Abstract: The invention described herein is directed to a method and apparatus for estimating an onset time t0 of a noisy waveform by producing a time t1 that a magnitude of the noisy waveform crosses a positive threshold T which is as small as possible while keeping the probability of false crossings due to noise at an acceptable level. The estimate of the onset time t0 uses an initial portion of a noisy waveform magnitude leading edge to avoid errors due to later-occurring multipath components. The invention also produces a derivative of the noisy waveform magnitude at time t1, which is used to normalize against errors due to variations to power level without having to use any portion of the noisy waveform beyond time t1. The waveform to which the invention applies can be a received signal, the cross-correlation function derived from a received signal, or another waveform where onset time needs to be estimated.

Abstract: Methods and apparatus for using an energy emanating device that finds a person (17a,b) object or system based on preselected attributes (33) stored in the energy emanating device (10) are disclosed. Searching Methods Using Genetic Responsivity Measurements are used to compare the attributes (33) of individuals, and a match is determined based upon the correlation of these attributes (33). The matching is accomplished using a variety of algorithms, including a “Genetic Responsivity Measurement Formula.” In alternative embodiments, the invention may be used in a search engine.

Abstract: Methods and apparatus for using an energy emanating device that finds a person (17a,b) object or system based on preselected attributes (33) stored in the energy emanating device (10) are disclosed. Searching Methods Using Genetic Responsivity Measurements are used to compare the attributes (33) of individuals, and a match is determined based upon the correlation of these attributes (33). The matching is accomplished using a variety of algorithms, including a “Genetic Responsivity Measurement Formula.” In alternative embodiments, the invention may be used in a search engine.

Abstract: Methods and apparatus for using an energy emanating device that finds a person (17a,b) object or system based on preselected attributes (33) stored in the energy emanating device (10) are disclosed. Searching Methods Using Genetic Responsivity Measurements are used to compare the attributes (33) of individuals, and a match is determined based upon the correlation of these attributes (33). The matching is accomplished using a variety of algorithms, including a “Genetic Responsivity Measurement Formula.” In alternative embodiments, the invention may be used in a search engine.

Abstract: Sub-microsecond time transfer in a GPS/GNSS receiver using a weak GPS/GNSS signal is provided. The digitized complex baseband signal and the generated PN code are cross-correlated for each code period so as to output a complex correlation value at each code epoch of the generated PN code, where a sequence of the output correlation values form a data stream representing the navigation message. Bit synchronization generates bit sync pulses at bit boundaries. The location of a target segment having a known sequence at a known bit location in the navigation message is detected by searching through a plurality of subframes and accumulating search results for the plurality of subframes. Transmission time of the target segment is determined from the detected location of the target segment, with a certain time ambiguity. Accurate local time is determined by solving the time ambiguity using approximate time obtained from an external source.

Abstract: A method and apparatus provide high-sensitivity GPS/GNSS signal acquisition in a stationary GPS/GNSS receiver. The uncertainty in frequency due to apparent Doppler shift is partitioned into a plurality of contiguous frequency bins, and the uncertainty in location of navigation data bit boundaries is partitioned into equally spaced trial bit boundary locations. For each combination of the trial bit boundary location and the frequency bin, a signal block of captured complex baseband signal is Doppler-compensated using a phase rotator, and then synchronously summed with a periodicity of one period of C/A code so as to produce a compressed sample block having N samples. Each compressed sample block is cross-correlated with one period of reference C/A code to produce an N-value correlation function. A predetermined number of magnitudes of the N-value correlation functions are stack-accumulated into an array with precession compensation so as to find a correlation peak having the largest value.

Abstract: A low-cost GPS/GNSS receiver receives a satellite signal at an RF frequency (fRF). The GPS/GNSS receiver includes a front end section for receiving the satellite signal and generating a digital complex signal having a first bandwidth, the received satellite signal being converted into a complex signal before digitizing, a signal capturing section for searching for and acquiring the satellite signal, the signal capturing section including a capture memory, a baseband processor for tracking the acquired satellite signal, and a signal splitter coupled to the front end section. The signal splitter splits the digital complex signal into two bandwidths, by generating a narrowband digital complex signal having a second bandwidth substantially smaller than the first bandwidth. The signal splitter provides the narrowband digital signal to the capture memory and the wider first bandwidth digital complex signal to the baseband processor.

Abstract: Sub-microsecond time transfer in a GPS/GNSS receiver using a weak GPS/GNSS signal is provided. The digitized complex baseband signal and the generated PN code are cross-correlated for each code period so as to output a complex correlation value at each code epoch of the generated PN code, where a sequence of the output correlation values form a data stream representing the navigation message. Bit synchronization generates bit sync pulses at bit boundaries. The location of a target segment having a known sequence at a known bit location in the navigation message is detected by searching through a plurality of sub-frames and accumulating search results for the plurality of subframes. Transmission time of the target segment is determined from the detected location of the target segment, with a certain time ambiguity. Accurate local time is determined by solving the time ambiguity using approximate time obtained from an external source.

