Dual-Rate, Auto-Notch Coupler-Loran With $50 Of Parts

Jesse Pipkin

Abstract:	Combining the advances of the last decade in both performance and integration of low-cost microcomputers with surface mount technology provides a new level of capability in a Loran-C receiver on a single printed circuit board as small as 111~ x 6 inches using less than $50 of standard, off-the-shelf parts. The 16MHz Motorola MC68HCllFl CMOS Microcontroller processes up to six signals from each of two chains to provide dual rate tracking. The built-in analog-to-digital converter measures interference sources and tunes automatic notch filters. Power requirements are only 50 mA at 9-l 5 volts ideal for marine, avionics, and AVL. Elimination of the large, digital components leaves only small, analog parts nearly all of which are available in surface mount packages producing a wler-sized bran: the COUPLORAN. More than 100,000 Loran-C receivers representing a dozen different brands in countless models use various versions of the MC68HCll. The highly integrated Fl has sufficient internal RAM to convert loran data to latitude-longitude. In addition, non-volatile memory remembers where the COUPLORAN was when it was last turned off for rapid, stand-alone restarting. Since position is computed, the proper loran GRI for operation is determined as well as the best back-up GRI for flawless handover as the operational area changes. A demultiplexed bus with progammable chip selects eliminates all support digital IC’s; the 68HCllFl operates with just an external ROM--no 0th~ c$&&/ pwts we requkeo! High-speed, 16MHz operation allows improved tracking over existing models. Control bits provide s&na/ cmdi?kwhg at the anfenna inpu The COUPLORAN is the true black-box loran receiver, a single PCB interfacing with only four wires for power, ground, and two-way asynchronous communication. It outputs latitude-longitude as well as loran TO’s, status, and GRl(s) to a display, navigation or other processing unit.
Published in:	Proceedings of the 1991 National Technical Meeting of The Institute of Navigation January 22 - 24, 1991 Sheraton San Marcos Hotel Phoenix, AZ
Pages:	147 - 153
Cite this article:	Pipkin, Jesse, "Dual-Rate, Auto-Notch Coupler-Loran With $50 Of Parts," Proceedings of the 1991 National Technical Meeting of The Institute of Navigation, Phoenix, AZ, January 1991, pp. 147-153.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In