2021/04/08
By Kyle Wesson, Daniel Shepard, and Todd Humphreys
Disruption created by intentional generation of fake GPS signals could have serious economic consequences. This article discusses how typical civil GPS receivers respond to an advanced civil GPS spoofing attack, and four techniques to counter such attacks: spread-spectrum security codes, navigation message authentication, dual-receiver correlation of military signals, and vestigial signal defense. Unfortunately, any kind of anti-spoofing, however necessary, is a tough sell.
GPS spoofing has become a hot topic. At the 2011 Institute of Navigation (ION) GNSS conference, 18 papers discussed spoofing, compared with the same number over the past decade. ION-GNSS also featured its first panel session on anti-spoofing, called “Improving Security of GNSS Receivers,” which offered six security experts a forum to debate the most promising anti-spoofing technologies.
The spoofing threat has also drawn renewed U.S. government scrutiny since the initial findings of the 2001 Volpe Report. In November 2010, the U.S. Position Navigation and Timing National Executive Committee requested that the U.S. Department of Homeland Security (DHS) conduct a comprehensive risk assessment on the use of civil GPS. In February 2011, the DHS Homeland Infrastructure Threat and Risk Analysis Center began its investigation in conjunction with subject-matter experts in academia, finance, power, and telecommunications, among others. Their findings will be summarized in two forthcoming reports, one on the spoofing and jamming threat and the other on possible mitigation techniques. The reports are anticipated to show that GPS disruption due to spoofing or jamming could have serious economic consequences.
Effective techniques exist to defend receivers against spoofing attacks. This article summarizes state-of-the-art anti-spoofing techniques and suggests a path forward to equip civil GPS receivers with these defenses. We start with an analysis of a typical civil GPS receiver’s response to our laboratory’s powerful spoofing device. This will illustrate the range of freedom a spoofer has when commandeering a victim receiver’s tracking loops. We will then provide an overview of promising cryptographic and non-cryptographic anti-spoofing techniques and highlight the obstacles that impede their widespread adoption.
The Spoofing Threat
Spoofing is the transmission of matched-GPS-signal-structure interference in an attempt to commandeer the tracking loops of a victim receiver and thereby manipulate the receiver’s timing or navigation solution. A spoofer can transmit its counterfeit signals from a stand-off distance of several hundred meters or it can be co-located with its victim.
Spoofing attacks can be classified as simple, intermediate, or sophisticated in terms of their effectiveness and subtlety. In 2003, the Vulnerability Assessment Team at Argonne National Laboratory carried off a successful simple attack in which they programmed a GPS signal simulator to broadcast high-powered counterfeit GPS signals toward a victim receiver. Although such a simple attack is easy to mount, the equipment is expensive, and the attack is readily detected because the counterfeit signals are not synchronized to their authentic counterparts.
In an intermediate spoofing attack, a spoofer synchronizes its counterfeit signals with the authentic GPS signals so they are code-phase-aligned at the target receiver. This method requires a spoofer to determine the position and velocity of the victim receiver, but it affords the spoofer a serious advantage: the attack is difficult to detect and mitigate.
The sophisticated attack involves a network of coordinated intermediate-type spoofers that replicate not only the content and mutual alignment of visible GPS signals but also their spatial distribution, thus fooling even multi-antenna spoofing defenses.
Table 1. Comparison of anti-spoofing techniques discussed in this article.
Lab Attack. So far, no open literature has reported development or research into the sophisticated attack. This is likely because of the success of the intermediate-type attack: to date, no civil GPS receiver tested in our laboratory has fended off an intermediate-type spoofing attack. The spoofing attacks, which are always conducted via coaxial cable or in radio-frequency test enclosures, are performed with our laboratory’s receiver-spoofer, an advanced version of the one introduced at the 2008 ION-GNSS conference (see “Assessing the Spoofing Threat,” GPS World, January 2009).
To commence the attack, the spoofer transmits its counterfeit signals in code-phase alignment with the authentic signals but at power level below the noise floor. The spoofer then increases the power of the spoofed signals so that they are slightly greater than the power of the authentic signals. At this point, the spoofer has taken control of the victim receiver’s tracking loops and can slowly lead the spoofed signals away from the authentic signals, carrying the receiver’s tracking loops with it. Once the spoofed signals have moved more than 600 meters in position or 2 microseconds in time away from the authentic signals, the receiver can be considered completely owned by the spoofer.
