UrsaNav’s Third Wide-Area Timing Tests

Monday, April 2, 2012

Rotating the PNT triangle. We’ve all become accustomed to the acronym for Positioning, Navigation, and Timing: PNT. Positioning and Navigation are key contributors to our way of life. We are consumed with knowing where we are, and where we are going. With advances in satellite technology, and its augmentations, we can slice our position ever more precisely into meters, centimeters, and even millimeters. For the large majority of us, however, meter-level accuracy is “more than sufficient” for our daily needs.

Now let’s think about time. Time helps us know where we are, as well as letting us know when we are. We continue to dissect time into smaller and smaller “ticks”: seconds, milliseconds, microseconds, and nanoseconds. Dare I say picoseconds?

Smaller increments of position help less of the general public. But what about smaller increments of time? The general public can still benefit from the provision of ever more precise time. The telecommunications, electrical generation, and financial industries, for example, are all improved when precise time is available.

So, we propose rotating the PNT triangle to put more emphasis on the “T”. Precise, high-integrity, wide-area, secure time is a multiplier for technology industries. Faster telecommunications, lower electrical losses, and better financial transaction synchronization come to mind.

At UrsaNav, it’s about LF Time. When GPS time is available, you should use it. When it is not, there is clearly a need for a robust alternative. That’s what we are testing now. For those of you following our efforts to provide a secure, wide-area, alternative timing solution to GPS, this is the third in a series of updates on our progress.

Last week, we transmitted both eLoran and other LF signals from the diamond Beach Facility, or “dBF”, in Wildwood, NJ. We successfully demonstrated that we could broadcast an LF signal with an advanced coding scheme and pulse shape in the 90-110 kHz frequency band using the Nautel NL transmitter. Transmitting at over 4,000 PPS, and without the use of any propagation corrections or differential monitoring, our preliminary, short-duration testing results showed UTC traceability to within +/- 40 ns at 350 miles, and +/- 65 ns at 500 miles. At all distances, our receivers met the ITU and ETSI Maximum Time Interval Error (MTIE) for Primary Reference Clocks.

In addition to providing precise time, our alternative LF signal provided significant radiated power gains, thereby allowing greater signal coverage and improved reception. Interference from other LF transmissions was an inherent issue with legacy systems, but our new signal implementation eliminates the effects of cross-rate interference. The new signal structure also expands options for “high speed” data rates in excess of 1,200 BPS.