Abstract: The earth's magnetic field has not been mined as a source of energy. With average field strength of 0.5×10?4 Tesla around the world it is easy to understand why. A disruptive technology is needed to mine the earth's magnetic field. Such a technology, graphene, is now at an early stage of development with excellent properties in the form of high conductivity, low resistivity sheets that are durable, light weight, and low cost. Multiple sheets of graphene provide a significant multiplier to earth's magnetic field yielding a feasible source of ecologically clean power. Graphene based EcoCharge units can be driven by electric motors putting graphene in motion to mine the earth's magnetic field.

Abstract: The earth's magnetic field has not been mined as a source of energy. With average field strength of 0.5×10?4 Tesla around the world it is easy to understand why. A disruptive technology is needed to mine the earth's magnetic field. Such a technology, graphene, is now at an early stage of development with excellent properties in the form of high conductivity, low resistivity sheets that are durable, light weight, and low cost. Multiple sheets of graphene provide a significant multiplier to earth's magnetic field yielding a feasible source of ecologically clean power. Graphene based EcoCharge units can be driven by electric motors putting graphene in motion to mine the earth's magnetic field. Estimates show that 150 EcoCharge units driven by 15 electric motors using 905 kW of input electrical power will generate 504 MW, the output power of a standard coal fired power plant.

Abstract: The earth's magnetic field has not been mined as a source of energy. With average field strength of 0.5×10?4 Tesla around the world it is easy to understand why. A disruptive technology is needed to mine the earth's magnetic field. Such a technology, graphene, is now at an early stage of development with excellent properties in the form of high conductivity, low resistivity sheets that are durable, light weight, and low cost. Multiple sheets of graphene provide a significant multiplier to earth's magnetic field yielding a feasible source of ecologically clean power. Graphene based EcoCharge units can be driven by electric motors putting graphene in motion to mine the earth's magnetic field. Estimates show that 150 EcoCharge units driven by 15 electric motors using 905 kW of input electrical power will generate 504 MW, the output power of a standard coal fired power plant.

Abstract: The earth's magnetic field has not been mined as a source of energy. With average field strength of 0.5×10?4 Tesla around the world it is easy to understand why. A disruptive technology is needed to mine the earth's magnetic field. Such a technology, graphene, is now at an early stage of development with excellent properties in the form of high conductivity, low resistivity sheets that are durable, light weight, and low cost. Multiple sheets of graphene provide a significant multiplier to earth's magnetic field yielding a feasible source of ecologically clean power. Graphene based EcoCharge units can be driven by electric motors putting graphene in motion to mine the earth's magnetic field. Estimates show that 150 EcoCharge units driven by 15 electric motors using 905 kW of input electrical power will generate 504 MW, the output power of a standard coal fired power plant.

Abstract: A technique for alerting a user of approaching moving objects from the side or rear includes a rear looking radar with audio alerts to the user. Feasibility of the Rear Looking Snow Helmet is shown using the skiing and snowboarding applications where variable frequency (distance related) audio alerts are provided to left and right earphones depending on the location of the approaching skier/snowboarder. The electronics driving the system are mounted in the skier's/snowboarder's helmet while two antenna elements are mounted on the rear of the helmet. A large ON/OFF switch is mounted on the helmet for easy access. We show feasibility of the concept using performance analysis and by proposing an implementation architecture for the skiing and snowboarding applications. We claim the system will meet an acceptable level of performance when parameters are varied and traded off and that the system is technology independent.

Abstract: A technique for determining the time of arrival of a signal involves correlating a received signal with a correlation function to produce a stream of correlation samples including a peak sample, pre-peak samples, and post-peak samples. A curve matching table includes sets of values, where each set of values represents discrete points of a correlation function having a peak at a respective different time shift relative to the timing of the peak sample. The sets of values include first sets of values that are matched with a first set of samples having no post-peak samples from the correlation samples, and second sets of values that are matched with a second set of samples having at least one post-peak sample. The time of arrival of the signal is determined from the timing of the peak of the correlation function represented by the set of values that produces the best match.

Abstract: 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.

Abstract: A technique for determining the time of arrival of a signal involves correlating a received signal with a correlation function to produce a stream of correlation samples including a peak sample, pre-peak samples, and post-peak samples. A curve matching table includes sets of values, where each set of values represents discrete points of a correlation function having a peak at a respective different time shift relative to the timing of the peak sample. The sets of values include first sets of values that are matched with a first set of samples having no post-peak samples from the correlation samples, and second sets of values that are matched with a second set of samples having at least one post-peak sample. The time of arrival of the signal is determined from the timing of the peak of the correlation function represented by the set of values that produces the best match.

Abstract: A spectral notch modulation technique for encoding information in a signal involves transforming the signal into the frequency domain via a fast Fourier transform (FFT) of length N, such that the signal is represented by N frequency bins, selectively nulling M of the N frequency bins, where nulled combinations of M frequency bins respectively correspond to encoded information bits, transforming the selectively nulled signal to the time domain via an inverse FFT, and transmitting the selectively nulled signal. At the receiving end, the signal is demodulated to recover the encoded information by transforming the signal into the frequency domain via a fast Fourier transform (FFT) of length N, identifying the set of M nulled frequency bins among the N frequency bins, and converting the set of M nulled frequency bins to corresponding information bits.

