James
Doherty, President, The Institute of Navigation
on emerging applications and technological innovations
Tell us about the Institute
of Navigation?
The
Institute of Navigation (ION) will celebrate its 62nd
anniversary at its Annual Meeting next year (April 2007,
Cambridge, Massachusetts).
I find the ION’s purpose statement a useful starting
point from which to describe this Institute: “The
ION is a scientific, nonprofit organization, whose programs
are directed toward advancing the science, art, and
standards of navigation by coordinating the knowledge
and achievements of practicing navigators, scientists,
and those involved in the development and production
of navigation equipment.”
The Institute’s membership includes about 3500
individual and nearly 100 corporate members, drawn from
throughout the United States and Canada. In addition
to the national organization, there are currently eleven
active local chapters, which we call Sections, with
several more in planning stages, plus a Satellite Division.
Any specific achievement
of the ION.
I am particularly proud of the ION’s work with
students. This is largely done through the Sections.
Most of our Sections have a Student Activities Committee.
For example, my own Section in Washington DC has a
program of activities with a number of local high
schools, in which Section members assist various science
teachers develop field projects to engage students
in using positioning, navigation, and timing related
technologies. The ION loans equipment and reference
materials, and Section members serve as mentors with
the teachers conducting and assessing field work.
Favorite projects are surveying the school’s
athletic field with GPS and other equipment, and analyzing
findings.
Other Sections, including Dayton Ohio and Rocky Mountain
(Colorado Springs Colorado area), Alberta Canada,
and Southern California, have programs to award undergraduate
and graduate scholarships. Once awarded, although
there are no strings attached, Section members frequently
offer to mentor students in the study activities or
onward research.
The ION Satellite Division has also created a number
of lesson plans on positioning, navigation, and timing
suitable for the junior high school (12- 14 year old)
level. These are available on the ION’s website
(www.ion.org).
The Dayton Section, supported by the ION’s Satellite
Division and several local sponsors, also runs the
annual Autonomous Lawnmower Competition. The course
is challenging—a fixed plot of grass, with obstacles
(in known and unknown locations), an upper time limit
for completion, a maximum speed limit, and a required
technical presentation on (among other things) system
affordability. Once started, the lawnmower must work
complete the course autonomously, without manual or
remote intervention. There are penalties for “cutting
outside the lines,” for failing to mow areas,
for hitting obstacles, and for taking an optional
restart. This year, I had the pleasure of watching
five university teams compete, and the competition
was heated. Ohio University’s team won. However,
I was most inspired when I talked with the students
from all the teams—they had been particularly
innovative in their integration of technologies, from
simple deadreckoning computing (based on compass and
wheel revolution counters) to integration of carrier
phase differential GPS with optical sensors and inertial
measurement units.
You
had been involved in the Maritime Differential GPS service
for the US. Would you like to elaborate on this?
In my last tour
of duty as an active duty officer of the United States
Coast
Guard, I was the Commanding Officer of the Navigation
Center. When I arrived there in 1996, the Maritime Differential
GPS (DGPS) had just achieved initial operational capability
(IOC). It was largely installed and operating, but it
had not yet been certified, and it was experiencing
a few equipment problems and maintenance difficulties.
There were standards in place for service operations
and receiver performance, and we had a number of users.
Over the next several years, the Navigation Center helped
focus a Coast Guard wide effort to update equipment,
standardize the sites, and certify coverage and system
performance to mandated standards. In March 1999, the
Secretary of Transportation and Commandant of the Coast
Guard, in a ceremony at the Navigation Center,
declared the Maritime DGPS fully operationally capable
(FOC)–in other words ready for full use by mariners.
By the time of FOC for the US DGPS network, virtually
all maritime nations of the world had installed their
own similar service, operating to the same standards
in their own critical ports and waterways. This made
it possible for mariners to travel anywhere in the world,
using GPS when in open water and taking advantage of
the improved accuracy and integrity of the DGPS when
entering virtually any port.
What
about nationwide DGPS expansion programme?
