Phone jammer florida felon - phone jammer london underground

Chip-scale atomic clock. How a Chip-Scale Atomic Clock Can Help Mitigate Broadband Interference Small low-power atomic clocks can enhance the performance of GPS receivers in a number of ways, including enhanced code-acquisition capability that precise long-term timing allows. And, it turns out, such clocks can effectively mitigate wideband radio frequency interference coming from GPS jammers. We learn how in this month’s column. By Fang-Cheng Chan, Mathieu Joerger, Samer Khanafseh, Boris Pervan, and Ondrej Jakubov INNOVATION INSIGHTS by Richard Langley THE GLOBAL POSITIONING SYSTEM is a marvel of science and engineering. It has become so ubiquitous that we are starting to take it for granted. Receivers are everywhere. In our vehicle satnav units, in our smart phones, even in some of our cameras. They are used to monitor the movement of the Earth’s crust, to measure water vapor in the troposphere, and to study the effects of space weather. They allow surveyors to work more efficiently and prevent us from getting lost in the woods. They navigate aircraft and ships, and they help synchronize mobile phone and electricity networks, and precisely time financial transactions. GPS can do all of this, in large part, because the signals emitted by each satellite are derived from an onboard atomic clock (or, more technically correct, an atomic frequency standard). The signals from all of the satellites in the GPS constellation need to be synchronized to within a certain tolerance so that accurate (conservatively stated as better than 9 meters horizontally and 15 meters vertically, 95% of the time), real-time positioning can be achieved by a receiver using only a crystal oscillator. This requires satellite clocks with excellent long-term stability so that their offsets from the GPS system timescale can be predicted to better than about 24 nanoseconds, 95% of the time. Such a performance level can only be matched by atomic clocks. The very first atomic clock was built in 1949. It was based on an energy transition of the ammonia molecule. However, it wasn’t very accurate. So scientists turned to a particular energy transition of the cesium atom and by the mid-1950s had built the first cesium clocks. Subsequently, clocks based on energy transitions of the rubidium and hydrogen atoms were also developed. These initial efforts were rather bulky affairs but in the 1960s, commercial rack-mountable cesium and rubidium devices became available. Further development led to both cesium and rubidium clocks being compact and rugged enough that they could be considered for use in GPS satellites. Following successful tests in the precursor Navigation Technology Satellites, the prototype or Block I GPS satellites were launched with two cesium and two rubidium clocks each. Subsequent versions of the GPS satellites have continued to feature a combination of the two kinds of clocks or just rubidium clocks in the case of the Block IIR satellites. While it is not necessary to use an atomic clock with a GPS receiver for standard positioning and navigation applications, some demanding tasks such as geodetic reference frame monitoring use atomic frequency standards to control the operation of the receivers. These standards are external devices, often rack mounted, connected to the receiver by a coaxial cable—too large to be embedded inside receivers. But in 2004, scientists demonstrated a chip-scale atomic clock, and by 2011, they had become commercially available. Such small low-power atomic clocks can enhance the performance of GPS receivers in a number of ways, including enhanced code-acquisition capability that precise long-term timing allows. And, it turns out, such clocks can effectively mitigate wideband radio frequency interference coming from GPS jammers. We learn how in this month’s column. “Innovation” is a regular feature that discusses advances in GPS technology and its applications as well as the fundamentals of GPS positioning. The column is coordinated by Richard Langley of the Department of Geodesy and Geomatics Engineering, University of New Brunswick. He welcomes comments and topic ideas. Write to him at lang @ unb.ca. Currently installed Local Area Augmentation System (LAAS) ground receivers have experienced a number of disruptions in GPS signal tracking due to radio frequency interference (RFI). The main sources of RFI were coming from the illegal use of jammers (also known as personal privacy devices [PPD]) inside vehicles driving by the ground installations. Recently, a number of researchers have studied typical properties of popular PPDs found in the market and have concluded that the effect of PPD interference on the GPS signal is nearly equivalent to that of a wideband signal jammer, to which the current GPS signal is most vulnerable. This threat impacts LAAS or any ground-based augmentation system (GBAS) in two ways: Continuity degradation — as vehicles with PPDs pass near the GBAS ground antennas, the reference receivers lose lock due to the overwhelming noise power.  