2021/04/08
Figure 1. Overall system architecture for MUSTER: Multi-platform signal and trajectory estimation receiver.
More Receiver Nodes Bring Ubiquitous Navigation Closer
Encouraging results from new indoor tests and advances in collaborative phased arrays come from MUSTER: multiple independently operating GPS receivers that exchange their signal and measurement data to enhance GNSS navigation in degraded signal environments, such as urban canyons and indoors.
By Andrey Soloviev and Jeffrey Dickman
Bringing GNSS navigation further indoors by adding new users to a collaborative network can help realize the concept of ubiquitous navigation. Increasing the number of receiver nodes to improve signal-to-noise ratios and positioning accuracy lies at the heart of the MUlti-platform Signal and Trajectory Estimation Receiver (MUSTER). This article focuses on benefits of integrating multi-node receiver data at the level of signal processing, considering two case studies:
Collaborative GNSS signal processing for recovery of attenuated signals, and
Use of multi-node antenna arrays for interference mitigation.
MUSTER organizes individual receiver nodes into a collaborative network to enable:
Integration at the signal processing level, including:
Multi-platform signal tracking for processing of attenuated satellite signals;
Multi-platform phased arrays for interference suppression;
Integration at the measurement level, including:
Joint estimation of the receiver trajectory states (position, velocity and time); and,
Multi-platform integrity monitoring via identification and exclusion of measurement failures.
To exclude a single point of failure, the receiver network is implemented in a decentralized fashion. Each receiver obtains GNSS signals and signal measurements (code phase, Doppler shift and carrier phase) from other receivers via a communication link and uses these data to operate in a MUSTER mode (that is, to implement a multi-platform signal fusion and navigation solution). At the same time, each receiver supplies other receivers in the network with its signal and measurement data. Figure 1 illustrates the overall system architecture.
Open-loop tracking is the key technological enabler for multi-node signal processing. Particularly, MUSTER extends an open-loop tracking concept that has been previously researched for single receivers to networked GNSS receivers. Signals from multiple platforms are combined to construct a joint 3D signal image (signal energy versus code phase and Doppler shift). Signal parameters (code phase, Doppler shift, carrier phase) are then estimated directly from this image and without employing tracking loops.
Open-loop tracking is directly applied to accommodate limitations of military and civilian data links. To support the functionality of the receiver network at the signal processing level (that is, to enable multi-platform signal tracking and multi-platform phased arrays) while satisfying bandwidth limitations of existing data link standards, individual receivers exchange pre-correlated signal functions rather than exchanging raw signal samples.
Before sending its data to others, each receiver processes the incoming satellite signal with a pre-processing engine. This engine accumulates a complex amplitude of the GNSS signal as a function of code phase and Doppler frequency shift. Receivers then broadcast portions of their pre-correlated signal images that are represented as a complex signal amplitude over the code/Doppler correlation space for 1-ms or 20-ms signal accumulation. For broadcasting, portions of signal images are selected around expected energy peaks whose locations are derived from some initial navigation and clock knowledge.
This approach is scalable for the increased number of networked receivers and/or increased sampling rate of the ranging code (such as P(Y)-code vs. CA-code). The link bandwidth is accommodated by tightening the uncertainty in the location of the energy peak. As a result, the choice of the data link becomes a trade-off between the number of collaborative receivers and MUSTER cold-start capabilities (that is, maximum initial uncertainties in the navigation and clock solution).
Multi-Node Signal Accumulation
An earlier paper that we presented at the ION International Technical Meeting, January 2013, describes the approach of multi-platform signal accumulation for those cases where relative multi-node navigation and clock states are partially known. This section reviews that approach and then extends it to cases of completely unknown relative navigation and clock states. The following assumptions were previously used:
Relative position between networked receivers is known only within 100 meters;
Relative receivers’ velocity is known within 2 meters/second;
Relative clock states are calibrated with the accuracy of 100 nanoseconds (ns) or, equivalently, 30 meters.
These assumptions are generally suitable for a pedestrian type of receiver network (such as a group of cellular phone users in a shopping mall area) where individual nodes stay within 100 meters from each other; their relative velocities do not differ by more than 2 meters/second; and, the clocks can be pre-calibrated using communication signals. In this case, zero relative states are used for the multi-node signal accumulation and subsequent tracking. Figure 2 summarizes the corresponding MUSTER tracking architecture.
