Bae Systems, Inc.

Bay Systems Plc

Andrew James Smith

Mohammed Nawaz

Christopher Ralph Pescod

Simon Charles Giles

Michael Andrew Scott

James Christopher Gordon Matthews

Shahbaz Nawaz

Mark Trevor Newman

Robert John Mark Longstone

David John Aitken

Guiseppe Carlos Sarno

Martin John White

Mohammed Namaz

According to an aspect of the invention, there is provided a control system for controlling a projectile, the control system comprising: a plurality of transmitters, wherein each transmitter of the plurality of transmitters is arranged to transmit an electromagnetic wave from a transmission position; a receiver associated with the projectile, the receiver being arranged to receive a plurality of electromagnetic waves transmitted from the plurality of transmitters; a controller associated with the projectile, the controller being arranged to: determine at least one of a position, a velocity or an acceleration of the projectile from transmission positions of the plurality of transmitters and Doppler measurements derived from the received plurality of electromagnetic waves; and generate a control signal for performing an action with the projectile depending on the determined at least one of position, velocity or acceleration of the projectile.

Control system for controlling a projectile

Methods and apparatus for controlling a bias voltage () supplied to an optical modulator that comprises a biasable component configurable to be biased by application of the bias voltage (), the method comprising: providing a target for the modulator output power; applying, to the biasable component, a bias voltage () that biases the biasable component so that the output power is within a pre-defined range of the target; monitoring the output power and, if the output power of the modulator is determined to be outside the pre-defined range, varying the value of the bias voltage () to bring the output power back within the pre-defined range; and monitoring the optical input to the modulator and, if it has been disabled, maintaining the bias voltage () at its current level for a pre-determined length of time that is dependent upon how long the modulator has been operating at quadrature.

Controlling bias voltages for optical modulators

An optical signal transmission apparatus () for a rotating antenna comprising a plurality of optical modulators () arranged for receiving a respective plurality of analog RF signals () and for modulating a respective plurality of optical signals therewith to produce a plurality of modulated analog optical signals (). A plurality of opto-electrical converters () each converts a respective modulated analog optical signal () into an analog electrical signal. The plurality of optical modulators () are rotationally coupled in optical communication with the plurality of opto-electrical converters () via an optical rotary joint () including a reversion prism.

Relating to antennas

Methods and apparatus for controlling a bias voltage supplied to an optical modulator, the modulator comprising a biasable component, the biasable component being configurable to be biased by application of the bias voltage () such that the modulator operates at quadrature, the method comprising: providing a target for the output power of the modulator, the target for the output power of the modulator being an output power corresponding to the modulator operating at quadrature; applying, to the biasable component, a bias voltage () having an initial value of 0V; and, thereafter, varying the bias voltage () until the value of the bias voltage () is the value that is closest to the initial value and that biases the biasable component so that the output power of the modulator is within a pre-defined range of the target output power.

Methods and apparatus for finding a bias voltage () corresponding to a quadrature point of an optical modulator, the modulator comprising a biasable component which is configurable to be biased by application of the bias voltage () such that the modulator operates at quadrature, the method comprising: providing a target for the output power of the modulator which corresponds to quadrature; applying, to the biasable component, a bias voltage () having an initial value; thereafter, finding a value for the bias voltage () that biases the biasable component such that the output power of the modulator is within a pre-defined range of the target by, starting at the initial value, alternately increasing and decreasing (or decreasing and increasing) the bias voltage () with gradually increasing amplitude; and identifying the found value for the bias voltage () as a bias voltage corresponding to a quadrature point of the optical modulator.

Finding bias voltages for optical modulators

An analog modem circuit and carrier recovery method are disclosed for use between an RF receiver and a digital modem circuit configured for receiving a baseband RF input signal, and including an up-converter with frequency supplied by an up-converter voltage controlled oscillator, VCO; a down-converter with frequency supplied by a down-converter VCO; a Costas loop sub-module; and baseband outputs from the down-converter to a digital modem circuit. The up-converter feeds the down-converter, and the Costas loop module performs Costas loop functionality on the output of the down-converter to control the up-converter VCO frequency output to thereby control modification of rotation of symbols of the baseband signal.

