Systems and methods for a low-frequency radio navigation system are described. The system may include a transmitter comprising a base coded modulator configured to generate a base modulation and a data coded modulator configured to generate a data modulation; wherein the transmitter radiates a continuous, constant-power chirped-FM spread spectrum signal, comprising: the base modulation; and the data modulation, wherein the data modulation is orthogonal to the base modulation. The system may also include a receiver comprising a digital signal processor, wherein at least one matched filter coupled to the digital signal processor, the at least one matched filter configured to decode said base modulation and data-encoded modulation and provide a correlation function for received signals received from at least three geographically-spaced transmitters.

An ultra wideband (UWB) dynamic positioning method and a system thereof are provided. A target UWB device detecting step includes driving a host UWB device to detect whether a target UWB device or at least one first-order seeking UWB device is around the host UWB device, and then a detecting result is generated. A host UWB device operation deciding step includes deciding an operating mode of the host UWB device according to the detecting result. When the target UWB device is around the host UWB device, the operating mode includes calculating a moving direction from the host UWB device to the target UWB device. When there is the first-order seeking UWB device around the host UWB device without the target UWB device, the operating mode includes switching on the first-order seeking UWB device to enter a seeking mode.

Systems and methods for a low-frequency radio navigation system are described. The system may include a transmitter comprising a base coded modulator configured to generate a base modulation and a data coded modulator configured to generate a data modulation; wherein the transmitter radiates a continuous, constant-power chirped-FM spread spectrum signal, comprising: the base modulation; and the data modulation, wherein the data modulation is orthogonal to the base modulation. The system may also include a receiver comprising a digital signal processor, wherein at least one matched filter coupled to the digital signal processor, the at least one matched filter configured to decode said base modulation and data-encoded modulation and provide a correlation function for received signals received from at least three geographically-spaced transmitters.

An improved aviation transponder is discussed herein. The improved aviation transponder demonstrates improved cohabitation and survivability characteristics, allowing the transponder to be placed near other antennas without causing or receiving interference, and reducing potential damage caused by high-energy electromagnetic fields, such as those experienced near an air traffic control (ATC) or military radar installation. Additionally, a small form factor of the transponder results in a smaller, more compact aircraft that consumes less energy, reduces heat dissipation, and maximizes battery life and/or flight time. The transponder may comply with modular interface standards, and may include a radio configured for transmitting 200-watt signals. Based at least in part on the improved performance, the transponder can be implemented in unmanned aerial vehicles (UAVs), for example.

A local navigation system includes: a plurality of beacons located in a local environment and being configured to send signals specified to different routes in said local environment; a plurality of mobile devices, each of them including a client controller; and a wireless communication link configured to receive the signals sent by the beacons; an output means configured to display/emit navigation guide data. In the local navigation system, the client controller is configured to process the signals received via the wireless communication link and to process this data into navigation guide data outputted on an output of the mobile device. Each route included in the local environment is assigned a unitary ID and each beacon is located in one specific location of the local environment along at least one of said routes. Each beacon is configured to send the IDs of all the routes passing along its specific location. The client controller obtains the route ID to a chosen destination from a destination input device of the local navigation system and/or of the mobile device. The client controller is configured to provide the navigation guide data in interaction with the beacons sending said route IDs of the chosen location. This system allows anonymous navigation in the local environment, possibly in a decentralized system without centralized or wired system components.

In one example, a device includes a receiver configured to receive a low-power X band radar transmission, and a transmitter operably coupled to the receiver and configured to transmit an X band transmission in response to receiving the low-power X band radar transmission.

An improved aviation transponder is discussed herein. The improved aviation transponder demonstrates improved cohabitation and survivability characteristics, allowing the transponder to be placed near other antennas without causing or receiving interference, and reducing potential damage caused by high-energy electromagnetic fields, such as those experienced near an air traffic control (ATC) or military radar installation. Additionally, a small form factor of the transponder results in a smaller, more compact aircraft that consumes less energy, reduces heat dissipation, and maximizes battery life and/or flight time. The transponder may comply with modular interface standards, and may include a radio configured for transmitting 200-watt signals. Based at least in part on the improved performance, the transponder can be implemented in unmanned aerial vehicles (UAVs), for example.

A method of determining a location of a mobile device includes: detecting, at the mobile device, at least one Radio Frequency transmitter; receiving information associated with a number of Radio Frequency transmitters located within a geographical area, the number of Radio Frequency transmitters being a subset of all Radio Frequency transmitters located within the geographical area, the information being decodable to provide global locations and identifiers of the number of Radio Frequency transmitters; comparing an identifier associated with the at least one detected Radio Frequency transmitter with the global locations and identifiers of the number of Radio Frequency transmitters; and determining the location of the mobile device within the geographical area; wherein the information is received in a reduced format.

A system for determining a user's path is described. The system comprises a location server arranged to receive location data of a communication device associated with the user, the location data defining the detected position of the communication device at a number of different points in time, the location server further arranged to receive sequence data associated with the location data indicative of the order in which the location data was determined; path determining means for determining the user's path passing through points defined by the received location data and the associated sequence data; and a comparator for comparing the determined path of the user with one or more predetermined user paths; wherein the location server processes the received location data depending upon the result of the comparison and corrects the determined user path with the processed location data.

A method and devices are disclosed, for localization of a radio beacon at a remote receiver in the framework of a satellite system. Such satellite system could be Cospas-Sarsat, for Search and Rescue of people, ships and aircraft in distress, and particularly its MEOSAR (Medium Earth Orbit Search and Rescue) segments: DASS/GPS, SAR/Galileo and SAR/Glonass; said beacon is typically one of a PLB (Personal Locator Beacon) or EPIRB (Emergency Position Indicating Radio Beacon) or ELT (Emergency Locator Beacon); and said remote receiver is typically a MEOLUT (Medium Earth Orbit Local User Terminal) base station. Present art MEOSAR localization is based on Time measurements and Frequency measurements on signals emitted by radio beacons, relayed by satellites and detected at a MEOLUT; however since the exact time of transmission of the beacon is unknown at the MEOLUT, Time Difference of Arrival (TDOA) equations are applied. The present invention however, discloses that by carefully configuring the time of transmission at said beacon, even without directly communicating that specific time to the MEOLUT, Time of Arrival (TOA) equations could be applied at the MEOLUT enabling enhanced localization accuracy and/or fewer satellites in view required to localize the beacon. In particular, localization is enabled even upon a single burst emitted by the beacon and relayed to the MEOLUT by a single satellite.