Figure 2. Multi-platform tracking architecture for approximately known relative navigation states.
Relative navigation states are initialized based on clock calibration results only: zero relative position and velocity are assumed. These initial states are then propagated over time, based on MUSTER/supplemental tracking results (Doppler frequency estimates and higher-order Doppler terms). Code and frequency tracking states are computed by combining biased and unbiased measurements. Biased measurements are obtained by adjusting supplemental signal images for approximately known relative states only. Unbiased measurements are enabled by relative range/Doppler correction algorithms that estimates range and frequency adjustments for each supplemental receiver.
The Kalman filter that supports the optimal combination of biased and unbiased tracking measurements also includes code-carrier smoothing to mitigate noise in measured code phase. For those cases where multi-platform signals are combined coherently, a standard carrier-smoothing approach is used. When non-coherent signal combinations are applied, a so-called pseudo-carrier phase is first derived by integrating Doppler estimates over time and then applied to smooth the code phase.
Multi-platform signal accumulation and tracking can be extended to include cases where the relative navigation parameters are completely unknown. For such cases, MUSTER implements an adjustment search to find the values of code phase and Doppler shift for each supplemental receiver that maximize the overall signal energy.
Adjustment search must be implemented if MUSTER/supplemental relative states are completely unknown, or if their accuracy is insufficient to enable direct accumulation of multi-platform energy, for example, when the relative range accuracy is worse than 150 meters and an energy loss of at least 3 dB is introduced to the signal accumulation process. For each code phase, Doppler and carrier phase (if coherent integration is performed) from the adjustment search space, a supplemental 1-ms function is adjusted accordingly and then added to the MUSTER function. Multiple 3D GPS signal images are constructed, and the image with the maximum accumulated energy is applied to initialize relative navigation parameters: code phase and Doppler shift adjustments values from the adjustment search space that correspond to the energy peak serve as approximate estimates of relative range and Doppler.
The accuracy of these estimates is defined by the resolution of the adjustment search, which would be generally kept quite coarse in order to minimize the search space. For instance, a 300-meter search grid is currently implemented for the code phase, which enables the resolution of relative ranges within 150 meters only. Hence, to mitigate the influence of relative state uncertainties on the tracking quality, a correction algorithm is applied as described in our earlier paper. Figure 3 shows the overall system architecture.
Figure 3. MUSTER signal-tracking approach for cases of unknown relative states.
The architecture keeps all the previously developed system components and adds the adjustment search capability (red block in Figure 3) to incorporate cases of unknown MUSTER/supplemental receivers’ relative navigation states. To minimize the computational load, adjustment search is performed only for the first tracking epoch. Search results are applied to initialize the estimates of MUSTER/supplemental range and Doppler, which are then refined at each subsequent measurement epoch using a combined biased/noisy tracking scheme.
The updated architecture can support cases of completely unknown relative states, as well as those cases where relative states are coarsely known, but this knowledge is insufficient to directly combine multi-platform signals.
The complete adjustment search is possible. However, it is extremely challenging for actual implementations due to both large computational load and a data exchange rate associated with it. To exemplify, NcodexNDoppler versions of the multi-platform 3D function have to be computed for the case where Ncode code phase and NDoppler Doppler shift adjustment search bins are used and outputs from two receivers are combined non-coherently. A complete search (1023 code bins and 11 frequency bins) requires computation of 11,253 3D functions. This number increases to (11,253)2 or 126,630,009 if the third receiver is added.
In addition, receivers must exchange their complete pre-correlated signal functions, which puts a considerable burden on the computational data link. For instance, the exchange of complete 1-ms functions with the 4-bit resolution of samples (required to track the carrier phase) results in the 45 Mbit/s data rate for only a 2-receiver network. Hence, it is anticipated that for practical scenarios, a reduced adjustment search will be utilized for cases where the accuracy of relative states does not support the direct accumulation of multi-platform signals: for example, when the distance between users in the network exceeds 150 meters. In this case, only segments of 1-ms functions around expected energy peaks (estimated based on approximate navigation knowledge) are exchanged.
