Transmitter Performance Section Participants –LSU –NAVCEN –NAVCEN (West) –Peterson Integrated Geo-positioning, Inc –BAH LORIPP Meeting #2 Portland, OR September 23-24, 2002

Tasking from LORIPP Meeting 1 TOTM calibration to USNO-UTC ABS threshold and time to blink from onset to fault, P(OOT w/o blink) Determine transmitted ECD and blink if OOT. Monitor requirements at transmitter and what certification requirements on monitors. Chain Operations (TOE verses SAM)

LRP Status NSSX sites –LSU –LORSTA George, WA –LORSTA Narrow Cape, AK –LORSTA Dana, IN SLEP TFE –MOD 5 –Delivery Feb 03

TOT Measurement System Digital Averaging O’scope Antenna current transformers Envelope Trigger Circuitry TrueTime XLDC GPS Timing Rcvr Event Time Input Computer RS-232 Temporary at antenna base Permanent USB Ethernet to LSU Temporary for calibration

Start of Pulse Standard Zero Crossing Strobe from Envelope Trigger

Start of Antenna Zero Transformer Time read from GPS receiver Oscilloscope Measurement (15.54us) 30 usec Zero Oscilloscope Delay: Transformer to Oscilloscope (148ns) Delay GPS to O’scope (15ns) Calibration value = – = us Example of Calibration (data is for Carolina Beach)

Note: * 133 = * 166 = sec.

Note: 8290M (Havre) off by 2.3usec per USCG TOTM and 0.1 usec per USNO. Note: 8970M (Dana) off by –0.9 usec per USCG TOTM and approx. 0 per USNO.

Pulse Analysis System Pentium PC w/ICS-650 (12 bit) or ICS-652 (14 bit) Prototype developed & tested at Baudette 9/05/ MHz P3, ICS-650 Logged TOT, ECD, and Amplitude of each pulse, no raw RF data Processed 2/3 of the PCI’s (one rate only) Will continue development on 2 GHz P4 w/ICS-652, log raw RF Antenna Current Transformer

Note: Outliers indicate need to log raw RF and visually verify why

Future Plans Visit to Seneca 8-10 Oct w/DCN (funded by NELS) –Effort to get common, worldwide, definition of what is meant by sync to UTC (presently 2.5 usec offset between USCG and NELS) Visit to Boise City –Test new pulse analysis system –2 usec Offset between USCG TOTM and USNO data Visit to Dana –Long transmission line to resolve sign of delay term Installation at what other secondaries? –TFE installation starts in Mar 03 in SEUS and will be about 1/month. Do we need the data now? –Gillette, Las Cruces, Searchlight, Middletown, etc. –Canada? –Have about 4 more GPS receivers available, do we procure more?

Conclusions TOTM system works well and is getting valuable data I have long felt that large secondary offsets in TOT may be due to offsets between published and actual emission delays –Hence a need for minimum of 12 months of data to establish new values to avoid large position jumps in legacy receivers when going to TOT control. –Getting this data now may enable earlier transition to TOT control –Large offsets may be in master TOT and new emission delays may be unnecessary