Range and orientation of a transmitter and a receiver are found by detecting the magnetoquasistatic field couplings between coils at the transmitter and receiver. Sum functions and ratio functions are calculated for each of the unique magnetoquasistatic field couplings between the transmitter and the receiver. The sum and ratio functions are inverted to determine the drift-free range and orientation. Linear and angular velocity and acceleration are calculated by applying a filter to reduce noise, and then taking the corresponding derivatives.

An instrument package for use during the drilling a wellbore. The instrument package includes a plurality of instruments such as accelerometers, gyroscopes, and magnetometers; a computer is configured to determine the current position of the plurality of instruments from a set of measurements produced by the plurality of instruments; and wherein the plurality of instruments are mechanically isolated from a drill head assembly by one or more multi-degree of freedom vibration isolators. The computer preferably has at least two modes different analytical modes of analyzing the set of measurements produced by the plurality of instruments, including a continuous mode and a survey mode, the continuous mode being operational during times that active drilling is occurring and the survey mode being operational during times that the active drilling is not occurring.

An instrument package for use during the drilling a wellbore. The instrument package includes a plurality of instruments such as accelerometers, gyroscopes, and magnetometers; a computer is configured to determine the current position of the plurality of instruments from a set of measurements produced by the plurality of instruments; and wherein the plurality of instruments are mechanically isolated from a drill head assembly by one or more multi-degree of freedom vibration isolators. The computer preferably has at least two modes different analytical modes of analyzing the set of measurements produced by the plurality of instruments, including a continuous mode and a survey mode, the continuous mode being operational during times that active drilling is occurring and the survey mode being operational during times that the active drilling is not occurring.

A drive device includes a noise signal calculation unit, a signal correction unit, and a drive controller. The noise signal calculation unit calculates a noise signal corresponding to a magnetic flux generated from a current flowing through a drive coil. The signal correction unit corrects a detection signal detected by a detector based on the noise signal. The drive controller controls a drive signal to be applied to the drive coil based on a corrected signal obtained by the signal correction unit. The noise signal calculation unit acquires an amplitude of a predetermined frequency band including a frequency of a high-frequency drive signal, and calculates the noise signal included in the detection signal based on the acquired amplitude.

A drive device includes a noise signal calculation unit, a signal correction unit, and a drive controller. The noise signal calculation unit calculates a noise signal corresponding to a magnetic flux generated from a current flowing through a drive coil. The signal correction unit corrects a detection signal detected by a detector based on the noise signal. The drive controller controls a drive signal to be applied to the drive coil based on a corrected signal obtained by the signal correction unit. The noise signal calculation unit acquires an amplitude of a predetermined frequency band including a frequency of a high-frequency drive signal, and calculates the noise signal included in the detection signal based on the acquired amplitude.

An accelerometer without internal mechanical attachments. Three parallel cylindrical magnets are fixed within a housing. Each cylindrical magnet has a long axis extending through the housing and a cylindrical cross-section. The cylindrical cross-sections of the cylindrical magnets are organized to form a triangular formation. The magnetization of the cylindrical magnets is tangential to the triangular formation. A diamagnetic mass object levitates within the three cylindrical magnets by the magnetization of the cylindrical magnets at an equilibrium position near the center of the triangular formation and near a central axis of the three parallel cylindrical magnets when no external force is applied. Sensors detect the location of the diamagnetic mass object when the diamagnetic mass object is displaced from the equilibrium position near the center of the triangular formation and the three parallel cylindrical magnets by an external force to the housing.

An accelerometer without internal mechanical attachments. Three parallel cylindrical magnets are fixed within a housing. Each cylindrical magnet has a long axis extending through the housing and a cylindrical cross-section. The cylindrical cross-sections of the cylindrical magnets are organized to form a triangular formation. The magnetization of the cylindrical magnets is tangential to the triangular formation. A diamagnetic mass object levitates within the three cylindrical magnets by the magnetization of the cylindrical magnets at an equilibrium position near the center of the triangular formation and near a central axis of the three parallel cylindrical magnets when no external force is applied. Sensors detect the location of the diamagnetic mass object when the diamagnetic mass object is displaced from the equilibrium position near the center of the triangular formation and the three parallel cylindrical magnets by an external force to the housing.

A trailer braking system having a surge component used in combination with an electric over hydraulic brake system. The surge component includes a sliding member with a magnetic sensor for detecting trailer deceleration, the sliding member providing an initial pressurization of the hydraulic system. A trailer mounted electrical circuit detects when the tow vehicle brakes are applied and includes a microcontroller for detecting the speed of deceleration provided by the magnetic sensor. A trailer mounted electric motor receives a signal from the circuit board to vary pressure to the brakes in accordance with the speed of deceleration.

A trailer braking system having a surge component used in combination with an electric over hydraulic brake system. The surge component includes a sliding member with a magnetic sensor for detecting trailer deceleration, the sliding member providing an initial pressurization of the hydraulic system. A trailer mounted electrical circuit detects when the tow vehicle brakes are applied and includes a microcontroller for detecting the speed of deceleration provided by the magnetic sensor. A trailer mounted electric motor receives a signal from the circuit board to vary pressure to the brakes in accordance with the speed of deceleration.

According to one embodiment, a physical quantity measuring apparatus includes a signal measurer configured to include sensors configured to measure component values of two axes from among component values of three axes including an X(Hx), a Y(Hy) and a Z(Hz) measured component value of a physical quantity to be measured, a sensor controller configured to select one from among the sensors to be controlled to output a measured value from the selected sensor, an A/D transformer configured to transform an outputted signal selected by the sensor control unit into a digital signal, and a signal processor configured to receive the digital signal from the A/D transformer and to combine the received digital signal with other received digital signals to calculate X, Y and Z component values of the physical quantity.