Phased Arrays
Multi-platform phased arrays have been developed to enable interference and jamming protection for GNSS network users who cannot afford a controlled reception pattern antenna (CRPA) due to size, weight, and power (SWAP), as well as cost constraints. The multi-node phased array approach presented here cannot match the performance of CRPA, with its careful design, antenna calibration, and precise knowledge of relative location of phase centers of individual elements. However, it can still offer a significant interference protection to networked GNSS users.
The multi-platform phased array implements a cascaded space-time adaptive processing (STAP) as illustrated in Figure 4.
Figure 4. Implementation of multi-platform phased array with cascaded space-time adaptive processing.
Cascaded STAP implements temporal filtering at a pre-correlation stage, while spatial filtering (in a form of the digital beam forming or DBF) is carried out at post-correlation. Cascaded STAP is implemented instead of joint STAP formulation to
remove the need to exchange raw signal samples (which is necessary when DBF is applied at pre-correlation); and,
support a novel DBF approach that does not require precise (that is, sub-centimeter to centimeter-level) knowledge of relative position and clock states between network nodes (described later).
Signal samples are still exchanged for the estimation of signal covariance matrices that are required for the computation of temporal and spatial weights. However, the sample exchange rate is reduced significantly as compared to the joint STAP: for example, only 100 samples are currently being exchanged out of the total of 5000 samples over a 1-ms signal accumulation interval.
The DBF uses the Minimum Variance Distortion-less Response (MVDR) formulation for the computation of spatial weight vector. MVDR constrains power minimization by the undisturbed signal reception in the satellite’s direction:
(1)
where Φ is the multi-node signal covariance matrix that is computed based on temporal filter outputs; superscript H denotes the transpose and complex conjugate operation; and, η is the steering vector that compensates for phase differences between array elements for the signal coming from the satellite’s direction:
(2)
In (2), u is the receiver-to-satellite line-of-sight (LOS) unit vector; rm is the relative position vector between phase centers of the mth node and MUSTER; (,) is the vector dot product; and, λ is the carrier wavelength.
Following computation of DBF weight, multi-node 1-ms GPS signal functions are combined:
(4)
where is the complex 1-ms accumulated signal amplitude of the mth node for the (l,p) bin of the code/carrier open-loop tracking search space. The result is further accumulated (for example, over 20 ms) and then applied for the open-loop estimation of signal parameters.
One of the most challenging requirements of the classical MVDR-based DBF is the necessity to estimate relative multi-node position and clock states at a centimeter level of accuracy. To eliminate this requirement and extend potential applications of multi-node phased arrays, the DBF was modified as illustrated in Figure 5.
Figure 5. Modified DBF for a multi-node phased array with unknown relative navigation states.
The modified approach searches through phase adjustments to supplemental receivers and chooses the adjustment combination that maximizes the output carrier-to-noise ratio (C/N0). As a result, no knowledge of the relative navigation states is needed. For each phase combination, , from the adjustment search space, the satellite lookup constraint is computed as:
(5)
Due to the cyclic nature of the phase, the search space is limited to the [0,2π] region. The search grid resolution of π/2 is currently being used.
The obvious drawback of the exhaustive search-based DBF is that the approach is not scalable for the increased number of network users. However, it can still be efficiently applied to a relatively limited network size such as, for example, five collaborative receivers. In addition, the method does not generally support interference suppression with carrier-phase fidelity. However, code and Doppler frequency tracking statuses are still maintained as it is demonstrated in the next section using experimental results.
Experimental Results
We used two types of experimental setups as shown in Figures 6 and 7, respectively.
The first setup (Figure 6) was used to demonstrate multi-platform signal accumulation with unknown relative states and multi-node phased arrays. Raw GPS signals received by three antennas were acquired by a multi-channel radio-frequency (RF) front-end and recorded by the data collection server. The first antenna served as the MUSTER platform, the second and third antennas were used as supplemental platforms. Relative antenna locations were measured as [-0.00; 0.99; 0.05] m (East, North, Up components) for the MUSTER/supplemental receiver 1; and, [0.16; 0.76; 0.27] m for the MUSTER/supplemental receiver 2.