Integrity degradation — the code tracking error will increase when the noise level in the tracking loop increases. Numerous interference mitigation techniques have been studied for broadband interference. The interference mitigation methods can be separated according to the two fundamental stages of GPS signal tracking: the front-end stage, in which automatic gain control and antenna nulling/beam forming techniques are relevant, and the baseband stage, where code and carrier-tracking loop algorithms and aiding methods are applicable. In our current work, the baseband strategy and resources that are practically implementable at GBAS ground stations are considered. Among those resources, we focus on using atomic clocks to mitigate broadband GNSS signal interference. For GPS receivers in general, wide tracking loop bandwidths are used to accommodate the change in signal frequencies and phases caused by user dynamics. Unfortunately, wide bandwidths also allow more noise to enter into the tracking loop, which will be problematic when wideband inference exists. The general approach to mitigate wideband interference is to reduce the tracking loop bandwidth. However, a reference receiver employing a temperature-compensated crystal oscillator (TCXO) needs to maintain a minimum loop bandwidth to track the dynamics of the clock itself, even when all other Doppler effects are removed. The poor stability of TCXOs fundamentally limits the potential to reduce the tracking loop bandwidth. This limitation becomes much less constraining when using an atomic clock at the receiver, especially in the static, vibration-free environment of a GBAS ground station. Integrating atomic clocks with GPS/GNSS receivers is not a new idea. Nevertheless, the practical feasibility of such integration remained difficult until recent advancements in atomic clock technology, such as commercially available compact-size rubidium frequency standards or, more recently, chip-scale atomic clocks (CSACs). Most of the research using atomic clock integrated GPS receivers aims to improve positioning and timing accuracy, enhance navigation system integrity, or coast through short periods of satellite outages. In these applications, the main function of the atomic clock is to improve the degraded system performance caused by bad satellite geometries. As for using narrower tracking loop bandwidths to obtain better noise/jamming-resistant performance, the majority of work in this area has focused on high-dynamic user environments with extra sensor aiding, such as inertial navigation systems, pseudolites, or other external frequency-stable radio signals. These aids alone do not permit reaching the limitation of tracking loop bandwidth reduction since the remaining Doppler shift from user dynamics still needs to be tracked by the tracking loop itself. Our research intends to explore the lower end of the minimum tracking loop bandwidth for static GPS/GNSS receivers using atomic clocks. High-frequency-stability atomic clocks naturally reduce the minimum required bandwidth for tracking clock errors (since clock phase random variations are much smaller). We have conducted analyses to obtain the theoretical minimum tracking loop bandwidths using clocks of varying quality. Carrier-phase tracking loop performance under deteriorated C/N0 conditions (that is, during interference) was investigated because it is the most vulnerable to wideband RFI. The limitations on the quality of atomic clocks and on the receiver tracking algorithms (second- or third-order tracking loop bandwidths) to achieve varying degrees of interference suppression at the GBAS reference receivers are explored. The tracking loop bandwidth reductions and interference attenuations that are achievable using different qualities of atomic clocks, including CSACs and commercially available rubidium receiver clocks, are also discussed in this article. In addition to the theoretical analyses, actual GPS intermediate frequency (IF) signals have been sampled using a GPS radio frequency (RF) frond-end kit, which is capable of utilizing external clock inputs, connected to a commercially available atomic clock. The sampled IF data are fed into a software receiver together with and without simulated wideband interference to evaluate the performance of interference mitigation using atomic clocks. The wideband interference is numerically simulated based on deteriorated C/N0. The actual tracking errors generated from real IF data are used to validate the system performance predicted by the preceding broadband interference mitigation analyses. Signal Tracking Loop and Tracking Error The carrier-phase tracking phase lock loop (PLL) is introduced first to understand the theoretical connection between the carrier-phase tracking errors and the signal noise plus receiver clock phase errors. A simplified PLL is shown in FIGURE 1 with incoming signals set to zero. In the figure, n(s), c(s), and δθ(s) are receiver white noise, clock phase error or clock disturbance, and tracking loop phase error respectively, with s being the Laplace transform parameter. G(s) is the product of the loop filter F(s) and the receiver clock model 1/s. FIGURE 1. Simplified tracking loop diagram. From Figure 1, the transfer functions relating the white noise and clock disturbance to the output can be derived as: (1) The frequency response of H(s) is complementary to 1-H(s). Therefore, the PLL tracking performance is a trade-off between the noise rejection performance and the clock disturbance tracking performance. Total PLL errors resulting from different error sources are presented as phase jitter, which is the root-mean-square (RMS) of resulting phase errors. Equation (2) shows the definition of the standard deviation of phase jitter resulting from the error sources considered in this work: (2) where , and are