A system includes a first jacket that contains seawater and a first tank storing a first fluid under pressure. A second jacket contains seawater and a second tank storing a second fluid under pressure. An actuator cylinder defines a space that receives the fluids from the first and second tanks. The actuator cylinder includes an actuator piston that divides the space into a first volume for the first fluid and a second volume for the second fluid. A hydraulic cylinder includes a hydraulic piston configured to move and change an amount of hydraulic fluid in the hydraulic cylinder, wherein the hydraulic piston is fixedly coupled to the actuator piston. A buoyancy plug changes a position in connection with the amount of the hydraulic fluid in the hydraulic cylinder, wherein the position of the buoyancy plug affects a buoyancy of a vehicle.

The invention relates to a portable electronic signal generator, and in particular a programmable multi-waveform radiofrequency generator for use as battlefield decoy.

Disclosed herein are systems, methods, apparatus, and non-transitory computer-readable storage media for detecting gunshots with improved accuracy. The system includes a plurality of acoustic sensing devices having intelligent modules for distinguishing gunshot events from other types of acoustic events.

Certain aspects of the present disclosure provide an apparatus comprising a battery encapsulated within a sealed enclosure, an electronic device encapsulated within the sealed enclosure, a power control circuit encapsulated within the sealed enclosure, and a loop of conductive medium connected to the power control circuit. The electronic device is in a deactivated state. At least a portion of the loop of conductive medium passes out of and back into the sealed enclosure. In response to severing of the at least portion of the loop of conductive medium which is outside of the sealed enclosure, the power control circuit is configured to cause activation of the electronic device.

Certain aspects of the present disclosure provide an apparatus comprising a battery encapsulated within a sealed enclosure, an electronic device encapsulated within the sealed enclosure, a power control circuit encapsulated within the sealed enclosure, and a loop of conductive medium connected to the power control circuit. The electronic device is in a deactivated state. At least a portion of the loop of conductive medium passes out of and back into the sealed enclosure. In response to severing of the at least portion of the loop of conductive medium which is outside of the sealed enclosure, the power control circuit is configured to cause activation of the electronic device.

Apparatus and methods determine the rotational position of a spinning object. A satellite positioning system can be used to determine the spatial position of an object, which in turn can be used to guide the object. An adaptive sideband filter is used to provide increased robustness against interference. However, when the object is spinning, such as an artillery shell, then the rotational orientation should be known in order to properly actuate the control surfaces, such as fins, which will also be spinning.

Systems, methods, and computer-readable media are disclosed for object tracking. An example method may include receiving satellite signals from GPS satellites. The satellite signals may be indicative of satellite locations associated with the one or more GPS satellites and satellite timestamps associated with respective satellite locations. The method may further include determining, based on the satellite signals, a first location associated with a first tracking device. The method may further include receiving a target location associated with a target via a satellite transmission. The method may further include sending the target location to a second tracking device via a mesh network. The method may further include determining that a first distance between the first location and the target location, and the method may further include determining, based on the first distance, one or more actions.

Systems, methods, and computer-readable media are disclosed for object tracking. An example method may include receiving satellite signals from GPS satellites. The satellite signals may be indicative of satellite locations associated with the one or more GPS satellites and satellite timestamps associated with respective satellite locations. The method may further include determining, based on the satellite signals, a first location associated with a first tracking device. The method may further include receiving a target location associated with a target via a satellite transmission. The method may further include sending the target location to a second tracking device via a mesh network. The method may further include determining that a first distance between the first location and the target location, and the method may further include determining, based on the first distance, one or more actions.

Systems and methods are provided for firearm event monitoring, including a motion sensor mounted on a firearm, a server device running application software that receives signals from the motion sensor, a machine learning module configured to create and run an identification algorithm, using data derived from the received signals, to determine a motion of the firearm indicative of an event and a controller coupled to the server device, the controller running application software configured to maintain a round count based at least in part on the indicated event.

Systems and methods are provided for firearm event monitoring, including an inertial measurement unit and a hall-effect sensor mounted on a firearm, a server device running application software that receives signals from the inertial measurement unit and the hall-effect sensor, and a machine learning module configured to create and run identification algorithms, using data derived from the received signals from the inertial measurement unit and the hall-effect sensor indicative of a discharge event type, wherein the discharge event type is one of an ammunition discharge event, a misfire discharge event or a dry-fire discharge event.