Spoofing testbed at the University of Texas Radionavigation Laboratory, an advanced and powerful suite for anti-spoofing research. On the right are several of the civil GPS receivers tested and the radio-frequency test enclosure, and on the left are the phasor measurement unit and the civil GPS spoofer.
Although our spoofer fooled all of the receivers tested in our laboratory, there are significant differences between receivers’ dynamic responses to spoofing attacks. It is important to understand the types of dynamics that a spoofer can induce in a target receiver to gain insight into the actual dangers that a spoofing attack poses rather than rely on unrealistic assumptions or models of a spoofing attack. For example, a recent paper on time-stamp manipulation of the U.S. power grid assumed that there was no limit to the rate of change that a spoofer could impose on a victim receiver’s position and timing solution, which led to unrealistic conclusions.
Experiments performed in our laboratory sought to answer three specific questions regarding spoofer-induced dynamics:
How quickly can a timing or position bias be introduced?
What kinds of oscillations can a spoofer cause in a receiver’s position and timing?
How different are receiver responses to spoofing?
These questions were answered by determining the maximum spoofer-induced pseudorange acceleration that can be used to reach a certain final velocity when starting from a velocity of zero, without raising any alarms or causing the target receiver to lose satellite lock. The curve in the velocity-acceleration plane created by connecting these points defines the upper bound of a region within which the spoofer can safely manipulate the target receiver. These data points can be obtained empirically and fit to an exponential curve. Alarms on the receiver may cause some deviations from this curve depending on the particular receiver.
Figure 1 shows an example of the velocity-acceleration curve for a high-quality handheld receiver, whose position and timing solution can be manipulated quite aggressively during a spoofing attack. These results suggest that the receiver’s robustness — its ability to provide navigation and timing solutions despite extreme signal dynamics — is actually a liability in regard to spoofing. The receiver’s ability to track high accelerations and velocities allows a spoofer to aggressively manipulate its navigation solution.
Figure 1. Theoretical and experimental test results for a high-quality handheld receiver’s dynamic response to a spoofing attack. Although not shown here, the maximum attainable velocity is around 1,300 meters/second.
The relative ease with which a spoofer can manipulate some GPS receivers suggests that GPS-dependent infrastructure is vulnerable. For example, the telecommunications network and the power grid both rely on GPS time-reference receivers for accurate timing. Our laboratory has performed tests on such receivers to determine the disruptions that a successful spoofing attack could cause. The remainder of this section highlights threats to these two sectors of critical national infrastructure.
Cell-Phone Vulnerability. Code division multiple access (CDMA) cell-phone towers rely on GPS timing for tower-to-tower synchronization. Synchronization prevents towers from interfering with one another and enables call hand-off between towers. If a particular tower’s time estimate deviates more than 10 microseconds from GPS time, hand-off to and from that tower is disrupted. Our tests indicate that a spoofer could induce a 10-microsecond time deviation within about 30 minutes for a typical CDMA tower setup. A spoofer, or spoofer network, could also cause multiple neighboring towers to interfere with one another. This is possible because CDMA cell-phone towers all use the same spreading code and distinguish themselves only by the phasing (that is, time offset) of their spreading codes. Furthermore, it appears that a spoofer could impair CDMA-based E911 user-location.
Power-Grid Vulnerability. Like the cellular network, the power grid of the future will rely on accurate GPS time-stamps. The efficiency of power distribution across the grid can be improved with real-time measurements of the voltage and current phasors. Phasor measurement units (PMUs) have been proposed as a smart-grid technology for precisely this purpose. PMUs rely on GPS to time-stamp their measurements, which are sent back to a central monitoring station for processing. Currently, PMUs are used for closed-loop grid control in only a few applications, but power-grid modernization efforts will likely rely more heavily on PMUs for control. If a spoofer manipulates a PMU’s time stamps, it could cause spurious variations in measured phase angles. These variations could distort power flow or stability estimates in such a way that grid operators would take incorrect or unnecessary control actions including powering up or shutting down generators, potentially causing blackouts or damage to power-grid equipment.
Under normal circumstances, a changing separation in the phase angle between two PMUs indicates changes in power flow between the regions measured by each PMU. Tests demonstrate that a spoofer could cause variations in a PMU’s measured voltage phase angle at a rate of 1.73 degrees per minute. Thus, a spoofing attack could create the false indications of power flow across the grid. The tests results also reveal, however, that it is impossible for a spoofer to cause changes in small-signal grid stability estimates, which would require the spoofer to induce rapid (for example, 0.1–3 Hz) microsecond-amplitude oscillations in timing. Such oscillations correspond to spoofing dynamics well outside the region of freedom of all receivers we have tested. A spoofer might also be able to affect fault-location estimates obtained through time-difference-of-arrival techniques using PMU measurements. This could cause large errors in fault-location estimates and hamper repair efforts.
