by Marcelo Ramos, VP of Engineering, RF Sources/Receivers
Radar simulation systems, comprising RF sources and/or receivers, depending on the application, must perform to an exacting minimum standard if they are to definitively prove the field-worthiness of electronic warfare (EW) systems. For example, transmitter frequency set-on time must be as fast as possible and frequency needs to be as stable as possible over the entire operational and temperature range, as well as across a wide bandwidth. A common demand is a set-on time of 1 microsecond (μs) and the frequency held within 1 millisecond (ms).
Similarly, receivers must measure frequency accurately, as fast as possible, while maintaining a stable frequency over the entire operational and temperature range, as well as across a wide bandwidth. Normally, one must (at least) measure within 100 nanoseconds (ns) with an accuracy of one megahertz (MHz). Of these two test elements, greater challenges are encountered with the transmitter due to testers’ desire for an ever-faster signaling time (even faster than 1 μs).
Test systems can be built in-house by companies in need, but often know-how or resources are lacking. Organizations seeking to achieve these efficiencies in-house often err in budget, timeframe, resources, expertise, or a combination of those factors. Some companies overestimate their in-house capabilities, while others underestimate the complexity of designing and building the product or miscalculate the cost of doing it in-house. Often, the extent of these companies’ problems only becomes apparent late in the engineering process. Designers discover that creating a solution with the proper capabilities — meeting specific size, weight, and power (SWaP) requirements, within their budget and timeline — is not possible.
For example, SWaP needs generally are rigid in these equipment specifications. Smaller platforms (e.g., a drone) are likely to have tight size specifications. Prime power, though, often represents the most challenging specification to fulfill. Customers always want a more efficient system, drawing less power. Generally, customers have a baseline number in mind.
Several options exist for creating and receiving a signal, and testers must determine optimal equipment relevant to their systems.
Both frequency-locked oscillators (FLOs) and voltage-controlled oscillators (VCOs) can cover a range of frequencies. FLOs can be designed to accommodate various modulations, such as AM, FM, and PM — representing one of their key desirable attributes.
As an alternative, synthesizers can achieve significantly faster signaling times than oscillator-based test systems, but synthesizer technology is limited by several disadvantages. Primarily, synthesizers cannot be easily modulated in FM, and bandwidth suffers. Further, synthesizers commonly suffer spurious signals (spurs) and, most critically, synthesizers cost almost 10 times more than oscillator-based test systems.
Finally, developers must consider system control elements. Antenna control units (ACUs) are able to play prerecorded antenna patterns and can compensate for platform movements. For example, they can compensate for tilt and roll when mounted on an aircraft. Instantaneous frequency measurement (IFM) units measure frequency and power level, as well as detect pulse on pulse signals.
Digital control units (DCUs), meanwhile, are capable of controlling a single FLO and other RF equipment. Integrated DCUs (IDCUs) combine the control and interface power of a DCU with the RF capabilities of a FLO and the capabilities of an ACU for a complete integrated system controller in a single unit.
Thus, while it absolutely is possible to create a radar simulation system in-house, it’s also pragmatic to acknowledge that your company likely can buy a superior system, cheaper, somewhere else.
Curious about how dB Control can help? Read the full article from Marcelo Ramos: https://www.rfglobalnet.com/doc/overcoming-radar-simulation-system-challenges-0001