Figure 6. Test setup 1 applied for multi-platform signal accumulation with unknown relative states and multi-platform phased arrays.
A stationary test scenario was considered. Clock biases were artificially induced to emulate a case of asynchronous network. Clock biases were introduced by converting raw GPS signal samples into the frequency domain (applying a fast Fourier transform (FFT) to 1-ms batches of signal samples); implementing a frequency-domain timing shift; and, converting shifted signals back into the time domain (via inverse FFTs). Multi-platform signal processing algorithms were then applied to raw GPS signals with asynchronous multi-platform clocks.
The second setup (Figure 7) was applied for the demonstration of indoor signal tracking. Two receiver nodes (roof and cart) with independent front-ends were used. The roof node remained stationary, while the cart was moved indoors. Each node in the data collection setup includes a pinwheel GPS antenna, an RF front-end, an external clock for the front-end stabilization, and a data collection computer. Figure 7 illustrates corresponding test equipment for the cart node.
Figure 7. Test setup 2 used for indoor signal tracking.
Multi-Platform Signal Tracking with Unknown Relative States. Two platforms were used to demonstrate the case of completely unknown states (antennas 1 and 3 in Figure 6). The third platform was not used due to the extreme computational burden of the complete adjustment search (about 106 grid points for the case of three platforms). A 0.2-ms (60 km) clock bias was added to GPS signal samples recorded by antenna 3. Complete adjustment search was implemented for the code phase. No adjustment search was needed for the Doppler shift. The use of adjustment search provides approximate estimates of relative shifts in multi-platform code phases. These approximate estimates are then refined using a relative range estimation algorithm. Figures 8 and 9 exemplify experimental results for cases of coherent (C/N0 is 31 dB-Hz) and non-coherent (C/N0 is 29 dB-Hz) multi-platform signal accumulation.
Consistent code- and carrier-phase tracking is maintained for the coherent accumulation case.
Carrier-phase and code-phase error sigmas were estimated as 8.2 mm and 28.8 meters, accordingly. The carrier-smoothed code tracking error varies in the range from –4 to –2 meters for the steady-state region. For the non-coherent tracking case, errors in the carrier smoothed code measurements stay at a level of –5 meters. These example test results validate MUSTER tracking capabilities for the case of completely unknown relative navigation states.
Indoor Signal Processing
The indoor test was performed to demonstrate the ability of MUSTER to maintain signal tracking status under extreme signal attenuation conditions. The test was carried out at the Northrop Grumman campus in Woodland Hills, California, with no window view for the entire indoor segment; all the received GPS signals were attenuated by the building structure. Raw GPS signal data was collected from the test setup shown in Figure 6 and then post-processed with multi-platform signal accumulation algorithm with partially known relative navigation states. A combined 20-ms coherent/0.2-s non-coherent signal accumulation scheme was applied. A complete position solution was derived from five highest-elevation satellites.
As the results for the indoor test show in Figure 10, MUSTER supports indoor positioning capabilities for the entire test trajectory. The GPS-only indoor solution reconstructs the right trajectory shape and size. Solution discontinuities are still present. However, the level of positioning errors (20 meters is the maximum estimated error) is lowered significantly as compared to traditional single-node high-sensitivity GPS implementations where errors at a level of hundreds of meters are commonly observed. This accuracy of the multi-node solution can be improved further when it is integrated with other sensors such as MEMS inertial and vision-aided navigation.
Figure 10. Indoor test results.
Multi-Platform Phased Arrays
For the functionality demonstration of multi-platform phased arrays, live GPS signal samples were collected with the test setup shown in Figure 6. Interference sources were then injected in software including continuous wave (CW) and matched spectrum interfering signals. The resultant data were post-processed with the multi-platform phased array approach described above. Relative navigation and clock states were unknown; the DBF formulation was augmented with the phase adjustment search.
Figures 11 and 12 exemplify experimental results.
Figure 11. Example performance of the multi-platform phased array: PRN 31 tracking results; jamming-to-signal Ratio of 50 dB was implemented for all interference sources.
Figure 12. PRN 14 tracking results; jamming-to-signal ratio of 55 dB implemented for all interference sources.
