Drones Free Dome (DFD) - Zickel...

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Drones Free Dome (DFD)

1. Scope

This document deals with anticipated operational needs of detection and interception of

low signature – low altitude UAVs (Unmanned Arial Vehicle), and describes the basics for

a system that protects selected assets and/or events.

2. Introduction

The use of low cost drones, such as quadcopters and hobby RC drones, for recreational,

commercial and security purposes is expected to ever grow in the decade ahead. The

result of this process will be an abundance of low cost drones accessible for all to

purchase or build freely.

Past experience shows that every new technology inherently attracts outlaws and terrorist

to adapt it for their activities. Hence, a simple threat analysis, taking into account this

obvious market trend together with past experience, predicts that the proliferation of

drones inevitably leads to criminal use of the technology. As a response to the threat there

will be regulations, laws and enforcement.

The proposed Drone Free Dome System provides protection against those who don’t

obey the laws and regulations.

2.1. The Typical Threat

As a first step in the process of mitigating the drones’ threat, a survey of the existing and

available drones, the possible detection methods to detect them and possible methods to

intercept them was conducted.

A typical off-the-shelf drone uses efficient electric motors with efficient batteries, powerful

processor, MEMS (Inertial, Magnetic & Baro) & GNSS for sensing, modern data links,

cameras, and low weight composite materials structure. It has a flight endurance of up to

30 minutes within a typical radius of a few hundreds of meters (under mile). The drone

weight is 1-10Kg and half of it can be payload. Such a drone cost is in the range of a few

hundred dollars to a few thousand dollars. Sample of small UAVs is shown in Figure 1.

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Figure 1 - Samples of small drones

2.2. Recent Events of Exposure to the Threat

At present, in 2015, FAA lists about 150 reported events of drones in the vicinity of the

flight path per month! Superposing the above rather obvious prediction with this FAA

report reveals a scary picture of a disaster knocking on our door and ready to drop onto

us. Counter measures must be developed, but the development cycle of 3 to 5 years must

not start only after the first event materialised, leaving all of us exposed to the threat for

that period.

To elaborate the previous statement, enclosed are just a handful of other examples from

recent events of people and sites that failed being kept secured, in spite of the obvious

necessity:

16 September 2013, Dresden, Germany,

A camera drone had a rough landing in front of Chancellor Angela Merkel at an election

campaign event in Germany after police told its operator to bring down the craft (fig 2).




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https://www.youtube.com/watch?v=1-5MDqGGon8

Figure 2 - Rough landing of a drone in front of Chancellor Angela Merkel

27 January 2015, Washington DC, USA

White House drone crash: drunk government employee crash lands Quadcopter on

Obama’s lawn. An investigation is still ongoing after a government worker reportedly

crashed his small recreational drone onto the White House lawn early Monday morning

(Fig 3).

https://www.youtube.com/watch?v=qRH6Ec82jR4

Figure 3 – Illustration of a drone in front of the White House

05 November 2014, Belleville-sur-Loire nuclear plant, France

Police arrested three people found in possession of remote-controlled drones near one

of the nuclear plants involved in a series of mystery overflights by the unmanned

aircraft (Fig 4).


https://www.youtube.com/watch?v=1-5MDqGGon8

https://www.youtube.com/watch?v=qRH6Ec82jR4



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https://www.youtube.com/watch?v=xIaVWP34FO0

Figure 4 – Illustration of a drone above a nuclear plant in France

13 June 2013, Taksim Square, Istanbul, Turkey

Police shoot down a camera carrying RC quadrocopter (Fig 5).

https://www.youtube.com/watch?v=_A-ufp5gY3s

Figure 5 – A drone shut by a police officer at Turkey

3. Threat Detection Method

The main difficulty for an early detection of a drone imposing a threat is its low signature

which leads to a close range of possible detection. Short range corresponds to a very

short time of detection and response. Furthermore, a low-signature light UAV may be

launched from a very close range from its target, escalating the above mentioned

difficulty.


https://www.youtube.com/watch?v=xIaVWP34FO0

https://www.youtube.com/watch?v=_A-ufp5gY3s



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The first key element in achieving an effective defence over a specific designated area

from such potential attack is short range fast detection with low rate of false alarms.

