Digital Libraries Extend Longevity of Programmable Communication Tools

Trends point to a time when equipment could be automatically upgraded by accessing stored codes and waveform algorithms.

Internet accessible data libraries are looming as an important element in the continuing evolution of communications devices. By being able to hold a variety of waveform and signal processing algorithms on chips and in databases, these information storehouses give users enhanced flexibility in selecting specific material when and where they need it.

An example of this trend is a new surveillance receiver with an internal architecture defined primarily by software instead of hardware. The device incorporates an internal data library with a standard set of digital signal processing (DSP) algorithms loaded by the manufacturer. However, if users need additional or new algorithms, they can either download them from the company or develop their own proprietary code libraries.

The advent of digital technologies has led to the development of more compact, efficient and powerful communications devices capable of storing and receiving new and improved codes in the field. Programmable radios, for example, save users the cost and downtime associated with hardware-based upgrade cycles because software can simply be uploaded into them (SIGNAL, August 1999, page 45). Data libraries, built into these new tools and accessible via the Internet, present a potential reservoir of information to maintain this equipment at peak performance and greatly enhance and extend its operational life.

The electronic library is a central part of a family of related technologies under development at Watkins-Johnson Telecommunications Group, a Gaithersburg, Maryland-based telecommunications company specializing in surveillance and direction finding equipment. At its core, the firm’s Sunrise technology allows the creation, storage and downloading of new algorithms into its receivers, tuners, demodulators and direction finders. Algorithms are stored on software that can be used across platforms and hardware architectures, from manportable direction finders to ship-borne surveillance suites, with little or no modification.

Sunrise was invented to create a new generation of surveillance receivers with a high degree of integration between receiver technologies and multipurpose, high-speed DSP platforms. The program’s goals were to produce a completely autonomous, high-quality, general-purpose signal-interception device and a digital receiver platform that allowed users to create and download their own DSP algorithms to meet specific mission requirements. According to Jeff Hughes, Watkins-Johnson’s account manager for the U.S. Navy, the company’s first product using this technology is the WJ-8629A receiver. It is capable of being dynamically reconfigured in the field to intercept, analyze, demodulate and decode most types of signals with DSP algorithms available from the company’s standard data libraries, a library contributed by third parties or from the user’s proprietary libraries.

However, the receiver is just the beginning for Sunrise, which is intended to span numerous hardware platforms. Key to this is the ability of the software to be ported across these architectures, Hughes says. Besides providing ease and speed of use for surveillance applications, it allows a device to reconfigure itself on the fly. For example, if an operator in the field is trying to track a signal, he or she could either get a specific algorithm from the waveform library built into his or her equipment or via the Internet by terrestrial or satellite links. Another option would be for users to develop their own solution using a utility kit that is provided with the equipment.

Because it is primarily concerned with cross-platform data portability, Sunrise does not define any specific hardware requirements or interfaces for the receiver. These specifications are left to the design needs of individual types of equipment, allowing for numerous configurations for easy adaptation to multiple applications and missions. Hughes sees this as one of the technology’s biggest values. Because it is software definable, the receiver is extremely flexible and capable of performing many functions in different configurations.

According to Hughes, Sunrise is aimed at two types of users: system operators and developers. The software allows developers access to demodulation, postprocessing of signals and programming affecting tuner functions. This in turn lets developers greatly enhance their receivers to monitor specific forms of communication. Once a signal is captured, it can be analyzed, demodulated, decrypted, decoded and demultiplexed within seconds. In effect, the tuner can be almost instantaneously retuned to follow a certain signal set. This process can be done without impinging on the system controller’s resources, he says. Likewise, system upgrades can be transmitted within hours through the Internet. This same capability also allows receivers to process data autonomously as a prequalifier, reducing the control system’s bandwidth and an operator’s workload, Hughes notes.

While Sunrise is aimed at adding value to the surveillance industry, the concept of the technology can be applied to the entire communications market, Hughes says. Specifically, it provides value through reduced equipment costs, increased security because customers can develop their own wave set libraries, protection from obsolescence through continuous software upgrades, and platform independence by being able to move from rack-mounted to manportable architectures.

Another advantage is that new waveforms can be disseminated via the Internet or floppy disk. The system controller will house the library present in the receiver and use an industry standard format to upload objects. The controller itself is a software-configurable computer residing in the device. Because the receiver is designed to be part of a rack of equipment, one of the controller’s jobs is to integrate it into a larger surveillance system. The Internet can also be used to issue commands to the surveillance suite so that it can upload data or reconfigure itself. To achieve maximum flexibility, the Sunrise operating system allows designers to create their own specialized demodulating and postprocessing capabilities for specific signal sets. “Instead of one big box, you can have an uploadable receiver,” Hughes points out.

The company also provides users with a developer’s kit, programmer’s guide and utilities to ease programming and troubleshooting. Utilities include a code wizard to help generate user algorithms, a debug utility, a tool to support custom design filters, and a download utility to load custom filters or application codes into the unit. The software is based on the C language and is cross-platform compatible with Windows or UNIX.

Hughes sees three ways that the demodulation algorithm library could be used by the surveillance industry. Users could simply rely on the standard suite of algorithms present in the equipment’s library, though he notes that the company can design for additional waveforms to meet specific customer needs. The second application would be by DSP designers themselves, who would use the technology as a development platform. They could buy the receiver and either select algorithms from a library or specific set, or they could generate their own specialized library. The third scenario involves end-users such as the government developing and disseminating its own specific and proprietary libraries.

Developmentally, there were hurdles in getting the entire process to work seamlessly between the hardware, software and modulation algorithms, Hughes observes. An additional hurdle is the marketplace. Because many of Watkins-Johnson’s customers are government agencies, there is a lag time between the introduction of a new technology and a customer’s ability to accommodate it within its own procurement cycles, he says.

The Sunrise-capable receiver that the firm is offering comes with a standard library set, Hughes states. The WJ-8629A features amplitude modulation, frequency modulation, single side band, continuous wave and frequency shift keying demodulators. He speculates that additions to the library will include algorithms for spectral display and direction finding. He adds that there will be more as the firm moves its existing library of DSP and demodulation algorithms onto the Sunrise platform. Third parties are also expressing interest in voice recognition and geolocation algorithms, he relates.

Hughes believes that Sunrise has a bright future. “This technology is going to show up in a lot of different forms such as small, lightweight systems and wideband topologies.”