A method for forming 3D image data representative of the subsurface of infrastructure located in the vicinity of a moving vehicle. The method includes: rotating a directional antenna, mounted to the moving vehicle, about an antenna rotation axis; performing, using the directional antenna whilst it is rotated about the antenna rotation axis, a plurality of collection cycles in which the directional antenna emits RF energy and receives reflected RF energy; collecting, during each of the plurality of collection cycles performed by the directional antenna.

A method for forming 3D image data representative of the subsurface of infrastructure located in the vicinity of a moving vehicle. The method includes: rotating a directional antenna, mounted to the moving vehicle, about an antenna rotation axis; performing, using the directional antenna whilst it is rotated about the antenna rotation axis, a plurality of collection cycles in which the directional antenna emits RF energy and receives reflected RF energy; collecting, during each of the plurality of collection cycles performed by the directional antenna.

A reception compensation apparatus based on airborne transient electromagnetic method is disclosed, and includes a receiver coil, a transmitter coil, at least one compensation coil, and at least one compensation magnetic core, where the transmitter coil is disposed around a periphery of the receiver coil. The at least one compensation magnetic core is disposed around an outer surface of the transmitter coil. The at least one compensation coil is disposed around an outer surface of the compensation magnetic core.

An aerial detection system includes an aerial vehicle unit and a hanging platform mechanically connected to an aerial vehicle by at least one flexible link. An EM sensor and hanging platform circuitry are mounted on the hanging platform. The hanging platform circuitry processes the EM sensor output signals. The aerial vehicle unit is attached the aerial vehicle and includes AVU circuitry which processes signals output by the hanging platform circuitry. The hanging platform circuitry and AVU circuitry are connected by one or more wired and/or wireless signal connections.

A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

A multi-sensor electromagnetic (EM) system and method for measuring gradients of EM signals. The multi-sensor EM system includes a frame; a transmitter device attached to the frame and configured to generate a primary EM field; a receiver device attached to the frame and configured to record a secondary EM field generated by the earth after being excited by the primary EM field; and a gradient sensor device attached to the frame and configured to record a gradient of the secondary EM field.

The invention relates to a dual detector with a detection head (10), comprising:—a platform (11) and—an induction sensor fastened to the platform (11) and comprising a transmitter coil (12) and a receiver coil (13), the transmitter coil (12) and the receiver coil (13) each forming a loop, the loop of the transmitter coil (12) overlapping the loop of the receiver coil (13) at least partially so as to form a coupling zone (14), the coupling zone (14) being elongated in a first longitudinal direction defining a first axis (X.sub.1), the handle (20) extending in a plan (P.sub.1) normal to the platform (11) and the first axis (X.sub.1) of the coupling zone (14) being transverse to this plane (X.sub.1).

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.

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.