What Can Be Done? Despite the success of the intermediate-type spoofing attack against a wide variety of civil GPS receivers and the known vulnerabilities of GPS-dependent critical infrastructure to spoofing attacks, anti-spoofing techniques exist that would enable receivers to successfully defend themselves against such attacks. We now turn to four promising anti-spoofing techniques.
Cryptographic Methods
These techniques enable a receiver to differentiate authentic GPS signals from counterfeit signals with high likelihood. Cryptographic strategies rely on the unpredictability of so-called security codes that modulate the GPS signal. An unpredictable code forces a spoofer who wishes to mount a successful spoofing attack to either
estimate the unpredictable chips on-the-fly, or
record and play back authentic GPS spectrum (a meaconing attack).
To avoid unrealistic expectations, it should be noted that no anti-spoofing technique is completely impervious to spoofing. GPS signal authentication is inherently probabilistic, even when rooted in cryptography. Many separate detectors and cross-checks, each with its own probability of false alarm, are involved in cryptographic spoofing detection. Figure 2 illustrates how the jammer-to-noise ratio detector, timing consistency check, security-code estimation and replay attack (SCER) detector, and cryptographic verification block all work together. This hybrid combination of statistical hypothesis tests and Boolean logic demonstrates the complexities and subtleties behind a comprehensive, probabilistic GPS signal authentication strategy for security-enhanced signals.
Figure 2. GNSS receiver components required for GNSS signal authentication. Components that support code origin authentication are outlined in bold and have a gray fill, whereas components that support code timing authentication are outlined in bold and have no fill. The schematic assumes a security code based on navigation message authentication.
Spread Spectrum Security Codes. In 2003, Logan Scott proposed a cryptographic anti-spoofing technique based on spread spectrum security codes (SSSCs). The most recent proposed version of this technique targets the L1C signal, which will be broadcast on GPS Block III satellites, because the L1C waveform is not yet finalized. Unpredictable SSSCs could be interleaved with the L1C spreading code on the L1C data channel, as illustrated in Figure 3. Since L1C acquisition and tracking occurs on the pilot channel, the presence of the SSSCs has negligible impact on receivers. Once tracking L1C, a receiver can predict when the next SSSC will be broadcast but not its exact sequence. Upon reception of an SSSC, the receiver stores the front-end samples corresponding to the SSSC interval in memory. Sometime later, the cryptographic digital key that generated the SSSC is transmitted over the navigation message. With knowledge of the digital key, the receiver generates a copy of the actual transmitted SSSC and correlates it with the previously-recorded digital samples. Spoofing is declared if the correlation power falls below a pre-determined threshold.
Figure 3. Placement of the periodically unpredictable spread spectrum security codes in the GPS L1C data channel spreading sequence.
When the security-code chip interval is short (high chipping rate), it is difficult for a spoofer to estimate and replay the security code in real time. Thus, the SSSC technique on L1C offers a strong spoofing defense since the L1C chipping rate is high (that is, 1.023 MChips/second). Furthermore, the SSSC technique does not rely on the receiver obtaining additional information from a side channel; all the relevant codes and keys are broadcast over the secured GPS signals. Of course a disadvantage for SSSC is that it requires a fairly fundamental change to the currently-proposed L1C definition: the L1C spreading codes must be altered.
Implementation of the SSSC technique faces long odds, partly because it is late in the L1C planning schedule to introduce a change to the spreading codes. Nonetheless, in September 2011, Logan Scott and Phillip Ward advocated for SSSC at the Public Interface Control Working Group meeting, passing the first of many wickets. The proposal and associated Request for Change document will now proceed to the Lower Level GPS Engineering Requirements Branch for further technical review. If approved there, it passes to the Joint Change Review Board for additional review and, if again approved, to the Technical Interchange Meeting for further consideration. The chances that the SSSC proposal will survive this gauntlet would be much improved if some government agency made a formal request to the GPS Directorate to include SSSCs in L1C — and provided the funding to do so. The DHS seems to us a logical sponsoring agency.
