Kujiraoka S.,Naval Air Warfare Center Weapons Division |
Proceedings of the International Telemetering Conference | Year: 2013
The physics associated with transmitting and receiving a telemetry signal at a frequency greater than an octave above the current operating band is such that an end-to-end evaluation of the complete data link system (both the transmit and receive side) is required. In 2012, Airborne Instrumentation Systems Division (AISD), Naval Air Warfare Center Weapons Division (NAWCWD) was sponsored by the Office of the Secretary of Defense (OSD) to develop a couple of short-range air-to-air missile platforms that use a specially-designed warheadreplaceable telemetry section incorporating three data links: (1) an S-band link to transmit Time-Space-Position Information (TSPI), (2) an C-band link, and (3) an additional S-band link where the latter two are transmitting the same pseudo-random bit sequence at the same effective radiated power level. Flight testing will consist of a series of captive tests conducted over land and water. The tests will be performed under a variety of conditions to induce potential issues caused by multipath, atmospheric ducting, fast-slewing of the tracking antenna, and large propagation losses. Flight testing will culminate with the live-fire of a missile over a military land range. This paper describes the continuing efforts of this test program from these series of flight tests, thus quantifying the performance of C-band telemetry data transmission as compared to the S-band.
News Article | June 8, 2016
The Federal Aviation Administration has released an advisory for expected GPS interference in several days this month, with the outages to be caused by testing to be done by the United States military. The expected GPS outages will be on June 7, 9, 21, 23, 28 and 30, all from 9:30 a.m. to 3:30 p.m. Pacific time. The testing would result to "unreliable or unavailable" GPS signals, with the duration of the tests possibly lasting the entire six-hour periods, according to the FAA. The mysterious part of the news, however, is that there is no indication on what kind of device will the military be testing that would lead to such GPS outages in the southwestern United States. The tests, which were announced by the FAA and not by the military, are centered near the largest installation of the United States Navy in the Mojave Desert, specifically on the 1.1-million-acre Naval Air Weapons Center in China Lake, California. The testing will disrupt GPS signals hundreds of miles in all directions, with different types of GPS to be affected. GPS systems of aircraft flying higher than 50 feet will be affected, which is what probably prompted the FAA to send out the advisory. The GPS disruption will reach the furthest at the higher altitudes, such as in the border of California and Oregon, which is 505 nautical miles from the center of testing and is at 40,000 feet above sea level. The disruptions will affect the flight controls of the Embraer Phenom 300 aircraft, which is a business jet, but commercial airliners will likely not be affected, according to experts. Pilots who would encounter GPS disruptions could simply navigate around the area as if they would be escaping bad weather. A phone call initiated by Gizmodo to Naval Air Warfare Center Weapons Division public affairs specialist Deidre Patin confirmed that the military was aware of the advisory that the FAA sent out. Patin, however, could not provide any more details regarding the testing, only stating that it will be "general testing" for the military's ranges. With the FAA and the Navy both keeping their mouths shut on the experiments that will be carried out, it is difficult to ascertain what kind of testing will happen. There are GPS jammers out in the market right now that can be purchased for below $200, but it seems that the military will be testing more potent systems that are able to disrupt the GPS of unmanned and manned aircraft. The military recently awarded SpaceX with an $82.7 million contract to launch into orbit a GPS satellite, which will meet the needs of both military and civilian users. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.
Atwood A.I.,Naval Air Warfare Center Weapons Division |
Curran P.O.,Naval Air Warfare Center Weapons Division |
Ford K.P.,Naval Air Warfare Center Weapons Division |
Baynar S.A.,Naval Air Warfare Center Weapons Division |
And 3 more authors.
International Journal of Energetic Materials and Chemical Propulsion | Year: 2010
The ignition threshold and combustion characteristics of two pyrotechnic powders (A and B) initiated by mechanical stimulation were examined. A piston-driven compaction (PDC) experiment was used to compare the two powders. The two powders differ in their oxidizer type and initial particle size distribution. It was found that Pyrotechnic A, formulated with potassium perchlorate, had a lower ignition threshold (~80 m/s) than Pyrotechnic B (~120 m/s), which was formulated with a blend of ammonium nitrate and barium nitrate. Compaction wave front velocities through the sample were a function of piston velocity and were comparable for the two samples; however, the characteristics of a "sustained" combustion front differed between the two samples. Powder models were developed for the two materials and used to simulate the PDC experiments. © 2010 by Begell House, Inc.
Matt H.M.,ATA Engineering, Inc. |
Napolitano K.,ATA Engineering, Inc. |
Todd M.D.,University of California at San Diego |
Hertz S.,Naval Air Warfare Center Weapons Division
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011
For future structural health monitoring (SHM) systems, the knowledge of past and present operational loads in the form of forces/moments at critical system interfaces will be invaluable for performing accurate prognostics and augmenting SHM capabilities. However, this information is not a direct product of traditional operational loads monitoring (OLM) techniques employed on current fleet aircraft and is not easily achieved using existing force measurement devices. In recognition of this limitation, this paper addresses the development of an accurate in-situ multiaxis force measurement system for directly monitoring dynamic operational loads at critical mechanical interfaces without altering the existing connector architecture. The proposed methodology utilizes a strain gage-based measurement technique in which a series of sensors is calibrated with a set of known loading configurations. The sensitivity matrix relating the measured strains to the loads forms the core of the system. The feasibility of the proposed technique was demonstrated both analytically and experimentally on a representative aircraft weapon store/rail interface exhibiting nonlinearity in the system. The results are conclusive in that the outlined trained network approach is able to accurately predict all six force/moment interface loads with less than 8 percent total error under various loading conditions. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
Zarras P.,Naval Air Warfare Center Weapons Division |
Buhrmaster D.,Air Force Research Lab |
Webber C.,Naval Air Warfare Center Weapons Division |
Anderson N.,Naval Air Warfare Center Weapons Division |
And 2 more authors.
Materials | Year: 2014
In this study, an electroactive polymer (EAP), poly(2,5-bis(N-methyl-N-hexylamino)phenylene vinylene) (BAM-PPV) was investigated as a potential alternative surface pretreatment for hexavalent chromium (Cr(VI))-based aerospace coatings. BAM-PPV was tested as a pretreatment coating on an aerospace aluminum alloy (AA2024-T3) substrate in combination with a non-Cr(VI) epoxy primer and a polyurethane Advanced Performance Coating (APC) topcoat. This testing was undertaken to determine BAM-PPV's adhesion, corrosion-inhibition, compatibility and survivability in laboratory testing and during outdoor field-testing. BAM-PPV showed excellent adhesion and acceptable corrosion performance in laboratory testing. The BAM-PPV aerospace coating system (BAM-PPV, non-Cr(VI) epoxy primer and polyurethane APC topcoat) was field tested for one year on the rear hatch door of the United States Air Force C-5 cargo plane. After one year of field testing there was no evidence of delamination or corrosion of the BAM-PPV aerospace coating system.