Unmanned Systems Integrated Roadmap FY2011-2036 - Defense ...

Unmanned Systems Integrated Roadmap FY2011-2036
mission areas. In addition, these SDS collect more information, and missions often require
greater bandwidths to send their information directly to warfighters. This latter consideration has
been seen within OEF missions where new ISR UAS have included wide area surveillance
sensors; alternative spectrum bands have been identified 38 to help address the wider bandwidths
needed by those systems. Also, mission areas are becoming more spectrally “noisy” because of
increasingly cluttered and hostile spectrum environments. As such, a continual demand for
improved spectrum efficiency and effectiveness is being placed on all DoD SDS. 39 All
unmanned systems must complete during their development process a spectrum supportability
and risk assessment in accordance with DODI 4650.01 to identify and mitigate regulatory,
technical, and operational spectrum supportability. Because national and international spectrum
rules and policies can rapidly change, 40
developers should maintain a close liaison with
appropriate DoD spectrum offices before finalizing communication system designs.
The use of LOS datalinks also supports missions where there is a denial of or impaired
service to SATCOM systems. Under such conditions, the demand for LOS spectrum will be
extended to support the need for improved spectrum use efficiency and effectiveness.
The Defense Advanced Research Projects Agency’s (DARPA’s) Next Generation (XG)
project and its follow-on Wireless Network after Next (WNaN) program demonstrated the
feasibility of dynamic spectrum access (DSA). DSA offers the ability to change frequency band
use based on other adjacent SDS actual use and nonuse of certain bands. The Joint Tactical
Radio System (JTRS) program is investigating the feasibility of integrating DSA technologies
into its system. The U.S. Army is also considering having WNaN become part of an Army
program of record. However, a recent USAF Scientific Advisory Board study said that DSA is
far from being proven technology. Developmental challenges include susceptibility to
countermeasures, costs of integrating with existing systems, developing standards (including
regulatory aspects), and co-site interference (2015).
Alternative technology advances should aid in the spectral efficiency challenge to include
internal and external EMI mitigation advances such as coherent signal cancellation, space-time
adaptive processing, polarization diversity, and adaptive digital beam forming.
38
OASD NII memo dated March 22, 2011 Subject: Department of Defense (DoD) Common Data Link (CDL)
Usage in Operation Enduring Freedom (OEF) Theater
39
All new and modified SDS programs now need to conduct a spectrum supportability and risk assessment prior to
Milestone B (source: DODI 4650.01).
40
Relatively near-term spectrum usage changes could come from the ITU and its 2011 Worldwide
Radiocommunication Conference (WRC); UAS spectrum use is a conference agenda item. Changes in frequency
band usage for UAS may also come from the FAA and the ICAO as part of the UAS operations in the NAS airspace
and in other nation-states’ airspace.
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