Joint Tactical Radio System Research Articles

Model-Based Systems Engineering: Lessons Learned from the Joint Tactical Radio System

The Joint Tactical Radio System was the first major program that sought to develop a new family of radio systems using a software-based architecture. A new software-oriented architecture, the Software Communications Architecture was developed as a common, interoperable foundation for this new family of tactical radios. The fundamental objective was to enable radio systems to support multiple waveforms, allow for software-only upgrades of operational capabilities and ultimately reduce the tail-end logistics, maintenance and upgrade costs. However, within the first few years the program experienced difficulties and setbacks resulting in cost and schedule overruns. Several program reviews and analyses were performed to assess the reasons for the problems encountered. Although multiple causes were cited for the failures, this paper puts forth the assertion that a key aspect of the engineering process, systems engineering, was not planned into the program and a fundamental cause for many of the issues encountered.

Classes of Attacks for Tactical Software Defined Radios

This survey presents a classification of attacks that Software Communications Architecture (SCA) compliant Software Defined Radios (SDR) can suffer. This paper also discusses how attack mitigation strategies can impact the development of a SCA-compliant software infrastructure and identifies several research directions related to SDR security. The SCA standard was originally proposed by the Joint Tactical Radio System program (JTRS), which is a program for the development of military tactical radios sponsored by the US Department of Defense. The classification presented in this paper is based on attack results on the radio set, which can also be associated with the adversary’s objectives when planning an intrusion. The identification of classes of attacks on a radio, along with the associated threats and vulnerabilities, is the first step in engineering a secure SDR system. It precedes the identification of security requirements and the development of security mechanisms. Therefore, the identification of classes of attacks is a necessary step for the definition of realistic and relevant security requirements.

A comparative review of commercial vs. tactical wireless networks

This article presents a comparison between commercial and tactical wireless networks, pointing to their different requirements, expectations, needs, and constraints for information assurance and so on. This comparative study demonstrates why commercial wireless networks have made more technological leaps than tactical wireless networks. The article introduces a model for tactical wireless networks based on the architectures that have been pursued (especially the Joint Tactical Radio System and the Future Force vision) within the last decade or so. The model draws parallels with commercial wireless networks to allow tactical wireless networks a plausible opportunity to achieve similar technological advancements.

Let battle connect

This article is discussing the various technologies used to enhance the battle winning strategies. These technologies are highly dependent on network integration, global information grid, network centric warfare, joint tactical radio system, airborne communication. All such techniques are used to share the information of battle field with the forces distributed over the war area and to unify all the necessary information for better execution of plan of action and future military strategy development. (4 pages)

Applying a Warfighter-Centric System Design Process to a Department of Defense Acquisition Program

This case study describes a user-centered system design process that was undertaken by a team of multidisciplinary engineers supporting the Joint Tactical Radio System Handheld, Manpack and Small Form Fit Program. Motivated by the need to manage the risk associated with designing a compact, software-programmable radio to meet the diverse needs of the joint forces, the team applied cognitive engineering methods at key points during the system development and demonstration phase of the acquisition process. To make sound, data-driven design decisions, the team conducted four research efforts with warfighters to understand their tactical communication needs and the impact that proposed designs would have on mission and individual performance. Key insights and lessons learned from the application of cognitive engineering methods during the process and their impact on system design are discussed.

Incorporating Reverse Engineering and Competitive Analysis Techniques into the System Design Process: A JTRS HMS Case Study

This case study highlights activities performed during a system design effort undertaken by the Joint Tactical Radio System Handheld, Manpack and Small Form Fit Program. A modified waterfall model comprised of three cyclic, yet overlapping phases (observation, visualization, and evaluation) provided structure for the iterative, Warfighter-centric system design process. Through analyses of existing commercial and military mobile handheld devices, the design team identified best practices that were worthy of emulation, practices that should be avoided, and practices that warranted further research. Design intelligence gleaned through the application of reverse engineering and competitive analysis techniques was used to guide interview question development and discussion during subject matter expert interviews, to narrow the scope of design options for test and evaluation, and to provide design direction. Insights gained from applying these techniques to system design and evaluation and the impact that their use had on the system's design are discussed.

