A ranging system and method to determine a relative distance and direction of a target borehole relative to a second borehole using a ranging tool that can make ranging measurements while the ranging tool is not rotating. An array of button electrodes included in the ranging tool can be fired in a sequential fashion so as to simulate rotation of one or more button electrodes, without the ranging tool rotating. The array of button electrodes can also be fired in a sequential fashion so as to simulate rotational and/or longitudinal movement of the ranging tool.

A ranging system and method to determine a relative distance and direction of a target borehole relative to a second borehole using a ranging tool that can make ranging measurements while the ranging tool is not rotating. An array of button electrodes included in the ranging tool can be fired in a sequential fashion so as to simulate rotation of one or more button electrodes, without the ranging tool rotating. The array of button electrodes can also be fired in a sequential fashion so as to simulate rotational and/or longitudinal movement of the ranging tool.

A method for improving a performance of a metal detector, including: determining positions of a sensor head of the metal detector with respect to a coordinate system as the sensor head is moved on top of a ground; processing a receive signal received by the sensor head to produce a substantially ground balanced signal that is substantially insensitive to signals due to the ground; and actively controlling the step of processing based on one or more of the determined positions as the metal detector is moved on top of the ground; wherein, during a continuous use of the metal detector, the determined positions are processed to control, without any instruction or indication from an operator of the metal detector to do so, the step of processing the receive signal to produce the substantially ground balanced signal.

A method for improving a performance of a metal detector, including: determining positions of a sensor head of the metal detector with respect to a coordinate system as the sensor head is moved on top of a ground; processing a receive signal received by the sensor head to produce a substantially ground balanced signal that is substantially insensitive to signals due to the ground; and actively controlling the step of processing based on one or more of the determined positions as the metal detector is moved on top of the ground; wherein, during a continuous use of the metal detector, the determined positions are processed to control, without any instruction or indication from an operator of the metal detector to do so, the step of processing the receive signal to produce the substantially ground balanced signal.

An image reconstruction algorithm system for hazardous source mapping. The algorithm system can be used to automate and optimize the search path of a movable vehicle (such as a UAV), equipped with detection capability. The algorithm allows the vehicle to localize hazardous sources in multiple scenarios effectively. Hazard mapping is formulated as an inverse problem and solved either with a deconvolution or a reconstruction algorithm, according to the problem complexity. The algorithms can use the Maximum a Posteriori (MAP) and the least square regression algorithm, respectively. However, alternative algorithms can be used as set forth herein. The source mapping algorithms are able to provide a quantitative estimation of the hazard source magnitude. A non-negative version of the least square algorithm is used to reconstruct the map at each step of the navigation algorithm of the vehicle. The navigation algorithm correctly located single and multiples simulated hazardous sources.

An image reconstruction algorithm system for hazardous source mapping. The algorithm system can be used to automate and optimize the search path of a movable vehicle (such as a UAV), equipped with detection capability. The algorithm allows the vehicle to localize hazardous sources in multiple scenarios effectively. Hazard mapping is formulated as an inverse problem and solved either with a deconvolution or a reconstruction algorithm, according to the problem complexity. The algorithms can use the Maximum a Posteriori (MAP) and the least square regression algorithm, respectively. However, alternative algorithms can be used as set forth herein. The source mapping algorithms are able to provide a quantitative estimation of the hazard source magnitude. A non-negative version of the least square algorithm is used to reconstruct the map at each step of the navigation algorithm of the vehicle. The navigation algorithm correctly located single and multiples simulated hazardous sources.

Fiber optic sensors are described for detecting the operational position of a downhole moveable device. In one example, an electric or magnetic field is emitted into the wellbore and interacts with the moveable assembly, thereby producing a secondary electric or magnetic field. The secondary field is detected by a fiber optic sensor which produces a corresponding response signal. The response signal is then processed in a variety of ways to determine the operational position of the moveable device. In another example, the operational position is determined using fiber optic temperature or acoustic sensors. A temperature or acoustic vibration reading is acquired before and after actuation of the moveable device. The two readings are then compared to determine the operation position of the moveable device.

Fiber optic sensors are described for detecting the operational position of a downhole moveable device. In one example, an electric or magnetic field is emitted into the wellbore and interacts with the moveable assembly, thereby producing a secondary electric or magnetic field. The secondary field is detected by a fiber optic sensor which produces a corresponding response signal. The response signal is then processed in a variety of ways to determine the operational position of the moveable device. In another example, the operational position is determined using fiber optic temperature or acoustic sensors. A temperature or acoustic vibration reading is acquired before and after actuation of the moveable device. The two readings are then compared to determine the operation position of the moveable device.

A magnetic compensation method based on an aeromagnetic compensation error model includes: acquiring an upper limit of an error of a magnetic noise caused by both an environmental background field in an exploration area and an aeromagnetic flight platform, by using the aeromagnetic compensation error model, before an actual flight; determining, according to the upper limit, whether the environmental background field and the aeromagnetic flight platform are suitable for the actual flight, and if so, performing a calibration flight to acquire a compensation coefficient; and acquiring data of an attitude term by performing the actual flight, calculating an interference magnetic field by the data of the attitude term and the compensation coefficient, and performing magnetic compensation.

A magnetic compensation method based on an aeromagnetic compensation error model includes: acquiring an upper limit of an error of a magnetic noise caused by both an environmental background field in an exploration area and an aeromagnetic flight platform, by using the aeromagnetic compensation error model, before an actual flight; determining, according to the upper limit, whether the environmental background field and the aeromagnetic flight platform are suitable for the actual flight, and if so, performing a calibration flight to acquire a compensation coefficient; and acquiring data of an attitude term by performing the actual flight, calculating an interference magnetic field by the data of the attitude term and the compensation coefficient, and performing magnetic compensation.