Radio frequency communication

A point-to-point radio frequency (RF) communication system having one or more communication units coupled to respective television cameras and displays; and a further communication unit; wherein the units transmit video data to the further communication unit at frequencies greater than or equal to 50 GHz and at data rates greater than or equal to 1 gigabit/second; and the units receive video data transmitted by the further communication unit at frequencies greater than or equal to 50 GHz and at data rates 250 megabits/second. The units can each include an antenna with a waveguide diplexer and an RF transceiver circuit board having sufficient transmit/receive isolation for the transmitting and receiving to take place point-to-point at distances greater than or equal to 1 km.

Apparatus for providing antenna diversity for a radio transmitter/receiver (TR) comprising measuring means for measuring relative received signal strengths in a plurality of antennas in a selectable frequency range, means for selecting the selectable frequency range according to a transmission frequency of the TR, and connecting means for connecting the antenna having the greatest received signal strength to the TR. The apparatus may be combined with a plurality of antennas to form a diversity antenna system, for example for use with a personal radio. The antennas may then be disposed spaced apart on the user's body e.g. by being incorporated into a garment.

Antenna diversity apparatus

A bias controller and a method for controlling the bias of an electro-optic modulator are provided. In the method, for a received indication of modulator temperature, steps are provided for accessing a look-up table to determine a corresponding value of bias voltage, for a required bias point, to apply to the modulator. If no such value is stored, additional steps are provided to generate a pilot tone for input to the modulator and to recognize, from the signal content of a modulated optical signal output by the modulator, operation of the modulator at the required bias point, adjusting the value of bias voltage being applied to the modulator as required. When operation at the required bias point is recognized, the respective value of bias voltage for that modulator temperature is stored in the look-up table. The same method is provided to configure a bias controller in respect of a given modulator, if necessary ab initio.

Bias controller

A bias controller for an optical modulator. The modulator includes a bias electrode that is operable when appropriately biased by an applied bias voltage to configure the modulator to operate at quadrature, and the bias controller includes: a generating arrangement for generating power signals indicative of the optical output power of the modulator; and a processor operably connected to the generating arrangement and said bias electrode and arranged to receive said power signals from said generating arrangement and to control the bias voltage applied to said bias electrode. The processor is configured to vary the bias voltage applied to said bias electrode and to determine from power signals received from said generating arrangement a peak optical output power for said modulator, and to determine in dependence upon said peak optical power a target optical power for quadrature with reference to a store of predetermined values for peak output power and respective corresponding values of target optical power for quadrature. Other embodiments relate to a multi-channel bias controller, and to a method for controlling voltage bias in a modulator.

Bias controller for an optical modulator

The present invention relates to a bias controller for a dual output electro-optic modulator and a method for controlling the bias of a dual output electro-optic modulator. The invention further comprises an optical commutator switch with a plurality of dual-output electro-optic modulators interconnected in a tiered arrangement, and control means for deriving measurements of optical power from each of the modulators. The optical commutator is further used for determining respective bias control signals to achieve and maintain operation of the modulators substantially at their quadrature bias points, and further for generating said respective bias control signals for applying them to the respective modulators.

This invention relates to optical delay lines, particularly to modifying an optical signal passing through an optical delay line. A method of applying a Doppler shift to an optical signal as it passes through an optical delay line is provided, the method comprising the step of progressively altering a property of the optical delay line during passage of the optical signal therethrough such that the time taken for the optical signal to pass therethrough is progressively lengthened or progressively shortened for successive portions of the optical signal. In addition, an optical delay line is provided that may be used in accordance with the above method.

Growing community of inventors

Chelmsford, United Kingdom

Andrew James Smith