Description:
OBJECTIVE: Demonstrate an approach for canceling cosite interference on dismounted soldiers as a result of collocated communications and an electronic warfare (EW) system without a physical connection between the EW and communications system. DESCRIPTION: Dismounted soldiers carry various Command, Control, Communications, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR) equipment associated with various mission profiles. The Army continues to strive to bring more information and extend the tactical network all the way down to the individual rifleman. This requires dismounted soldiers to carry various wireless communications equipment which is spectrum dependent. In addition to communicating over the Network, some missions necessitate the need for soldiers to carry electronic warfare (EW) for force protection. Soldiers carrying both radios and EW systems become at risk for electromagnetic fratricide between the systems. This can lead to degraded communications and the inability to deliver timely situational awareness and mission command in a friendly force EW environment. Solving this issue for dismounted soldiers introduces unique challenges as the size, weight, and power (SWaP) associated with equipment must be conducive to dismounted soldier operations. Adding additional cabling between the EW and communications systems introduces additional weight, snag hazards, and mobility issues. The Army is seeking an innovative solution to the cosite interference issue with minimal increase to soldier load. The solution shall consist of an applique that is integrated onto the communications radio. Such an approach may consist of a"sleeve"for a handheld radio that provides the interference cancellation capability. The size of the applique shall not increase the size of the integrated system (handheld + applique) to more than 50% of the standalone handheld radio. The target platform for this applique is the AN/PRC-154"Rifleman Radio". The applique shall be battery powered with interconnections that are compatible with the Rifleman Radio. The approach must address in-band (within the modulation bandwidth of the primary communications signal) interference generated by the EW system. This interference can be a result of products of intermodulation, harmonics, spurious emissions, and an elevated noise floor generated by the EW system. The approach shall also address out of band interference generated by the aforementioned effects as well as interference generated by the primary EW signal(s). It is assumed that the communications signal is not assigned to a targeted EW frequency. The proposed approach cannot change the output of the EW system. The approach shall also consider the effects of near-by EW systems operating on adjacent soldiers in close proximity. The approach shall also consider the desensitation effects that occur within the communications system as described in [1]. The solution shall address the Soldier Radio Waveform (SRW) operating over a tuning range of 225 MHz 2 GHz. The solution shall provide at least 25 decibels (dB) of interference reduction, with a target of 40 dB, within the modulation bandwidth of the SRW channel. This shall be accomplished without a priori knowledge of the EW signal (i.e. reference signal). PHASE I: The Phase I effort shall include feasibility study outlining problem considerations and potential solutions. An analysis of theoretical limits of the various technical approaches shall be presented in additional to practical limitations. The Phase I effort will identify the best approach and provide a recommendation for Phase II implementation. The Phase I deliverable will be a report documenting the results of the Phase I effort. PHASE II: The Phase II effort shall construct and demonstrate the operation of a prototype that will cancel cosite interference on the Soldier Radio Waveform. The prototype shall cover the 225 MHz 450 MHz military Ultra High Frequency (UHF) communications band. The effort shall include power considerations with respect to battery life associated with the developed hardware. The Phase II prototype will be tested at a government facility in an operationally representative environment and shall demonstrate at least 25 dB restoration in receiver sensitivity in the presence of the EW system. The prototype shall be delivered to the government with an associated user manual, interconnect diagram, and a report documenting the results of the Phase II effort. PHASE III: Phase III efforts will focus on reducing the size, weight, and power of the Phase II prototype and integrating into Army Program of Record SRW radios. This work will include extending the Phase II prototype to cover additional frequency bands. The Phase III work may also target additional commercial off the shelf (COTS) SRW radios that are demonstrated during the Army"s Network Integration Events (NIE) which currently occur twice a year. The technology developed under Phase II may also be modified and transitioned to the commercial cellular for use in mitigating the strong interferers in Code Division Multiple Access (CDMA) systems.
