PART 4
Balancing Innovation and Cost Symmetry Against Newer Threats
Since the dawn of radar, defense and national security leaders have had two choices: high-performance, high-cost electronically scanned array (ESA) radar or low-performance, low-cost angle of arrival (AoA) radar. The performance gap between the choices is substantial, with AoA radars generally being a poor fit for defense and national security applications. Given the existential drivers, the only true choice for these applications has been ESA radar. Because of the extensive capital investment required, high operational costs, and long development times, ESA radar advances are driven by defense requirements rather than market forces. Even today, after decades of development and effort, ESA radars are defense-restricted products with a lead time measured in years and decades.
As long as the national security need was defined by detecting and tracking missiles and large aircraft from a small handful of adversarial nations, there was little incentive to change this development dynamic. With each party confronting similar costs for offensive and defensive postures, these conflicts achieved an equilibrium of risk and reward. With the rise of non-state actors employing guerrilla tactics through access to inexpensive yet lethal tools, change is rippling through these traditional security frameworks. Rather than well-known points of origin for traditional adversaries, todays’ non-state actors can appear at any location at any time. Instead of high altitude flights with relatively straight trajectories, today’s threats fly low, fast, and often without any detectable RF transmissions. Threat-detection symmetry is lost, leaving nation states unprepared for drone threats.
COTS ESA - Low Cost, Attritable, High Performance
If a non-state actor can launch a drone attack that costs less than $0.02M, the answer for detecting this type of threat cannot be a multi-million dollar system bristling with $1+M interceptors designed for yesterday’s adversary. If the adversary employs low-cost, disposable, effective weapons, then the security framework must become both more effective, attritable, and financially competitive. This shift in symmetry has prompted many defense and national security system operators to seek commercial-off-the-shelf (COTS) products to regain the balance between threat and threat detection.
While there are defense and national security applications that benefit from private industry development, the idea of using COTS products in defense and national security applications is largely novel. Hunting, for example, remains a popular pastime that supports development of weapons, scopes, ammunition, and clothing. For many applications though, the opportunity for dual use is limited both by market needs and defense export restrictions, especially International Traffic in Arms Regulations (ITAR). Still, the idea of COTS in defense remains an attractive option.
For sensors that detect, track, classify, identify, and target intruders, the challenge is even greater. Outside of defense and national security, there is little dual use for traditional ESA radars or the radio frequency (RF) tools essential to combating drone threats. It was not until recently that a true breakthrough in radar technology occurred with the development of a low-cost COTS product with ESA performance.
Let’s examine how to evaluate using new COTS radars for contemporary defense and national security threats.
Evaluating Radar for Contemporary Threats
As the number of airborne objects continues to increase, the potential threats caused by drones are expanding beyond what national security organizations are responsible for monitoring. As covered in Part 1, traditional ESA radar systems are not practical options for monitoring these newer threats - it’s not feasible to bring a high-cell-count ESA to a national or a mass gathering, for example. The selected threat detection system needs to track all objects of interest while also understanding where blue forces are located, or which are legitimate commercial aircraft, or who is flying near the National Mall. Selecting the sensors appropriate to so many needs is a paper unto itself. Here, we focus on evaluating radar within threat detection and response systems.
Detection Range
Every conversation seems to begin with a question of detection range, so let’s start there. While many might claim range is the most important consideration, it must now strive for symmetry with the drone threat, creating a price-performance filter to range. With the size and maneuverability threats posed by drones and especially in the context of identification and targeting, the level of precision data delivered by the radar creates another evaluation filter. Lastly, there is replacement of the radar, or its attritability - how replaceable is it and at what operational cost?
As a general rule of thumb, range is a result of power times aperture. The bigger the aperture and the more power available, the longer the range. But range is relative to the type of threat likely for a particular risk. Defense applications may consider all drone types a threat but only some small fraction will require the capabilities to detect and track Group 3 or larger drones. The idea of range, then, requires a specific drone or type of drone as the baseline. Identifying a type of drone, say a DJI Phantom 4, and requiring a certain range, say 3 kilometers, starts to sketch the evaluation criteria.
There is also the idea of range for which particular function and at what confidence interval. Some radar manufacturers will cite a detection range that is all too often well beyond actual capabilities, but that’s a story for a different day. In evaluation, the relevant aspect of a cited detection range is how often will that range be achieved; this is the confidence interval. If a radar’s description refers to ranges, always ask about the confidence interval. Anything less than 50% is a coin flip and generally means that only some fraction of that range will be achieved on a consistent basis. A range curve for drone types relative to your risk profile with the confidence interval stated should be available.
Function
Which leads us back to function. Function references resources used by the radar to acquire data pertinent to a threat detection system and actionable for system operators. Many radars will refer to “detection ranges” of certain distances. Detections are the least valuable data element produced by the radar. Only when signal processing and software intelligence determines the object should be TRACKED - classifying the object as a drone, devoting more radar resources to the intruder, providing faster position updates for slew-to-cue optical, and, where applicable, cueing kinetic mitigation systems - does the threat detection system benefit from radar in the solution. The evaluation should focus not on radar detections but radar Tracks and the value of that data to other sensors and to the system.
