Surveillance Drone (Why thermal matters)

The Surveillance Drone


Surveillance – early detection with thermal sensor

What makes an ideal surveillance drone? To appreciate the answer to this question it is important to first understand what Surveillance is.

Security and Surveillance speak to some of the most basic of human needs: safety– how the environment gears up to ensure security, and with that, the safety of individuals.

Early detection of threats or intrusion. Is key, and this is where the ability to ‘see’, with thermal cameras, what the naked eye cannot, provides the competitive advantage to anticipate and neutralize danger before harm can be done.

Security and Surveillance Applications (UAVs)


– Perimeter Surveillance & Monitoring

– Emergency Communication Networks

– Border Surveillance

– Coastal Surveillance

– Anti-Piracy Operations

– Crowd Control

– Anti-Terror Operations

– Criminal Investigations

– Traffic Monitoring


Security and Surveillance Concepts

ISR terms



Surveillance is part of a practice commonly referred to as Intelligence, Surveillance and Reconnaissance (ISR). ISR is the coordinated and integrated acquisition, processing and provision of timely, accurate, coherent and assured information and intelligence to support operational decision in a security context.



ISR is a variation of Intelligence, Surveillance, Target Acquisition and Reconnaissance (ISTAR). Both of these practices aid in Situational Awareness (SA) and in operational responses to security incidents. They rely on a collection of electronic sensors to be informed which includes alerting, object identification and tracking, situational awareness, and characterization of the operational environment.


Wikipedia defines ISR as “a capability for gathering data and information on an object or in an area of interest (AOI) on a persistent, event-driven, or scheduled basis using imagery, signals, and other collection methods”. Generally, this type of surveillance requires an element of stealth or low-noise footprint/or see in the dark, to avoid detection as well.


Persistence is further described as “access that provides predictable coverage of an area of interest (AOI). Most space-based intelligence collection capabilities consist of multiple satellites operating in concert, or supplemented by other sensors, when continuous surveillance of an area is desired. Persistent sensors must provide sufficient surveillance revisit timelines to support a security response at any given time”.



In military circles, identification is used along with detection, and recognition as part of the DRI criteria established by John Johnson. These DRI terms are also used in surveillance applications.

  • Detection: We sometimes detect or observe something moving in the distance.  We require different resolution for each of these applications, so we have to define what we mean before calculating the resolution
  • Orientation: This additional criterion focuses on the aspect of an object or its orientation
  • Recognition: Sometimes we use this term when we want to recognize the object as a man or a woman.  In this case we are interested in how people or vehicles are moving, rather than the details (identity) of the objects.
  • Identification: In surveillance applications we usually mean identifying who a person is, or the license plate number, or maybe the numbers on the tail of a plane.

To be able to meet these DRI criteria, the thermal and optical cameras used in surveillance will need to be selected with these in mind. Thermal camera resolution is measured differently compared with optical IP camera resolution: thermal cameras are measured using line pairs, and optical cameras use pixels/ft. (or pixels/m). The level of resolution of the cameras will determine which of the DRI functions can be effectively executed. Below is a comparison of the different resolution requirements for each level of criteria requirements:

DRI metrics


Distance vs Resolution

Obviously, there will be a trade-off between stealth (distance) and level of detail (proximity) captured, ie. a stronger sensor will allow more stealth (distance) from the Point of Interest (POI).


Drone distance from target

ISTAR is the process of integrating the intelligence process with surveillance, target acquisition and reconnaissance tasks in developing intelligence to improve an operational supervisor’s situational awareness and consequently his/her decision-making.


So, what is all this decision-making during surveillance activities all about?



Decision Making during a security operation situation is based on SA (Situational Awareness). According to a SA model developed by Endsley, there are 3 progressive levels of awareness which are enabled by the levels of DRI data that are accumulated:

Levels of Situational Awareness

During security and surveillance operations site supervisors can be more proactive with better levels of understanding gleaned from better insight.


