Abstract: The disclosure is directed to a universal tracking system configured for tracking a plurality of supported sources and/or signal types. The universal tracking system may include an acquisition module configured to execute a serial or parallel search to detect visible signals. The universal tracking system may include at least one universal channel capable of extracting tracking data from a plurality of supported signal types. The universal channel may include complex correlators configured to correlate digital samples associated with one or more ranging signals utilizing primary, sub-carrier, and/or secondary codes. The universal channel may be configured to determine tracking data associated with at least one ranging signal of the plurality of supported signal types. The universal tracking system may further include a navigation processor configured to determine location utilizing tracking data received from one or more universal channels.

Abstract: An efficient voice activity detection method and system suitable for real-time operation in low SNR (signal-to-noise) environments corrupted by non-Gaussian non-stationary background noise. The method utilizes rank order statistics to generate a binary voice detection output based on deviations between a short-term energy magnitude signal and a short-term noise reference signal. The method does not require voice-free training periods to track the background noise nor is it susceptible to rapid changes in overall noise level making it very robust. In addition a long-term adaptation mechanism is applied to reject harmonic or tonal interference.

Abstract: A direct digital sampling and synthesis general purpose radio system is disclosed which employs single or multiple receiver and/or transmitter sub-systems that require no analog frequency conversion or translation circuitry. Receiver signal processing is disclosed that describes methods of conditioning and digitizing an entire received RF signal band in which the down conversion, channelization and demodulation are performed digitally. In addition, a method for direct synthesis of transmitter signals is also disclosed where up conversion and carrier modulation is performed digitally. Several mitigation techniques are described which aid in overcoming device limitations as well as overcoming problems created by combining multiple digital transmitters and receivers into a single integrated system. One embodiment of the invention describes an integrated VHF/UHF aircraft NAV/COMM radio system which combines a VHF transmitter with four VHF/UHF receivers all of which require no IF circuitry.

Abstract: An efficient voice activity detection method and system suitable for real-time operation in low SNR (signal-to-noise) environments corrupted by non-Gaussian non-stationary background noise. The method utilizes rank order statistics to generate a binary voice detection output based on deviations between a short-term energy magnitude signal and a short-term noise reference signal. The method does not require voice-free training periods to track the background noise nor is it susceptible to rapid changes in overall noise level making it very robust. In addition a long-term adaptation mechanism is applied to reject harmonic or tonal interference.

Abstract: A TCAS receiver/transmitter which uses an improved calibration scheme for improving the ability of the device to transmit in a narrow directional field where the device uses the transmitter frequency source to generate signals for calibration purposes. The calibration uses a technique of simultaneously transmitting from two antennas and manipulating the phase of the signal through successive settings. The signals are monitored by the remaining two antennas and calibration adjustments are made in response thereto.

Abstract: A TCAS receiver, including a relative bearing measurement radio receiving apparatus for use with an antenna array having four antennas where each antenna has associated with it, its own receiver capable of demodulating both I and Q components of transmissions from an intruding aircraft.