Todd Hubing. Clemson Vehicular Electronics Laboratory Clemson University

Transcription

1 Todd Hubing Clemson Vehicular Electronics Laboratory Clemson University

2 FCC Emissions Test Radiation from a shielded commercial product with attached cables May 28 2

3 Typical Field Strengths FCC Class A Device at 3 m FCC Class B Device at 3 m ~3 mv/m ~1 mv/m These field strengths are readily detectable and can be much stronger than fields from intentional transmitters located further away. May 28 3

4 There is ample signal strength to detect these devices! Detecting unintentional emissions from electronic devices is simply a matter of recognizing the desired signal when it is buried in the noise from hundreds of other sources (both intentional and unintentional). May 28 4

5 Techniques developed to identify and trace sources of EMI AM/FM Demodulation Observation of Side Bands Short Term FFT Frequency Domain Signature Time Domain Signature Wavelet Filtering Combinations of the above May 28 5

6 Amp [dbuv] Can we identify electronic devices based on their unintentional electromagnetic emissions? Buried signal Freq [Hz] x 1 8 May 28 6

7 Radiated emissions were recorded from a variety of radio receivers used in IEDs. Results were analyzed by: Extracting characteristics of emissions in both the time and frequency domain. Re-sampling high-frequency electromagnetic recordings at audio frequencies to demonstrate unique characteristics of signals. Emission characteristics were used to build an instrument capable of automatically detecting and identifying emissions. May 28 7

8 Time domain amplitude) Frequency (Hz) Time domain amplitude) Frequency (Hz) Remote Control Toy Truck 5 x x x x 18 4 Receiver Transmitter x x 1-4 May 28

9 Time domain amplitude) Frequency (Hz) Time domain amplitude) Frequency (Hz) Wireless Doorbell 1 Receiver Transmitter 1 x x x x x x 1-4 May 28

10 Time domain amplitude) Frequency (Hz) Time domain amplitude) Frequency (Hz) Wireless Doorbell 2 Receiver Transmitter 1 x x x x x x 1-4 May 28

11 Time domain amplitude) Frequency (Hz) Wireless Phone Receiver 5 x x x 1-4 May 28

12 Voltage (volt) Frequency (GHz) Digital Camera x x 1-4 May 28

13 Time domain amplitude) Frequency (Hz) Video Camera 1 x x x 1-4 May 28

14 Toy Truck Reference In noisy environment Processed representation of reference Filtered representation of signal in noisy environment May 28

15 Automatic detection and identification has been demonstrated with 1% accuracy in noisy environments Currently detecting receivers 1 m away using readily available equipment with no analog filters or amplifiers Significantly improved algorithms and more sophisticated instrumentation promises a substantial increase in standoff distance May 28

16 Our latest detection algorithms are able to recognize the presence of signals that are deeply buried in the noise from other sources, even when those sources are operating at the same frequency. May 28

17 Military-class low-noise receiver with programmable input filters Military-class highspeed, 14-bit digitizer with programmable IF filters Integrated antenna Laptop or hardened, embedded PC implementing detection algorithms. May 28

18 Presence and location of components used in IEDs may be detected at safe distances Technique is not easily defeated Does not depend on known background RF environment It is very difficult to eliminate EM emissions from receivers Emissions from receiver may be stronger than those from the transmitter Detection instrument can be highly configurable and adaptable to new threats May 28 18

19 Detection may be accomplished automatically or by including a human in the loop May use small or existing antennas Instrumentation can fit in a very small (backpack size) package Can be easily combined with other detection techniques, such as chemical sniffing, or neutralization techniques, such as jamming May be mounted on a robot (close-range detection, neutralization, verification) or on a truck or UAV (stand-off detection of roadside bombs) May 28 19

20 Well suited for rural or urban environments Urban environment may contain a large number of emission sources. Interference and false alarms may be minimized by: Limiting the view to relevant areas; Reducing the detection range; Targeting specific receivers; Eliminating known, fixed sources from analysis; Using an operator to make better informed decisions. May 28 2

21 Radio receivers used in IEDs emit unique and detectable levels of electromagnetic radiation. The ability to detect, identify, and locate these receivers has been demonstrated in noisy environments. Other electronic devices (not only receivers) can also be readily detected using this same technique. May 28 21