A vessel location validation method and apparatus are provided. The vessel location validation method includes receiving a wireless signal from a vessel, acquiring location information of the vessel from the received wireless signal, and determining whether the acquired location information is valid based on the acquired location information and a signal strength of the received wireless signal.

Methods, systems and computer program products for radionavigation for swimmers are described. A mobile device configured to estimate a location using radio frequency signals can estimate a position of the swimmer when the mobile device is worn on a limb of the swimmer and periodically submerged. The mobile device can supply auxiliary information to a radionavigation subsystem to correct a navigation solution affected by limb motion of the swimmer and affected by the periodic submersion of the mobile device.

An Automatic Identification System (AIS) for tracking a plurality of maritime vessels may include a ground AIS server and a constellation of Low-Earth Orbit (LEO) satellites in communication with the ground AIS server. Each LEO satellite may include an AIS payload configured to receive AIS messages from the plurality of maritime vessels and determine therefrom reported vessel position data, determine an actual frequency of arrival (FOA) for each of the AIS messages, determine an expected FOA for each of the AIS messages based upon the reported vessel position data for each AIS message, determine a potential spoofing maritime vessel based upon a difference between a corresponding expected FOA and actual FOA for a given AIS message, and send a potential spoof alert to the ground AIS server.

Proposed is an underwater drift tracking system based on a maritime positioning platform. The underwater drift tracking system may include a plurality of underwater drifting objects configured to transmit sound wave signals including their own water depth information by using sound wave communication while drifting underwater. The underwater drift tracking system may also include a maritime drift tracker configured to track real-time underwater locations of the underwater drifting objects by moving on the sea under its own power, receiving the transmitted sound wave signals from the plurality of underwater drifting objects, and calculating absolute location information of the plurality of underwater drifting objects using the received sound wave signals.

A system for tracking a vehicle includes a transceiver configured to receive a first signal including first surveillance data from the vehicle at a first time, and receive a second signal from the vehicle at a second time. The system further includes processing circuitry configured to determine a first location and a first course of the vehicle at the first time based on the first surveillance data, and determine a change in power level from the first signal to the second signal. The processing circuitry is further configured to predict a maneuver for the vehicle based on the first location, the first course, and the change in power level from the first signal to the second signal.

A control unit for automatically controlling at least part of an anchoring function of a marine vessel is arranged to obtain a predetermined relationship between keel depth and preferred distance from land for dropping anchor from the storage medium, to receive first sensor data indicative of a current distance between the marine vessel and land, to receive second sensor data indicative of a current keel depth of the marine vessel, to determine a suitable location and/or time period for dropping anchor based on the first sensor data, the second sensor data, and the predetermined relationship between keel depth and preferred distance from land for dropping anchor, and to control at least part of the anchoring function of the marine vessel based on the determined suitable location and/or time period for dropping anchor.

Systems and methods for vessel position reporting and monitoring. Methods and systems for augmenting e-Navigation messages to provide ancillary information, such as a history of previous vessel positions. A compact representation is provided, in which transmitters may select among a plurality of possible position layouts to provide a compact representation. Transmitted messages are received by a satellite or other surveillance platform employing a compatible radio frequency receiver to collect message signals over a large area or great distance.

Systems and methods for vessel position reporting and monitoring. Methods and systems for augmenting e-Navigation messages to provide ancillary information, such as a history of previous vessel positions. A compact representation is provided, in which transmitters may select among a plurality of possible position layouts to provide a compact representation. Transmitted messages are received by a satellite or other surveillance platform employing a compatible radio frequency receiver to collect message signals over a large area or great distance.

Systems and methods for vessel position reporting and monitoring. Methods and systems for augmenting e-Navigation messages to provide ancillary information, such as a history of previous vessel positions. A compact representation is provided, in which transmitters may select among a plurality of possible position layouts to provide a compact representation. Transmitted messages are received by a satellite or other surveillance platform employing a compatible radio frequency receiver to collect message signals over a large area or great distance.

Systems (100) and methods (400) for space-based geolocation. The methods involve receiving by at least two first satellites a maritime signal transmitted from a vessel on or near Earth. The first satellites are deployed in space so as to have overlapping coverage areas. The maritime signal (received at the at least two first satellites) is then used to determine a geographic location of the vessel on Earth using at least one of a Time Difference of Arrival (TDOA) and a Frequency Difference of Arrival (FDOA).