Electronic warfare (EW), such as communications jamming, spoofing signals, and cyber attacks, have become increasingly critical in modern defense strategies. It’s not only enemies that can negatively impact the successful operation of EW systems, however.
Weak signals from amplifiers and signal generators may prevent an EW system from operating effectively. Kinks in RF cables or damaged connectors will cause signal degradation, as can the harsh environments where EW operates. All these factors make maintaining high-level signal transmissions a top priority for mission success.
For these reasons, measuring these elements' performance is essential for EW systems to perform as required. Selecting the proper test solutions is necessary to ensure those measurements are accurate and reliable.
EW in Aerial Warfare
EW systems play a critical role in modern aerial warfare. They enhance aircraft survivability and mission effectiveness in contested environments. Examples of EW include:
- Jamming systems for offensive missions
- Electronic countermeasures to thwart radar-guided missiles and similar threats
- Advanced systems with multi-spectral self-protection, situation awareness, and electronic attack capabilities
EW Amplifiers and Signal Generators
Amplifier transmission systems are crucial in EW systems because they boost signal strength to enhance communication or disrupt enemy communications. Furthermore, effective EW amplifier transmission systems operate across different frequencies, showcasing their adaptability to changing battlefield conditions and ability to process signals to achieve the necessary jamming effects quickly. They also optimize power usage to extend operational duration and seamlessly integrate with different aircraft systems and configurations, instilling confidence in their versatility.
Signal generators help EW systems operate effectively in complex electromagnetic interference (EMI) environments. Testing EW signal generators is necessary to ensure they generate the proper signals to jam enemy communications and radar systems, effectively neutralizing threats. But more than that, they also play a crucial role in creating tactical advantages, an essential aspect of modern warfare. EW signal generators also aid in signal intelligence (SIGINT), further enhancing their strategic importance.
Amplifiers and signal generators are susceptible to the same environmental challenges as all EW system components. EMI, shock, vibration, and extreme temperatures can adversely affect their performance. Spectrum analysis tools conduct measurements to verify amplifiers, including output power, gain, signal quality, and impedance. Test solutions must accurately measure frequency range, amplitude, modulation types, and signal accuracy to monitor signal generator performance.
Proper integration of amplifiers and signal generators within an EW system is also necessary to achieve specified performance. Their maintenance is part of a complete system approach, including testing cable and antenna systems.
Military aircraft use RF cables specialized to handle high-frequency signals and reduce signal loss and interference. Specialized shielding is typically used on these cables to protect against EMI and maintain signal integrity. Ruggedized connectors and interfaces also withstand high vibration and harsh environmental conditions during missions.
Testing the EW System
Insertion and return loss are critical measurements to ensure EW systems perform as designed. These measurements are conducted with a cable and antenna analyzer. Newer instruments, such as the Site Master™ MS2089A from Anritsu (figure 1), integrate advanced Real-Time Spectrum Analysis (RTSA) to quickly identify and address EMI and signal integrity to maintain the security of EW systems. Cable and antenna analysis must also be conducted. Additionally, the MS2089A has IQ capture and streaming, so intricate signal data can be gathered in real time, allowing for comprehensive analysis and troubleshooting.
Figure 1: Advanced test solutions such as the Site Master MS2089A integrate cable and antenna analysis with spectrum analysis for comprehensive EW system testing.
Troubleshooting EW Systems
While return loss can verify the health of an EW system, distance-to-fault (DTF) is the best technique for troubleshooting systems and locating problems. The most effective DTF measurement uses a fast Fourier transform (FFT) to convert frequency data to the time domain and display signal reflections with respect to distance. A standard trace math feature found in some analyzers can monitor small relative frequency changes over time.
Some analyzers have a split-screen display (Figure 2) that simultaneously shows return loss and DTF to expedite analysis and locate issues in the EW system. This allows the highest reflections in an RF cable to be pinpointed while displaying overall return loss. Identifying the issue through this feature speeds up the resolution of the fault.
Importance of Fast, Accurate Tests
EW systems, like all military systems, must perform in mission-critical environments. When a return loss measurement identifies a cable and antenna path that is out of specification, the cause of the reflection must be found and repaired ASAP. A basic DTF measurement quickly locates the distance of the individual reflections from the input test port. For long cable runs, the more information gathered on the reflection cause, the quicker and easier the repair becomes.
That is why TDR measurements are so valuable. They display impedance against distance, with a normal 50-ohm line running across the center of the display.
Transmission measurements must be conducted on fixed transmission lines, including coaxial cables within aircraft wings and fuselage. A USB sensor can be integrated into the Site Master to make transmission measurements. Some Anritsu models allow the measurement to be made simultaneously with reflection (return loss or VSWR) or DTF to facilitate system verification.
Compact Design, Comprehensive Testing
Much like the EW systems they test, the instruments must be durable to record consistent results. Anritsu analyzers meet MIL-PRF-28800F Section 4.5.6.3 Explosive Atmosphere requirements for safe usage on flight decks and in areas with high volatility. Additionally, the solutions must be compact so they can be carried and used in the tight confines of the aircraft.
You can access this application note to learn more about test solutions for EW systems.