Achieving this objective is feasible only through multi-domain sensors fusion.

The proposed detection system is flexible, modular and scalable. In the heart of the

system, the real-time data-fusion, classification, and analysis, scenario driven algorithms

and software.

3.1. Sensing

The following table summarises the basic characteristics of some of the common

detection methods.

Method Characteristic

Radar

Suites for use in open, unpopulated areas.

Problematic to use in densely populated areas.

For achieving effective results a scanning system is required or a

number of passively staring systems or a combination of the two.

Optics, Visual

Daylight use.

At dark, the need for an external light source restricted effectiveness.

Using a variety of cameras concurrently enables fast detection,

classification and verification process.

Optics, IR Most effective in dark / cold ambience.

Complimentary to the vision range wavelength.

Laser Scanner Efficient pointing to suspect targets

Acoustics

Mostly a complimentary system for warning. Limited use in noisy

environment.

For some types of drones, in a quiet environment and with a properly

distributed array of microphones this method enables to detect angle of

arrival, velocity and the type of threat by its acoustic signature.

Radio

Suites for RC drones. Such drones use specific frequencies between

VHF up to 5.8GHz.

Locating the source of radio transmission enables neutralising the

operator and greatly decreases the false alarm rate while increasing the

probability of drone detection.

Cyber Details can not be disclosed at present.

Table 1 – Available detection methods




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3.2. From Data Fusion to Sinergy

In the heart of the threat detection and verification system lay a number of powerful

parallel distributed processing units which fully share information among themselves. The

system collects the data from all sensors and using advanced data fusion and pattern

recognition algorithms, some of which mimic human’s brain methods, it recognises any

abnormal patterns and behaviour. Thus, it is possible to identify multiple potential threats

in a complex scene. The below table demonstrates part of the sensors and their

respective contribution to the threat detection analysis.

Range, m 20 40 80 150 300 600

Threat level Acute High Medium Low None

Phase Verification Identification Detection

Radio

spectrogram

Phase Verification Identification Detection Suspicion

Visual

image

0.25mr/Pix

Phase Identification Detection Suspicion

Thermal

image

0.5mr/Pix

Phase Detection Suspicion

360° Image

1mr/Pix

Phase Detection Suspicion

Aucoustic

spectrogram

Image relative

size

Table 2 – Expected detection range with various sensors

A dynamic signature bank of known threats and non-threats is to be integrated into the

system. As the system is operationally deployed, this bank automatically expands and




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enhanced by the system’s classification and learning algorithms. A shared repository

would let all authorised systems to be updated in real time or offline.

At present, in order to establish a seed for this signatures bank, we have classified a few

dozen models of drones. The classification is based on basic characteristics of the drone

physical qualities, type of communication, navigation and command systems, range of

operation, etc. Here is a partial list of the classes used:

Command method: pre-programmed, online, hybrid, man in the loop, autonomous

Range: line of sight, BVR1, distance

Navigation system: None, Baro & Compass, GNSS2, INS3, Hybrid

Radio link: up-link, down-link, frequency, bandwidth, spectral signature, etc.

Video use: no camera, live use of video input onboard vs. at base station.

Homing system: man in the loop, autonomous, radio locked, video assisted, etc.

Propulsion system and thermal signature.

The different class correspond to different drone size and different ambient signatures,

hence to different means of detection and threat mitigation.

4. System’s Objectives and Design

4.1. Shielding Target Zones

Enforcing a no-fly-zone and shielded area varies with the nature of the target or event at

hand. At the lowest end, a small specific target over a small confinement, such as a

personal protection of a VIP on a political rally. Such a limited target system is of a

relatively low cost, tribute to the size of the shielded zone, limited features and the

possibility to provide the target some other extra means of complimentary protection.

