TECHNOLOGY AREAS: Sensors, Electronics, Battlespace

ACQUISITION PROGRAM: PMW120, Cryptologic Carry-On Program (CCOP) ACAT III

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.

OBJECTIVE: The objective of this topic is to provide an active but analog solution to the co-site interference problem experienced by highly sensitive receivers on ships. This is one of several complementary approaches that may be combined to maximize the interference protection while also minimizing the system complexity. While other approaches may be proposed, one means of achieving this objective is to implement a Cryogenic RF Excision System (CRES).

The CRES architecture employs multiple antennas and angle-of-arrival (AOA) algorithms to perform below decks EMI cancellation (rejection). The algorithms are based on AOA characteristics of co-site and SOI. The multiple antennas sense energy from different angles-of-arrival for each co-site interferer and a single AOA for each off-board SOI. As a consequence of the variation between co-site and SOI angles-of-arrival, algorithms can derive a co-site cancellation signal. The use of cryogenic temperatures and superconducting materials to implement the architecture minimizes signal attenuation and thermal noise, yielding more accurate cancellation.

The CRES architecture is composed of transversal spatial notch filters (SNF) that combine the outputs of multiple antennas to synthesize and subtract an analog estimation of the interferer waveform at the receiver. The coefficients of these filters are adjusted by real-time computerized feedback based upon blind excision techniques. The coefficients are adjusted to track the effects of such things as rotating antennas, doors opening, antenna resonant changes, water wave effects, etc. Once the interference power at the receiver has been reduced to reasonable levels, new processing algorithms detect, copy, and DF low-level target signals by compensating for the effects of the SNF.

DESCRIPTION: On board Navy ships, the intercept of agile signals in the presence of co-site, co-channel agile communications, radar, and jamming signals is not currently possible without the introduction of significant RF attenuation. The high power nature of these transmitters can produce power levels approaching 10 Watts at the intercept receivers. This power level is large enough to cause severe intermodulation and saturation effects in addition to damage within these receivers. The agile nature of the transmitted waveform is difficult to track and notch out using conventional notch filter technology.

The CRES technology has the potential to substantially reduce this co-site Interference and lower system noise figure, thereby increasing the exploitation range of modern signals of interest (SOIs) and reducing ship vulnerability to anti-ship missiles in the littorals.

PHASE I: Phase one will develop a preliminary design that will be modeled and its predicted performance will be evaluated to determine the feasibility of proceeding to a Phase II development and demonstration.

PHASE II: After an initial component system design and component development period, the components will be fabricated and integrated onto a cooler. The superconducting version of the system will utilize superconducting channelizers with cryogenic amplification, power limiting and dual tunable band pass and/or notch filters in each channel (Dual Tunable Filter LNAs - DTFLs). The CRES analog excisor will follow and be implemented as narrow band if necessary � a narrow band version of the fundamental component has already been demonstrated in the lab. If possible, CRES components will have both a narrow band (freq domain) and wide band (time domain) capability with automatic equalization. Demonstrate a 3 channel RF excision system which utilizes Space-Time Adaptive Processing (STAP) and frequency isolation while achieving low system noise temperature, e.g. via the use of cryogenically cooled components. The target performance value for the CRES is a 30-dB interference rejection with a 5 dB signal noise figure.

PHASE III: The expected transition of the product within the government as a result of the Phase II will be into classified military VHF and UHF antenna systems where strong co-site interference is present. Several appropriate Navy systems have been identified.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The private-sector application of the product will be in the Communications and Wireless industry where strong co-site interference is present.

REFERENCES:
1. V. P. Koshelets and S. V. Shitov, "Integrated superconducting receivers," Supercond. Sci. Technol., vol. 13, pp. 53�69, 2000.

2. T. Van Duzer and C. W. Turner, Principles of Superconducting Devices and Circuits, 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, 1999.

3. M. Kadin, Introduction to Superconducting Circuits. New York: Wiley, 1999.

4. Abelson and G. Kerber, "Superconductor integrated circuit fabrication technologies," in Proc. IEEE, vol. 92, Oct. 2004, pp. 1517�1533

KEYWORDS: Superconducting electronics; cryogenics; filters; EMI mitigation; SIGINT; co-site interference

TPOC: Deborah VanVechten
Phone: (703)696-4219
Fax: (703)696-8496
Email: [email protected]
2nd TPOC: Anna Leese de Escobar
Phone: (619)553-5987
Fax: (619)553-1090
Email: [email protected]
3rd TPOC: William Kordela
Phone: (619)524-7316
Fax: (619)524-7374
Email: [email protected]