TECHNOLOGY AREAS: Ground/Sea Vehicles, Sensors, Battlespace

ACQUISITION PROGRAM: PEO-C4I Ships Signal Exploitation Equipment (SSEE) Increment E, 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: Develop electronically tuned SINCGARS (Single Channel Ground and Airborne Radio System) hopping notch filters using canceller or other asynchronous technology that will suitably remove all interference (including multi path) from up to 8 SINCGARS co-located interfering radios. This would allow SIGINT systems to receive low level signals in the SINCGARS frequency band while up to eight of these SINCGARS radios are operating. The desired rejection of the SINCGARS (Single Channel Ground and Airborne Radio System) signals is 30 dB threshold and 50 dB objective.
The objective of this task is to develop asynchronous SINCGARS (Single Channel Ground and Airborne Radio System) hopping filters that can reject 8 or more SINCGARS radios operating simultaneously at a maximum input of 1 Watt with a goal of 50 dB rejection of these signals (30 dB minimum) and a maximum filter -6 dB notch width of 2 MHz with a goal of less than 1 MHz. The size of a single channel device is limited to a 7u height of a standard 19 inch equipment rack. To reduce complexity and possible security issues, it is desired for this system to operate independent of a tuning signal or any other output from the SINCGARS (Single Channel Ground and Airborne Radio System )radio. It is expected that this may be accomplished by using adaptive signal canceller technology or other advanced filter technology. A possible method of implementation would be to utilize the interfering SINCGARS (Single Channel Ground and Airborne Radio System) signal as the reference signal for a canceller system. Artificial Intelligence or other digital learning methods could be used to "remember" cancellation weights versus frequency to ensure rapid cancellation and filtering. Separate cancellers may be required for discrete portions of the SINCGARS (Single Channel Ground and Airborne Radio System) band to insure 8 or more transmitters can be cancelled while minimally affecting the remainder of the band.

DESCRIPTION: Navy SINCGARS (Single Channel Ground and Airborne Radio System) systems are required to receive low level signals in the HF, VHF and UHF frequency bands usually on multiple channels to provide direction finding capability. The SINCGARS (30-88 MHz) band occupies part of the VHF frequency band where signal reception is required. U.S. Navy ships will have from 2 to 8 SINCGARS transmitters installed, which are used to communicate with shore operational units. SINCGARS (Single Channel Ground and Airborne Radio System) radios use a frequency hopping signal to prevent jamming and interception, which is difficult to remove and prevent electromagnetic interference to the SIGINT receivers. Current SINCGARS (Single Channel Ground and Airborne Radio System) systems use signal cancellers or frequency hopping filters to remove this signal. Cancellers require a sample of the transmitted signal as well as individual canceling stages for each transmitter and respective multi-path signals. This method has the advantage of only canceling the interfering signal allowing reception of low level signals in the entire band. It has the disadvantage of complexity due to the required aforementioned sampling numerous canceling stages needed for each radio including its multi-path signals. Frequency hopping filters also require synchronization with each transmitting radio in order to tune the filter to the expected hop frequency. This technology also has the disadvantage of high complexity; a hopping filter for each transmitter and synchronization with each transmitter is required. Due to the complexity required to eliminate the SINCGARS signals both of these methods are usually limited to only 2 or 3 SINCGARS (Single Channel Ground and Airborne Radio System) interferers.

Currently interference cancellers are used to remove frequency hopping signals but typically, because the canceller size doubles for each signal cancelled and each multi-path signal, cancellation is limited to one or two co-located signals. This proposal is innovative because it attempts to merge canceller and hopping filter technology into a hybrid stand-alone hopping filter that can eliminate up to 8 co-located SINCGARS signals; will be independent of transmitter outputs; and will maintain performance in the presence of multi-path signals combining at the antenna.

PHASE I: Conduct an analysis of the proposed technologies/architecture to predict the expected notch filter performance over the required frequency range. Develop a concept for how such a filter network could be constructed to meet surface ship requirements. Develop a filter simulation to demonstrate the concept and validate performance. Develop a plan for the development of the required capability including cost, schedule, and required support.

PHASE II: Develop a full-scale prototype and demonstrate the ability to meet threshold objectives with the prototype filter network. Develop a production plan to manufacture fully military (USN ship) qualified versions of the product in the smallest form factor possible.

PHASE III: Develop a highly reliable, fully military specification compliant system, meeting objective requirements suitable for the intended employment on board Navy surface combatant ships. Fully developed system must effectively integrate with shipboard tactical crypto logic and communication systems. The system will meet all applicable EMC and RA requirements.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: This tunable filter technology will encourage the development of additional filter technologies and architectures that will be of great interest to both military and commercial organizations. Tunable filter technology can be used to great advantage to extend communications range, reduce interference, allow more dense frequency re-use, and reduce the effects of multi-path. These benefits apply equally for military and civilian applications. Military applications of this technology could be extended to remove other hopping transmitter interferers including JTIDS/MIDS and Havequick.

REFERENCES:
1. Lee A. Q. et al. "An evaluation of collocation interference mitigation approach SINCGARS radios". Military Communications Conference, 1995. MILCOM '95, Conference Record, IEEE.

2. Kub, F.J. et al. "Self Calibrating Hybrid Analog CMOS Co-Site Interference Canceller". Military Communications Conference Proceedings, 1999. MILCOM 1999. IEEE.

3. Lee, Thomas H. 2004 Planar Microwave Engineering. New York, NY: Cambridge University Press.

KEYWORDS: Tunable hopping filter; Canceller; SINCGARS; VHF; Cancellation; Havequick.

** TOPIC AUTHOR (TPOC) **

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