Abstract: An apparatus for determining operating characteristics of radio-frequency (RF) transmitting devices while the devices are in normal operation transmitting over-the-air RF signals. The apparatus comprises at least one signal sensor for receiving the RF signals, each sensor responsive to the RF signals received at a plurality of antennas or received at a directional antenna, an analyzer for determining signal parameters of received RF signals and for determining operating characteristics of the transmitting devices from the signal parameters, wherein each RF signal includes an identifier of the transmitting device, the apparatus using the identifier to link operating characteristics determined from the RF signals to the transmitting device, and a graphical user interface for displaying the operating characteristics for each transmitting device.

Abstract: An apparatus for determining a health of radio-frequency transmitters each transmitting a transmitted signal during normal operation. The apparatus comprises a receiver for receiving received signals, each received signal responsive to a transmitted signal, a first element for determining signal parameters of each received signal, the signal parameters responsive to an operating condition of a transmitter, each transmitted signal and each associated received signal including an identifier of the transmitter that transmitted the transmitted signal, the apparatus using the identifier to link determined signal parameters with the transmitter that transmitted the transmitted signal and a second element for determining a health of the transmitter that transmitted the transmitted signal, the health responsive to a relationship between one or more signal parameters and a selected value or a range of selected values for each signal parameter.

Abstract: An apparatus for determining operating characteristics of radio-frequency (RF) transmitting devices while the devices are in normal operation transmitting over-the-air RF signals. The apparatus comprises at least one signal sensor for receiving the RF signals, each sensor responsive to the RF signals received at a plurality of antennas or received at a directional antenna, an analyzer for determining signal parameters of received RF signals and for determining operating characteristics of the transmitting devices from the signal parameters, wherein each RF signal includes an identifier of the transmitting device, the apparatus using the identifier to link operating characteristics determined from the RF signals to the transmitting device, and a graphical user interface for displaying the operating characteristics for each transmitting device.

Abstract: A method for determining a location of a wireless transmitting device transmitting a digitally modulated transmitted radio frequency signal. The method comprises, at spaced-apart receivers: generating a received radio frequency signal and including time tags therein responsive to the transmitted radio frequency signal, detecting a destination message signal responsive to the received radio frequency signal, comparing the destination message signal and the received radio frequency signal and determining a time of arrival of the destination message signal responsive to the step of comparing and responsive to the time tags. The method further comprises determining a pairwise time difference of arrival of the received radio frequency signal for two pairs of receivers and determining the location of the device responsive to the pairwise time difference of arrival.

Abstract: A method for testing each one of a plurality of receiving sites operative in a time difference of arrival geo-location system. The method comprises determining a theoretical time of arrival of a test message at each receiving site assuming the test message was transmitted from a test message transmitting antenna at a known location; determining a measured time of arrival of the test message at each receiving site, the test message transmitted from the test message transmitting antenna; determining a true time of arrival of the test message at each receiving site, the true time of arrival comprising the measured time of arrival less a start time of the test message; determining a difference between the theoretical and the true times of arrival for each receiving site, wherein the difference for each receiving site is indicative of a health of the receiving site.

Abstract: A method of detecting and correcting bit errors in a digitally encoded data stream includes correlating a received bit transition in the data stream with a multitude of possible bit transitions to generate corresponding correlated bit transition values. A bit transition decision corresponding to a greatest correlated bit transition value is then generated for the received bit transition. Consecutive bit transition decisions generated for the data stream are compared to identify bit transition decision errors. Respective bit transition decisions are examined to determine if each decision is consistent with a prior adjacent bit transition decision in the data stream. If a bit transition decision error is identified, then the next greatest correlated bit transition decision is substituted for the bit transition decision in error.

Abstract: A method for determining a location of a digital radio transmitter includes detecting, by at least three spatially separated receivers, a digitally encoded radio signal, having a known pattern of bit transitions, radiated from the transmitter. Once detected, a time of arrival of the bit transitions at each of the receivers is determined. Then, an indication of the time of arrival at each respective receiver for the bit transitions is transmitted from each of the receivers to a central processor. At the central processor, time of arrival differences of common bit transitions among the receivers are determined. Based on the time of arrival differences, the central processor may calculate the location of the transmitter.