Abstract: A method and system is provided for detecting and characterizing pulsed threat radar emitters through heavy in-band interference. System includes an advanced digital signal processing method provides spatial and temporal interference cancellation, super-resolution direction-finding, and high resolution spectrum analysis techniques. The system receives the digitized output of a discriminator bank and produces highly accurate threat pulse radio frequency estimates. The invention further provides a two-channel configuration for a DF subsystem, to perform adjacent-beam direction-finding through severe interference environments. The invention provides increased sensitivity, increased frequency accuracy, and up to 40 dB of increased interference look-through capability in ES system but remains transparent to ES system functioning and to ES system operators.

Abstract: A method and system is provided for detecting and characterizing pulsed threat radar emitters through heavy in-band interference. System includes an advanced digital signal processing method provides spatial and temporal interference cancellation, super-resolution direction-finding, and high resolution spectrum analysis techniques. The system receives the digitized output of a discriminator bank and produces highly accurate threat pulse radio frequency estimates. The invention further provides a two-channel configuration for a DF subsystem, to perform adjacent-beam direction-finding through severe interference environments. The invention provides increased sensitivity, increased frequency accuracy, and up to 40 dB of increased interference look-through capability in ES system but remains transparent to ES system functioning and to ES system operators.

Abstract: A navigation satellite receiver that nulls interference and enhances satellite signals using differences in their spatial positions and that includes four antennas in a spatial array respectively connected to four amplitude and phase balanced receiver downconverter channels. Five satellite tracking channels are each connected to all four receiver channels and each includes despreaders and I/Q accumulators for early, late and punctual correlation. The despreader and accumulator combinations provide four-by-one vectors called aperture estimates. A code-gated maximum likelihood processor whitens these by multiplication with the mathematical inverse Cholesky factor of the interference data. This vector is generated in a millisecond block "k" and is multiplied by a similarly generated vector formed in a previous millisecond block "k-1". The magnitude of the resulting product is used for code tracking, and the phase of the result provides for carrier tracking.

Abstract: A rawinsonde system embodiment of the present invention includes a digital GPS snapshot buffer and a serial communications controller for transmitting message frames formed of a combination of digital GPS data from the snapshot buffer and digitized hardwired meteorological data input from a humidity-temperature-pressure instrument. The message frames are telemetered at a relatively low rate over a meteorological radio band to a ground station. Substantially all of the conventional GPS digital signal processing is performed by the ground station, including carrier recovery, PRN code locking, pseudo-range extraction, ephemeris data extraction, almanac collection, satellite selection, navigation solution calculation and differential corrections. Ground processing further includes Kalman filter wind velocity calculation.