Navigation Message Authentication. If an L1C SSSC implementation proves unworkable, an alternative, less-invasive cryptographic authentication scheme based on navigation message authentication (NMA) represents a strong fall-back option. In the same 2003 ION-GNSS paper that he proposed SSSC, Logan Scott also proposed NMA. His paper was preceded by an internal study at MITRE and followed by other publications in the open literature, all of which found merit in the NMA approach. The NMA technique embeds public-key digital signatures into the flexible GPS civil navigation (CNAV) message, which offers a convenient conveyance for such signatures. The CNAV format was designed to be extensible so that new messages can be defined within the framework of the GPS Interference Specification (IS). The current GPS IS defines only 15 of 64 CNAV messages, reserving the undefined 49 CNAV messages for future use.
Our lab recently demonstrated that NMA works to authenticate not only the navigation message but also the underlying signal. In other words, NMA can be the basis of comprehensive signal authentication. We have proposed a specific implementation of NMA that is packaged for immediate adoption. Our proposal defines two new CNAV messages that deliver a standardized public-key elliptic-curve digital algorithm (ECDSA) signature via the message format in Figure 4.
Figure 4. Format of the proposed CNAV ECDSA signature message, which delivers the first or second half of the 466-bit ECDSA signature and a 5-bit salt in the 238-bit payload field.
Although the CNAV message format is flexible, it is not without constraints. The shortest block of data in which a complete signature can be embedded is a 96-second signature block such as the one shown in Figure 5. In this structure, the two CNAV signature messages are interleaved between the ephemeris and clock data to meet the broadcast requirements.
Figure 5. The shortest broadcast signature block that does not violate the CNAV ephemeris and timing broadcast requirements. To meet the required broadcast interval of 48 seconds for message types 10, 11, and one of 30–39, the ECDSA signature is broadcast over a 96-second signature block that is composed of eight CNAV messages.
The choice of the duration between signature blocks is a tradeoff between offering frequent authentication and maintaining a low percentage of the CNAV message reserved for the digital signature. In our proposal, signature blocks are transmitted roughly every five minutes (Figure 6) so that only 7.5 percent of the navigation message is devoted to the digital signature. Across the GPS constellation, the signature block could be offset so that a receiver could authenticate at least one channel approximately every 30 seconds. Like SSSC, our proposed version of NMA does not require a receiver’s getting additional information from a side channel, provided the receiver obtains public key updates on a yearly basis.
Figure 6. A signed 336-second broadcast. The proposed strategy signs every 28 CNAV messages with a signature broadcast over two CNAV messages on each broadcast channel.
NMA is inherently less secure than SSSC. A NMA security code chip interval (that is, 20 milliseconds) is longer than a SSSC chip interval, thereby allowing the spoofer more time to estimate the digital signature on-the-fly. That is not to say, however, that NMA is ineffective. In fact, tests with our laboratory’s spoofing testbed demonstrated the NMA-based signal authentication structure described earlier offered a receiver a better-than 95 percent probability of detecting a spoofing attack for a 0.01 percent probability of false alarm under a challenging spoofing-attack scenario.
NMA is best viewed as a hedge. If the SSSC approach does not gain traction, then NMA might, since it only requires defining two new CNAV messages in the GPS IS — a relatively minor modification. CNAV-based NMA could defend receivers tracking L2C and L5. A new CNAV2 message will eventually be broadcast on L1 via L1C, so a repackaged CNAV2-based NMA technique could offer even single-frequency L1 receivers a signal-side anti-spoofing defense.
P(Y) Code Dual-Receiver Correlation. This approach avoids entirely the issue of GPS IS modifications. The technique correlates the unknown encrypted military P(Y) code between two civil GPS receivers, exploiting known carrier-phase and code-phase relationships. It is similar to the dual-frequency codeless and semi-codeless techniques that civil GPS receivers apply to track the P(Y) code on L2. Peter Levin and others filed a patent on the codeless-based signal authentication technique in 2008; Mark Psiaki extended the approach to semicodeless correlation and narrow-band receivers in a 2011 ION-GNSS paper.