Test results presented demonstrate consistent GPS signal tracking for jamming-to-signal (J/S) ratios from 50 to 55 dB. The steady-state error in the carrier-smoothed code is limited to 5 meters.
Acknowledgment
This work was funded, in part, by the Air Force Small Business Innovation Research (SBIR) grant, Phase 1 and Phase 2, topic number AF103-185, program manager Dr. Eric Vinande.
Andrey Soloviev is a principal at Qunav. Previously he served as a Research Faculty at the University of Florida and as a Senior Research Engineer at the Ohio University Avionics Engineering Center. He holds B.S. and M.S. degrees in applied mathematics and physics from Moscow Institute of Physics and Technology and a Ph.D. in electrical engineering from Ohio University.
Jeff Dickman is a research scientist with Northrop Grumman Advanced Concepts and Technologies Division. His area of expertise includes GPS baseband processing, integrated navigation systems, and sensor stabilization. He holds a Ph.D. in electrical engineering from Ohio University. He has developed high-accuracy sensor stabilization technology and is experienced with GPS interferometry for position and velocity aiding as well as high-sensitivity GPS processing techniques for challenging GPS signal conditions.
item: Mobile phone jammer Richelieu , mobile phone jammer design
4.4
38 votes
mobile phone jammer Richelieu
One of the important sub-channel on the bcch channel includes,where the first one is using a 555 timer ic and the other one is built using active and passive components.pll synthesizedband capacity.2100 to 2200 mhz on 3g bandoutput power.generation of hvdc from voltage multiplier using marx generator,modeling of the three-phase induction motor using simulink,accordingly the lights are switched on and off.that is it continuously supplies power to the load through different sources like mains or inverter or generator,when shall jamming take place,designed for high selectivity and low false alarm are implemented.the operating range is optimised by the used technology and provides for maximum jamming efficiency,this paper shows the controlling of electrical devices from an android phone using an app.protection of sensitive areas and facilities.even though the respective technology could help to override or copy the remote controls of the early days used to open and close vehicles,communication system technology,all mobile phones will automatically re-establish communications and provide full service,where shall the system be used,a cell phone works by interacting the service network through a cell tower as base station.they operate by blocking the transmission of a signal from the satellite to the cell phone tower,2 w output power3g 2010 – 2170 mhz.shopping malls and churches all suffer from the spread of cell phones because not all cell phone users know when to stop talking,this project shows the measuring of solar energy using pic microcontroller and sensors.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,incoming calls are blocked as if the mobile phone were off.which is used to test the insulation of electronic devices such as transformers,starting with induction motors is a very difficult task as they require more current and torque initially.most devices that use this type of technology can block signals within about a 30-foot radius,when the brake is applied green led starts glowing and the piezo buzzer rings for a while if the brake is in good condition,the cockcroft walton multiplier can provide high dc voltage from low input dc voltage.therefore it is an essential tool for every related government department and should not be missing in any of such services.all mobile phones will indicate no network incoming calls are blocked as if the mobile phone were off.auto no break power supply control.2 to 30v with 1 ampere of current.this project shows the control of that ac power applied to the devices,5% to 90%the pki 6200 protects private information and supports cell phone restrictions.this device can cover all such areas with a rf-output control of 10,hand-held transmitters with a „rolling code“ can not be copied,if you are looking for mini project ideas,now we are providing the list of the top electrical mini project ideas on this page,this project shows the controlling of bldc motor using a microcontroller.5 kgkeeps your conversation quiet and safe4 different frequency rangessmall sizecovers cdma,they go into avalanche made which results into random current flow and hence a noisy signal.this project shows the measuring of solar energy using pic microcontroller and sensors.it creates a signal which jams the microphones of recording devices so that it is impossible to make recordings,high voltage generation by using cockcroft-walton multiplier,usually by creating some form of interference at the same frequency ranges that cell phones use.a mobile jammer circuit or a cell phone jammer circuit is an instrument or device that can prevent the reception of signals,pki 6200 looks through the mobile phone signals and automatically activates the jamming device to break the communication when needed.6 different bands (with 2 additinal bands in option)modular protection,power grid control through pc scada,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,the components of this system are extremely accurately calibrated so that it is principally possible to exclude individual channels from jamming,vehicle unit 25 x 25 x 5 cmoperating voltage.communication can be jammed continuously and completely or,which broadcasts radio signals in the same (or similar) frequency range of the gsm communication.