GaN-on-Si HEMTs: From Device Technology to Product Insertion

ABSTRACTIn the last decade, GaN-on-Si has progressed from fundamental crystal growth studies to product realization and reliability demonstration. GaN-on-Si HEMTs addressing cellular, WiMAX, and broadband RF applications are now commercially available and offer GaN performance attributes in a cost-competitive platform. This presentation will briefly describe the underlying GaN-on-Si material, process, and packaging technology, then focus primarily on performance of these products in both commercial and military applications.All Nitronex NRF1 GaN-on-Si products are grown by MOCVD on 100 mm float-zone Si (111) substrates. A proprietary, strain-compensating (Al,Ga)N transition layer and an amorphous SixAl1-xNy nucleation layer are employed to accommodate lattice and thermal expansion mismatch between the substrate and the epilayers. The wafer fabrication process employs Ti/Al-based ohmic contacts, ion implant device isolation, 0.5 um dielectrically-defined gates, gold airbridge interconnects, and through-wafer source vias. Typical inline DC parametrics include 2DEG sheet resistance of 490 ohms/sq., on-resistance of 3 ohm-mm, peak drain current density of 830 mA/mm, and breakdown voltage of >100V. Packaging solutions include traditional LDMOS-style air cavity outlines with thermally-enhanced flange materials and low-cost plastic SOIC.A family of devices addressing emerging OFDM-based applications such as WiMAX has been developed. WiMAX amplifiers require several watts of linear output power with frequency band allocations ranging from 2.3 to 5.8 GHz and instantaneous bandwidth up to ∼15%. Translated to the transistor level, this implies simultaneous high frequency and high voltage capability – attributes well-suited to the inherent advantages of GaN-based devices. The flagship product in this family is NPT25100, delivering 125W of peak envelope power at 2.5 GHz. Under 2.5 GHz single-carrier OFDM modulation and 10 MHz channel bandwidth, this device produces 10W linear power at 2.0% EVM with 16.5dB associated gain and 26% drain efficiency. The excellent bandwidth of NRF1 devices enables the same device to operate at cellular frequencies from 2.11 - 2.17 GHz, producing >20W average power at an adjacent channel power ratio of -35 dBc.Primary military insertion opportunities include communications (e.g., JTRS - Joint Tactical Radio System) and electronic warfare (e.g., jammers). For EW applications, broadband operation reduces system-level component count and decreases weight / footprint. A family of 48V GaN-on-Si broadband HEMTs has been developed to deliver power levels from 40W - 180W in a compact package. In the highest power case, packaged “power density” (defined as peak output power divided by package volume) reaches ∼650 W/cm3. These power levels – in an outline suitable for highly portable systems – enable improved communications transmit distance and extend the umbrella size of electronic protection units.

Low Cost, Broadband Tunable Ferroelectric Filters for JTRS Cluster 5 Applications

Tunable ferroelectric ceramic capacitors have shown great promise in reducing the size, weight, and power (SWAP) of traditional varactor-based devices. Ferroelectric devices fabricated from Barium Strontium Titanate (BST) have been demonstrated in the laboratory and are just now becoming available for commercial narrowband applications. This paper presents some of the tradeoffs in designing a small form factor (SFF), easily manufacturable, broadband tunable filter utilizing high volume, low-cost BST devices. Development status for filters that cover the 225 MHz to 2.7 GHz frequency range with superior narrowband performance, low in-band insertion loss, and high out-of-band rejection that is directly applicable to the stringent requirements of Joint Tactical Radio System (JTRS) Cluster 5 Software Defined Radio (SDR) is also presented. These Manufacturing Readiness Level (MRL) 4 filters currently provide a 50% reduction in size over traditional approaches, and future short-term plans promise further reductions in unit production cost (UPC) and SWAP.

Soldier-Level Communications Environment (SLICE)/Soldier Radio Waveform (SEW)

Future Combat Systems (FCS) and Future Force Warrior (FFW) will rely on unattended, tactical sensors to detect and identify enemy targets to avoid enemy fires and enable precise networked fire to survive on the future battlefield with less armor protection. Successful implementation of these sensor fields requires a communications network infrastructure to disseminate sensor data and provide relevant and accurate situational awareness information to the tactical common operating picture. Networked Sensors for the Future Force (NSFF) Advanced Technology Demonstration (ATD) Communications is realizing this capability with advanced communications technologies developed under the Soldier Level Integrated Communications Environment (SLICE) Soldier Radio Waveform (SRW) project. These technologies include robust, self-organizing/healing networking protocols, energy management techniques, and secure, jam resistant radio equipment for a significantly enhanced communications capability that will transition to the Joint Tactical Radio System (JTRS). CERDEC laboratory and field demonstrations in 2004 will be reviewed to show early SRW development in preparation for the NSFF ATD as well as development of affordable systems for disposable sensor applications.

Network Centric Operations Impact on Avionics

In network centric operations, avionics on an aircraft will be both a source and destination of information. The U.S. Department of Defense (DoD) has mandated capabilities required for transforming to network centric operations. These capabilities are called out in the Joint Technical Architecture (JTA) Version 6.0 (Ref. 2). The Weapon Systems Domain, Aviation Subdomain, identifies preferred interoperability standards for communications, data links, navigation/landing aids, and identification aids. Communications, navigation, and surveillance (CNS) avionics systems and functions impacted by the JTA include nearly all avionics hardware, software, and the human system interface. Existing avionics architectures may require major changes for integration in network centric operations. A key question is whether these changes are affordable. The controller pilot data link communication (CPDLC) retrofit into existing commercial aircraft is expensive and many airlines are in bankruptcy or have a weak financial report. Most existing military aircraft have wiring installed during production, with few upgrades since the aircraft went into service. Aircraft still in the design phase will utilize a network centric architecture that will be upgradeable as technology advances provide new “plug and play” processors, displays, and sensors and the cost of new technology such as CPDLC will be built into the aircraft cost. Architecture. Network centric operations require integrated information from many avionics systems that were originally “stand alone” and implemented a function such as navigation, or had an output to the automatic flight control system. Many current avionics systems, both military and civilian, employ a federated architecture. The federated architectures are not highly integrated since they descend from stand-alone systems employed in analog avionics and first generation digital avionics. Current aircraft architectures and avionics compatibility with the capabilities required present interesting data flow challenges. Two key requirements that an architecture must provide are high bandwidth and low data latency. Technologies. Keys to implementation of net centric capabilities are software programmable radios, Gigabit Ethernet, and “smart” displays. The Joint Tactical Radio System (JTRS) software programmable radio plans to provide up to eight channels which must connect with a multiband antenna. The Gigabit Ethernet can be fiber or