Abstract: Apparatus and methods for sensing one or more physical parameters at a remote location while minimizing or eliminating contact between reservoir fluids and the like at the remote location and the sensor used to sense the physical parameters. In one example arrangement, the apparatus includes a tubing containing a communication cable and a sensor in communication with the cable, the sensor being located within the tubing proximate the remote location. The apparatus is configured to impose a barrier of a fluid between the sensor and the environment at the remote location. A fluid barrier reservoir containing the barrier fluid is also provided in some example arrangements.

Abstract: A vibrating cylindrical rate sensor (10) is mechanically balanced and mode aligned with respect to the vibrating portion of the sensor (10) by removing material from a vibrating portion of the vibrating cylinder (34) after the drive and pick-off transducers (30, 32, 30a, 18, 20) are fixed to the vibrating portion of the vibrating cylinder (34) of the cylindrical rate sensor (10).

Abstract: Apparatus for the remote measurement of physical parameters comprising sensing means (1) for sensing at least one physical parameter, instrumentation means (2) for interrogating the sensing means (1) and making a measurement, cable means (3) for communicating between the sensing means (1) and the instrumentation means (2), container means (4) for containing the sensing means (1) and the cable means (3) prior to installation of the sensing means (1), container holder means (5) for providing a support for the container means (4) at a convenient location, channel means (6) for providing a channel between the container means (4) and a measurement location where the channel is suitable for accepting the cable means (3) and the sensing means (1), and cable installation means (9) for installing the sensing means (1) and cable means (3) from inside the container means (4) into the channel means (6) and placing the sensing means (1) at the measurement location.

Abstract: A vibrating cylindrical rate sensor (10) is mechanically balanced and mode aligned with respect to the vibrating portion of the sensor (10) by removing material from a vibrating portion of the vibrating cylinder (34) after the drive and pick-off transducers (30, 32, 30a, 18, 20) are fixed to the vibrating portion of the vibrating cylinder (34) of the cylindrical rate sensor (10).

Abstract: A single axis rate sensor comprising a cylinder positioned about an axis and having primary and secondary drive and pick-off transducers and primary and secondary control loops. The primary control loop is provided for maintaining resonance of the cylinder by generating a ninety-degree phase shift between the primary drive transducer and the primary pick-off transducer. The secondary control loop is provided for receiving a signal from the secondary pick-off transducer indicative of rotation of the cylinder and for nulling the secondary drive transducer to zero. The primary control loop includes a phase-locked loop having a phase detector configured to operate at quadrature. By operating the demodulator in quadrature the demodulator and loop filter combination are a linear device which will not mix the microphonic baseband signal with the carrier. There will therefore be a reduction and possibly an elimination of the modulation of the voltage controlled oscillator by microphonic noise.

Abstract: A vibrating planar ring or hoop-like structure is disclosed. The structure is suspended in space by a suitable support mount for detecting turning rate, linear acceleration and angular acceleration. Turning rate is sensed by detecting vibrations coupled by Coriolis forces, whereas linear acceleration and angular acceleration are sensed by lateral, vertical and rocking movement of the entire ring or hoop-like structure within its mount.

Abstract: This invention relates to a single axis solid state attitude sensor in which, the spatial orientation of a resonant rode on a resonant body is maintained in alignment with the inertial angle K8 of the resonant body.

Abstract: A fibre optic gyroscope which reduces the sensitivity of the gyroscope to offsets in the demodulator, the reduction in sensitivity being achieved by modulating the radiation passing through the gyroscope by a first waveform which is derived from second and third periodic waveforms, the third waveform having a frequency substantially less than that of the second waveform in use and the second waveform having a frequency of about 1/2T where T is the time taken for the radiation to travel through the gyroscope, and detecting said radiation which is subsequently demodulated with respect to both second and third waveforms in order to minimize any offset introduced by the demodulation with respect to the second waveform.

Abstract: This invention relates to a method and apparatus, i.e. a "wavelength meter", for determininhg the wavelength of optical radiation, e.g., visible radiation. Radiation is subjected to two or more wavelength dependent phase modulations having a net effect which is wavelength dependent and is zero at a predetermined wavelength. The net modulation is then determined so as to obtain the difference between the predetermined wavelength and the actual wavelength of the radiation.

Abstract: A sensor for sensing magnetic fields. A single mode optical fiber has a core which is wound into a helical shape. The fiber is formed with a former and a core, and the core is preferably attached to the inner surface of the former and wound into a helical shape tracing its inner periphery. The core is also offset from the central axis of the fiber former.