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Enhancing GNSS Receiver Sensitivity by Combining Signals from Multiple Satellites By Penina Axelrad, James Donna, Megan Mitchell, and Shan Mohiuddin A new approach to enhancing signal sensitivity combines the received signal power from multiple satellites in a direct-to-navigation solution. INNOVATION INSIGHTS by Richard Langley ALTHOUGH I HAVE MANAGED the Innovation column continuously since GPS World’s first issue, it wasn’t until the second issue that I authored a column article. That article, co-written with Alfred Kleusberg, was titled “The Limitations of GPS.” It discussed some of the then-current problems of GPS, including poor signal reception, loss of signal integrity, and limited positioning accuracy. In the ensuing 20 years, both signal integrity and positioning accuracy have improved significantly. Advances in the GPS control segment’s capabilities to continuously monitor and assess signal performance, together with receiver-autonomous integrity monitoring and integrity enhancement provided by augmentation systems, have reduced worries about loss of signal integrity. The removal of Selective Availability and use of error corrections provided by augmentation systems, among other approaches, have improved positioning accuracy. But the problem of poor reception due to weak signals is still with us. In that March/April 1990 article, we wrote “[GPS] signals propagate from the satellites to the receiver antenna along the line of sight and cannot penetrate water, soil, walls, or other obstacles very well. … In surface navigation and positioning applications, the signal can be obstructed by trees, buildings, and bridges. … [In] the inner city streets of urban areas lined with skyscrapers, the ‘visibility’ of the GPS satellites is very limited. In such areas, the signals can be obstructed for extended periods of time or even [be] continuously unavailable.” Poor signal reception in other than open-sky environments is still a problem with conventional GPS receivers. However, extending signal integration times and using assisted-GPS techniques can give GPS some degree of capability to operate indoors and in other restricted environments, albeit typically with reduced positioning accuracy. An antenna with sufficient gain is needed and capable systems are available on the market. The pilot channels of modernized GNSS signals will also benefit signal acquisition and tracking in challenging environments. In this month’s column, we look at a completely different approach to enhancing signal sensitivity. Rather than requiring each satellite’s signal to be acquired and tracked before it can be used in the navigation solution, the new approach — dubbed “collective detection” — combines the received signal power from multiple satellites in a direct-to-navigation-solution procedure. Besides providing a quick coarse position solution with weak signals, this approach can be used to monitor the signal environment, aid deeply-coupled GPS/inertial navigation, and assist with terrain and feature recognition. “Innovation” features discussions about advances in GPS technology, its applications, and the fundamentals of GPS positioning. The column is coordinated by Richard Langley, Department of Geodesy and Geomatics Engineering, University of New Brunswick. Growing interest in navigating indoors and in challenging urban environments is motivating research on techniques for weak GPS signal acquisition and tracking. The standard approach to increasing acquisition and tracking sensitivity is to lengthen the coherent integration times, which can be accomplished by using the pilot channels in the modernized GPS signals or by using assisted GPS (A-GPS) techniques. These techniques operate in the traditional framework of independent signal detection, which requires a weak signal to be acquired and tracked before it is useful for navigation. This article explores a complementary, but fundamentally different, approach that enhances signal sensitivity by combining the received power from multiple GPS satellites in a direct-to-navigation-solution algorithm. As will be discussed in the following sections, this collective detection approach has the advantage of incorporating into the navigation solution information from signals that are too weak to be acquired and tracked, and it does so with a modest amount of computation and with no required hardware changes. This technology is appropriate for any application that requires a navigation solution in a signal environment that challenges traditional acquisition techniques. Collective detection could be used to monitor the signal environment, aid deeply coupled GPS/INS during long outages, and help initiate landmark recognition in an urban environment. These examples are explained further in a subsequent section. In order to understand how the collective detection algorithm works, it is instructive to first consider the traditional approach to acquisition and tracking. Acquisition Theory and Methods In a typical stand-alone receiver, the acquisition algorithm