Drones also challenge radar performance by their miniscule size and maneuverability, especially relative to traditional adversaries, risks, and threat vectors. The response to this is highly precise data delivered at high speed from the primary sensor layer, radar. Accuracy and data speed are key metrics for performance evaluation. Without high degrees of accuracy, optical sensors cannot be trained to the intruder for “eyes on object”. Without high data rates, optical sensors cannot smoothly follow the intruder’s flight path. In radar terms, precision is the radar’s Angular Accuracy. Think of this the tightness of the box around the intruding drone - the tighter the box, the more accurate the optical track, and the faster data, the more fluid the optical performance.
Accuracy
Perhaps one of the biggest new filters to consider when evaluating COTS radar solutions is accuracy on target. While generally not discussed when considering ESAs, accuracy on target is critical as data without accuracy is just anxiety, causing worry over the possibility of something being present without enough data to know if the object is actually a threat. To guarantee accuracy on target, the radar system must first be able to appropriately classify the object, suppressing false positives and negatives.
Then, the radar must be capable of maintaining a lock on the object so that other sensors and systems can use the radar data to train their focus on the object as well. This will then let the system trigger highly efficient targeting, using the least amount of munitions possible to defeat the intruder if required. The radar data serves as the fundamental baseline data that makes everything else in this chain work. With this type of high-fidelity data generated by a COTS radar solution, performance will greatly increase while costs remain low.
Flexibility / Malleability
It is also important to evaluate which features can be tweaked in newer software-defined radar systems, leading to even greater accuracy. With software-defined radar systems, users can adjust waveform, beam schedules, and other configurations of the system to adapt to operator, location, and mission requirements. With a range mask for example, a user can program the radar to only communicate data for objects detected within a certain range, such as < 3 km for a certain volume of airspace. The radar will continue to detect objects at greater distance but will not clutter the user interface, allowing operators to focus on the pertinent data.
Capital / Cost
It’s also important to consider both upfront capital and lifecycle costs. This involves looking at both maintenance and operational costs, including if downtime is required to maintain the system and how this would be handled in mission-critical scenarios. A unique cost-related characteristic of COTS equipment is that COTS equipment is attritable, meaning if it is destroyed for any reason, it can typically be replaced quickly and easily without significant monetary or time investments.
Let’s now look at how to apply this evaluation criteria to three key areas that need radar to monitor these fast-evolving new threats – defense, government, and critical infrastructure.
Radar Considerations for New Threats to Defense Applications
Today’s rapidly evolving drone threats are now requiring counter-uncrewed aircraft systems (C-UAS) technology be incorporated across a variety of defense applications such as base security, portable ISR, and remote weapons stations (RWS). While range is still a driver in monitoring for drone threats, data fidelity makes a huge difference in performance and outcomes. Therefore, radar that provides superior situational awareness of all movement – people, vehicles, vessels, and drones – is a crucial component for a layered threat detection system for defense applications. This is because the command and control (C2) software needs to receive highly accurate data from all aspects of the system to present mission operators information pertinent to the decision and action process steps. Plus, maintaining optical lock on fast, agile intruders is necessary for all processes, making accuracy on target a key consideration for new or supplemental radar solutions.
Additionally, as the number of new threats that are not multi-million-dollar jets and missiles continues to increase, the way defense organizations evaluate threat detection costs also needs to shift. For detecting newer drone threats, the large, multi-million-dollar ESAs defense organizations are accustomed to are not a great fit. Instead, to create capital symmetry between threat technology and threat detection systems for defense applications, it is much more practical to consider a high-performance, low-cost, low-SWap, attritable COTS radar.
Radar Considerations for Government and High-Risk Civilian Applications
Drones are also a growing problem for federal and state agencies managing public safety. While many of these agencies are used to using ground surveillance equipment, radar can offer a tactical advantage by providing public safety teams with fast, high-fidelity airspace situational awareness data. Instead of requiring long-range radar systems, these applications need radar systems that provide high accuracy even when buildings and other structures in these environments create chaotic and confusing landscapes. Instead, newer short-range radar systems thrive at providing high-accuracy data in these more crowded environments. Additionally, capital symmetry, as mentioned in the prior section, is also important to how these organizations evaluate costs.
Radar Considerations for New Critical Infrastructure Protection Requirements
For critical infrastructure sites such as airports, ports, electric generation and transmission plants, water and wastewater treatment facilities, and chemical, oil and gas, and nuclear sites, range becomes a much softer requirement while accuracy is pivotal as the drone problem scales. Many of these facilities have traditionally relied on ground security systems as air threats were historically not considered a threat; yet this is quickly changing. Since these organizations already have effective ground monitoring tools in place, when bringing in new tools such as radar, integration with the information provided by the existing ground monitoring systems is critical. Additionally, for these systems to work well together, precision radar must be the data-driver for a variety of functions such as accurate and timely control, slewing optics, sounding alarms, reducing false alarm rates, and making better decisions. Ultra-low SWaP-C radar is a high-value addition to critical infrastructure protection solutions at high-risk sites.
While this post touched on some of the different key application areas for COTS radar, part 5 will expand on the benefits of using COTS radar solutions to achieve threat symmetry and highly accurate threat detection for defense applications. For more about enhancing situational awareness using radar for government applications, jump to part 6.
