By Saeed Daneshmand, Ali Jafarnia-Jahromi, Ali Broumandan, and Gérard Lachapelle Most anti-spoofing techniques are computationally complicated or limited to a specific spoofing scenario. A new approach uses a two-antenna array to steer a null toward the direction of the spoofing signals, taking advantage of the spatial filtering and the periodicity of the authentic and spoofing signals. It requires neither antenna-array calibration nor a spoofing detection block, and can be employed as an inline anti-spoofing module at the input of conventional GPS receivers. GNSS signals are highly vulnerable to in-band interference such as jamming and spoofing. Spoofing is an intentional interfering signal that aims to coerce GNSS receivers into generating false position/navigation solutions. A spoofing attack is, potentially, significantly more hazardous than jamming since the target receiver is not aware of this threat. In recent years, implementation of software receiver-based spoofers has become feasible due to rapid advances with software-defined radio (SDR) technology. Therefore, spoofing countermeasures have attracted significant interest in the GNSS community. Most of the recently proposed anti-spoofing techniques focus on spoofing detection rather than on spoofing mitigation. Furthermore, most of these techniques are either restricted to specific spoofing scenarios or impose high computational complexity on receiver operation. Due to the logistical limitations, spoofing transmitters often transmit several pseudorandom noise codes (PRNs) from the same antenna, while the authentic PRNs are transmitted from different satellites from different directions. This scenario is shown in Figure 1. In addition, to provide an effective spoofing attack, the individual spoofing PRNs should be as powerful as their authentic peers. Therefore, overall spatial energy of the spoofing signals, which is coming from one direction, is higher than other incident signals. Based on this common feature of the spoofing signals, we propose an effective null-steering approach to set up a countermeasure against spoofing attacks. This method employs a low-complexity processing technique to simultaneously de-spread the different incident signals and extract their spatial energy. Afterwards, a null is steered toward the direction where signals with the highest amount of energy impinge on the double-antenna array. One of the benefits of this method is that it does not require array calibration or the knowledge of the array configuration, which are the main limitations of antenna-array processing techniques. Processing Method The block diagram of the proposed method is shown in Figure 2. Without loss of generality, assume that s(t) is the received spoofing signal at the first antenna. Figure 2. Operational block diagram of proposed technique. The impinging signal at the second antenna can be modeled by , where θs and μ signify the spatial phase and gain difference between the two channels, respectively. As mentioned before, the spoofer transmits several PRNs from the same direction while the authentic signals are transmitted from different directions. Therefore, θs is the same for all the spoofing signals. However, the incident authentic signals impose different spatial phase differences. In other words, the dominant spatial energy is coming from the spoofing direction. Thus, by multiplying the conjugate of the first channel signals to that of the second channel and then applying a summation over N samples, θs can be estimated as (1) where r1 and r2 are the complex baseband models of the received signals at the first and the second channels respectively, and Ts is the sampling duration. In (1), θs can be estimated considering the fact that the authentic terms are summed up non-constructively while the spoofing terms are combined constructively, and all other crosscorrelation and noise terms are significantly reduced after filtering. For estimating μ, the signal of each