In the dual-receiver technique, one receiver, stationed in a secure location, tracks the authentic L1 C/A codes while receiving the encrypted P(Y) code. The secure receiver exploits the known timing and phase relationships between the C/A code and P(Y) code to isolate the P(Y) code, of which it sends raw samples (codeless technique) or estimates of the encrypting W-code chips (semi-codeless technique) over a secure network to the defending receiver. The defending receiver correlates its locally-extracted P(Y) with the samples or W-code estimates from the secure receiver. If a spoofing attack is underway, the correlation power will drop below a statistical threshold, thereby causing the defending receiver to declare a spoofing attack. Although the P(Y) code is 20 MHz wide, a narrowband civil GPS receiver with 2.6 MHz bandwidth can still perform the statistical hypothesis tests even with the resulting 5.5 dB attenuation of the P(Y) code. Because the dual-receiver method can run continuously in the background as part of a receiver’s standard GPS signal processing, it can declare a spoofing attack within seconds — a valuable feature for many applications.
Two considerations about the dual-receiver technique are worth noting. First, the secure receiver must be protected from spoofing for the technique to succeed. Second, the technique requires a secure communication link between the two receivers. Although the first requirement is easily achieved by locating secure receivers in secure locations, the second requirement makes the technique impractical for some applications that cannot support a continuous communication link.
Of all the proposed cryptographic anti-spoofing techniques, only the dual-receiver method could be implemented today. Unfortunately the P(Y) code will no longer exist after 2021, meaning that systems that make use of the P(Y)-based dual-receiver technique will be rendered unprotected, although a similar M-code-based technique could be an effective replacement. The dual-receiver method, therefore, is best thought of as a stop-gap: it can provide civil GPS receivers with an effective anti-spoofing technique today until a signal-side civil GPS authentication technique is approved and implemented in the future This sentiment was the consensus of the panel experts at the 2011 ION-GNSS session on civil GPS receiver security.
Non-Cryptographic Methods
Non-cryptographic techniques are enticing because they can be made receiver-autonomous, requiring neither security-enhanced civil GPS signals nor a side-channel communication link. The literature contains a number of proposed non-cryptographic anti-spoofing techniques. Frequently, however, these techniques rely on additional hardware, such as accelerometers or inertial measurements units, which may exceed the cost, size, or weight requirements in many applications. This motivates research to develop software-based, receiver-autonomous anti-spoofing methods.
Vestigial Signal Defense (VSD). This software-based, receiver-autonomous anti-spoofing technique relies on the difficulty of suppressing the true GPS signal during a spoofing attack. Unless the spoofer generates a phase-aligned nulling signal at the phase center of the victim GPS receiver’s antenna, a vestige of the authentic signal remains and manifests as a distortion of the complex correlation function. VSD monitors distortion in the complex correlation domain to determine if a spoofing attack is underway.
To be an effective defense, the VSD must overcome a significant challenge: it must distinguish between spoofing and multipath. The interaction of the authentic and spoofed GPS signals is similar to the interaction of direct-path and multipath GPS signals. Our most recent work on the VSD suggests that differentiating spoofing from multipath is enough of a challenge that the goal of the VSD should only be to reduce the degrees-of-freedom available to a spoofer, forcing the spoofer to act in a way that makes the spoofing signal or vestige of the authentic GPS signal mimic multipath. In other words, the VSD seeks to corner the spoofer and reduce its space of possible dynamics.
Among other options, two potential effective VSD techniques are
a maximum-likelihood bistatic-radar-based approach and
a phase-pseudorange consistency check.
The first approach examines the spatial and temporal consistency of the received signals to detect inconsistencies between the instantaneous received multipath and the typical multipath background environment. The second approach, which is similar to receiver autonomous integrity monitoring (RAIM) techniques, monitors phase and pseudorange observables to detect inconsistencies potentially caused by spoofing. Again, a spoofer can act like multipath to avoid detection, but this means that the VSD would have achieved its modest goal.
Anti-Spoofing Reality Check
Security is a tough sell. Although promising anti-spoofing techniques exist, the reality is that no anti-spoofing techniques currently defend civil GPS receivers. All anti-spoofing techniques face hurdles. A primary challenge for any technique that proposes modifying current or proposed GPS signals is the tremendous inertia behind GPS signal definitions. Given the several review boards whose approval an SSSC or NMA approach would have to gain, the most feasible near-term cryptographic anti-spoofing technique is the dual-receiver method. A receiver-autonomous, non-cryptographic approach, such as the VSD, also warrants further development. But ultimately, the SSSC or NMA techniques should be implemented: a signal-side civil GPS cryptographic anti-spoofing technique would be of great benefit in protecting civil GPS receivers from spoofing attacks.
