by all US Department of Transportation agencies of the recommendations made by
the Volpe Center report on GPS signal vulnerability has led the DOT to adopt an
action plan to ensure existing radionavigation systems support GPS adequately.
the viewpoint of aviation and other safety-critical transport applications, the
report’s most important and controversial recommendations established that GPS
signals were vulnerable to jamming, intentional or unintentional, and that GPS
could not be relied on for sole-source navigation.
report – which was released publicly on 10 September – concluded that back-up
navigation systems were needed. This conclusion was so unpopular to the DOT and
FAA that they allegedly kept the report under wraps for more than a year, as
they tried to find a way to persuade the Volpe National Transportation Systems
Center to soften its recommendations.
the Volpe Center did little if anything to amend the thrust of the report. And
today, announcing the DOT’s decision to put the action plan into effect, US
Transportation Secretary Norman Mineta said the DOT would ensure GPS
vulnerabilities would “not affect the safety and security of our transportation
system as we work to ensure that GPS fulfills its potential as a key element”
of US transportation infrastructure.
DOT action plan lists six major areas of action to maintain infrastructure
viability. These are:
- Ensuring that adequate
back-up systems are maintained
- For the DOT to maintain its
partnership with the US Department of Defense (DOD) to continue
modernizing GPS by adding additional civil signals at new frequencies
- Facilitating the transfer of
appropriate anti-jam technology from the US military to commercial
manufacturers for civil use
- Working with the electronics
manufacturing and transportation industries to develop GPS receiver
- Working with state and local
transportation departments to promote education advising users about GPS
- Completing a detailed
assessment of US radionavigational capabilities across all transportation
modes to identify the most appropriate mix of systems – in terms of a
balance between capabilities and cost – to serve along with GPS for at
least the next decade. This review would include completing the
inter-agency evaluation of the long-term need to continue the US Loran-C
DOT’s director for radionavigation, Mike Shaw, says the department does not yet
have a definitive idea of the specific actions that will be involved in
pursuing the six initiatives.
Shaw stresses the DOT has no preconceived bias as to which existing
radionavigation systems should be kept and which should be decommissioned. It
plans to establish a task force next year to focus on the problem.
by polling all of its mode-specific agencies to find the mix that works best
for each transport mode and synthesizing their preferences to achieve a
workable balance between cost and adequate functionality will the DOT learn
which systems it can dispense with, he says.
the end we are hoping for a reduced number of mixes [of different
radionavigation systems] to serve everyone,” Shaw remarks, noting that the FAA
only finished last month its review of Loran-C functionality for aviation.
Other aviation radionavigation systems to be assessed will include instrument
landing systems, microwave landing systems and VOR/DME equipment.
concedes much of the basic analytical work on the usefulness of different
radionavigation systems as back-ups for GPS has been done “at various levels
with various organizations”. New to the action plan, however, is the idea of
taking a comprehensive look at how well these systems support GPS across the
range of transportation modes.
DOT also believes its work with the DOD on introduction of new civil GPS
frequencies, such as the 1227.60MHz ‘L-2’ second frequency to be introduced
next year and the 1176.445MHz ‘L-5’ third signal for 2005, is particularly
with work to help transfer declassified military anti-jamming technologies to
the civil sector, Shaw says introducing additional civil GPS frequencies is
highly important in increasing the robustness of the signal against
says the DOT is now involved in the US government’s GPS 3 program study, which aims
to design and develop a new generation of GPS satellites for 2009 and beyond,
offering greatly increased functionality for a range of applications.
existing GPS satellites were launched from 1978 onwards and their signals were
only made available for civil use in 1993. “In many respects we’re trying to do
things with the current constellation that weren’t thought of the in the ’70s
and that the system wasn’t designed to do,” says Shaw.
concedes that a larger constellation of GPS satellites – as a Heritage
Foundation report recommended to the White House last month – would be
desirable in terms of signal clarity, but points out the cost and funding
implications involved might make the idea unworkable.