reconstructed for adjusting the phase of the subcarrier to a continuous condition. Then spectral peak analysis is performed on a spatial array signal by means of orthogonality between a signal subspace and a noise subspace, thereby obtaining an angle peak value and an arrival time of the signal. Finally a support vector machine is utilized for classifying the peak values, thereby determining a direct arrival angle from many decisions. For aiming at a defect in processing a multipath problem of a wireless signal, the accurate target positioning method effectively overcomes an influence of a wireless environment multipath effect and provides a new conception based on channel state information positioning.

An embodiment of the invention provides an ultrasonic positioning method, device and system. The ultrasonic positioning method comprises sending a first ultrasonic signal from a reference point to a point to be measured, and recording signal sending time; receiving a second ultrasonic signal at the reference point, recording signal receiving time, enabling the second ultrasonic signal to be a responding signal after the first ultrasonic signal is received at the point to be measured, and enabling the frequency of the first ultrasonic signal and the frequency of the second ultrasonic signal to be different; and positioning the point to be measured according to the signal sending time, the signal receiving time and the position of the reference point. By enabling the frequency of the ultrasonic signal sent at the reference point to be different from the frequency of the frequency fed back by the point to be measured, the multipath effect in the ultrasonic propagation process and positioning disturbance caused by the ultrasonic wave reflected by other subjects are avoided, and the accuracy of ultrasonic positioning is improved.

A hybrid beamforming apparatus and method are proposed for a communication system. The hybrid beamforming apparatus includes a plurality of antennas, a plurality of FFT, a plurality of hybrid weight-coefficient generators and a plurality of adders. In each of the hybrid weight-coefficient generators, the weight coefficient for each subcarrier is calculated by a time-domain correlation matrix and a cross-correlation vector, which is calculated by a frequency domain signal and a training signal. The hybrid beamforming apparatus and method according to the present invention can enhance immunity for multipath effect with lower system complexity.

A system for providing high resolution imaging of objects having sub-millimeter dimensions comprised of at least one transmitter, at least one receiver, a coupling chamber, and a processor for recording attenuation and time of flight profiles of the transmitted signals. The signals are conditioned in a manner to provide high signal-to-noise ration (SNR) and minimal crosstalk and multipath effects at the receiver.

A radar system and method with reduced multipath effects include a first component of a radar sensor module on which at least one antenna element is formed, the at least one antenna element having a surface at which radar radiation is received or transmitted, the at least one antenna element having a radiation aperture. A second component in proximity to the antenna element such that a portion of the radar radiation impinges on the second component comprises an angled surface forming an angle with the surface of the antenna element. The angled surface of the second component comprises a texture such that when the portion of the radiation impinges on the angled surface, the amount of multipath signal propagating through the radiation aperture of the antenna element is reduced.

Systems and methods for receiving ADS-B messages in environments where multipath propagation corrupts the messages or blocks the reception of the messages. An exemplary system combines RF signal processing and digital signal processing techniques to make it possible to receive ADS-B messages in the presence of multipath reflections from nearby structures and / or farther out structures. The system uses an array of horizontally spaced antennas. The RF signals from the antennas are combined by the receiver so as to form a set of beams with different azimuth antenna patterns to increase the probability that the multipath does not combine destructively with the line-of-sight path in at least one of the beams. This effectively removes multipath reflections where the delay of the multipath relative to the line-of-sight path is less than 100-200 nanoseconds. The system is also configured to remove multipath reflections with greater delays relative to the line-of-sight path.

The invention discloses a novel DOA (direction of arrival) estimation and beam forming combined multipath signal receiving method. The method includes: by the aid of the characteristic that spatial information carried in path signals in multipath signals is different and by combined application of DOA estimation and beam forming, processing the received multipath signals, effectively estimating an angle of arrival of each path signal, and distinguishing the path signals from the point of view of space; performing beam forming on the path signals of each angle so as to separate the path signals; extracting a main path signal from the path signals, and demodulating and decoding the main path signal. The core concept of the method is combined application of the DOA estimation and beam forming, the multipath signals are effectively separated, and a receiving end extracts the main path signal to have the same demodulated and decoded, thus impact of multipath effect is eliminated fundamentally, and receptivity of an OFDM (orthogonal frequency division multiplexing) communication system is improved.

