Assessment Concerns

and various other entities deemed necessary to assess GPS test impacts and negotiate acceptable

GPS test parameters.

NAVCEN will develop specific standard operating procedures based upon general

guidelines in this Instruction. NAVCEN will receive notification of proposed testing from

the FAA and will analyze the impact on the maritime community as part of the

aforementioned IDCT process. Expected turnaround time for reply to FAA for proposed

testing will be five working days for those tests that will not affect navigable waters.

NAVCEN shall approve these requests.

Each District shall designate a point of contact for maritime safety and other GPS

interference testing impact review. Should NAVCEN determine the potential exists for

testing to impinge on U.S. navigable waters, they will request a review by that District of

maritime safety impacts based upon knowledge of local conditions, types of maritime

traffic, hazardous cargoes being transported, local events, local pilot dependency upon

GPS/DGPS, planned events or operations, and other impacts of the tests. Districts shall

respond to NAVCEN within 5 days. If the District determines the impact is acceptable,

NAVCEN shall approve the request and issue appropriate Notice to Mariners.

NAVCEN shall ensure that the District's point of contact is made aware of the "Cease

Buzzer" procedures in the event that the testing needs to be halted for reasons detailed later

in this Instruction.

If NAVCEN's preliminary review or the Districts' impact results in a recommendation that

the testing should not be approved, NAVCEN shall refer the case to Commandant (G-OP)

for final determination. Specific examples that will require Commandant (G-OP) review

include testing that will impact a Maritime DGPS broadcast site or that will impact a major

port or waterway, such as New York Harbor, San Francisco Bay, or others.

ASSESSMENT CONCERNS. There are two primary areas of concern to consider when

making an assessment of the impact of proposed GPS interference testing on the maritime

community. The first concern involves interference testing that directly affects a DGPS

broadcast site. When a DGPS broadcast site is affected, the effects of the testing extend far

beyond the originally intended test area, perhaps as much as 200 nautical miles. The second

area of concern involves interference testing affecting navigable waters. Of primary interest are

critical waterways such as harbor entrance approaches, restricted waterways in which there

exists high-density traffic involving hazardous cargoes or passenger traffic, or hazardous inlets

where vessels are known to rely on GPS/DGPS to effect a safe passage. There may be other

concerns involving either planned or emergency situations or critical operations that may be

heavily dependent upon availability of GPS/DGPS signals.