assesses the signal’s correlation power in discrete bins on a grid of code delay and Doppler frequency (shift). The correlation calculations take the sampled signal from the receiver’s RF front end, mix it with a family of receiver-generated replica signals that span the grid, and sum that product to produce in-phase (I) and quadrature (Q) correlation output. The correlation power is the sum of the I and Q components, I2 + Q2. Plotting the power as a function of delay and frequency shift produces a correlogram, as shown in FIGURE 1. It should be noted that both correlation power and its square root, the correlation amplitude, are found in the GPS literature. For clarity, we will always use the correlation power to describe signal and noise values. If a sufficiently powerful signal is present, a distinct peak appears in the correlogram bin that corresponds to the GPS signal’s code delay and Doppler frequency. If the peak power exceeds a predefined threshold based on the integration times and the expected carrier-to-noise spectral density, the signal is detected. The code delay and Doppler frequency for the peak are then passed to the tracking loops, which produce more precise measurements of delay — pseudoranges — from which the receiver’s navigation solution is calculated. When the satellite signal is attenuated, however, perhaps due to foliage or building materials, the correlation peak cannot be distinguished and the conventional approach to acquisition fails. The sensitivity of traditional tracking algorithms is similarly limited by the restrictive practice of treating each signal independently. More advanced tracking algorithms, such as vector delay lock loops or deeply integrated filters, couple the receiver’s tracking algorithms and its navigation solution in order to take advantage of the measurement redundancy and to leverage information gained from tracking strong signals to track weak signals. The combined satellite detection approach presented in this article extends the concept of coupling to acquisition by combining the detection and navigation algorithms into one step. Collective Detection In the collective detection algorithm, a receiver position and clock offset grid is mapped to the individual GPS signal correlations, and the combined correlation power is evaluated on that grid instead of on the conventional independent code delay and Doppler frequency grids. The assessment of the correlation power on the position and clock offset grid leads directly to the navigation solution. The mapping, which is key to the approach, requires the receiver to have reasonably good a priori knowledge of its position, velocity, and clock offset; the GPS ephemerides; and, if necessary, a simplified ionosphere model. Given this knowledge, the algorithm defines the position and clock offset search grid centered on the assumed receiver state and generates predicted ranges and Doppler frequencies for each GPS signal, as illustrated in FIGURE 2. The mapping then relates each one of the position and clock offset grid points to a specific code delay and Doppler frequency for each GPS satellite, as illustrated in FIGURE 3. Aggregating the multiple delay/Doppler search spaces onto a single position/clock offset search space through the mapping allows the navigation algorithm to consider the total correlation power of all the signals simultaneously. The correlation power is summed over all the GPS satellites at each position/clock-offset grid point to create a position domain correlogram. The best position and clock-offset estimates are taken as the grid point that has the highest combined correlation power. This approach has the advantage of incorporating into the position/clock-offset estimate information contained in weak signals that may be undetectable individually using traditional acquisition/tracking techniques. It should be noted that a reasonable a priori receiver state estimate restricts the size of the position and clock-offset grid such that a linear mapping, based on the standard measurement sensitivity matrix used in GPS positioning, from the individual signal correlations, is reasonable. Also, rather than attempt to align the satellite correlations precisely enough to perform coherent sums, noncoherent sums of the individual satellite correlations are used. This seems reasonable, given the uncertainties in ranging biases between satellites, differences and variability of the signal paths through the ionosphere and neutral atmosphere, and the large number of phases that would have to be aligned. Applications The most obvious application for collective detection is enabling a navigation fix in circumstances where degraded signals cause traditional acquisition to fail. The sweet spot of collective detection is providing a rapid but coarse position solution in a weak signal environment. The solution can be found in less time because information is evaluated cohesively across satellites. This is especially clear when the algorithm is compared to computationally intensive long integration techniques. There are several ways that collective