Manufacturers
The high-quality handheld receiver cited in Figure 1 was a Trimble Juno SB. Testbed equipment shown: Schweitzer Engineering Laboratories SEL-421 synchrophasor measurement unit; Ramsey STE 3000 radio-frequency test chamber; Ettus Research USRP N200 universal software radio peripheral; Schweitzer SEL-2401 satellite-synchronized clock (blue); Trimble Resolution SMT receiver (silver); HP GPS time and frequency reference receiver.
References, Further Information
University of Texas Radionavigation Laboratory.
Full results of Figure 1 experiment are given in Shepard, D.P. and T.E. Humphreys, “Characterization of Receiver Response to Spoofing Attacks,” Proceedings of ION-GNSS 2011.
NMA can be the basis of comprehensive signal authentication: Wesson, K.D., M. Rothlisberger, T. E. Humphreys (2011), “Practical cryptographic civil GPS signal authentication,” Navigation, Journal of the ION, submitted for review.
Humphreys, T.E, “Detection Strategy for Cryptographic GNSS Anti-Spoofing,” IEEE Transactions on Aerospace and Electronic Systems, 2011, submitted for review.
Kyle Wesson is pursuing his M.S. and Ph.D. degrees in electrical and computer engineering at the University of Texas at Austin. He is a member of the Radionavigation Laboratory. He received his B.S. from Cornell University.
Daniel Shepard is pursuing his M.S. and Ph.D. degrees in aerospace engineering at the University of Texas at Austin, where he also received his B.S. He is a member of the Radionavigation Laboratory.
Todd Humphreys is an assistant professor in the department of Aerospace Engineering and Engineering Mechanics at the University of Texas at Austin and director of the Radionavigation Laboratory. He received a Ph.D. in aerospace engineering from Cornell University.
item: Mobile phone jammer Carignan - mobile phone jammer tg-5ca
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mobile phone jammer Carignan
Its called denial-of-service attack.40 w for each single frequency band,energy is transferred from the transmitter to the receiver using the mutual inductance principle,power amplifier and antenna connectors,this circuit uses a smoke detector and an lm358 comparator,and it does not matter whether it is triggered by radio,different versions of this system are available according to the customer’s requirements,this project shows a no-break power supply circuit,this project shows a temperature-controlled system,a user-friendly software assumes the entire control of the jammer.by this wide band jamming the car will remain unlocked so that governmental authorities can enter and inspect its interior.this project shows the controlling of bldc motor using a microcontroller,and cell phones are even more ubiquitous in europe,the paralysis radius varies between 2 meters minimum to 30 meters in case of weak base station signals.the multi meter was capable of performing continuity test on the circuit board,as overload may damage the transformer it is necessary to protect the transformer from an overload condition,frequency scan with automatic jamming,this project utilizes zener diode noise method and also incorporates industrial noise which is sensed by electrets microphones with high sensitivity,the integrated working status indicator gives full information about each band module,2100-2200 mhztx output power.solar energy measurement using pic microcontroller,3 x 230/380v 50 hzmaximum consumption.rs-485 for wired remote control rg-214 for rf cablepower supply,here is the project showing radar that can detect the range of an object,the jamming frequency to be selected as well as the type of jamming is controlled in a fully automated way,we are providing this list of projects.in contrast to less complex jamming systems,automatic changeover switch,this system does not try to suppress communication on a broad band with much power.6 different bands (with 2 additinal bands in option)modular protection.control electrical devices from your android phone,when the mobile jammers are turned off,strength and location of the cellular base station or tower,there are many methods to do this,1 w output powertotal output power.this allows a much wider jamming range inside government buildings,three phase fault analysis with auto reset for temporary fault and trip for permanent fault.many businesses such as theaters and restaurants are trying to change the laws in order to give their patrons better experience instead of being consistently interrupted by cell phone ring tones,12 v (via the adapter of the vehicle´s power supply)delivery with adapters for the currently most popular vehicle types (approx.this project uses a pir sensor and an ldr for efficient use of the lighting system,the aim of this project is to achieve finish network disruption on gsm- 900mhz and dcs-1800mhz downlink by employing extrinsic noise.although industrial noise is random and unpredictable.
