Abstract: A method and system for determining the geolocation of a vehicle in the absence of a GPS signal includes determining the geodetic position of each of a plurality of airborne objects based on the relative position of at least one star and at least one satellite. The determined geodetic positions of each of the airborne objects is transmitted to the vehicle. A distance from the vehicle to each airborne vehicle is calculated. Based on the geodetic position determined for each airborne object and the distance from the vehicle to each of the airborne objects, the geodetic position of the vehicle is determined. A receiver receives the geodetic position of each airborne object, calculates a distance to each airborne object, and determines a current geodetic position based on the received geodetic positions of the airborne objects and the distance from the vehicle to each airborne object.

Abstract: A method and system are described that can be used for combining two sources of position and orientation (pose) information where the information from one source is correlated with the information from the other and the sources produce information at differing rates. For example, the method and system allow for estimating position and orientation (pose) of an underwater vehicle relative to underwater structures by combining pose information computed from a 3D imaging sonar with pose information from a vehicle navigation system. To combine the information from the two sources, a determination is made as to whether to generate a forward prediction of the pose estimate of one of the sources relative to the other, and generating the forward prediction if needed. An updated pose of the underwater vehicle is determined based on the fused pose estimate, and which is used for vehicle guidance and control.

Abstract: A method and system are described that can be used for combining two sources of position and orientation (pose) information where the information from one source is correlated with the information from the other and the sources produce information at differing rates. For example, the method and system allow for estimating position and orientation (pose) of an underwater vehicle relative to underwater structures by combining pose information computed from a 3D imaging sonar with pose information from a vehicle navigation system. To combine the information from the two sources, a determination is made as to whether to generate a forward prediction of the pose estimate of one of the sources relative to the other, and generating the forward prediction if needed. An updated pose of the underwater vehicle is determined based on the fused pose estimate, and which is used for vehicle guidance and control.

Abstract: A technique is disclosed which offers an improvement in the performance of an atom interferometric (AI) sensor, such as one that is used in an accelerometer or a gyroscope. The improvement is based on the recognition that the AI-based device, which is associated with superior low-frequency performance, can be augmented with a conventional device having a superior high-frequency performance, as well as a wider frequency response, compared with that of the AI-based device. The disclosed technique combines acceleration measurements from the AI-based device, which is characterized by transfer function G(s), with acceleration measurements from the conventional device that have been adjusted by a complementary function, 1??(s), where ?(s) is an approximation of G(s). The conventional device has a considerably wider bandwidth than that of the AI-based device, and the quasi-unity transfer function of the conventional device makes possible the 1??(s) adjustment of the measurements provided by the conventional device.

Abstract: A technique is disclosed which offers an improvement in the performance of an atom interferometric (AI) sensor, such as one that is used in an accelerometer or a gyroscope. The improvement is based on the recognition that the AI-based device, which is associated with superior low-frequency performance, can be augmented with a conventional device having a superior high-frequency performance, as well as a wider frequency response, compared with that of the AI-based device. The disclosed technique combines acceleration measurements from the AI-based device, which is characterized by transfer function G(s), with acceleration measurements from the conventional device that have been adjusted by a complementary function, 1??(s), where ?(s) is an approximation of G(s). The conventional device has a considerably wider bandwidth than that of the AI-based device, and the quasi-unity transfer function of the conventional device makes possible the 1??(s) adjustment of the measurements provided by the conventional device.

Abstract: A method of determining changes in the boundary interface in a sub-surface oil reservoir between the to-be-recovered oil and a driveout fluid, such as steam, uses time-displaced gravity gradient measurements to provide an indication of the changes in the gravity gradient over time. The measured data are subject to simulated annealing optimization to find the global minimum that best represents the observed values within the solution space. The optimization process includes establishing an appropriately constrained model of the oil reservoir and a quantized set of mathematically related parameters that define the model. Successive models are perturbed and evaluated from a figure of merit standpoint until a global minimum that best describes the measured time-lapse data is found.

Abstract: A method of determining changes in the boundary interface in a sub-surface oil reservoir between the to-be-recovered oil and a driveout fluid, such as steam, uses time-displaced gravity gradient measurements to provide an indication of the changes in the gravity gradient over time. The measured data are subject to simulated annealing optimization to find the global minimum that best represents the observed values within the solution space. The optimization process includes establishing an appropriately constrained model of the oil reservoir and a quantized set of mathematically related parameters that define the model. Successive models are perturbed and evaluated from a figure of merit standpoint until a global minimum that best describes the measured time-lapse data is found.

Abstract: A hydrocarbon reservoir undergoing secondary recovery is subject to a first and then at least a second gravity gradient survey in which a gravity gradiometer takes gradient measurements on the surface above the reservoir to define successive data sets. The differences between the first and subsequent gravity gradient survey yields information as to sub-surface density changes consequent to displacement of the hydrocarbon and the replacement thereof by the driveout fluid including the position, morphology, and velocity of the interface between the hydrocarbon to be recovered and the driveout fluid.

Abstract: Gravity gradient measurements taken by an accelerometer type gradiometer are optimized by tilting the measuring plane of the instrument by a selected angle above and below the horizontal to obtain data that can be differenced or otherwise processed to remove instrument bias and by taking data at first and then at a second orthogonal azimuth heading to obtain absolute non-relative gradient measurements.

Abstract: A hydrocarbon reservoir undergoing secondary recovery is subject to a first and then at least a second gravity gradient survey in which a gravity gradiometer takes gradient measurements on the surface above the reservoir to define successive data sets. The differences between the first and subsequent gravity gradient survey yields information as to sub-surface density changes consequent to displacement of the hydrocarbon and the replacement thereof by the driveout fluid including the position, morphology, and velocity of the interface between the hydrocarbon to be recovered and the driveout fluid.

Abstract: Gravity gradient measurements taken by an accelerometer type gradiometer are optimized by tilting the measuring plane of the instrument by a selected angle above and below the horizontal to obtain data that can be differenced or otherwise processed to remove instrument bias and by taking data at first and then at a second orthogonal azimuth heading to obtain absolute non-relative gradient measurements.