Abstract: An object ranging system operates by transmitting pulses derived from a frequency-swept signal and determining the beat frequency of a combination of the frequency-swept signal and its reflection from an object. A second (or higher) order harmonic is derived from the combination signal. Accordingly, determination of the beat frequency, and hence object range, is significantly enhanced. The frequency sweep is such that frequency changes occur at a substantially higher rate at the beginning of each the pulse repetition interval than at the end. Accordingly, because the frequency changes are concentrated in the period of pulse transmission, even reflections 'from a close object, where the time delay between the source signal and the reflection is very short, will cause a high beat frequency.

Abstract: A technique is described for determining the correct locations of a plurality of objects by processing signals emitted by a transmitter and reflected by the objects to a plurality of receivers, No angle or elevation information is used. Object-receiver pair time difference of arrival measurements are made to calculate the time difference of arrival between the signals received at each pair of receivers from each object. Hyperbolic localisation is then performed to identify possible locations for each object. Direct-reflected signal time reception measurements are made for each receiver-object pair to calculate the time difference between the reception by the receiver of the direct signal from the transmitter and the signal reflected by the object.

Abstract: A technique is described for determining the correct locations of a plurality of objects by processing signals emitted by a transmitter and reflected by the objects to a plurality of receivers, No angle or elevation information is used. Object-receiver pair time difference of arrival measurements are made to calculate the time difference of arrival between the signals received at each pair of receivers from each object. Hyperbolic localisation is then performed to identify possible locations for each object. Direct-reflected signal time reception measurements are made for each receiver-object pair to calculate the time difference between the reception by the receiver of the direct signal from the transmitter and the signal reflected by the object.

Abstract: An object ranging system operates by transmitting pulses derived from a frequency-swept signal and determining the beat frequency of a combination of the frequency-swept signal and its reflection from an object. A second (or higher) order harmonic is derived from the combination signal. Accordingly, determination of the beat frequency, and hence object range, is significantly enhanced. The frequency sweep is such that frequency changes occur at a substantially higher rate at the beginning of each the pulse repetition interval than at the end. Accordingly, because the frequency changes are concentrated in the period of pulse transmission, even reflections ‘from a close object, where the time delay between the source signal and the reflection is very short, will cause a high beat frequency.

Abstract: This invention relates to an inhalation apparatus for dispensing an inhalable substance and, in particular, but not exclusively, to an apparatus for use in the delivery of therapeutic substances to the human lung. There is provided and apparatus for dispensing an aerosol of electrostatically charged droplets including a housing having an open end duct in which are located a first electrode having an upper surface lying in a generally longitudinal plane of the duct and a second electrode spaced from the first electrode. The apparatus further includes means for delivering a metered quantity of liquid to the upper surface of the first electrode for atomization, and charging means for applying a higher potential to the second electrode with respect to the first electrode to effect atomization.