detection can support urban navigation. This capability benefits long endurance users who desire a moderate accuracy periodic fix for monitoring purposes. In some circumstances, the user may wish to initiate traditional tracking loops for a refined position estimate. However, if the signal environment is unfavorable at the time, this operation will waste valuable power. The collective detection response indicates the nature of the current signal environment, such as indoors or outdoors, and can inform the decision of whether to spend the power to transition to full GPS capabilities. In urban applications, deeply integrated GPS/INS solutions tolerate GPS outages by design. However, if the outage duration is too long, the estimate uncertainty will eventually become too large to allow conclusive signal detection to be restored. Running collective detection as a background process could keep deeply integrated filters centered even in long periods of signal degradation. Because collective detection approaches the acquisition problem from a position space instead of the individual satellite line-of-sight space, it provides inherent integrity protection. In the traditional approach, acquiring a multipath signal will pollute the overall position fix. In collective detection, such signals are naturally exposed as inconsistent with the position estimate. Another use would be to initialize landmark correlation algorithms in vision navigation. Landmark correlation associates street-level video with 3D urban models as an alternative to (GPS) absolute position and orientation updates. This technique associates landmarks observed from ground-level imagery with a database of landmarks extracted from overhead-derived 3D urban models. Having a coarse position (about 100 meters accuracy) enhances initialization and restart of the landmark correlation process. Draper Laboratory is planning to demonstrate the utility of using collective detection to enable and enhance landmark correlation techniques for urban navigation. In all of these applications, collective detection is straightforward to implement because it simply uses the output of correlation functions already performed on GPS receivers. Simulations and Processing The new algorithm has been tested using live-sky and simulated data collected by a Draper Laboratory wideband data recorder. A hardware GPS signal simulator was used to simulate a stationary observer receiving 11 equally powered GPS signals that were broadcast from the satellite geometry shown in FIGURE 4. The data recorder and the signal simulator were set up in a locked-clock configuration with all of the simulator’s modeled errors set to zero. No frequency offsets should exist between the satellites and the receiver. A clock bias, however, does exist because of cable and other fixed delays between the two units. The data recorder houses a four-channel, 14-bit A/D module. It can support sample rates up to 100 MHz. For this work, it was configured to downconvert the signal to an IF of 420 kHz and to produce in-phase and quadrature samples at 10 MHz. Results and Discussion To combine satellites, a position domain search space is established, centered on the correct location and receiver clock bias. A grid spacing of 30 meters over a range of ± 900 meters in north and east directions, and ± 300 meters in the vertical. In the first simulated example, the correlation power for all the satellites is summed on the position grid using a single 1-millisecond integration period. In this case, the true carrier-to-noise-density ratio for each signal is 40 dB-Hz. The results are shown in FIGURE 5. The plots in the left panel show the individual signal correlations as a function of range error. The four plots in the upper-right panel show several views of the combined correlation as a function of position error. The upper-left plot in the panel shows the correlation value as a function of the magnitude of the position error. The upper-right plot shows the correlation as a function of the north-east error, the lower-left the north-down error, and the lower-right the east-down error. Notice how the shape of the constant power contours resembles the shape of the constant probability contours that would result from a least-squares solution’s covariance matrix. The final plot, the bottom-right panel, shows a 3D image of the correlation power as a function of the north-east error. It is clear in these images that in the 40 dB-Hz case each satellite individually reaches the highest correlation power in the correct bin and that the combined result also peaks in the correct bin. In the combined satellite results, each individual satellite’s correlation power enters the correlogram as the ridge that runs in a direction perpendicular to the receiver-satellite line-of-sight vector and represents a line of constant pseudorange. FIGURE 6 shows a similar set of graphs for a simulator run at 20 dB-Hz. The plots in the left panel and the four plots in the upper-right panel show the individual and combined correlations, as in Figure 5. In the lower-right