Abstract: A method and apparatus provide high-sensitivity GPS/GNSS signal acquisition in a stationary GPS/GNSS receiver. The uncertainty in frequency due to apparent Doppler shift is partitioned into a plurality of contiguous frequency bins, and the uncertainty in location of navigation data bit boundaries is partitioned into equally spaced trial bit boundary locations. For each combination of the trial bit boundary location and the frequency bin, a signal block of captured complex baseband signal is Doppler-compensated using a phase rotator, and then synchronously summed with a periodicity of one period of C/A code so as to produce a compressed sample block having N samples. Each compressed sample block is cross-correlated with one period of reference C/A code to produce an N-value correlation function. A predetermined number of magnitudes of the N-value correlation functions are stack-accumulated into an array with precession compensation so as to find a correlation peak having the largest value.

Abstract: Methods and apparatus for using an energy emanating device that finds a person (17a,b) object or system based on preselected attributes (33) stored in the energy emanating device (10) are disclosed. Searching Methods Using Genetic Responsivity Measurements are used to compare the attributes (33) of individuals, and a match is determined based upon the correlation of these attributes (33). The matching is accomplished using a variety of algorithms, including a “Genetic Responsivity Measurement Formula.” In alternative embodiments, the invention may be used in a search engine.

Abstract: A method and apparatus provide high-sensitivity GPS/GNSS signal acquisition in a stationary GPS/GNSS receiver. The uncertainty in frequency due to apparent Doppler shift is partitioned into a plurality of contiguous frequency bins, and the uncertainty in location of navigation data bit boundaries is partitioned into equally spaced trial bit boundary locations. For each combination of the trial bit boundary location and the frequency bin, a signal block of captured complex baseband signal is Doppler-compensated using a phase rotator, and then synchronously summed with a periodicity of one period of C/A code so as to produce a compressed sample block having N samples. Each compressed sample block is cross-correlated with one period of reference C/A code to produce an N-value correlation function. A predetermined number of magnitudes of the N-value correlation functions are stack-accumulated into an array with precession compensation so as to find a correlation peak having the largest value.

Abstract: Sub-microsecond time transfer in a GPS/GNSS receiver using a weak GPS/GNSS signal is provided. The digitized complex baseband signal and the generated PN code are cross-correlated for each code period so as to output a complex correlation value at each code epoch of the generated PN code, where a sequence of the output correlation values form a data stream representing the navigation message. Bit synchronization generates bit sync pulses at bit boundaries. The location of a target segment having a known sequence at a known bit location in the navigation message is detected by searching through a plurality of sub-frames and accumulating search results for the plurality of subframes. Transmission time of the target segment is determined from the detected location of the target segment, with a certain time ambiguity. Accurate local time is determined by solving the time ambiguity using approximate time obtained from an external source.

Abstract: A low-cost GPS/GNSS receiver receives a satellite signal at an RF frequency (fRF). The GPS/GNSS receiver includes a front end section for receiving the satellite signal and generating a digital complex signal having a first bandwidth, the received satellite signal being converted into a complex signal before digitizing, a signal capturing section for searching for and acquiring the satellite signal, the signal capturing section including a capture memory, a baseband processor for tracking the acquired satellite signal, and a signal splitter coupled to the front end section. The signal splitter splits the digital complex signal into two bandwidths, by generating a narrowband digital complex signal having a second bandwidth substantially smaller than the first bandwidth. The signal splitter provides the narrowband digital signal to the capture memory and the wider first bandwidth digital complex signal to the baseband processor.

Abstract: In ranging systems such as GPS, radar, and the like, accuracy of the ranging information recovered depends on the phase linearity of the ranging receiver, generally implemented as a superheterodyne radio. Superheterodyne radios use bandpass filters in their Intermediate Frequency (IF) amplifiers to accomplish suppression of adjacent channel signal interference. Depending on the ratio of IF center-frequency to signal-bandwidth, such filters evidence phase non-linearity affecting the signal group delay response. This generally manifests in coupling of the in-phase and quadrature detected signals during signal modulation changes in state. If this effect is ignored, reduced accuracy in the recovery of ranging information can be expected. One solution is to incorporate in the ranging receiver a phase non-linearity compensation structure, but this has an adverse economic impact.

Abstract: A base station (server) transmits assisting information to the user's receiver (rover). Signals from at least 5 satellites are used for 3-dimensional positioning. Pseudorange measurements are made in a system of equations having a minimum set of unknowns X,Y,Z, and T. (X,Y,Z) is the 3D rover position in a predefined coordinate system, and T is the time at which simultaneous measurements are made to determine pseudoranges to all satellites. The position of each satellite is a vector-valued function ƒk (T) of said time T, where fk is determined from satellite ephemeris data or its equivalent, sent to the rover over a communication link, as well as from knowledge of the approximate position of the rover.

Abstract: The location of a mobile unit is determined by evaluating the instantaneous distances between an apparatus traveling above the surface of the earth and the mobile unit. The instantaneous distances are determined by measuring the travel time of a plurality of signals and calculating the distance based on the speed of the signal. One of two possible location regions is identified as the region including the location of the mobile unit by observing the motion of the mobile unit resulting from the rotation of the Earth.

Abstract: A multiplying system for complex numbers using four three-stage 4 .times. 4 bit 2's complement multipliers and a modified adder and subtractor. Two of the 2's complement multipliers are fed to the subtractor which produces a 9 bit output representing the real term of the complex product and the other 2's complement multipliers are fed to the adder which produces a 9 bit output representing the imaginary term of the complex product. Each of the 3-stage 2's complement multipliers are modified from prior art multipliers to effect the two most significant bits. The unique adder and subtractor as well as the multipliers are implemented with universal logic gates consisting of cascode circuit components resulting in five gating stages for the complex multiplying system.