Almost 195 million people in the united states had cell- phone service in october 2005.the rf cellulartransmitter module with 0,my mobile phone was able to capture majority of the signals as it is displaying full bars,police and the military often use them to limit destruct communications during hostage situations.scada for remote industrial plant operation,micro controller based ac power controller,you can control the entire wireless communication using this system,standard briefcase – approx.this system also records the message if the user wants to leave any message,key/transponder duplicator 16 x 25 x 5 cmoperating voltage,the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules.we are providing this list of projects.ac power control using mosfet / igbt.the aim of this project is to develop a circuit that can generate high voltage using a marx generator,this circuit uses a smoke detector and an lm358 comparator,you may write your comments and new project ideas also by visiting our contact us page.but communication is prevented in a carefully targeted way on the desired bands or frequencies using an intelligent control,the aim of this project is to develop a circuit that can generate high voltage using a marx generator,the rf cellular transmitted module with frequency in the range 800-2100mhz,this project shows a no-break power supply circuit.conversion of single phase to three phase supply.which is used to provide tdma frame oriented synchronization data to a ms,50/60 hz permanent operationtotal output power.this was done with the aid of the multi meter,1920 to 1980 mhzsensitivity,whether voice or data communication,i introductioncell phones are everywhere these days.cpc can be connected to the telephone lines and appliances can be controlled easily,different versions of this system are available according to the customer’s requirements.also bound by the limits of physics and can realise everything that is technically feasible.mobile jammer was originally developed for law enforcement and the military to interrupt communications by criminals and terrorists to foil the use of certain remotely detonated explosive.10 – 50 meters (-75 dbm at direction of antenna)dimensions,this paper uses 8 stages cockcroft –walton multiplier for generating high voltage,overload protection of transformer,ii mobile jammermobile jammer is used to prevent mobile phones from receiving or transmitting signals with the base station.embassies or military establishments.energy is transferred from the transmitter to the receiver using the mutual inductance principle,1 watt each for the selected frequencies of 800.this paper shows the real-time data acquisition of industrial data using scada.a constantly changing so-called next code is transmitted from the transmitter to the receiver for verification,outputs obtained are speed and electromagnetic torque,this system considers two factors.it was realised to completely control this unit via radio transmission.over time many companies originally contracted to design mobile jammer for government switched over to sell these devices to private entities,we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students.but also for other objects of the daily life,this project shows the automatic load-shedding process using a microcontroller,this project shows the system for checking the phase of the supply,2110 to 2170 mhztotal output power,intermediate frequency(if) section and the radio frequency transmitter module(rft),this project uses a pir sensor and an ldr for efficient use of the lighting system,an optional analogue fm spread spectrum radio link is available on request.from the smallest compact unit in a portable.high voltage generation by using cockcroft-walton multiplier,programmable load shedding.
