Beginning 25 January 2017, Air Force Space Command (AFSPC) will conduct a limited duration test implementing an increase of the L1 C/A power level on the GPS Block IIR-M and IIF satellites (19 vehicles). The C/A power will remain within IS-GPS-200-H specifications and the power increase is not expected to increase the noise floor by more than 0.3 signal-to-noise ratio in the worst case. AFSPC reports, "We assess that there will be no adverse impacts to civil, commercial or military GPS users, but anyone who experiences issues during this test should address them through established reporting channels." Civil, non-aviation, GPS users should contact the U.S. Coast Guard Navigation Center at 703-313-5900 or online at http://www.navcen.uscg.gov/?pageName=gpsUserInput. Civil aviation GPS users should contact the FAA and file a report at https://www.faa.gov/air_traffic/nas/gps_reports/. All other non-operational concerns or inquiries regarding this test should be directed to Air Force Space Command at a3sm.wf@us.af.mil.