COMDTINST 16575.1
AUG 24 1999
9.
PROCEDURES.
a.
NAVCEN is responsible for analyzing the information to determine the impact of
interference/testing on the U.S. Coast Guard's DGPS broadcast sites, navigable waterways
and maritime users. After careful analysis and district input, NAVCEN will either approve
the testing or refer the request to Commandant (G-OP).
b.
NAVCEN will transmit approval responses to the FAA. The FAA will produce an
"Electronic Countermeasure (ECM) Authorization" message before the requested test date.
Commandant (G-OP) will prepare and forward any disapproval to NAVCEN for further
c.
"Cease Buzzer" is a procedure whereby authorized officials can quickly halt a specific test
because the test is creating problems that were not anticipated or expected during the test
planning phase. NAVCEN will be responsible for having at the ready all "Cease Buzzer"
information on the days of testing. For each test the "Cease Buzzer" information will be
found within the body of the FAA ECM Authorization message. District points of contact
should be aware of this procedure and notify NAVCEN's watchstander at (703) 313-5900
for any of the reasons indicated below to stop the testing. NAVCEN is authorized to call
the "Cease Buzzer" point of contact to stop the testing if:
(1) There is reason to believe the testing is adversely impacting search and rescue efforts,
etc.; or
(2) There are events/traffic that will be adversely impacted by the loss of GPS/DGPS in
the maritime area, e.g., Liquefied Natural Gas (LNG) Carrier in final approach to
designated harbor; or
(3) There is reason to believe the testing is affecting areas not expected to be affected,
e.g., DGPS sites.
10. SUMMARY. Conformance with policy outlined in this Instruction should be sufficient to
manage GPS interference requests under normal circumstances. Negotiating mutually
acceptable interference test scenarios at the lowest possible organizational level is of prime
importance. Every effort must be made to avoid denial of necessary GPS interference testing,
while at the same time avoiding the creation of a hazardous transportation
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