The
Nationwide DGPS (or NDGPS) expansion began with a test
station in the Pacific Northwest, which began operating
in 1997. The test station filled a gap in maritime coverage
in the upper reaches of the Columbia River and also
provided coverage for terrestrial user tests, dominantly
railroad users. As a result of the tests, the Department
of Transportation made a decision to move forward with
the NDGPS. The Federal Railroad Administration sponsored
the system, with additional sponsorship by the Federal
Highway Administration, and the Coast Guard agreed to
develop, operate, and maintain the service as reimbursed
by the other agencies. The NDGPS would be operated to
the same standards as, and in concert with, the maritime
DGPS service.
Most of the NDGPS sites were developed economically
using decommissioned United States Air Force GWEN stations.
These sites were nearly perfect for broadcast of the
DGPS correction signals, and the site infrastructure
was ruggedly built. It was relatively simple to add
reference station and integrity monitor receivers, and
then modify the signal generators to update a GWEN site
to NDGPS operations. The first few NDGPS sites were
also declared operational in the March 1999 FOC ceremony
for the maritime service.
DGPS and NDGPS are specified as 10-meter accuracy systems,
but in reality most users experience closer to meter
level accuracies. There is a new variant, called High
Accuracy NDGPS, or HA-NDGPS. Employing long range carrier
phase corrections, it appears possible to upgrade the
installed DGPS and NDGPS infrastructure for decimeter
level accuracies nationwide. I am hopeful to see these
developments occur.
What
is your focus area of the work in Institute of Defence
Analysis?
I retired from
active military service with the Coast Guard in June
1999, and about two weeks later I began a second career
with the Institute for Defense Analyses (IDA). It is
hard for me to believe that I have been with IDA for
more than 7 years. At IDA, I am a member of the GPS
Independent Review Team. I also participate in or lead
various reviews and assessments of position-navigationtime
(PNT) and other technologies for the Department of Defense
and on occasion for other Federal agencies.
What
trends you see in the field of navigation in terms of
technological innovations?
Very clearly GPS/GNSS has put navigation literally
“on the map” for many users worldwide.
The major trends I see include: increases in efficiency
and safety in traditional maritime and aviation navigation
applications; new applications in automobiles and
personal navigation; increased demands for global
position and time information to support new, non-navigation
but navigation-related, applications; miniaturization
of user equipment; and new integrations of user equipment.
In the Coast Guard, I served as navigator aboard a
Coast Guard Cutter early in my career, and even earlier,
as a cadet at the Coast Guard Academy, I sailed aboard
a 44-foot sailboat in several ocean races. I was then
part of an elite group of mariners and aviators who
could call themselves “navigators.” In
those days, we used sextants, compass, fathometer,
charts, and even though we had some radionavigation
systems, such as radiobeacons and Loran-A, navigation
was a tough-to-master, learned skill, which required
constant practice to remain proficient. Later in my
Coast Guard career, I was a circuit and system engineer
working on the more modern Loran-C system, upgrading
transmitter and receiver systems to improve performance
and automate or remotely control operations. Still,
the art and science of navigation remained the domain
of the skilled professional.
Today those professionals have a new tool, more accurate
than ever before, and more universally available—GPS.
With the Wide Area Augmentation System (WAAS) and
other spacebased augmentations, DGPS/NDGPS, new signals
of GPS modernization, and companion elements of GNSS
(Galileo, GLONASS, et al), not only do the navigation
professionals have access to these services but so
also everyone else. More and more people, with limited
or no “navigation” training, are using
the position and time information from this robust
GNSS. For example, road maps have not quite disappeared
from auto club shelves, but increasing numbers of
drivers are relying on factory installed or after
market GPS-based navigation systems.
So, with all that as background, what’s next?
Users demand new services, market forces generate
innovations to meet those user needs and expectations.
Sometimes users are disappointed with their new GPSbased
services, for example when their automobile navigation
system stops working in an urban canyon, tunnel, or
parking garage. Some smart innovator then integrates
the GPS unit with maps, odometer, and differential
wheel counters to enable higher accuracy dead reckoning
through the interruption in signal reception. I look
for this type of integration within user equipment
to continue.
Would you like to highlight
some of the emerging application areas?
