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 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 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.

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.

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 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.

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.

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 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.