by

Mohamed Loey Ramadan

Improving the Performance of Anti-GPS Signal

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Agenda

1. Introduction

2. GPS Tracking

3. GPS Signal Structure

4. Jamming Design Issues

5. Anti-GPS Simulation

6. Conclusion and Future Work

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1.1 What is GPS?

Global Positioning System (GPS) is a satellites based navigation system

made up of a network of 24 satellites.

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1.2 GPS Application

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1.3 What is Anti-GPS ?

Anti-GPS is a technology that prevents the GPS loggers,

trackers and GPS/GSM devices to get GPS positions from

the satellites.

Why ?

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1.4 GPS Misuse

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1.5 GPS in Military

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1.6 Joint Direct Attack Munition

JDAM equipped bombs are guided to their target by an integrated

inertial guidance system coupled with a Global Positioning System

(GPS) receiver for enhanced accuracy

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Agenda

1. Introduction

2. GPS Tracking

3. GPS Signal Structure

4. Jamming Design Issues

5. Anti-GPS Simulation

6. Conclusion and Future Work

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2.1 Definition

Technology allows anyone to track anyone else

using GPS technology.

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2.2 GPS Tracking Types

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2.3 Passive or Logger Tracking Device

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2.4 Real Time or Active Tracking Devices

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2.5 Detecting Tracing Device

Tracking device is the most difficult to detect and

defend against.

These devices can be as small as a matchbook and

can be hidden just about anywhere.

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2.6 Detectors

Radio Frequency (RF) detector/scanner

– Smart R.F. Counter

– Micro Bug Detector

Price from 100-1000$

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2.7 Disadvantage RF Detectors

Only detects the transmissions of the GPS device

when the device is actually transmitting.

Difficult to block and see GPS tracking devices.

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2.8 GPS JAMMING SIGNAL

Anti-GPS is a advice that prevents the GPS

devices from getting positions from satellites.

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2.8 GPS Jamming Signal

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Agenda

1. Introduction

2. GPS Tracking

3. GPS SIGNAL STRUCTURE

4. JAMMING DESIGN ISSUES

5. Anti-GPS Simulation

6. Conclusion and Future Work

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3.1 Definition

To design a simulation software for GPS signals. It

is necessary to know the characteristics of the signal

and data transmitted from the GPS satellites and

received by the GPS receiver antenna.

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3.2 GPS Signal Characteristics

GPS signals are Ultra High Frequency (UHF), UHF

band from 500 MHz to 3 GHz.

GPS navigation data has a bit rate of 50 bps.

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3.2 GPS Signal Characteristics

GPS signals have two codes

– C/A (coarse acquisition) code is 1,023 bits long a pseudo random code (PRN) which looks like a random code but is clearly defined for each satellite.

– P(Y) code is 6.1871 × 1012 bits long a PRN To prevent unauthorized users

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3.2 GPS Signal Characteristics

Carrier signal is:– L1=1575.42 MHz– L2=1227.60 MHz

Carrier signal and data signals are modulated using binary phase shift keying (BPSK)

L1 carry C/A + P(Y) code but L2 only carry P(Y) code

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3.2 GPS SIGNAL STRUCTURE

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Agenda

1. Introduction

2. GPS Tracking

3. GPS Signal Structure

4. Jamming Design Issues

5. Anti-GPS Simulation

6. Conclusion and Future Work

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4.1 Definition

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4.1 JAMMING DESIGN ISSUES

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4.3.1 Accuracy

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4.3.2 Frequency

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4.3.3 Pulse

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4.3.4 Modulation

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4.3.5 Jamming Signal Ratio (J/S) Range

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4.4 Jamming Signals

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4.4.1 Amplitude Modulation

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4.4.2 Frequency Modulation

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4.4.3 Band-limited White Noise

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Agenda

1. Introduction

2. GPS Tracking

3. GPS Signal Structure

4. Jamming Design Issues

5. Anti-GPS Simulation

6. Conclusion and Future Work

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5.1 Anti-GPS Simulation

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5.2 Anti-GPS Fuzzy Controller

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5.2.1 Membership Functions

A curve that defines how each point in the input

space is mapped to a membership value (or degree

of membership) between 0 and 1.

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5.2.1.1 Frequency Membership Function

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5.2.1.2 Pulse Repetition Frequency Membership Function

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5.2.1.3 Duty Cycle Frequency Membership Function

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5.2.1.4 GPS Error Signal Membership Function

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5.2.1.5 Jamming/Signal Membership Function

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5.2.1.6 Frequency Offset Membership Function

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5.2.1.7 Jamming Signal Membership Function

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5.2.2 Anti-GPS Fuzzy Controller Rules

1. If (GPSErrorSiganl is not Good) then (JammingSignal is NotAffect)

2. If (GPSErrorSignal is Good) and (Frequency is Same) and (pulseRepetitionFrequency is Medium) and (Duty is Medium) and (JammingSignalRatio is Medium) and FrequencyOffset is Inside) then (JammingSignal is Affect)

3. If (PulseRepetitionFrequency is VerySmall) or (DutyCycle is VerySmall) Then (JammingSignal is NotAffect)

4. If (PulseRepetitionFrequency is VeryLarge) or (DutyCycle is VeryLarge) Then (JammingSignal is Continues)

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5.2.2 Anti-GPS Fuzzy Controller Rules

5. If (FrequencyOffect is not Inside) then (JammingSignal is NotAffect)

6. If (JammingSignalRatio is Low) then (JammingSignal is NotAffect)

7. If (JammingSignalRatio is High) then (JammingSignal is NotAffect)

8. If (Frequecy is High) then (JammingSignal is NotAffect)

9. if (Frequency is Low) then (JammingSignal is NotAffect)

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5.2.3 Anti-GPS Fuzzy System Controller

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5.3 Modeling Process

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5.4 Jamming Signal Simulation

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5.4.1 Band-Limited White Noise

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5.4.1 Band-Limited White Noise

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5.4.1 Band-Limited White Noise + GPS Signal

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5.4.2 FM Jamming Signal

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5.4.2 FM Jamming Signal

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5.4.2 FM Jamming Signal +GPS Signal

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5.4.3 Multiband-Limited White Noise

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5.4.3 Multiband-Limited White Noise

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5.4.3 Multiband-Limited White Noise

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5.5 Anti-GPS in A Laboratory Environment

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5.6 Test Results

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5.6 Test Results

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5.6 Test Results

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5.6 Test Results

ComparisonsBand –limit white noise

Frequency modulation

Multi-Band limit white

noise

Noise PowerLowHighMedium

Jamming PowerHighLowMedium

Jamming DetectionEasyToo HardHard

Data DestroyLowMediumHigh

Anti-JammingEasyHardToo Hard

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Agenda

1. Introduction

2. GPS Tracking

3. GPS Signal Structure

4. Jamming Design Issues

5. Anti-GPS Simulation

6. Conclusion and Future Work

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6.1 Conclusion

We recommend our proposed with new schema called Multiband-limit white noise as:

– It has multi channel of band-limit white noise so it more jamming signal.

– It is difficult to detect using anti-jamming.

Develop new fuzzy controller that simulate jamming controller in laboratory test.

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6.2 Contributions

HESHAM N. ELMAHDY and MOHAMED L. Ramadan, “Improving the Performance of Anti-GPS Signal,”, In Proceedings of WSEAS SIP 09: The 8th World Scientific and Engineering Academy and Society international conference on Signal Processing , Istanbul, Turkey, June 2009.

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6.3 Future work

Simulate more complex and strong jamming GPS signal with less

power consume.

Make jamming controller using neuro-fuzzy.

Make our simulation result in laboratory test.

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