Lockheed Martin Corporation

Anaren, Inc.

Carl Gerst

James A Johnson

Steven V Czarnecki

Clifford M Gray

George A VerWys

Jeffrey C Merrill

A Guanella type balun with a conductive enclosure (for example, a re-entrant box) between its coupled lines and the magnetic material enclosing its coupled lines. Some embodiments use coupled strip lines. Some embodiments have dielectric material, such as printed circuit board material inside the re-entrant box along with the coupled strip lines. Preferably, the magnetic material is ferrimagnetic. Some preferred magnetic materials are non-conductive.

Wideband balun using re-entrant coupled lines and ferrite material

In a system for locating the position of a transmitter, a platform containing an antenna is moved through a measurement path. The frequency received by the antenna is measured at measurement points distributed along a measurement path. The frequency is measured by cross correlating coherent pulses of the received frequency signal. An inertial navigation system on the platform indicates the position of the measurement path. A computer determines estimated locations by non-linear least squares convergence starting from trial locations. The non-linear least squares convergence is based on the frequency equation for the received frequency ##EQU1## in which f.sub.0, is the transmitter frequency, V is the antenna velocity and r is the range of the transmitter. The computer evaluates a cost function derived from the frequency equation, for each location estimated by the non-linear least squares convergence and selects the estimated location with the lowest cost function as the best solution.

Doppler triangulation transmitter location system

In a system for locating the position of a transmitter, a platform containing an antenna is moved through a measurement path. The frequency received by the antenna is measured at measurement points distributed along a measurement path. The frequency is measured by cross correlating coherent pulses of the received frequency signal. An inertial navigation system on the platform indicates the position of the measurement path. A computer determines estimated locations by non-linear least squares convergence starting from trial locations. The non-linear least squares convergence is based on the frequency equation for the received frequency ##EQU1## in which f.sub.0 is the transmitter frequency, V is the antenna velocity and r is the range of the transmitter. The computer evaluates a cost function derived from the frequency equation, for each location estimated by the non-linear least squares convergence and selects the estimated location with the lowest cost function as the best solution.

In a long base line interferometer system for determining the position of a transmitter, the phase differences between the signal received by the antennas at each end of the base line are monitored as the interferometer moves through a measurement path to obtain phase difference measurements distributed along the measurement path. A cost function involving measuring the sum of the squares of the differences between measured values and predicted values is determined for each of a set of trial location grid points and the grid point with the lowest cost function is selected as a starting point for determining the transmitter location by least squares convergence. In evaluating the cost function, the predicted values are obtained from the equation: ##EQU1## in which .o slashed..sub.0 is unknown phase offset and the X and Y coordinates of the transmitter are unknown. The least squares convergence is carried out by iteratively adding corrections to predicted values for the unknowns until convergence occurs.

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Skaneateles, NY, United States of America

Carl Gerst