Roke Manor Research Limited

James Joseph Fisher

Robert John Weedon

Timothy John Quilter

Roderick Leonard Wallace Stevens

Philip Edward Roy Galloway

In a multilateration system receivers are grouped into two groups. The first group is used to determine a position of a signal source, for example, an aircraft equipped with a SAR transponder. From the determined position, predicted time of arrival values are produced for the second group receivers. These are compared with the actual time of arrival values for the signals arriving at the second group receivers. A difference is determined and then the variation of that difference is determined as the aircraft travels in its track. The groupings are then varied and further variations determined. When the minimum variation is determined an alert is given that the second group has a receiver which is operating with a larger than desirable group time delay.

Apparatus and method for determining receiver performance in a multilateration system

A dual polarised antennahas two types of antenna elements combined. Each type of antenna element is formed on a planar substrate. The substrates are furnished with inter-engaging slots to enable assembly of the elements. Signal feeds are connected to the active parts of the elements by means of connection points furnished at off axis positions. The off-axis positions for connection enable an arrangement in which the locus of the effective phase centres of the antenna element scan be co-located yielding a convenient arrangement with good performance.

Antenna

A directional, wideband, planar antenna arrangement is a class of Vivaldi aerial constructed as a plurality of conductive layers disposed on at least one substrate layer. The conductive layers are arranged to form a flared notch, which widens from a closed end to an open end, and is arranged to conform to a hybrid curve. The hybrid curve comprises a plurality of self-similar curve sections, and, as the flare widens, each successive curve section is scaled up by a scaling factor and joined at its wider end with a neighboring curve section. The hybrid flared notch can also be implemented in antipodal and balanced antipodal Vivaldi aerials.

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Romsey, United Kingdom

James Joseph Fisher