October 28, 2002 International Loran Association Modernization of Nii Jima Transmitter Control Presented by Michael Weisenbloom

Goals and Objectives Reduce cost of ownership –Remote capability for unattended transmitter operation –Modern, reduced component count for greater reliability and tighter integration Improve operator control and interface –Graphical user interface display and control at local and remote locations –Time synchronization to UTC-USNO via built-in GPS

Goals and Objectives Provide easy upgrade path for current systems –Existing transmitter cables and equipment fully compatible –Fits in existing footprint and power requirements Provide for future upgrades and growth –Flexible system architecture with embedded software and programmable hardware, each with designed in reserve –Commercial off-the-shelf modules and subcomponents

Transmitter Control System Diagram Nii Jima Replace 4 rack Control Console Unit with new 3 rack software controlled Transmitter Control Unit Chiba Replace 1 rack Remote Control Unit rack with PC workstation and graphical remote control software New graphical display and user interface Remote networked interface for unattended transmitter operation NTT lease line network Time sync to UTC via built-in GPS Redundant PC workstation with UPS back-up UPS and battery backup Direct connection to existing transmitter cables Similar installation upgrades also planned for Gesashi and Tokatibuto stations in NW Pacific chain for 2003 and 2004

Transmitter Control Unit Replace existing CCU with new Transmitter Control Unit (TCU) –3 Rack System –Modern off-the-shelf parts –Software and graphical user interface control –UPS and battery backup –Ethernet/HUB interface to NTT leased network for Chiba remote control

Loran Timer Subsystem (LTS) Loran Timer Assemblies –Generates Loran pulse timing (MPTs) UTC Sync Assemblies -Provides UTC synchronized timing source from GPS Loran Receivers (Locus) Loran Timer Assemblies (LTAs) UTC Sync Assemblies (USAs) Cesium Units

Loran Timer Assembly (LTA) Circuit board Top View Inside Chassis 19” Power Supply Front Panel View 3U Generates dual-rate Loran pulse timing Automatic detection and adjustment of transmitted pulse reference Local and remote user controlled phase adjust Single board design with embedded software and logic 19” wide by 3U rack mounted assembly

UTC Sync Assembly Cesium clock synchronization to GPS UTC Time-of-coincidence generation and error checking Time-of-day setting and error checking with external GPS Single board design with embedded software and logic 19” wide by 2U rack mounted assembly Circuit board Top View Inside Chassis 19” Power Supply Front Panel View 2U

Loran Timer Subsystem Interconnect Diagram

Transmitter Control Subsystem (TCS) Alarm/Status Panel Touchscreen Display Retractable Keyboard Tray TCA (Transmitter Control Assembly) AC Input Power Phase Switcher UPS Fan Assembly Cable Connector Assembly (CCA) TCC (Transmitter Control Console) #1 TCC (Transmitter Control Console) #2 Redundant Transmitter Control Consoles

Chiba Control Workstation for Nii Jima Install new control workstation at Chiba –Remote operator control of Nii Jima TCU and transmitter –Graphical user interface –Ethernet/HUB interface to NTT leased network