Abstract: Arrangement for detecting water in a material flow during drilling, wherein the arrangement includes a control unit, a data acquisition unit and a sensor, wherein the sensor includes at least two probes, wherein the at least two probes are to be arranged in contact with the material flow and are connected to a programmable voltage source and a programmable voltage receiver. The arrangement is configured to measure a ratio between a received voltage waveform and an applied voltage waveform for a set of pre-determined frequencies; determine a complex impedance between the at least two probes for each of the pre-determined frequencies, based on the measured ratio; and determine a set of time mean values of the determined complex impedance for each of the pre-determined frequencies, using a time window.

Abstract: Arrangement for detecting water in a material flow during drilling, wherein the arrangement includes a control unit, a data acquisition unit and a sensor, wherein the sensor includes at least two probes, wherein the at least two probes are to be arranged in contact with the material flow and are connected to a programmable voltage source and a programmable voltage receiver. The arrangement is configured tomeasure a ratio between a received voltage waveform and an applied voltage waveform for a set of pre-determined frequencies; determine a complex impedance between the at least two probes for each of the pre-determined frequencies, based on the measured ratio; and determine a set of time mean values of the determined complex impedance for each of the pre-determined frequencies, using a time window.

Abstract: A submillimeter wavelength radar system has a receiver (20, 27, 90) for receiving and downconverting signals from content in a field of view of the system and a signal processor (30) arranged to determine information about the content from the downconverted signals, the radar system being arranged to obtain signals of the same points in the field of view from different illumination or receiving angles by having multiple illumination or receive positions, and the signal processor being arranged to use the determined information from the signals from the two or more angles to determine location or orientation of the content. By using information from different angles, it becomes possible to address or overcome the drawback of submillimeter wavelengths that most of the reflection is specular and so only surfaces of an object facing the radar system are detectable, meaning that many objects are unrecognisable.

Abstract: A signal processor (30) for a submillimeter wavelength active radar system (10, 20, 30) processes signals received and downconverted by the radar system, the downconverted signals corresponding to a given pixel of the field of view having time varying amplitude and phase components which have a periodic component which is dependent on content. Information about the content is discriminated from the periodic component. By using phase rather than only amplitude, there is additional information in the downconverted signals. The phase is more sensitive to changes in the content such as objects, background and atmospheric conditions, than amplitude alone. The phase information enables the periodic component to be retained which can be characteristic of the content owing to content flutter, changes in submillimeter standing waves and interference fringes in received reflections of submillimeter illumination if surface layers have a thickness of a number of half wavelengths.

Abstract: An antenna (80,90) has a one dimensional or multidimensional array of elements (20,40), wherein spacings between successive elements of at least part of the array are non periodic and correspond to a series of multiples of a unit spacing, the multiples following a Fibonacci sequence. Two dimensional arrays can be arranged as a Fibonacci grid or as a Fibonacci square tiling. The number of elements can be reduced for a given measure of resolution, while still enabling the signal being transmitted or received to have a peak in a single unique direction and thus form a beam. Furthermore, since there will be some elements clustered close together and a few which are well spaced, it can be more suitable for vehicles (30) than a regularly spaced array. It can be used as a transmit antenna or as a receive antenna for a submillimeter radar system.

Abstract: A signal processor (30) for a submillimeter wavelength active radar system (10, 20, 30) processes signals received and downconverted by the radar system, the downconverted signals corresponding to a given pixel of the field of view having time varying amplitude and phase components which have a periodic component which is dependent on content. Information about the content is discriminated from the periodic component. By using phase rather than only amplitude, there is additional information in the downconverted signals. The phase is more sensitive to changes in the content such as objects, background and atmospheric conditions, than amplitude alone. The phase information enables the periodic component to be retained which can be characteristic of the content owing to content flutter, changes in submillimeter standing waves and interference fringes in received reflections of submillimeter illumination if surface layers have a thickness of a number of half wavelengths.

Abstract: An antenna (80,90) has a one dimensional or multidimensional array of elements (20,40), wherein spacings between successive elements of at least part of the array are non periodic and correspond to a series of multiples of a unit spacing, the multiples following a Fibonacci sequence. Two dimensional arrays can be arranged as a Fibonacci grid or as a Fibonacci square tiling. The number of elements can be reduced for a given measure of resolution, while still enabling the signal being transmitted or received to have a peak in a single unique direction and thus form a beam. Furthermore, since there will be some elements clustered close together and a few which are well spaced, it can be more suitable for vehicles (30) than a regularly spaced array. It can be used as a transmit antenna or as a receive antenna for a submillimeter radar system.

Abstract: A submillimeter wavelength radar system has a receiver (20, 27, 90) for receiving and downconverting signals from content in a field of view of the system and a signal processor (30) arranged to determine information about the content from the downconverted signals, the radar system being arranged to obtain signals of the same points in the field of view from different illumination or receiving angles by having multiple illumination or receive positions, and the signal processor being arranged to use the determined information from the signals from the two or more angles to determine location or orientation of the content. By using information from different angles, it becomes possible to address or overcome the drawback of submillimeter wavelengths that most of the reflection is specular and so only surfaces of an object facing the radar system are detectable, meaning that many objects are unrecognisable.