Abstract: A highly sensitive, high-speed dual tunnel diode detector is described for use in Ultra Wideband (UWB) object detection systems, such as a radar. The extended capability of the detector to both extremely short (sub-foot) and long distance (tens of thousands of feet) ranges is unique and permits the application of low power UWB radar to a wide variety of applications including high resolution radar altimetry at altitudes exceeding 10,000 feet and for autonomous on-deck landing operations (e.g., one-foot altitudes), the detection of extremely low radar cross section (RCS) targets for such applications as suspended wire detection for helicopters and other manned and unmanned craft, etc. High noise and interference immunity of the detector permits co-location of a UWB radar sensor with other active systems. The invention has immediate and significant application to all areas, both military and commercial, of precision distance measurement, intrusion detection, targeting, etc. over a wide range of distances.

Abstract: An ultra wideband (UWB) or short-pulse transmission system that enables precise tracking or geolocation of a target over distances of several kilometers. The system includes a set of N (where N>2) untethered UWB transceivers located at fixed positions, an untethered UWB receiver at the target, and a processor at the target for resolving time-of-flight measurement ambiguities of received pulses to determine precise geolocation by solving a set of equations according to time-of-flight measurements and surveyed positions of N-1 transceivers. To eliminate a clock distribution system, self-synchronizing of pulse timing is achieved by generating a start pulse at one of the untethered transceivers. Alternatively, a timing source may be provided by a GPS or other timing generator at the transceivers in order to synchronize emissions of their pulses.

Abstract: A waveform adaptive transmitter that conditions and/or modulates the phase, frequency, bandwidth, amplitude and/or attenuation of ultra-wideband (UWB) pulses. The transmitter confines or band-limits UWB signals within spectral limits for use in communication, positioning, and/or radar applications. One embodiment comprises a low-level UWB source (e.g., an impulse generator or time-gated oscillator (fixed or voltage-controlled)), a waveform adapter (e.g., digital or analog filter, pulse shaper, and/or voltage variable attenuator), a power amplifier, and an antenna to radiate a band-limited and/or modulated UWB or wideband signals. In a special case where the oscillator has zero frequency and outputs a DC bias, a low-level impulse generator impulse-excites a bandpass filter to produce an UWB signal having an adjustable center frequency and desired bandwidth based on a characteristic of the filter.

Abstract: An UWB receiver utilizing a microwave tunnel diode as a single pulse detector for short pulse, impulse, baseband or ultra wideband signals. The tunnel diode detector's bias point is set at system start-up, through an automatic calibration procedure to its highest sensitivity point relative to the desired bit error rate performance (based upon internal noise only) and remains there during the entire reception process. High noise immunity is achieved through the use of a high speed, adaptive dynamic range extension process using a high speed, Gallium Arsenide (GaAs) voltage variable attenuator (VVA) whose instantaneous attenuation level is determined by a periodic sampling of the ambient noise environment. Microprocessor-controlled detector time-gating is performed to switch the tunnel diode detector to the receiver front end circuitry for reception of an incoming UWB pulse, and alternately to ground through a resistor to discharge stored charge on the tunnel diode detector.

Abstract: A batteryless sensor includes a small and concealed permanent magnet motor which operates as a generator to convert rotational or translational energy to an ersatz Vcc transient power supply via a mechanical arrangement to radiate a coded VHF oscillator signal to a repeater or central processing unit located as far as one mile from the sensor. The receiver is able to monitor a multiplicity of sensor units over a given time period.