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This Defense Intelligence Reference Document, DIA-08-1004-005, is dated 6 April 2010. The Defense Intelligence Agency's Defense Warning Office prepared it under the Advanced Aerospace Weapon System Applications program. It reviews proposed laboratory generators and detectors for high-frequency gravitational waves. It favors a piezoelectric approach for proof-of-concept tests, IR-excited molecules for an operational transmitter and the Li-Baker detector as the receiver. It estimates about 1.9 million bits per second over 7,000 km through the Earth and discusses timing standards and interplanetary navigation uses.
From the source:Release of 2026-09-18 Incident: 4/6/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD examines whether high-frequency gravitational waves could serve as a communications medium while avoiding the attenuation that limits radio-frequency systems. The report surveys proposed transmitter and detector concepts, argues that gravitational-wave communications could support secure point-to-point links, timing standards, and interplanetary navigation, and gives particular attention to laboratory generator concepts and the Li-Baker detector as possible building blocks for such a system. The document makes clear, however, that the entire concept depends on capabilities that had not been demonstrated in practice, including laboratory-scale generation and reliable detection of usable high-frequency gravitational-wave signals. It is an exploratory systems-oriented review built around a future communications concept.
UNCLASSIFIED/ /iiOR OiiiilCI OL lallili QPIL¥ Figure 17. In general, an EM signal Si will be used to actuate some type of GW generation device, and this device will have a conversion efficiency of μeg, which represents the ratio of power of the EM input signal to power of the GW signal generated. Not all of the GW generated will be constructively used to radiate in the desired direction; some of the GW power will be lost to destructive interference, and some will not be radiated through the antenna aperture. Thus the transmitter will have a less than unity radiated power efficiency, Rx. ---- An end-to-end power link budget from the transmitter to the receiver must be also calculated to support a communications link design. Transmitter Terms Receiver TermsLinkA r --.. Loss r ~ GW GW μgeT E~ So IRrisi M~eg 1G~1 j I GW I I I I IReceiver Input EM/GW Radiated Propagation GW/EM OutputAntennaXmit Ant. LossesSignal Conversion Conversion Signal: PowerPower (TransmissionPower Efficiency Efficiency PowerEfficiency Factor) Efficiency Figu re 17. A Block Diagram of a Typical Link Budget Then there will be propagation link loss, or transmission loss, T, which will be t he antenna pattern integrated across the solid angle of t he receiver antenna aperture as seen from t he source. The receiver may have an GW anten na t hat aids in foc using an otherwise wider solid angle into a narrower detection aperture, and if t his is true, then there will be an efficiency associated with this receiver antenna, designated here as Rr . At the receiver's detector, there is another conversion factor to account for, the conversion efficiency of GW signa l power to EM signa l power μ9e, which would be much less than unity, except that the Q factor enters the equation as a component of μ9e. Of course Q may also impact the bandwidth range over which the signa l is collected, Ll to L2. There is also a hidden integral here which occurs over the sample time, which is understood. Al l of these terms will have to be defined and well understood before a communication system can be successfully designed. Many of these parameters have been predicted for the components reviewed in prior sections, however, they will not be verified until a successful experiment can be performed. UNCLASSIFIED/ / FOR OiiiilCl.t.k HS I!! efl ti 24
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 57 pages are in the text index: search them above, or from the library's search.