Abstract: A technique is described for determining the timing of a received signal that includes one or more time-delayed versions of a reference signal traveling over respective different signal paths. The technique includes correlating the received signal with the reference signal to produce a correlated signal; determining whether the correlated signal includes a signal peak that corresponds to the direct path of the received signal; and iterative repeating these operations until a signal peak is determined to correspond to the direct path of the received signal. In each successive iteration, the reference signal corresponding to at least the greatest signal peak in the correlated signal is regenerated, and contributions from each regenerated reference signal are removed from the received signal prior to correlating the received signal in the next iteration.

Abstract: A technique for transmitting a spread spectrum signal using plural non-contiguous frequency bands separated by segments of frequency spectrum excluded from use involves: generating a digital time-domain spread spectrum signal; converting the time-domain signal to a frequency-domain signal via an FFT; excising a portion of the frequency-domain signal by selectively removing frequency bins of the frequency-domain signal to cause spectral nulling of the transmit signal at the frequencies of the excluded segments; and converting the excised frequency-domain signal to an excised time-domain signal via an inverse FFT, which is then converted to an analog signal for transmission.

Abstract: 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.

Abstract: The position of a non-cooperating emitter is determined by detecting a signal from the emitter at three or more receiver communication devices positioned at different locations. The receiver communication devices determine respective detection times of the emitted signal in respective local time reference frames. To establish a common time reference frame for the emitted signal detections, each receiver communication device exchanges time synchronization signals with a reference communication device. Since any of the receiver communication devices and the reference communication device may be mobile, the signal exchange allows each receiver communication device to accurately determine the signal propagation time between itself and the reference communication device and factor the signal propagation time into an accurate adjustment of the local time reference frame.

Abstract: A position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging signals is accurately determined to yield the range estimates required to calculate the position of the mobile radio. The master radio transmits ranging signals to plural reference radios which respond by transmitting reply ranging signals. Upon reception of the reply ranging signal, the master radio determines the range to the reference radio from the signal propagation time. Any combination of fixed or mobile radios having known positions can be used as the reference radios for another mobile radio in the system. Individual radios do not need to be synchronized to a common time reference, thereby eliminating the need for highly accurate system clocks. Errors in TOA estimates are minimized by performing internal delay calibration, Doppler compensation, leading-edge-of-the-signal curve fitting and frequency diversity techniques.

Abstract: A spread spectrum position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging messages is accurately determined to yield the range estimates required to calculate the position of the mobile radio via trilateration. The master radio transmits outbound ranging messages to plural reference radios which respond by transmitting reply ranging messages. Upon reception of the reply ranging message, the master radio determines the range to the reference radio from the signal propagation time calculated by subtracting the far-end turn around time from the round-trip elapsed time. Any combination of fixed or mobile radios of known positions can be used as the reference radios for another mobile radio in the system, thereby providing adaptability under varying transmission conditions.

Abstract: The position of a non-cooperating emitter is determined by detecting a signal from the emitter at three or more receiver communication devices positioned at different locations. The receiver communication devices determine respective detection times of the emitted signal in respective local time reference frames. To establish a common time reference frame for the emitted signal detections, each receiver communication device exchanges time synchronization signals with a reference communication device. Since any of the receiver communication devices and the reference communication device may be mobile, the signal exchange allows each receiver communication device to accurately determine the signal propagation time between itself and the reference communication device and factor the signal propagation time into an accurate adjustment of the local time reference frame.

Abstract: 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.

Abstract: A spread spectrum position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging messages is accurately determined to yield the range estimates required to calculate the position of the mobile radio via trilateration. The master radio transmits outbound ranging messages to plural reference radios which respond by transmitting reply ranging messages. Upon reception of the reply ranging message, the master radio determines the range to the reference radio from the signal propagation time calculated by subtracting the far-end turn around time from the round-trip elapsed time. Any combination of fixed or mobile radios of known positions can be used as the reference radios for another mobile radio in the system, thereby providing adaptability under varying transmission conditions.

Abstract: A spread spectrum position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging messages is accurately determined to yield the range estimates required to calculate the position of the mobile radio via trilateration. The master radio transmits outbound ranging messages to plural reference radios which respond by transmitting reply ranging messages. Upon reception of the reply ranging message, the master radio determines the range to the reference radio from the signal propagation time calculated by subtracting the far-end turn around time from the round-trip elapsed time. Any combination of fixed or mobile radios of known positions can be used as the reference radios for another mobile radio in the system, thereby providing adaptability under varying transmission conditions.

Abstract: A position location communication system determines the position of a mobile master radio using a round-trip messaging scheme in which the time of arrive (TOA) of ranging signals is accurately determined to yield the range estimates required to calculate the position of the mobile radio. The master radio transmits ranging signals to plural reference radios which respond by transmitting reply ranging signals. Upon reception of the reply ranging signal, the master radio determines the range to the reference radio from the signal propagation time. Any combination of fixed or mobile radios having known positions can be used as the reference radios for another mobile radio in the system. Individual radios do not need to be synchronized to a common time reference, thereby eliminating the need for highly accurate system clocks. Errors in TOA estimates are minimized by performing internal delay calibration, Doppler compensation, leading-edge-of-the-signal curve fitting and frequency diversity techniques.