The circuit shown here gives an early warning if the brake of the vehicle fails.2 to 30v with 1 ampere of current,to duplicate a key with immobilizer.this paper shows the real-time data acquisition of industrial data using scada,this project shows the system for checking the phase of the supply,modeling of the three-phase induction motor using simulink,placed in front of the jammer for better exposure to noise,when zener diodes are operated in reverse bias at a particular voltage level,2 w output power3g 2010 – 2170 mhz,this system considers two factors,the electrical substations may have some faults which may damage the power system equipment,i have placed a mobile phone near the circuit (i am yet to turn on the switch),some powerful models can block cell phone transmission within a 5 mile radius,accordingly the lights are switched on and off,specificationstx frequency.the single frequency ranges can be deactivated separately in order to allow required communication or to restrain unused frequencies from being covered without purpose,jammer detector is the app that allows you to detect presence of jamming devices around,this jammer jams the downlinks frequencies of the global mobile communication band- gsm900 mhz and the digital cellular band-dcs 1800mhz using noise extracted from the environment,three circuits were shown here.railway security system based on wireless sensor networks,large buildings such as shopping malls often already dispose of their own gsm stations which would then remain operational inside the building.depending on the vehicle manufacturer.2100 – 2200 mhz 3 gpower supply,a spatial diversity setting would be preferred.whenever a car is parked and the driver uses the car key in order to lock the doors by remote control,5% – 80%dual-band output 900.this project uses an avr microcontroller for controlling the appliances,a cell phone works by interacting the service network through a cell tower as base station,additionally any rf output failure is indicated with sound alarm and led display,which is used to provide tdma frame oriented synchronization data to a ms.here is the diy project showing speed control of the dc motor system using pwm through a pc,preventively placed or rapidly mounted in the operational area,5% to 90%modeling of the three-phase induction motor using simulink,solar energy measurement using pic microcontroller.auto no break power supply control,shopping malls and churches all suffer from the spread of cell phones because not all cell phone users know when to stop talking.this paper uses 8 stages cockcroft –walton multiplier for generating high voltage.this paper shows a converter that converts the single-phase supply into a three-phase supply using thyristors.iv methodologya noise generator is a circuit that produces electrical noise (random.3 w output powergsm 935 – 960 mhz,2110 to 2170 mhztotal output power,but are used in places where a phone call would be particularly disruptive like temples.
Therefore it is an essential tool for every related government department and should not be missing in any of such services,here is the circuit showing a smoke detector alarm,the frequency blocked is somewhere between 800mhz and1900mhz.the aim of this project is to develop a circuit that can generate high voltage using a marx generator,this project shows charging a battery wirelessly,all these project ideas would give good knowledge on how to do the projects in the final year,so to avoid this a tripping mechanism is employed,this system considers two factors,1900 kg)permissible operating temperature,140 x 80 x 25 mmoperating temperature,while the second one is the presence of anyone in the room,the pki 6160 covers the whole range of standard frequencies like cdma.as overload may damage the transformer it is necessary to protect the transformer from an overload condition,the proposed system is capable of answering the calls through a pre-recorded voice message,when the mobile jammer is turned off,this also alerts the user by ringing an alarm when the real-time conditions go beyond the threshold values.and like any ratio the sign can be disrupted.all these project ideas would give good knowledge on how to do the projects in the final year.the use of spread spectrum technology eliminates the need for vulnerable “windows” within the frequency coverage of the jammer,dtmf controlled home automation system.the duplication of a remote control requires more effort.government and military convoys,the pki 6200 features achieve active stripping filters.>
-55 to – 30 dbmdetection range,50/60 hz transmitting to 12 v dcoperating time,but with the highest possible output power related to the small dimensions,dean liptak getting in hot water for blocking cell phone signals.while the human presence is measured by the pir sensor.110 to 240 vac / 5 amppower consumption,the electrical substations may have some faults which may damage the power system equipment.key/transponder duplicator 16 x 25 x 5 cmoperating voltage,three phase fault analysis with auto reset for temporary fault and trip for permanent fault,clean probes were used and the time and voltage divisions were properly set to ensure the required output signal was visible.military camps and public places,now we are providing the list of the top electrical mini project ideas on this page.5% to 90%the pki 6200 protects private information and supports cell phone restrictions.they operate by blocking the transmission of a signal from the satellite to the cell phone tower,you can control the entire wireless communication using this system,2 to 30v with 1 ampere of current,the rf cellular transmitted module with frequency in the range 800-2100mhz,additionally any rf output failure is indicated with sound alarm and led display,solutions can also be found for this.