channel is multiplied by its conjugate in the next epoch to prevent noise amplification. It can easily be shown that μ can be estimated as (2) where T is the pseudorandom code period. Having and a proper gain can be applied to the second channel in order to mitigate the spoofing signals by adding them destructively as (3) Analyses and Simulation Results We have carried out simulations for the case of 10 authentic and 10 spoofing GPS signals being transmitted at the same time. The authentic sources were randomly distributed over different azimuth and elevation angles, while all spoofing signals were transmitted from the same direction at azimuth and elevation of 45 degrees. A random code delay and Doppler frequency shift were assigned to each PRN. The average power of the authentic and the spoofing PRNs were –158.5 dBW and –156.5 dBW, respectively. Figure 3 shows the 3D beam pattern generated by the proposed spoofing mitigation technique. The green lines show the authentic signals coming from different directions, and the red line represents the spoofing signals. As shown, the beam pattern’s null is steered toward the spoofing direction. Figure 3. Null steering toward the spoofer signals. In Figure 4, the array gain of the previous simulation has been plotted versus the azimuth and elevation angles. Note that the double-antenna anti-spoofing technique significantly attenuates the spoofer signals. This attenuation is about 11 dB in this case. Hence, after mitigation, the average injected spoofing power is reduced to –167.5 dBW for each PRN. As shown in Figure 4, the double-antenna process has an inherent array gain that can amplify the authentic signals. However, due to the presence of the cone of ambiguity in the two-antenna array beam pattern, the power of some authentic satellites that are located in the attenuation cone might be also reduced. Figure 4. Array gain with respect to azimuth and elevation. Monte Carlo simulations were then performed over 1,000 runs for different spoofing power levels. The transmitted direction, the code delay, and the Doppler frequency shift of the spoofing and authentic signals were changed during each run of the simulation. Figure 5 shows the average signal to interference-plus-noise ratio (SINR) of the authentic and the spoofing signals as a function of the average input spoofing power for both the single antenna and the proposed double antenna processes. A typical detection SINR threshold corresponding to PFA=10-3 also has been shown in this figure. Figure 5. Authentic and spoofed SINR variations as a function of average spoofing power. In the case of the single antenna receiver, the SINR of the authentic signals decreases as the input spoofing power increases. This is because of the receiver noise-floor increase due to the cross-correlation terms caused by the higher power spoofing signals. However, the average SINR of the spoofing signals increases as the power of the spoofing PRNs increase. For example, when the average input spoofing power is –150 dBW, the authentic SINR for the single-antenna process is under the detection threshold, while the SINR of the spoofing signal is above this threshold. However, by considering the proposed beamforming method, as the spoofing power increases, the SINR of the authentic signal almost remains constant, while the spoofing SINR is always far below the detection threshold. Hence, the proposed null-steering method not only attenuates the spoofing signals but also significantly reduces the spoofing cross-correlation terms that increase the receiver noise floor. Early real-data processing verifies the theoretical findings and shows that the proposed method indeed is applicable to real-world spoofing scenarios. Conclusions The method proposed herein is implemented before the despreading process; hence, it significantly decreases the computational complexity of the receiver process. Furthermore, the method does not require array calibration, which is the common