DRI and SA

Terrestrial, air and space platforms have critical ISR roles in supporting operations in general. By amassing ISR assets, allowing a period of immersion, developing layering and cross-cueing of sensors, an improved clarity and depth of knowledge can be established. ISR encompasses multiple activities related to the planning and operation of systems, that collect, process, and disseminate data in support of current and future security operations.




sUAS (Small Unmanned Aircraft Systems), or mini-drones, can be used individually for ISR, or because of its ability to get closer to targetsas a key supplement ISR systems including satellites, manned aircraft, unmanned aircraft systems, other ground-, air-, sea-, or space-based equipment, as well as human intelligence teams. The intelligence data provided by these ISR systems can take many forms, including optical, radar, or infrared images or electronic signals.


Surveillance Drone Criteria

So, what selection criteria for a surveillance drone can one extract from the operational conditions for surveillance described above?


Low noise/visual foot print.

  1. Obviously many ISR operations require a discreet presence and to ability function and monitor without detection.
  2. For this, having a rotor design that minimizes noise as well as strong sensor payloads that enable sufficient distance from objects of interest is vital.
  3. Combining a low noise footprint with a minimal visual footprint (thermal detection at nighttime) is a lethal combination.

RECOMMENDATION: Select a UAV (Multi-rotor) which uses large rotor blades that reduce the noise footprint to become indiscernible at, preferably less than, 200 meters. At this distance the drone is hardly visually hardly discernable anyway. Include a strong thermal sensor.



  1. Surveillance operations require a level of persistence and for that longer flight times are a priority.

RECOMMENDATION:In the multi-rotor market most drones have flight times of less than 30 minutes. Much of this is also consumed by the RTL (Return to Landing) function. To achieve the best out of the sensor payload it is ideal to keep it airborne as long as possible for every flight mission. Flight times should ideally exceed 50 minutes.



  1. Satellites and Hale or Male (High or Medium altitude long range) drones lend themselves well to low resolution, scheduled surveillance missions. When an event driven response, or the ability to hover around a point (or an area) of interest (POI) is required, the small UAV provides a perfect supplement to other options, especially when a closer level of scrutiny and higher resolution is required.

RECOMMENDATION:Long Range Multi-rotor, especially for event driven operations where a POI requires specific scrutiny, but where persistent airborne presence is also required. A high-endurance Multi-copter can also bring more airborne functionality to bear at a POI.


High Payload Capacity

  1. In order to keep sufficient distance for discreet surveillance, a large enough payload capacity that can carry sufficiently strong sensors, is required.

RECOMMENDATION:Dual sensor payloads and optical and thermal sensors that will meet your DRI (see above) requirements. Consider the anticipated distance from target for avoid detection as per 1) above.


High Capacity Connectivity

  1. Broad and secure bandwidth over an extended range, provides real-time feedback during operational conditions.

RECOMMENDATION:If real-time observation and reaction are required objectives in surveillance operations, high-end datalink capabilities are essential.


Intelligent Sensing.

  1. UAV based object-detection and tracking: this capability, especially when paired up with AI, creates a superior ISR solution that is extremely effective in the field.

RECOMMENDATION: A UAV platform that integrates object-detection and tracking as a key element in surveillance operations.


The following table highlights the difference between consumer class drones and a Beyond Visual Line of Sight (BVLOS) drones:

UAV Comparison Regular UAV (Consumer) BVLOS UAV
Typical flight-time 15 – 25min 45 – 90min
Typical payload 200g (simple) Up to 2kgs (complex, powerful)

Telemetry / FPV

HD download of up to 24Mb
Range 2 – 5km 12 – 35km

The value of every extra minute of flight time is graphically illustrated below. When a drone is used to respond to a security incident which could be in any direction from the point of take-off, simplydoubling flight timeadds exponentially more strike arearange each time

target areas for different flight times


Potential meters2covered for 15km, 30km and 60km flight ranges (assuming 60km/h flight speed):

increasing strike range



Criteria extractedfrom typical STAR operations indicate a need for persistent and discreet aerial presence, high payload and connectivity bandwidthalong with the ability to adjust flight paths mid-mission and detect and pursue a target.

Long range multi-coptersare an ideal match, either with an extended air, space and terrestrial surveillance infrastructure, or as a standalone solution.


The Vanguard

For Surveillance and Security the Airborne Drones’ Vanguard provides for:

  • Persistent aerial presence with long flight times
  • Improve situational awareness with powerful sensor  payloads
  • Early intrusion detection with thermal sensors and low noise footprint
  • Night time operations with thermal sensors
  • Tactical flexibility with both scheduled and event-driven missions