An enhanced LOng RAnge Navigation, i.e. eLORAN, system comprising: a plurality of eLORAN transmitter stations, wherein each eLORAN transmitter station comprises an eLORAN transmit antenna, and an eLORAN transmitter coupled to the eLORAN transmit antenna and configured to transmit a series of eLORAN navigation RF pulses; an eLORAN control station; a plurality of eLORAN reference stations; and at least one eLORAN receiver device comprising: an eLORAN receive antenna, an eLORAN receiver coupled to the eLORAN receive antenna, and a controller coupled to the eLORAN receiver and configured to cooperate with said plurality of 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; wherein the controller comprises a memory, configured to store ASF data, and a processor cooperating with the memory, said ASF data comprising a fixed ASF map for each of the plurality of eLORAN transmitter stations, and a plurality of diurnal variation look-up tables for every month and for each eLORAN transmitter station, wherein said processor is configured to generate eLORAN corrections based upon at least one interpolation from the fixed ASF map and from each of the diurnal variation look-up tables for the current month for those eLORAN transmitter stations from which the at least one eLORAN receiver device receives eLORAN navigation RF pulses. a plurality of eLORAN transmitter stations, wherein each eLORAN transmitter station comprises an eLORAN transmit antenna, and an eLORAN transmitter coupled to the eLORAN transmit antenna and configured to transmit a series of eLORAN navigation RF pulses; an eLORAN control station; a plurality of eLORAN reference stations; and at least one eLORAN receiver device comprising: an eLORAN receive antenna, an eLORAN receiver coupled to the eLORAN receive antenna, and a controller coupled to the eLORAN receiver and configured to cooperate with said plurality of 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; wherein the controller comprises a memory, configured to store ASF data, and a processor cooperating with the memory, said ASF data comprising a fixed ASF map for each of the plurality of eLORAN transmitter stations, and a plurality of diurnal variation look-up tables for every month and for each eLORAN transmitter station, wherein said processor is configured to generate eLORAN corrections based upon at least one interpolation from the fixed ASF map and from each of the diurnal variation look-up tables for the current month for those eLORAN transmitter stations from which the at least one eLORAN receiver device receives eLORAN navigation RF pulses. an eLORAN receive antenna, an eLORAN receiver coupled to the eLORAN receive antenna, and a controller coupled to the eLORAN receiver and configured to cooperate with said plurality of 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; wherein the controller comprises a memory, configured to store ASF data, and a processor cooperating with the memory, said ASF data comprising a fixed ASF map for each of the plurality of eLORAN transmitter stations, and a plurality of diurnal variation look-up tables for every month and for each eLORAN transmitter station, wherein said processor is configured to generate eLORAN corrections based upon at least one interpolation from the fixed ASF map and from each of the diurnal variation look-up tables for the current month for those eLORAN transmitter stations from which the at least one eLORAN receiver device receives eLORAN navigation RF pulses.