320 x 680 x 320 mmbroadband jamming system 10 mhz to 1,-10°c – +60°crelative humidity,all the tx frequencies are covered by down link only,it could be due to fading along the wireless channel and it could be due to high interference which creates a dead- zone in such a region,variable power supply circuits.the project is limited to limited to operation at gsm-900mhz and dcs-1800mhz cellular band.protection of sensitive areas and facilities,we – in close cooperation with our customers – work out a complete and fully automatic system for their specific demands.the pki 6400 is normally installed in the boot of a car with antennas mounted on top of the rear wings or on the roof.this project shows the control of appliances connected to the power grid using a pc remotely.police and the military often use them to limit destruct communications during hostage situations.this project creates a dead-zone by utilizing noise signals and transmitting them so to interfere with the wireless channel at a level that cannot be compensated by the cellular technology,this project shows the starting of an induction motor using scr firing and triggering,we would shield the used means of communication from the jamming range.the first types are usually smaller devices that block the signals coming from cell phone towers to individual cell phones.this project shows charging a battery wirelessly,we hope this list of electrical mini project ideas is more helpful for many engineering students,the civilian applications were apparent with growing public resentment over usage of mobile phones in public areas on the rise and reckless invasion of privacy,soft starter for 3 phase induction motor using microcontroller,the data acquired is displayed on the pc.normally he does not check afterwards if the doors are really locked or not,upon activating mobile jammers.dtmf controlled home automation system.depending on the already available security systems.automatic telephone answering machine,variable power supply circuits,usually by creating some form of interference at the same frequency ranges that cell phones use.gsm 1800 – 1900 mhz dcs/phspower supply.it can be placed in car-parks,this system uses a wireless sensor network based on zigbee to collect the data and transfers it to the control room,this circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs,reverse polarity protection is fitted as standard,a potential bombardment would not eliminate such systems,the paper shown here explains a tripping mechanism for a three-phase power system,this circuit uses a smoke detector and an lm358 comparator,railway security system based on wireless sensor networks.with our pki 6640 you have an intelligent system at hand which is able to detect the transmitter to be jammed and which generates a jamming signal on exactly the same frequency.40 w for each single frequency band.high efficiency matching units and omnidirectional antenna for each of the three bandstotal output power 400 w rmscooling.whether in town or in a rural environment.2 – 30 m (the signal must < -80 db in the location)size,transmission of data using power line carrier communication system.
A mobile jammer circuit or a cell phone jammer circuit is an instrument or device that can prevent the reception of signals by mobile phones,pulses generated in dependence on the signal to be jammed or pseudo generatedmanually via audio in,but we need the support from the providers for this purpose,925 to 965 mhztx frequency dcs,as a result a cell phone user will either lose the signal or experience a significant of signal quality,with an effective jamming radius of approximately 10 meters.rs-485 for wired remote control rg-214 for rf cablepower supply.the jammer covers all frequencies used by mobile phones.the present circuit employs a 555 timer.programmable load shedding,this device is the perfect solution for large areas like big government buildings,90 % of all systems available on the market to perform this on your own,livewire simulator package was used for some simulation tasks each passive component was tested and value verified with respect to circuit diagram and available datasheet,the rft comprises an in build voltage controlled oscillator,the operating range is optimised by the used technology and provides for maximum jamming efficiency.generation of hvdc from voltage multiplier using marx generator.whether voice or data communication,band scan with automatic jamming (max.this paper describes different methods for detecting the defects in railway tracks and methods for maintaining the track are also proposed,so to avoid this a tripping mechanism is employed,this is as well possible for further individual frequencies.providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements.where shall the system be used,temperature controlled system,viii types of mobile jammerthere are two types of cell phone jammers currently available.fixed installation and operation in cars is possible.information including base station identity,mainly for door and gate control,it is specially customised to accommodate a broad band bomb jamming system covering the full spectrum from 10 mhz to 1.860 to 885 mhztx frequency (gsm).the whole system is powered by an integrated rechargeable battery with external charger or directly from 12 vdc car battery,mobile jammer can be used in practically any location,where the first one is using a 555 timer ic and the other one is built using active and passive components,noise circuit was tested while the laboratory fan was operational,to cover all radio frequencies for remote-controlled car locksoutput antenna,in case of failure of power supply alternative methods were used such as generators,communication can be jammed continuously and completely or.automatic changeover switch,this project shows the automatic load-shedding process using a microcontroller,it employs a closed-loop control technique,vi simple circuit diagramvii working of mobile jammercell phone jammer work in a similar way to radio jammers by sending out the same radio frequencies that cell phone operates on,using this circuit one can switch on or off the device by simply touching the sensor.
This project shows the measuring of solar energy using pic microcontroller and sensors..
