Life cycle analysis of a radar system

The objective of this report was to employ the "systems" methodology for solving a complex problem, in particular, to illustrate the approach used to design a replacement for an aging airborne radar system. The AWG-9 radar set had served the Navy's F-14 admirably for more than twenty years, but there are physical limits to the quantity of data and processing speed that the radar set's analog technology can ever hope to execute, and these slower rates are unacceptable by today's standards.

Once the problem was clearly defined, a feasibility study was performed to see what viable solutions might be available. Although an upgraded version of the AWG-9 would be the least expensive, it would only marginally satisfy the data processing requirements, and certainly would not be capable of any future expansion for some of the more sophisticated missile systems already envisioned. A completely new radar system, by far the most costly avenue, could not be developed and manufactured in a timely manner. Consequently, cost was not the critical factor in either of the first two alternatives since the first alternative could not produce the desired radar set, and the second alternative could not deliver the desired radar set when it was needed. The third option was to digitalize the signal processing components of the AWG-9 radar set, while retaining those assets that generate and control the radar’s power. This last alternative was selected as the recommended solution, and the proposed radar set was renamed the AN/APG-71 radar system. Designing and building this radar system will solve the problem stated, that is, the AN/APG-71 will maintain the power and range of the older system, and it will increase the signal processing throughput more than six (6) times. Also note that the digitalized system will require fewer components, for better reliability and maintainability, and will have far greater capacity for expansion, i.e., making it readily adaptable for advanced electronic warfare algorithms, and provide for significant growth.

Following the systems methodology, functional diagrams of the operational flow of the radar set were developed, with the emphasis on what was to be done, not on how to do it. One example of the functional diagram's possibilities was given by expanding one block to the second operational level, and then continuing by exploring a potential malfunction to three levels of maintenance. The functional diagrams help to solidify the direction that the process should follow from the initial “definition of requirements" stage to final distribution of the product.

One point to be made is that the design process is not a simple, step-by-step procedure that can always be followed in a logically progressive manner. The life cycle analysis is an iterative process that depends on continuous feedback from all the key elements to arrive at an optimal system design. For instance, it might be observed during the procurement phase of the functional analysis that potential support equipment needed to test the components as designed was readily available from the Navy's current assets. With this information, the software engineer can write the self-test programs to accommodate the tester, rather than to “re-invent the wheel” by requesting new test gear.

The primary intent of this report was to show that the radar system in question was not the end result of an action-reaction evolutionary development. Rather, a methodical approach was applied to design a supportable state-of-the-art radar system in the most cost effective and efficient manner. As the department of defense continues to downsize through the remainder of this century, it will become increasingly important for the military to choose and fund its projects wisely. Systems engineering provides a vehicle for accomplishing these ends.