5 benefits of software defined radios (SDRs) over legacy RF systems

RF receivers and hardware used to be bulky: they filled racks inside remote shelters strung along borders or were stuffed into large green military trucks. The racks produced large amounts of heat, so cooling units had to be attached to the shelter or truck. Tuning was manually intensive, and the system was large and clumsy on the battlefield, limiting where and how it was employed by EW commanders. 

While many militaries are now employing modern low-SWaP (size, weight, and power) software-defined radio (SDR) RF receivers, some legacy systems persist. The modern battlefield demands sensors that enable dispersed mission command operations. SDRs are crucial for all types of military operations as they impact every military capability and help secure tactical advantages. 

What is an SDR communication system? 

An SDR system is a radio communication system that uses software to modulate, demodulate, and decode radio frequency (RF) signals. It is a substitute for traditional hardware components specifically built and designed for these tasks. A typical SDR setup comprises an RF front-end connected to a computer that performs analog to digital conversions and the inverse to receive or send a signal. Because of their modular design, scalability, and programmable advantages, SDRs are fast becoming the principal RF transceivers for many military RF applications. 

What are the disadvantages of analog RF systems?

Prior to SDRs, all RF transmissions were transported as electronic pulses with varying magnitudes that continuously changed. Analog systems are much faster in comparison to their digital counterparts. However, because RF signals are delivered in their original forms, the RF transmissions are impacted by radio frequency interference. In turn, this compromises data fidelity—affecting accurate spectrum monitoring and SIGINT gathering.

As military systems are increasingly digitized, the associated RF components have become smaller but more innovative in their capabilities. Advanced SDR systems are needed to exploit leading-edge military technologies—not just for automation and data fidelity purposes but to transform RF data into actionable intelligence in real-time.

Advanced SDRs allow users to monitor the spectrum environment, visualize its usage for strategic decision-making, and geolocate RFI signals of interest that jam or interfere with military PACE plans. For EW and SIGINT operators, SDRs enable more sensors to be placed across the theater, thus increasing RF coverage.  

What are the benefits of SDRs over legacy RF systems?

1. Multi-user, multi-mission

As they are scalable and configurable, SDR systems empower military and defense units to exploit the RF spectrum by making it available to more non-technical users. Advanced SDR systems are both compact and standalone, making them easily deployable for a range of applications: from tactical radios carried by soldiers on the ground to air traffic controllers and GPS-guided weapon controllers to SATCOM systems and SIGINT gathering.

2. Less maintenance

Analogue RF systems require a large amount of unique and bulky hardware as different RF processing applications are device-specific. These individual machines comprise many moving components that are susceptible to failure. They also need to be housed in large, power-hungry command centers.

As well as eliminating hardware failure challenges, SDRs will automatically detect and flag any RF abnormalities. SDRs offer a maximum return on investment, as there is no need to replace a product every time a new version is launched. Firmware can be installed and updated remotely and operated by a single officer, allowing troops on the ground to deal with more pressing matters. Multiple SDR systems can be managed centrally via a single console, permitting legacy comms rooms to be repurposed for other uses.

3. Seamless integration with third-party technologies

Agile SDR systems with open application programming interfaces (APIs) can be seamlessly interfaced with wider EW systems, including:

• EWMPT
• Decoding and demodulation software
• Air defense systems (when used as a TDoA sensor)
• Counter-unmanned aircraft systems (C-UAS)

4. 24/7 remote operability

SDR systems can be configured to carry out a range of activities, including proactive system monitoring, streamlining operations, and around-the-clock monitoring of predefined frequency ranges (or the entire RF spectrum). Moreover, SDR systems can be installed as standalone systems or as a fixed network of strategically deployed sensors—if large or remote areas need permanent monitoring.

Lone operators no longer need to look after an extensive SIGINT system in the field; the operator can now remotely access multiple SDRs.

5. Simple technology updates 

SDRs can be easier to upgrade in the field through remote firmware installations, meaning operational force sensors can keep pace with current industry trends. In comparison, legacy RF systems must be removed from the field and sent back to a depot where components are removed and updated.

Rather than being periodically deactivated for hardware updates, a single SDR can remain operational for over ten years with remote software updates.

Conclusion

Combat zones are highly volatile, constantly changing environments. And command and control offices must make critical decisions in real-time—impossible without agile SDR systems that enable theater-wide sensor coverage, mitigate personnel shortages, and support mission command operations.