Two main differentiators classify the different shielded zones and the means to protect

them: the size of the shielded area and the level of potential damage. As the protected

target gets bigger and the potential global damage is greater, e.g. a sport event or a

nuclear plant, the complexity of the required shielding system increases.

1 BVR – Beyond Vision Range

2 GNSS – Global Navigation Satellite System

3 INS – Inertial Navigation System




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Among other, here is a partial list of typical facilities needed to be protected:

Communication Infrastructure: Radio / TV / Phone broadcasting base stations, etc.

Energy Infrastructure: Power plants, Fuel reservoirs, etc.

State facilities and borders: Army camps, Jails, Hospitals, Courts, Borders, etc.

Events: Sport events, Open air concerts, Parades, etc.

4.2. System Structure

The basic features of the system are: modularity, scalability and hierarchically. All end

units are designed to communicate and co-operate directly and or through a local

command and control unit or via a global command centre. Thus, a bigger system is

easily assembled from a number of ready modules and sub-systems, incorporating sensor

units, communication units and command units. Whether and ad-hoc deployment of a

fixed installation, the system is fast to deploy, simple to maintain and bears low total cost

of ownership. It is ready to connect to the clients’ infrastructure via a connectivity module.

This design also ensures redundancy and high survivability of the system.

5. Preliminary Tests

Sample visual and thermal pictures of drones at various ranges were taken, acoustics

recording were analysed, and radio tracking of WiFi source was performed. The results

points out that there is no technological gap, and the expected results are listed in table 2

above.

5.1. Optical Detection

To achieve fast detection with low false alarm range a mix of visual and thermal cameras

is required. wide FOV and narrow FOV cameras is required as shown in Fig 6.

Figure 6 – Visual & Thermal images of a drone




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5.2. Acoustic Detection

Drones’ propellers have a typical acoustic signature. Appropriate filtering can distinguish

between ambient noise and drone acoustic signature. Adding wind information will

improve the detection . Figure 7 demonstrates the spectrogram of a quadcopter together

with ambient noise.

Figure 7 – Acoustic Spectrogram of a Drone

5.3. Radio Tracking

A 6 antennas radio signal tracking was used to track radio signal of a drone. The test

demonstrated the ability to find direction to a radio source with reasonable effort. The

required number of antennas and their locations will be determined to fit the expected

scenarios. Test results are shown in Figure 8.

Figure 8 – Preliminary radio tracking results




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6. Threat Interception

The interception process starts in analyzing the drone broadcast and if possible analyzing

the operator broadcast. Once the broadcast protocols are identified, the possibility to

perform virtual interception by overtaking the drone up-link will be examined.

Drones interception is divided into categories according to the nature of the protected area

and according to the configuration of the detected drone:

Immediate intercept, fits in sterile areas, can be done: by jamming of the radio

channels of the drone, by another combat drone, firing, or energy weapon.

Diverting the drone to a sterile area by overtaking the up-link or spoofing the GPS.

Return home – Jamming the GPS will typically cause the drone to return home.

Controlled landing – to be performed by overtaking the up-link.

Capture – the drone can be physically captured by a larger combat drone.

Taking over the command and control station – following detection of the drone, the

command station can be located and the drone mission will be aborted.

The interception process might include GPS jamming for large areas or jamming to a

focused area surrounding the drone. The focused jamming might require the use of a

combat drone to fly above the threat.




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7. Example of Shielding the Yankee Stadium in New York

Figure 9 demonstrates deployment of 3 detection stations of the DFD with visual and radio

capabilities to cover the stadium. The DFD allow lock on drone and interception above the

open park to minimize the peripheral damage.

Figure 9 – Drone Free Dome shields Yankee Stadium

8. Live Demo

The interception system integrates COTS products as well as custom made elements.

The main activity is the development of detection algorithms, data fusion algorithms,

target characteristic signatures, full coding of the software and system integration.

Following this parallel development GANTT it would be possible to achieve a live demo

shortly.

To start activity we need a requirements worksheet and a budget framework for the pilot.

The demonstration will be carried out within 12 month ARO.


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