burden with array-processing techniques. These features make it suitable for real-time applications and, thus, it can be either employed as a pre-processing unit for conventional GPS receivers or easily integrated into next-generation GPS receivers. Considering the initial experimental results, the required antenna spacing for a proper anti-spoofing scenario is about a half carrier wavelength. Hence, the proposed anti-spoofing method can be integrated into handheld devices. The proposed technique can also be easily extended to other GNSS signal structures. Further analyses and tests in different real-world scenarios are ongoing to further assess the effectiveness of the method. Saeed Daneshmand is a Ph.D. student in the Position, Location, and Navigation (PLAN) group in the Department of Geomatics Engineering at the University of Calgary. His research focuses on GNSS interference and multipath mitigation using array processing. Ali Jafarnia-Jahromi is a Ph.D. student in the PLAN group at the University of Calgary. His research focuses on GNSS spoofing detection and mitigation techniques. Ali Broumandan received his Ph.D. degree from Department of Geomatics Engineering, University of Calgary, Canada. He is a senior research associate/post-doctoral fellow in the PLAN group at the University. Gérard Lachapelle holds a Canada Research Chair in wireless location In the Department of Geomatics Engineering at the University of Calgary in Alberta, Canada, and is a member of GPS World’s Editorial Advisory Board.
a cell phone blockerJammer free bluetooth device upon activation of the mobile jammer,if you are looking for mini project ideas.mgp f10603-c ac adapter 12v-14v dc 5-4.28a used 2.5 x 5.4 x 12.1.pelouze dc90100 adpt2 ac adapter 9vdc 100ma 3.5mm mono power sup.cui stack dv-530r 5vdc 300ma used -(+) 1.9x5.4mm straight round.vipesse a0165622 12-24vdc 800ma used battery charger super long.ssb-0334 adapter used 28vdc 20.5v 1.65a ite power supply 120vac~.cpc can be connected to the telephone lines and appliances can be controlled easily.d-link cg2412-p ac adapter 12vdc 2a -(+) used 1.2x3.75mm europe.this can also be used to indicate the fire,a cell phone signal amplifier,tc98a 4.5-9.5v dc max 800ma used travel charger power supply.frequency counters measure the frequency of a signal,nexxtech mu04-21120-a00s ac adapter 1.5a 12vdc used -(+)- 1.4 x,10% off on icici/kotak bank cards.basically it is way by which one can restrict others for using wifi connection,replacement pa3201u-1aca ac adapter 19vdc 6.3a power supply tosh,eng 41-12-300 ac adapter 12vdc 300ma used 2 x 5.4 x 11.2 mm 90 d,kvh’s new geo-fog 3d inertial navigation system (ins) continuously provides extremely accurate measurements that keep applications operating in challenging conditions,uttar pradesh along with their contact details &,so that pki 6660 can even be placed inside a car,commodore dc-420 ac adapter 4.5vdc 200ma used -(+) phone jack po,pantech pta-5070dus ac dc adapter 5v 700ma cellphone battery cha.ihomeu150150d51 ac adapter 15vdc 1500ma -(+) 2.1x5.5x10mm roun.bti veg90a-190a universal ac adapter 15-20v 5.33a 90w laptop pow.startech usb2sataide usb 2.0 to sata ide adapter.skil class ii battery charger 4.1vdc 330ma used flexi charge int,basler electric be116230aab 0021 ac adapter 5v 30va plug-in clas,thomson du28090010c ac adapter 9vdc 100ma used -(+) cut wire cor.produits de bombe jammer+433 -+868rc 315 mhz.jabra fw7600/06 ac adapter 6vdc 250ma used mini 4pin usb connec.katana ktpr-0101 ac adapter 5vdc 2a used 1.8x4x10mm,changzhou un-d7.2v200 ac dc adapter 7.2vdc 200ma -(+) used 120va.fujitsu seb100p2-19.0 ac adapter 19vdc 4.22a -(+) used 2.5x5.5mm,the black shell and portable design make it easy to hidden and use,bellsouth products dv-9300s ac adapter 9vdc 300ma class 2 transf,this cell phone jammer is not applicable for use in europe.pa-1700-02 replacement ac adapter 19v dc 3.42a laptop acer.csec csd1300150u-31 ac adapter 13vdc 150ma used -(+)- 2x5.5mm.toshiba pa2501u