An enhanced LOng RAnge Navigation (eLORAN) system may include a plurality of eLORAN stations, each having an eLORAN antenna and an eLORAN transmitter that may transmit data over an eLORAN data channel and may transmit a series of eLORAN navigation RF pulses. An eLORAN control station may generate station specific eLORAN data and non-station specific eLORAN data, divide the non-station specific eLORAN data into non-specific eLORAN data subsets, and cause each eLORAN station to transmit the station specific eLORAN data and a corresponding non-station specific eLORAN data subset over the eLORAN data channel in a manner to optimize data throughput.

A long range navigation system may include radio frequency (RF) transmitter stations at fixed geographical locations, each having an RF transmitter and an RF modulator coupled to the RF transmitter, and configured to generate a direct sequence spread spectrum (DSSS) RF signal being spectrally shaped so that 99% of power from the RF transmitter is within the frequency range of 90-110 KHz. Movable RF receiver units each include an RF receiver and a demodulator coupled to the RF receiver configured to demodulate the DSSS RF signal to determine a position of the movable RF receiver unit.

An enhanced LOng RAnge Navigation (eLORAN) system may include a plurality of eLORAN transmitter stations, and at least one eLORAN receiver device. The eLORAN receiver device may include an eLORAN receive antenna, an eLORAN receiver coupled to the eLORAN receive antenna, and a controller coupled to the eLORAN receiver. The controller may be configured to cooperate with the eLORAN transmitter stations to determine an eLORAN receiver position and receiver clock error corrected from additional secondary factor (ASF) data, the ASF data based upon different geographical positions and different times for each different geographical position.

An enhanced LOng RAnge Navigation (eLORAN) system may include a plurality of eLORAN stations, each having an eLORAN antenna and an eLORAN transmitter that may transmit data over an eLORAN data channel and may transmit a series of eLORAN navigation RF pulses. An eLORAN control station may generate station specific eLORAN data and non-station specific eLORAN data, divide the non-station specific eLORAN data into non-specific eLORAN data subsets, and cause each eLORAN station to transmit the station specific eLORAN data and a corresponding non-station specific eLORAN data subset over the eLORAN data channel in a manner to optimize data throughput.

An eLORAN receiver may include an antenna and eLORAN receiver circuitry coupled to the antenna. The antenna may have a ferromagnetic core including a ferromagnetic medial portion and ferromagnetic arms extending outwardly, and a respective electrically conductive layer surrounding each of the ferromagnetic arms and having a slot.

A method for generating private eLoran signals includes receiving, by a transmitter site, a transmission key. The transmitter site is configured to transmit a timing signal at a fixed time. The method also includes determining, by the transmitter site, for the timing signal configured to be transmitted at the fixed time, a pseudo-random transmission time for transmitting the timing signal, and initiating transmission, by the transmitter site, of the timing signal at the pseudo-random transmission time.]. A method for receiving private timing signals includes determining, by the receiver device and using the fixed time, a pseudo-random time for receiving the timing signal from the transmitter site, receiving, by the receiver device, the timing signal at the pseudo-random time, and using, by the receiver device, the timing signal to determine at least one of a time, a longitude, and a latitude at the receiver device.

A method for passively locating a non-movable transmitter on the ground implemented by a group of at least one receiving station, each of the receiving stations comprising a detector of radars and a time reference, the set of time references being mutually synchronized, the transmitter transmitting a set of periodic pulses, wherein a first estimation of the position of the transmitter is carried out by the Bancroft scheme on the basis of the mean arrival times of the pulses transmitted by the transmitter at the level of each station of the group of at least one receiving station, the result obtained being used thereafter as point for initializing a maximum likelihood scheme so as to converge toward the position of the transmitter.

A method and system for increased position tracking resolution in a localized environment for use in GPS-denied areas such as within buildings or enclosed structures, comprising: multiple reference nodes each transmitting a synchronization pulse to a multitude of body-worn or device-mounted receiving units; a high speed clock circuit in each receiver capable of measuring the Time Difference of Arrival of said sync pulses to the resolution needed for precise positioning; a central processing computer used to calculate actual position of the receiving units relative to some fixed reference point; and a display system to monitor the position of the receiving units in real time as they move around within the target area overlaid onto available GIS data or building CAD drawings.

A method and system are provided for converting an enhanced Long Range Navigational (eLORAN) signal to a Precision Time Protocol (PTP) signal. Network devices can be located within buildings and not have access to a GPS signal directly from a GPS satellite. Network devices may also be located in a line of sight of a GPS satellite but may lose the GPS signal. An adapter is provided that takes an eLORAN signal, when a GPS signal is lost or not available, and converts the signal into a PTP and other signals to act as timing, synchronization, and syntonization inputs into the network devices. In some cases, the network devices can have a PTP client to receive the PTP signal, one pulse per second signal, and a ten (10) megahertz frequency signal. In other cases, the network devices do not have a PTP client, but can receive a time of day message, one pulse per second signal, and the 10 megahertz frequency signal.

An antenna receiver system is provided. The antenna receiver system includes an E-field antenna, a first H-field antenna, a second H-field antenna; three antenna radio frequency paths to amplify, filter, and convert three respective outputs from the three antennas to respective first, second, and third signals. Filters in the antenna paths simultaneously receive at least two of: eLORAN radio navigation signals from eLORAN ground stations; an EM pulse from lightning; and one of: CW unmodulated signals-ON/OFF modulated signals from a NDB radio navigation ground station; or an AM CW signal received from an AM radio broadcast station. A processor processes the first, second, and third signals and outputs information indicative of two or more of: a geographical latitude and longitude position of the vehicle derived from the eLORAN radio navigation signals; a lightning bearing and a lightning range; and a bearing of the vehicle.