When people ask
me this question, I like to turn it back on them …
but with a bit of a hint. That is, how do you think
having access to a globally consistent, precise and
accurate, position and time grid will help you? Will,
for example, having upto- the-minute traffic information,
keyed to your current position and planned route, be
helpful? Or, how about having your cell phone call ahead
to your home to reset the furnace or air conditioner
and make other preparations for your comfortable arrival?
On a more serious note, highways are getting more crowded,
as are all modes of transportation. At the same time,
there is a continuing demand to move goods and people
faster and more directly from point to point, and while
also improving the level of safety. Intelligent transportation
system (ITS) technologies will help increase automation
to improve efficiency in transportation, and I believe
if done right, improve safety.
Any specific issue you would
like to raise?
You have seen
my comment above about the student activities of the
ION.
When one of my sons graduated from high school (longer
ago than I care to remember), I remember the graduation
speaker’s theme—“if you can dream
it, in your lifetime you will have the chance to achieve
it.” That one line particularly resonated with
me.
I knew then that some technologies I worked on enabled
some dreams to become reality for my generation. I would
like to see that same opportunity for future generations.
To that end, I hope to see the ION and other professional
organizations continue to have active student programs—to
get young students interested in technology and what
it can do to improve the quality of life … and
to stimulate some of them to further their formal technology
education to become the innovators of the future.
What
is your perception about the Galileo initiative?
I believe that
GPS provided a breakthrough capability—ubiquitous
position and time information—that has led to
major productivity and quality of life gains. Galileo
will add robustness to the overall GNSS services, in
that it will provide more satellites and thus improved
geometry when users have a limited view of the sky.
The key is that the services be interoperable, such
that the sum is greater than the total of the parts.
Some the countries like
India don’t want to depend on US GPS. Please comment.
It has been Presidential
policy since the 1980s that GPS be provided free of
direct user charges for peaceful global use. There is
even a law enacted
by Congress to that effect. You are aware of the US-EU
agreement on GPS and Galileo which also supports such
a policy. In a democracy such as ours, I figure that
is about as good a guarantee as one can get. Additionally,
there are two formal user groups, those “professional
navigators,” which help assure consistent global
quality in GPS and all GNSS services. That is, the International
Maritime Organization (IMO) and the International Civil
Aviation Organization (ICAO) set rigorous standards
for the operation and use of GPS/GNSS in maritime and
aviation safety applications worldwide.
Those are the facts. But let me add a few thoughts.
It is not an inexpensive venture to develop, deploy,
operate, maintain, and sustain a GNSS constellation
of satellites. Yet it is clear from the widespread acceptance
of GPS that it has proven a boon to all who would use
it. GPS is not alone in providing GNSS services. GLONASS
remains in operation, and Galileo has launched its first
test satellite. Thus, there are definite indications
that GNSS will become more robust. In that light, your
question might be considered in benefit vs. cost terms—can
countries afford not to take advantage of those services
offered by others?
Finally, it is clear that through their own DGPS or
WAAS-like spacebased augmentation services, each country
has the capability to establish the ultimate accuracy
and assure the integrity of GPS and other GNSS for their
own users. And, if a local or regional backup service
were desired, there are several legacy radionavigation
systems, such as Loran-C and modernized variants (e.g.,
“Enhanced Loran”), as well as mode-specific
systems (e.g., VOR/DME), that would provide a measure
of independence within critical infrastructures.
Jim
Doherty retired from the U.S. Coast Guard
at the rank of Captain in 1999; his last duty
assignment was Commanding Officer of the Navigation
Center. Under his leadership, the Maritime Differential
GPS service achieved full operational capability,the
Nationwide DGPS expansion was initiated, and the
first phase of Loran recapitalization was begun.
He also served as Deputy Chair of the Department
of Transportation’s Civil
GPS Service Interface Committee.
Jim
is currently a Senior Analyst at the Institute
for Defense Analyses, Science & Technology
Division. Among his responsibilities, he serves
on GPS Independent Review Team and the WAAS Independent
Assessment Team.
He has served on the Council of the Institute
of Navigation and in various elected national
offices of the ION since 1999. He was Chair of
the Washington DC ION Section from 2000 until
2005. In June 2005, he became the Institute’s
President, a position he will hold until January
2007.