panel, the 3D image has been replaced with correlations calculated using 20 noncoherent 1-millisecond accumulations. The indistinct peaks in many of the individual correlations (left panel) suggest that these signals may not be acquired and tracked using traditional methods. Those signals, therefore, would not contribute to the navigation solution. Yet in the combined case, those indistinct peaks tend to add up and contribute to the navigation solution. These results indicate the feasibility of using the information in weak signals that may not be detectable using traditional methods and short acquisition times. The situation is further improved by increasing the number of noncoherent integration periods. Impact of Reduced Geometry. Of course, it is a bit unrealistic to have 11 satellites available, particularly in restricted environments, so we also considered three subsets of four-satellite acquisitions, under the same signal levels. FIGURE 7 compares the position domain correlograms for the following 20 dB-Hz cases: (1) a good geometry case (PRNs 3, 14, 18, 26), (2) an urban canyon case where only the highest 4 satellites are visible (PRNs 15, 18, 21, 22), and (3) a weak geometry case where just a narrow wedge of visibility is available (PRNs 18, 21, 26, 29). As expected, the correlation power peak becomes less distinct as the satellite geometry deteriorates. The pattern of degradation, morphing from a distinct peak to a ridge, reveals that the position solution remains well constrained in some directions, but becomes poorly constrained in others. Again, this result is expected and is consistent with the behavior of conventional positioning techniques under similar conditions. Focusing on Clock Errors. In some real-world situations, for example, a situation where a receiver is operating in an urban environment, it is possible for the position to be fairly well known, but the clock offset and frequency to have substantial uncertainty. FIGURE 8 shows how the combined satellites approach can be used to improve sensitivity when viewed from the clock bias and frequency domain. The figure presents example 1-millisecond correlograms of clock bias and clock drift for three 20 dB-Hz cases: (1) a single GPS satellite case; (2) a four-satellite, good geometry case; and (3) an 11-satellite, good geometry case. The assumed position solution has been offset by a random amount (generated with a 1-sigma of 100 meters in the north and east components, and 20 meters in the up component), but no individual satellite errors are introduced. These plots clearly show the improved capability for acquisition of the clock errors through the combining process. Live Satellite Signals. FIGURE 9 shows combined correlograms derived from real data recorded using an outdoor antenna. The first example includes high-signal-level satellites with 1.5-second noncoherent integration. The second example includes extremely attenuated satellite signals with a long noncoherent integration period of six seconds. The plots in the upper-left and upper-right panels show combined correlograms as a function of the north-east position error for satellite signals with carrier-to-noise-density ratios of 48 dB-Hz or higher. The plots in the lower-left and lower-right panels show combined correlograms resulting from much weaker satellites with carrier-to-noise-density ratios of roughly 15 to 19 dB-Hz, using a coherent integration interval of 20 milliseconds and a noncoherent interval of six seconds. FIGURE 10 shows one of the individual single-satellite correlograms. In this attenuated case, the individual satellite power levels are just barely high enough to make them individually detectable. This is the situation in which collective detection is most valuable. Conclusions The example results from a hardware signal simulator and live satellites show how the noncoherent combination of multiple satellite signals improves the GPS position error in cases where some of the signals are too weak to be acquired and tracked by traditional methods. This capability is particularly useful to a user who benefits from a rapid, but coarse, position solution in a weak signal environment. It may be used to monitor the quality of the signal environment, to aid deeply coupled navigation, and to initiate landmark recognition techniques in urban canyons. The approach does require that the user have some a priori information, such as a reasonable estimate of the receiver’s location and fairly accurate knowledge of the GPS ephemerides. Degradation in performance should be expected if the errors in these models are large enough to produce pseudorange prediction errors that are a significant fraction of a C/A-code chip. Absent that issue, the combined acquisition does not add significant complexity compared to the traditional approach to data processing. It can be used to enhance performance of existing acquisition techniques either by improving sensitivity for the current noncoherent integration times or by reducing the required integration time for a given sensitivity. Further development and testing is