The invention provides a single-pulse high-precision angle measuring system and method, and belongs to the field of navigation management secondary radars. According to the scheme, base band digital signals are demodulated through synchronized PN codes, original useful signals are restored, and then noise and interference signals are restrained; the amplitude of the restored original useful signals is detected; phase judgment is conducted through the amplitude of a sum channel and the amplitude of a difference channel, and sum amplitude information, difference amplitude information and a phase judgment result are resolved; an OBA value function is acquired according to the resolved sum amplitude information, the resolved difference amplitude information and the resolved phase judgment result for target azimuth calculation. Anti-interference capacity of a novel secondary radar system can be improved, the influence of the multipath effect can be reduced, and the angle measuring accuracy of the novel secondary radar system can be further improved through an improved amplitude single-pulse angle measuring technology adopting an OBA curved surface function method and an accumulated weight processing method.

The invention discloses a secondary-radar-based achieving method of a target multipath effect suppression technology. The method comprises the following steps that history trace point data are received and saved in real time, code matching is carried out, and period updating judgment is carried out after code matching is successful; target false judgment is conducted on updated new trace point data in a period according to multipath effect judgment criteria within the scanning period, data meeting requirements are reported, and data which do not meet the requirements are regarded as false trace point data and are discarded; initial target false judgment is rigidly conducted on new trace point data which are not updated in the period according to multipath effect judgment criteria within different scanning periods, data meeting requirements are reported, and data which do not meet the requirements are judged again. When being applied to a secondary ground radar and an airplane-mounted secondary radar, the secondary-radar-based achieving method can improve data quality of monitored targets and improves reliability and stability of a secondary radar system.

The invention relates to a signal intensity-based multi-object positioning method in a dynamic environment. According to the method, a wireless signal map is established only by utilizing received signal intensity information when a multipath effect exists indoor, so that the map can be used for determining the positions of a plurality of target objects at the same time; and moreover, the map does not need to be established repeatedly when the environment changes. According to the method, fingerprint identification information is acquired first, a signal intensity value corresponding to sight distance is stored in a database, and then comparison is performed during a target object positioning stage; the obtained sight signal intensity can be directly applied to positioning by distinguishing a sight path from a plurality of paths; and therefore, the positioning accuracy is improved; and the precise positioning is performed in a dynamic indoor environment.

The present invention provides a blind search method and device for frequency points of LTE system terminals, belonging to the field of mobile communications. The method adopts a three-step search method, and the fine control of step size gradually reduces the range of search frequency bands, position repeatability and frequency. The point continuity ensures that the actual system frequency is gradually approached, and the local primary synchronization signal is used for correlation detection to find the correct frequency point while also obtaining the real local primary synchronization signal and synchronization position; the invention also discloses a LTE system terminal frequency point blind search device; compared with the prior art, the present invention can effectively resist the influence of noise and multipath, the probability of finding the correct frequency point in the candidate frequency points is increased by more than 30%, and the blind search time of frequency points is shortened by more than 35%, which greatly Improve the performance of frequency point blind search.

The invention discloses a passive positioning method for combining received signal strength indication (RSSI) and pattern matching, which mainly solves the problem that the conventional passive positioning method has low positioning precision due to the influence of multipath effect in a wireless sensor network. The method comprises the following steps of: (1) gridding network rules, detecting a channel by using single pulse signals, and calculating the fading characteristic value of the channel; (2) selecting 4 reference receivers according to the magnitude of average received signal intensity of each receiver and the relative position; (3) randomly selecting two receivers during positioning, calculating the average received signal intensity difference delta Pr of the two receivers and the fading characteristic differences delta Loss from the grids to the receivers; (4) matching the fading characteristic differences delta Loss of all grids and the opposite number -delta Pr of the average received signal intensity difference; and (5) repeating the steps (3) to (4) for three times, and taking the center of the grid with highest average matching degree as the positioning result. Themethod can still ensure high precision under the influence of the multipath effect, improves the precision of the conventional positioning method, and can be used for passive positioning of the wireless sensor network in an urban environment.