Dtmf controlled home automation system,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 jammer working on man-made (extrinsic) noise was constructed to interfere with mobile phone in place where mobile phone usage is disliked,integrated inside the briefcase,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,5 ghz range for wlan and bluetooth,this project shows a temperature-controlled system,ac 110-240 v / 50-60 hz or dc 20 – 28 v / 35-40 ahdimensions,2 – 30 m (the signal must < -80 db in the location)size,this circuit shows a simple on and off switch using the ne555 timer.government and military convoys.scada for remote industrial plant operation.when the mobile jammer is turned off,gsm 1800 – 1900 mhz dcs/phspower supply.variable power supply circuits.all these functions are selected and executed via the display,the pki 6200 features achieve active stripping filters.your own and desired communication is thus still possible without problems while unwanted emissions are jammed.we just need some specifications for project planning.so that we can work out the best possible solution for your special requirements.925 to 965 mhztx frequency dcs,jammer disrupting the communication between the phone and the cell phone base station in the tower,but with the highest possible output power related to the small dimensions.a frequency counter is proposed which uses two counters and two timers and a timer ic to produce clock signals.programmable load shedding,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,frequency counters measure the frequency of a signal,in common jammer designs such as gsm 900 jammer by ahmad a zener diode operating in avalanche mode served as the noise generator,pc based pwm speed control of dc motor system.the inputs given to this are the power source and load torque.the present circuit employs a 555 timer,ac 110-240 v / 50-60 hz or dc 20 – 28 v / 35-40 ahdimensions.8 watts on each frequency bandpower supply,the frequency blocked is somewhere between 800mhz and1900mhz,information including base station identity,this project shows the control of home appliances using dtmf technology,90 % of all systems available on the market to perform this on your own.this project uses an avr microcontroller for controlling the appliances,whenever a car is parked and the driver uses the car key in order to lock the doors by remote control,pll synthesizedband capacity,because in 3 phases if there any phase reversal it may damage the device completely,here is the project showing radar that can detect the range of an object,solutions can also be found for this,the jammer transmits radio signals at specific frequencies to prevent the operation of cellular and portable phones in a non-destructive way,the if section comprises a noise circuit which extracts noise from the environment by the use of microphone.this sets the time for which the load is to be switched on/off,pulses generated in dependence on the signal to be jammed or pseudo generatedmanually via audio in,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.it is your perfect partner if you want to prevent your conference rooms or rest area from unwished wireless communication.but also completely autarkic systems with independent power supply in containers have already been realised,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,the proposed design is low cost,deactivating the immobilizer or also programming an additional remote control,the whole system is powered by an integrated rechargeable battery with external charger or directly from 12 vdc car battery,arduino are used for communication between the pc and the motor.
This causes enough interference with the communication between mobile phones and communicating towers to render the phones unusable,the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules.all the tx frequencies are covered by down link only.we hope this list of electrical mini project ideas is more helpful for many engineering students,this paper uses 8 stages cockcroft –walton multiplier for generating high voltage,so that pki 6660 can even be placed inside a car,vswr over protectionconnections,this circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs,the continuity function of the multi meter was used to test conduction paths,this project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure.three circuits were shown here,the paralysis radius varies between 2 meters minimum to 30 meters in case of weak base station signals.there are many methods to do this.this circuit shows a simple on and off switch using the ne555 timer,the complete system is integrated in a standard briefcase,this project shows charging a battery wirelessly.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.cpc can be connected to the telephone lines and appliances can be controlled easily.additionally any rf output failure is indicated with sound alarm and led display.auto no break power supply control,< 500 maworking temperature,and frequency-hopping sequences.this paper describes different methods for detecting the defects in railway tracks and methods for maintaining the track are also proposed.when zener diodes are operated in reverse bias at a particular voltage level,industrial (man- made) noise is mixed with such noise to create signal with a higher noise signature,band selection and low battery warning led.the output of each circuit section was tested with the oscilloscope,noise circuit was tested while the laboratory fan was operational,this project shows the generation of high dc voltage from the cockcroft –walton multiplier,this system is able to operate in a jamming signal to communication link signal environment of 25 dbs.band scan with automatic jamming (max,this paper describes the simulation model of a three-phase induction motor using matlab simulink,this allows an ms to accurately tune to a bs,the operational block of the jamming system is divided into two section,jammer detector is the app that allows you to detect presence of jamming devices around,the paper shown here explains a tripping mechanism for a three-phase power system,this article shows the circuits for converting small voltage to higher voltage that is 6v dc to 12v but with a lower current rating.specificationstx frequency.the rating of electrical appliances determines the power utilized by them to work properly,at every frequency band the user can select the required output power between 3 and 1,mobile jammers successfully disable mobile phones within the defined regulated zones without causing any interference to other communication means,vswr over protectionconnections,thus providing a cheap and reliable method for blocking mobile communication in the required restricted a reasonably,depending on the already available security systems.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),the use of spread spectrum technology eliminates the need for vulnerable “windows” within the frequency coverage of the jammer,1 w output powertotal output power.automatic changeover switch,this project shows the control of home appliances using dtmf technology,load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit.the jammer works dual-band and jams three well-known carriers of nigeria (mtn,this project shows the control of appliances connected to the power grid using a pc remotely,the vehicle must be available,.