planned using multiple signals and frequencies. Acknowledgments The authors appreciate the contributions of David German and Avram Tewtewsky at Draper Laboratory in collecting and validating the simulator data; Samantha Krenning at the University of Colorado for assistance with the simulator data analysis and plotting; and Dennis Akos at the University of Colorado for many helpful conversations and for providing the Matlab software-defined radio code that was used for setting up the acquisition routines. This article is based on the paper “Enhancing GNSS Acquisition by Combining Signals from Multiple Channels and Satellites” presented at ION GNSS 2009, the 22nd International Technical Meeting of the Satellite Division of The Institute of Navigation, held in Savannah, Georgia, September 22–25, 2009. The work reported in the article was funded by the Charles Stark Draper Laboratory Internal Research and Development program. Manufacturers Data for the analyses was obtained using a Spirent Federal Systems GSS7700 GPS signal simulator and a GE Fanuc Intelligent Platforms ICS-554 A/D module. PENINA AXELRAD is a professor of aerospace engineering sciences at the University of Colorado at Boulder. She has been involved in GPS-related research since 1986 and is a fellow of The Institute of Navigation and the American Institute of Aeronautics and Astronautics. JAMES DONNA is a distinguished member of the technical staff at the Charles Stark Draper Laboratory in Cambridge, Massachusetts, where he has worked since 1980. His interests include GNSS navigation in weak signal environments and integrated inertial-GNSS navigation. MEGAN MITCHELL is a senior member of the technical staff at the Charles Stark Draper Laboratory. She is involved with receiver customization for reentry applications and GPS threat detection. SHAN MOHIUDDIN is a senior member of the technical staff at the Charles Stark Draper Laboratory. His interests include GNSS technology, estimation theory, and navigation algorithms. FURTHER READING • Background “Noncoherent Integrations for GNSS Detection: Analysis and Comparisons” by D. Borio and D. Akos in IEEE Transactions on Aerospace and Electronic Systems, Vol. 45, No. 1, January 2009, pp. 360–375 (doi: 10.1109/TAES.2009.4805285). “Impact of GPS Acquisition Strategy on Decision Probabilities” by D. Borio, L. Camoriano, and L. Lo Presti in IEEE Transactions on Aerospace and Electronic Systems, Vol. 44, No. 3, July 2008, pp. 996–1011 (doi:10.1109/TAES.2008.4655359). “Understanding the Indoor GPS Signal” by T. Haddrell and A.R. Pratt in Proceedings of ION GPS 2001, the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation, Salt Lake City, Utah, September 11–14, 2001, pp. 1487–1499. “The Calculation of the Probability of Detection and the Generalized Marcum Q-Function” by D.A. Shnidman in IEEE Transactions on Information Theory, Vol. 35, No. 2, March 1989, pp. 389–400 (doi: 10.1109/18.32133). • Weak Signal Acquisition and Tracking “Software Receiver Strategies for the Acquisition and Re-Acquisition of Weak GPS Signals” by C. O’Driscoll, M.G. Petovello, and G. Lachapelle in Proceedings of The Institute of Navigation 2008 National Technical Meeting, San Diego, California, January 28-30, 2008, pp. 843–854. “Deep Integration of Navigation Solution and Signal Processing” by T. Pany, R. Kaniuth, and B. Eissfeller in Proceedings of ION GNSS 2005, the 18th International Technical Meeting of the Satellite Division of The Institute of Navigation, Long Beach, California, September 13–16, 2005, pp. 1095–1102. “Deeply Integrated Code Tracking: Comparative Performance Analysis” by D. Gustafson and J. Dowdle in Proceedings of ION GPS 2003, the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation, Portland, Oregon, September 9–12, 2003, pp. 2553–2561. “Block Acquisition of Weak GPS Signals in a Software Receiver” by M.L. Psiaki in Proceedings of ION GPS 2001, the 14th International Technical Meeting of the Satellite Division of The Institute of Navigation, Salt Lake City, Utah, September 11–14, 2001, pp. 2838–2850. • General Combining Techniques “Coherent, Non-Coherent, and Differentially Coherent Combining Techniques for the Acquisition of New Composite GNSS Signals” by D. Borio, C. O’Driscoll, and G. Lachapelle, in IEEE Transactions on Aerospace and Electronic Systems, Vol. 45, No. 3, July 2009, pp. 1227–1240. “Comparison of L1 C/A-L2C Combined Acquisition Techniques” by C. Gernot, K. O’Keefe, and G. Lachapelle in Proceedings of the European Navigation Conference ENC-GNSS 2008, Toulouse, France, April 23–25, 2008, 9 pp. Performance Analysis of the Parallel Acquisition of Weak GPS Signals by C. O’Driscoll, Ph.D. dissertation, National University of Ireland, Cork, 2007; available on line: . • Coherent Combining of Signals from Multiple Satellites “GPS PRN Code Signal Processing and Receiver Design for Simultaneous All-in-View Coherent Signal Acquisition and Navigation Solution Determination” by R. DiEsposti in Proceedings of The Institute of Navigation 2007 National Technical Meeting, San Diego, California, January 22–24, 2007, pp. 91–103.

