Directions 2000:
Think Smarter, Not Harder

by

David W. Allan, President
Allan’s TIME

GPS World, Dec. 1999, p. 36

We live in an era of enormous opportunities as we have entered the information age. How will the Global Navigation Satellite Systems architects respond to all this information, and responsible government officials, who will provide the funding for GNSS over the next decade? It is easy to enter into saturation with all this information and loose track of priorities. Ockham’s Razor still is an extremely important operating guideline (sometimes also called the LAW OF ECONOMY or LAW OF PARSIMONY).

Though Ockham’s original statement in Latin was a negative statement (non multiplicanda entia praeter necessitatem), its simplest positive equivalent is, "The simplest is often the best!" Nature tends to give us elegant and simple natural laws with very broad applications; i.e. E = mc² and T²%r³ (Kepler’s Third Law). We anticipate that a fundamental unified field theory equation will also be simple and elegant.

Kepler’s Third Law is particularly fascinating given the current capabilities of space clocks and zero-g devices. It opens the opportunity to "leap-frog" GPS and provide real-time, centimeter accuracy for a satellite’s position without a cross-link satellite system and without performing the calculations from a massive set of ground information. In a much simpler architecture, a factor of 100 improvement is very reasonably obtainable, if the priorities are set and the funds made available for GNSS.

If we had centimeter accuracies in space, then, as well, we would want centimeter accuracies for receivers in real time. As we move into the centimeter and picosecond regimes, three fundamental things are required:

1) Improved architecture and spectrum utilization;

2) Clock technology support, utilization and integration, and

3) Measured, rather than modeled, ionospheric and tropospheric delay corrections.

An innovative solution is still needed for inexpensively measuring the tropospheric delay in real time — an important challenge for the next decade. Ockham’s Razor is critically needed in providing the simplest and most elegant clock solutions for GPS and GNSS. To date, the best and most elegant technology remains untapped for these systems.

We have seen an impressive number of spin-off applications utilizing GPS. If we will keep our priorities in balance and take advantage of the available opportunities, it is most probable that the future spin-off applications are beyond our comprehension. Given that resources are limited, one of the most important directions for a healthy future will be to learn that cooperation is a much more useful operating principle than is competition. Such healthy cooperation will require of us to also think with the heart.