Abstract: A surgical instrument is disclosed herein. The surgical instrument can include an end effector that includes jaws configured to transition between an opened condition and a closed condition, a plurality of electrodes positioned within the jaws of the end effector, a control circuit, and a memory configured to store an algorithm configured to cause the control circuit to determine an impedance signal based on signals received from the plurality of electrodes, detect a media positioned between the jaws of the end effector based on the determined impedance signal, determine a position of the detected media based on the received signals, and generate an alert associated with the detected media and the determined position.

Abstract: A method and system for navigating an unmanned aerial vehicle (UAV) for aerial refueling is described. A system processor in the UAV receives navigation data from a tanker aircraft and calculates a plurality of relative navigation solutions with respect to the tanker aircraft. The system processor compares the plurality of relative navigation solutions to identify any inconsistent solutions. The inconsistent solutions are discarded and the system processor navigates the UAV in position for refueling using the remaining relative navigation solutions.

Abstract: A method and apparatus for calculating corrections to a navigation solution based on differential GPS data includes receiving GPS ephemeris from at least three GPS satellites. A PVT solution is resolved from the GPS ephemeris. The PVT solution includes a Circular Error Probable (CEP). Differential GPS data for calculating the corrections to the PVT solution is received. A corrected PVT solution is then based upon the differential GPS data. The corrected PVT solution is compared to an area defined by the CEP. Where the corrected PVT solution is not within the area, the corrected PVT solution is rejected in favor of the PVT solution for determining an accurate navigational solution.

Abstract: A system and method for detecting and excluding false GPS signals are disclosed, which predict a GPS measurement value with a high degree of confidence, compare the predicted value with measured values, and reject a false measurement based on the comparison results. As one example, a tightly coupled GPS/Inertial Navigation System (GPS/INS) is disclosed, which uses a Kalman filter for comparison of a predicted GPS measurement value with measured values (e.g., the residuals) to form the basis for the rejection of false measurements. This rejection is referred to as a chi-squared reject, and can be extended in time in order to apply the same test to a reacquired signal following the loss of an original validated GPS signal. The Kalman filter propagates the receiver's clock bias rate, and enables the system to predict the GPS measurements at the time of reacquisition. The residuals are compared to a limit defined by the uncertainties of the prediction and the measurement errors expected to be involved.

Abstract: A method and apparatus for calculating corrections to a navigation solution based on differential GPS data includes receiving GPS ephemeris from at least three GPS satellites. A PVT solution is resolved from the GPS ephemeris. The PVT solution includes a Circular Error Probable (CEP). Differential GPS data for calculating the corrections to the PVT solution is received. A corrected PVT solution is then based upon the differential GPS data. The corrected PVT solution is compared to an area defined by the CEP. Where the corrected PVT solution is not within the area, the corrected PVT solution is rejected in favor of the PVT solution for determining an accurate navigational solution.

Abstract: A method and system for navigating an unmanned aerial vehicle (UAV) for aerial refueling is described. A system processor in the UAV receives navigation data from a tanker aircraft and calculates a plurality of relative navigation solutions with respect to the tanker aircraft. The system processor compares the plurality of relative navigation solutions to identify any inconsistent solutions. The inconsistent solutions are discarded and the system processor navigates the UAV in position for refueling using the remaining relative navigation solutions.

Abstract: A multipath error detection system includes a first antenna configured to receive a right hand circular polarized signal from a satellite and a second antenna configured to receive a left hand circular polarized signal from the satellite. At least one processor is in signal communication with the first and second antennas, and is programmed to determine, from the right hand circular polarized signal and left hand circular polarized signal, respective first and second values of a first parameter and respective third and fourth values of a second parameter. The at least one processor is further configured to determine, based on the values, the presence of a multipath error associated with at least one of the polarized signals.

Abstract: Methods and systems for providing an estimate of effectiveness of a selected weapon against a selected target prior to release of the weapon are described. One described method comprises receiving a position uncertainty for a weapon platform, receiving a position uncertainty for a selected target, and determining an ability of the selected weapon to navigate to the selected target. An estimated effectiveness of the selected weapon is determined utilizing one or more of the weapon platform position uncertainty, the target position uncertainty, the navigation capability of the selected weapon, and a kill radius for the selected weapon.

Abstract: A relative GPS landing system is provided for approach and landing of aircraft where an accurate site survey of the GPS platform is unavailable. Data containing information on all GPS satellites in view is uplinked from a ground station to an aircraft. A relative solution is derived at the aircraft. Based upon the calculated solution, aircraft guidance signals are generated for approach and landing of the aircraft at a desired point.