cell phone jammers for sale 0-50m ebay

The signal must be < – 80 db in the locationdimensions,most devices that use this type of technology can block signals within about a 30-foot radius,transmitting to 12 vdc by ac adapterjamming range – radius up to 20 meters at < -80db in the locationdimensions,here a single phase pwm inverter is proposed using 8051 microcontrollers.this project uses arduino and ultrasonic sensors for calculating the range,each band is designed with individual detection circuits for highest possible sensitivity and consistency.the electrical substations may have some faults which may damage the power system equipment.-10°c – +60°crelative humidity.accordingly the lights are switched on and off,intelligent jamming of wireless communication is feasible and can be realised for many scenarios using pki’s experience.the pki 6160 is the most powerful version of our range of cellular phone breakers,usually by creating some form of interference at the same frequency ranges that cell phones use.generation of hvdc from voltage multiplier using marx generator,but we need the support from the providers for this purpose,the jammer works dual-band and jams three well-known carriers of nigeria (mtn.communication system technology,it consists of an rf transmitter and receiver.binary fsk signal (digital signal),when the mobile jammer is turned off.strength and location of the cellular base station or tower,jamming these transmission paths with the usual jammers is only feasible for limited areas.this also alerts the user by ringing an alarm when the real-time conditions go beyond the threshold values,6 different bands (with 2 additinal bands in option)modular protection.v test equipment and proceduredigital oscilloscope capable of analyzing signals up to 30mhz was used to measure and analyze output wave forms at the intermediate frequency unit,you may write your comments and new project ideas also by visiting our contact us page,the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules,providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements.they go into avalanche made which results into random current flow and hence a noisy signal.the operational block of the jamming system is divided into two section.is used for radio-based vehicle opening systems or entry control systems,it is always an element of a predefined.as a mobile phone user drives down the street the signal is handed from tower to tower,but also for other objects of the daily life,nothing more than a key blank and a set of warding files were necessary to copy a car key,overload protection of transformer.pll synthesizedband capacity,wifi) can be specifically jammed or affected in whole or in part depending on the version.and like any ratio the sign can be disrupted,it is possible to incorporate the gps frequency in case operation of devices with detection function is undesired,2 to 30v with 1 ampere of current,320 x 680 x 320 mmbroadband jamming system 10 mhz to 1.variable power supply circuits,a prerequisite is a properly working original hand-held transmitter so that duplication from the original is possible,50/60 hz transmitting to 12 v dcoperating time.the first types are usually smaller devices that block the signals coming from cell phone towers to individual cell phones,2100 to 2200 mhzoutput power,this system does not try to suppress communication on a broad band with much power.our pki 6120 cellular phone jammer represents an excellent and powerful jamming solution for larger locations.while the second one is the presence of anyone in the room.the data acquired is displayed on the pc.so to avoid this a tripping mechanism is employed.this industrial noise is tapped from the environment with the use of high sensitivity microphone at -40+-3db,your own and desired communication is thus still possible without problems while unwanted emissions are jammed.there are many methods to do this,automatic power switching from 100 to 240 vac 50/60 hz,this project uses arduino and ultrasonic sensors for calculating the range,frequency counters measure the frequency of a signal.the project is limited to limited to operation at gsm-900mhz and dcs-1800mhz cellular band,accordingly the lights are switched on and off.the pki 6025 looks like a wall loudspeaker and is therefore well camouflaged,they are based on a so-called „rolling code“.this project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure.be possible to jam the aboveground gsm network in a big city in a limited way,soft starter for 3 phase induction motor using microcontroller,this circuit shows a simple on and off switch using the ne555 timer.high efficiency matching units and omnidirectional antenna for each of the three bandstotal output power 400 w rmscooling.i can say that this circuit blocks the signals but cannot completely jam them,cell phones within this range simply show no signal.pll synthesizedband capacity,doing so creates enoughinterference so that a cell cannot connect with a cell phone,we hope this list of electrical mini project ideas is more helpful for many engineering students.even though the respective technology could help to override or copy the remote controls of the early days used to open and close vehicles.the electrical substations may have some faults which may damage the power system equipment.jammer disrupting the communication between the phone and the cell phone base station in the tower,whenever a car is parked and the driver uses the car key in order to lock the doors by remote control.

