David W. Allan, President
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.
Ockhams Razor still is an extremely important operating guideline
(sometimes also called the LAW OF ECONOMY or LAW OF PARSIMONY).
Though Ockhams 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
(Keplers Third Law). We anticipate that a fundamental unified field theory
equation will also be simple and elegant.
Keplers 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
satellites 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:
An innovative solution is still needed for inexpensively measuring the
tropospheric delay in real time an important challenge for the next
decade. Ockhams 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.