ac adapter 15v 2a 30w laptop power supply,the unit is controlled via a wired remote control box which contains the master on/off switch.jentec jta0202y ac adapter +5vdc +12v 2a used 5pin 9mm mini din,ad-4 ac adapter 6vdc 400ma used +(-) 2x5.5mm round barrel power.in-li yl-12-12 ac adapter 12vac 12va used ~(~) 2pin din female p.viewsonic adp-80ab ac adapter 12vdc 6.67a 3.3x6.4mm -(+)- power,oem ads0243-u120200 ac adapter 12vdc 2a -(+)- 2x5.5mm like new p.lenovo 41r0139 ac dc auto combo slim adapter 20v 4.5a,dura micro dm5133 ac adapter 12vdc 2a -(+) 2x5.5mm power supply.laser jammers are active and can prevent a cop’s laser gun from determining your speed for a set period of time,acbel ada017 ac adapter 12vdc 3.33a used -(+) 2.5x6.2x9mm round,jammer disrupting the communication between the phone and the cell phone base station in the tower.ibm 02k6794 ac adapter -(+) 2.5x5.5mm16vdc 4.5a 100-240vac power,digital adp-45gb rev.d a ac adapter used 19vdc 2.4a.sunbeam gb-2 ac adapter 110-120vac used transformer shaver canad.wada electronics ac7520a ac ac adapter used 7.5vdc 200ma.2110cla ac adapter used car charger,0450500df ac adapter 4.8vdc 250ma used 2pin class 2 power supply,black & decker vpx0320 used 7.4vdc 230ma dual port battery charg.acbel api3ad14 19vdc 6.3a used -(+)- 2.5x5.5mm straight round,delta adp-135db bb ac adapter 19vdc 7110ma used,cardio control sm-t13-04 ac adapter 12vdc 100ma used -(+)-,netbit dsc-51f 52100 ac adapter 5.2vdc 1a used usb connector wit,the pki 6085 needs a 9v block battery or an external adapter,direct plug-in sa48-18a ac adapter 9vdc 1000ma power supply,energizer fm050012-us ac adapter 5v dc 1.2a used 1.7x4x9.7mm rou.motorola psm5049a ac adapter dc 4.4v 1.5a cellphone charger,gateway lishin 0220a1990 ac adapter 19vdc 4.74a laptop power sup,directed dsa-35w-12 36 ac dc adapter 12v 3a power supply,but also completely autarkic systems with independent power supply in containers have already been realised,dve dsa-0151a-12 s ac adapter 12vdc 1.25a used 2.1 x 5.4 x 9.4 m.sl waber ds2 ac adapter 15a used transiet voltage surge suppress,a jammer working on man-made (extrinsic) noise was constructed to interfere with mobile phone in place where mobile phone usage is disliked.320 x 680 x 320 mmbroadband jamming system 10 mhz to 1,the pki 6160 covers the whole range of standard frequencies like cdma.cidco dv-9200 ac adapter 9vdc 200ma used -(+) 2.2x5.4mm straight.a cell phone jammer is a device that blocks transmission or reception of signals.video digital camera battery charger used 600ma for db70 s008e b.asus ex0904yh ac adapter 19v dc 4.74aa -(+)- 2.5x5.5mm 100-240vd.it is specially customised to accommodate a broad band bomb jamming system covering the full spectrum from 10 mhz to 1,lei iu40-11190-010s ac adapter 19vdc 2.15a 40w used -(+) 1.2x5mm,delta eadp-45bb b ac adapter 56vdc 0.8a used -(+) 2.5x5.5x10.4mm,this sets the time for which the load is to be switched on/off.
Hewlett packard series hstnn-la12 19.5v dc 11.8a -(+)- 5.1x7.3,sunny sys1308-2424-w2 ac adapter 24vdc 0.75a used -(+) 2x5.5x9mm,u075015a12v ac adapter 7.5vac 150ma used ~(~) 2x5.5x10mm 90 degr.philips hq 8000 ac adapterused charger shaver 100-240v 50/6.cui inc 3a-161wu06 ac adapter 6vdc 2.5a used -(+) 2x5.4mm straig.compaq series 2872a ac adapter 18.75v 3.15a 41w? 246960-001.hb hb12b-050200spa ac adapter 5vdc 2000ma used 2.3 x 5.3 x 11.2,ap3911 ac dc adapter5v dc 500ma new +(-) 1.3x3.4x7.5mm straigh,hon-kwang hk-u-090a060-eu european ac adapter 9v dc 0-0.6a new.panasonic pv-a19-k ac adapter 6vdc 1.8a used battery charger dig.recoton ad300 adapter universal power supply multi voltage.ibm aa20210 ac adapter 16vdc 3.36a used 2.5 x 5.5 x 11mm round b.kodak k5000 li-ion battery charger4.2vdc 650ma for klic-5000 kli,finecom stm-1018 ac adapter 5vdc 12v 1.5a 6pin 9mm mini din dual.this project shows the system for checking the phase of the supply,globtek gt-21089-1515-t3 ac adapter 15vdc 1a 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