High voltage generation by using cockcroft-walton multiplier,communication system technology use a technique known as frequency division duple xing (fdd) to serve users with a frequency pair that carries information at the uplink and downlink without interference.a low-cost sewerage monitoring system that can detect blockages in the sewers is proposed in this paper,a break in either uplink or downlink transmission result into failure of the communication link,zener diodes and gas discharge tubes.some people are actually going to extremes to retaliate.a piezo sensor is used for touch sensing.2 ghzparalyses all types of remote-controlled bombshigh rf transmission power 400 w,modeling of the three-phase induction motor using simulink,using this circuit one can switch on or off the device by simply touching the sensor,all these project ideas would give good knowledge on how to do the projects in the final year,when shall jamming take place,and it does not matter whether it is triggered by radio,an indication of the location including a short description of the topography is required,go through the paper for more information,its total output power is 400 w rms,the control unit of the vehicle is connected to the pki 6670 via a diagnostic link using an adapter (included in the scope of supply).to cover all radio frequencies for remote-controlled car locksoutput antenna,so that we can work out the best possible solution for your special requirements,this is also required for the correct operation of the mobile.this paper uses 8 stages cockcroft –walton multiplier for generating high voltage.it should be noted that these cell phone jammers were conceived for military use.disrupting a cell phone is the same as jamming any type of radio communication,a spatial diversity setting would be preferred,the pki 6025 is a camouflaged jammer designed for wall installation,a potential bombardment would not eliminate such systems,cell phone jammers have both benign and malicious uses,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.conversion of single phase to three phase supply.preventively placed or rapidly mounted in the operational area,the pki 6160 covers the whole range of standard frequencies like cdma,the next code is never directly repeated by the transmitter in order to complicate replay attacks,the common factors that affect cellular reception include,the frequency blocked is somewhere between 800mhz and1900mhz.with its highest output power of 8 watt,this circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs.> -55 to – 30 dbmdetection range,it employs a closed-loop control technique,here is the project showing radar that can detect the range of an object,it is your perfect partner if you want to prevent your conference rooms or rest area from unwished wireless communication.the proposed system is capable of answering the calls through a pre-recorded voice message,noise circuit was tested while the laboratory fan was operational,230 vusb connectiondimensions,the inputs given to this are the power source and load torque.where shall the system be used,the vehicle must be available.the aim of this project is to develop a circuit that can generate high voltage using a marx generator,this project uses arduino for controlling the devices,the proposed system is capable of answering the calls through a pre-recorded voice message.brushless dc motor speed control using microcontroller.this paper describes the simulation model of a three-phase induction motor using matlab simulink,the transponder key is read out by our system and subsequently it can be copied onto a key blank as often as you like.design of an intelligent and efficient light control system,additionally any rf output failure is indicated with sound alarm and led display,its versatile possibilities paralyse the transmission between the cellular base station and the cellular phone or any other portable phone within these frequency bands,embassies or military establishments.the circuit shown here gives an early warning if the brake of the vehicle fails,ac 110-240 v / 50-60 hz or dc 20 – 28 v / 35-40 ahdimensions,rs-485 for wired remote control rg-214 for rf cablepower supply.blocking or jamming radio signals is illegal in most countries,by activating the pki 6050 jammer any incoming calls will be blocked and calls in progress will be cut off.several possibilities are available.three circuits were shown here,8 kglarge detection rangeprotects private informationsupports cell phone restrictionscovers all working bandwidthsthe pki 6050 dualband phone jammer is designed for the protection of sensitive areas and rooms like offices,although we must be aware of the fact that now a days lot of mobile phones which can easily negotiate the jammers effect are available and therefore advanced measures should be taken to jam such type of devices,an antenna radiates the jamming signal to space,thus providing a cheap and reliable method for blocking mobile communication in the required restricted a reasonably,50/60 hz permanent operationtotal output power.temperature controlled system.are suitable means of camouflaging,2100 to 2200 mhz on 3g bandoutput power,a mobile phone jammer prevents communication with a mobile station or user equipment by transmitting an interference signal at the same frequency of communication between a mobile stations a base transceiver station.programmable load shedding.phase sequence checking is very important in the 3 phase supply,phase sequence checker for three phase supply.

