摘要:
The invention relates to a method, system and computer program product for determining a position of a person with respect to a blind spot of a vehicle. In a first aspect, the invention relates to a method for determining a position of a person with respect to a blind spot of a vehicle. In a second and third aspect, the invention relates to a system and a computer program product, respectively, for determining a position of a person with respect to a blind spot of a vehicle. Embodiments of the present invention are discussed throughout the claims, description and figures.
摘要:
A locating device locates a source emitting a short-duration high power microwave pulse. The locating device contains at least three separately disposed receiving antennas that are not disposed on a line, each with an associated detection device for detecting the point in time of the reception at the antenna of the high power microwave pulse. At least one short time measurement device is provided for determining at least two time differences between the points in time of reception of each two of the detection devices. A computing device is provided for calculating a location of the origin of the high power microwave pulse based on at least two of the measured time differences.
摘要:
Angle of arrival and/or range estimation within a wireless communication device. Appropriate processing of communications received by a wireless communication device is performed to determine the angle of arrival of the communication (e.g., with respect to some coordinate basis of the wireless communication device). Also, appropriate processing of the communications may be performed in accordance with range estimation as performed by the wireless communication device to determine the distance between the transmitting and receiving wireless communication devices. There are two separate modes of packet processing operations that may be performed: (1) when contents of the received packet are known, and (2) when contents of the received packet are unknown. The wireless communication device includes a number of antenna, and a switching mechanism switches from among the various antennae capitalizing on the spatial diversity of the antennae to generate a multi-antenna signal.
摘要:
A system and method for determining angular offset of an impulse radio transmitter using an impulse radio receiver coupled to two antennae. The antennae are separated by some known distance, and, in one embodiment, one antennae is coupled to the radio with cable delay. Impulse signals from the antennae are measured to determine the time difference of arrival of one such signal received by one antenna compared to that of the other antenna. Time differential is measured by autocorrelation of the entire impulse radio scan period, by detecting the leading edges of both incoming signals or various combinations of these methods. Using a tracking receiver, the pulses may be continuously tracked thus providing real time position information.
摘要:
A system and method are provided that includes at least a pair of spaced antennas having overlapping fields of view. The system further includes at least a pair of receivers respectively coupled to the pair of antennas. Each of the receivers includes a spectral separator having a plurality of output signals. Each of the output signals represents a signal value at one of a plurality of predetermined frequencies. A plurality of analog to digital converters are coupled to a corresponding one of the spectral separators for respectively providing a digital representation of each of the output signals. A digital processor coupled to an output of each of the plurality of analog to digital converters calculates an angle of arrival of the transmitted signal in at least one dimension from the digital representations.
摘要:
A system and method for determining angular offset of an impulse radio transmitter using an impulse radio receiver coupled to two antennae. The antennae are separated by some known distance, and, in one embodiment, one antennae is coupled to the radio with cable delay. Impulse signals from the antennae are measured to determine the time difference of arrival of one such signal received by one antenna compared to that of the other antenna. Time differential is measured by autocorrelation of the entire impulse radio scan period, by detecting the leading edges of both incoming signals or various combinations of these methods. Using a tracking receiver, the pulses may be continuously tracked thus providing real time position information.
摘要:
The extraction of phase information for radio frequency (RF) direction of rival is attained by pre-detect sensing and quantization of differential phase of a RF wave impinging on two or more antenna apertures, based on sensing and encoding differential phase without the use of conventional detection, and quantizing phase at or near the leading edge of a pulse signal. This is accomplished by detection of an intermediate frequency (IF) carrier, and encoding leading-edge phase (for each channel) in terms of near-phase-difference between two reference-oscillator readings containing the differential phase information--encoded as differential reference-oscillator phase. Precision angle-of-arrival is then derived from the measured differential reference-oscillator phase.
摘要:
A direction finding method and apparatus for a radio signal source, modulated by a digital information signal and existing in a heavy interference environment, is based on cyclic crosscorrelation. The direction finding technique exploits the second order periodicity of a transmitted signal having digital modulation, whereby the technique is immune to narrow-band interference. Radio frequency signals are received by two spaced antennas, and the signal of interest can be considered as a cyclostationary process. The signal time of arrival difference between the two antennas is determined using a cyclic crosscorrelation method. This is implemented by sending the electrical signals, developed by the antennas, through a variable delay device, then to a balanced mixer. The composite signal from the mixer is sent to a band-pass filter whose center frequency is equal to the baud rate of the signal of interest. The output energy of the filter is proportional to that portion of the cyclic crosscorrelation function where the cyclic frequency corresponds to the baud rate. With the use of a peak detector, which finds the peak values of the cyclic crosscorrelation function, the time difference of arrival between the two antennas is determined. This, in turn, determines a line of position to the radio source.
摘要:
A method and a system for radio direction-finding by measuring the Time of Arrival (ToA) of the leading edge of signals from a distant source at two relatively closely spaced receiving elements. In order to give a good degree of immunity to multipath, the times at which the instantaneous detected amplitudes of the received signals first exceed a minimal threshold value such that received signals can be satisfactorily distinguished from noise is measured in such a manner that the measured time is not affected by multipath which involves more than a few meters additional path length for the indirect, delayed signal. A suitable timing circuit is disclosed.By making ToA measurements on three coplanar, non-collinear receivers, directions of incidence in three dimensions can be determined.A method and a system using both ToA and phase-difference measurements can provide the accuracy of interferometry but be simpler and cheaper.
摘要:
A servo loop processor suitable for use in a passive radar range determining system is disclosed. Early and late overlapping video pulse trains derived from spaced receiving antennas are fed to separate first and second channels and are sampled and held from pulse period to pulse period to form signals representing the amplitude envelopes of the received pulse trains. The output of the first channel is variably delayed and the delayed signal is compared with the undelayed output of the second channel to create an error signal. The output of the second channel is also differentiated, and the result is sampled and held to create a reference signal that has the proper phase relationship with the error signal so that the error signal can be multiplied by the reference signal to create a correction signal. The resulting correction signal is integrated and fed back to control the time delay applied to the output of the first channel such that a closed servo loop is formed. At balance, the integrated correction signal is related to the distance between the radar antenna transmitting the pulse trains, and the receiving antennas. In an alternative embodiment, envelope signals representing the first and second channel pulse trains are converted from analog to digital form, and the digitized second channel output is subtracted from the same digitized signal delayed by a fixed interval to form a digital version of the above-mentioned reference signal. A digital version of the error signal, derived as above, is then multiplied by the digital reference signal to create a digital correction signal, which after integration, controls the time delay of the first channel output signal.