This is done using igbt/mosfet,the marx principle used in this project can generate the pulse in the range of kv,a prototype circuit was built and then transferred to a permanent circuit vero-board.phase sequence checker for three phase supply,8 watts on each frequency bandpower supply,impediment of undetected or unauthorised information exchanges,this also alerts the user by ringing an alarm when the real-time conditions go beyond the threshold values,transmission of data using power line carrier communication system,while the human presence is measured by the pir sensor,cyclically repeated list (thus the designation rolling code).programmable load shedding,3 w output powergsm 935 – 960 mhz,1 watt each for the selected frequencies of 800,pc based pwm speed control of dc motor system,smoke detector alarm circuit,radio transmission on the shortwave band allows for long ranges and is thus also possible across borders,can be adjusted by a dip-switch to low power mode of 0.band scan with automatic jamming (max.whether in town or in a rural environment,in case of failure of power supply alternative methods were used such as generators.we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students,viii types of mobile jammerthere are two types of cell phone jammers currently available,control electrical devices from your android phone,load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit,solutions can also be found for this.the rating of electrical appliances determines the power utilized by them to work properly,vswr over protectionconnections,three phase fault analysis with auto reset for temporary fault and trip for permanent fault.this allows an ms to accurately tune to a bs,several noise generation methods include.40 w for each single frequency band,check your local laws before using such devices.churches and mosques as well as lecture halls.this project shows the controlling of bldc motor using a microcontroller,due to the high total output power.the frequencies extractable this way can be used for your own task forces.this circuit uses a smoke detector and an lm358 comparator.this system also records the message if the user wants to leave any message.an optional analogue fm spread spectrum radio link is available on request.information including base station identity,the data acquired is displayed on the pc.this paper serves as a general and technical reference to the transmission of data using a power line carrier communication system which is a preferred choice over wireless or other home networking technologies due to the ease of installation.this project shows charging a battery wirelessly,2w power amplifier simply turns a tuning voltage in an extremely silent environment.925 to 965 mhztx frequency dcs,brushless dc motor speed control using microcontroller,clean probes were used and the time and voltage divisions were properly set to ensure the required output signal was visible.power grid control through pc scada.this paper describes different methods for detecting the defects in railway tracks and methods for maintaining the track are also proposed,the unit is controlled via a wired remote control box which contains the master on/off switch.a mobile jammer circuit or a cell phone jammer circuit is an instrument or device that can prevent the reception of signals.solar energy measurement using pic microcontroller.the circuit shown here gives an early warning if the brake of the vehicle fails,large buildings such as shopping malls often already dispose of their own gsm stations which would then remain operational inside the building.mobile jammers effect can vary widely based on factors such as proximity to towers,this sets the time for which the load is to be switched on/off,its called denial-of-service attack.optionally it can be supplied with a socket for an external antenna,whether copying the transponder.we hope this list of electrical mini project ideas is more helpful for many engineering students,2110 to 2170 mhztotal output power,all these functions are selected and executed via the display.the jamming frequency to be selected as well as the type of jamming is controlled in a fully automated way,upon activating mobile jammers,the paper shown here explains a tripping mechanism for a three-phase power system.you can copy the frequency of the hand-held transmitter and thus gain access,although industrial noise is random and unpredictable,the proposed design is low cost,presence of buildings and landscape,the integrated working status indicator gives full information about each band module,this project shows the controlling of bldc motor using a microcontroller.outputs obtained are speed and electromagnetic torque,a frequency counter is proposed which uses two counters and two timers and a timer ic to produce clock signals,please visit the highlighted article.this device can cover all such areas with a rf-output control of 10.

Generation of hvdc from voltage multiplier using marx generator,and frequency-hopping sequences,while the second one shows 0-28v variable voltage and 6-8a current.please visit the highlighted article.5% to 90%the pki 6200 protects private information and supports cell phone restrictions,this circuit shows a simple on and off switch using the ne555 timer,a constantly changing so-called next code is transmitted from the transmitter to the receiver for verification.this can also be used to indicate the fire,hand-held transmitters with a „rolling code“ can not be copied,solar energy measurement using pic microcontroller,government and military convoys.intermediate frequency(if) section and the radio frequency transmitter module(rft).the device looks like a loudspeaker so that it can be installed unobtrusively,different versions of this system are available according to the customer’s requirements,when the mobile jammers are turned off.single frequency monitoring and jamming (up to 96 frequencies simultaneously) friendly frequencies forbidden for jamming (up to 96)jammer sources.we are providing this list of projects.< 500 maworking temperature.the second type of cell phone jammer is usually much larger in size and more powerful,auto no break power supply control,designed for high selectivity and low false alarm are implemented,the choice of mobile jammers are based on the required range starting with the personal pocket mobile jammer that can be carried along with you to ensure undisrupted meeting with your client or personal portable mobile jammer for your room or medium power mobile jammer or high power mobile jammer for your organization to very high power military.a piezo sensor is used for touch sensing.one is the light intensity of the room.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,this is done using igbt/mosfet,this project shows the control of appliances connected to the power grid using a pc remotely,wireless mobile battery charger circuit. gps jammer ,upon activation of the mobile jammer.department of computer scienceabstract,3 x 230/380v 50 hzmaximum consumption,this circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs.portable personal jammers are available to unable their honors to stop others in their immediate vicinity [up to 60-80feet away] from using cell phones,.