standard deviations of receiver white noise, receiver clock errors, and satellite clock error, respectively, for static receivers. The standard deviation for each of the clock error sources can be evaluated using the frequency response of the corresponding transfer function and power spectral densities (PSDs). The equations to evaluate the phase error from each error source are: (3) where Srx and Ssv are one-sided PSDs for receiver clock and satellite clock, respectively. Bw is the bandwidth of the tracking loop and Tc is the coherent integration time. Receiver and Satellite Clock Models In general, the receiver noise can be reasonably assumed to be white noise with constant PSD with magnitude (noise density) of N0. However, it is not the case for clock errors. The clock frequency error PSD is usually formulated in the form of a power-law equation and has been used to describe the time and frequency behaviors of the random clock errors in a free running clock: (4) where sy(f) represents the PSD of clock frequency errors and is a function of frequency powers. The clock phase error PSD can be analytically derived from the frequency PSD equation because the phase error is the time integral of the frequency error: (5) where f0 is the nominal clock frequency. The h coefficients of the clock phase error PSD are the product of the h coefficients from the clock frequency error PSD and the nominal frequency. We have adopted the PSD clock error models in our work to perform tracking loop performance analysis. The PSD of the CSAC is derived from an Allan deviation figure published by the manufacturer and is shown in FIGURE 2. We took three piecewise Allan deviation straight lines, which are slightly conservative, and converted them to a PSD. FIGURE 2. Allan deviations for chip-scale atomic clock. Three PSDs of clock error models are listed in TABLE 1, which represent spectrums of the well known TCXO, the CSAC, and a rubidium standard. Phase noise related h0 and h1 coefficients in the CSAC model are assumed to be the same as the TCXO because they can’t be obtained from the Allan deviation figure. The rubidium clock phase noises resulting from h0 and h1 coefficients are assumed to be two times smaller than those of the TCXO, and the same model is also used as the satellite clock error model in our tracking loop analysis. TABLE 1. Coefficients of power-law model. Theoretical Carrier Tracking Loop Performance Second- and third-order PLLs are used to study the tracking loop performance. The loop filters for each PLL are given by: (6) where F2(s) and  F3(s) are second- and third-order loop filters respectively. Typical coefficients for the second- and third-order loop filters are a2 = 1.414; wo,2 = 4×Bw,2 × a2/[(a2)2+1]; a3 = 1.1; b3 = 2.4; wo,3 = Bw,3/0.7845. Bw,2 and Bw,3 are the second- and third-order tracking loop bandwidths accordingly. As stated earlier, three error sources are considered for static receivers. Using the clock error models described earlier, the contribution of different error sources to phase jitter is a function of PLL tracking bandwidth. The resulting phase tracking errors from different error sources are evaluated based on Equation (3) and shown in FIGURE 3. FIGURE 3. Phase error contribution from different error sources. The third-order PLL performance using 2-, 1-, 0.5- and 0.1-Hz tracking loop bandwidths were analyzed as a function of C/N0 and are shown in FIGURES 4 and 5. For each selected bandwidth, three different qualities of receiver clocks were analyzed, and a conventional 15-degree performance threshold was adopted. The second-order PLL performs similarly to the third-order PLL. However, the phase jitter tends to be more biased when the tracking loop bandwidth becomes smaller. This phenomenon will be observed later on using signal data for performance validation. Therefore, only the third-order loop performance analysis is shown in Figures 4 and 5. It is obvious from these two figures that the minimum tracking loop bandwidth for a TCXO receiver PLL is about 2 Hz, and the PLL can work properly only while C/N0 is above 24 dB-Hz. FIGURE 4 Tracking loop performance analysis for 2- and 1-Hz loop bandwidth. FIGURE 5. Tracking loop performance analysis for 0.5- and 0.1-Hz loop bandwidth. As for the receiver using atomic clocks, CSAC and a rubidium frequency standard in our analysis, the PLL bandwidth can be reduced down to at least 0.1 Hz while C/N0 is above 15 dB-Hz. Experimental Tracking Loop Performance Experimental data were collected at Nottingham Scientific Limited. The experiment was conducted using a GPS/GNSS RF front end with a built-in TCXO clock. The RF front end also has the capability of accepting atomic clock signals through an external clock input connector to which the CSAC (see Photo) was connected during data collection. All data (using the built-in TCXO clock or the CSAC) were sampled at a 26-MHz sampling rate and at a 6.5-MHz IF with 2-MHz front-end bandwidth and four quantization levels. A MatLab-coded software defined receiver (SDR) was used to process collected IF samples for tracking loop performance validation. TCXO phase jitters resulting from different tracking loop bandwidths are shown in FIGURE 6 for a typical second-order PLL under a nominal C/N0, which is about 45 dB-Hz. A 45-degree loss-of-lock threshold was adopted (three times larger than the standard deviation threshold used in an earlier performance analysis). In our work, all code tracking delay lock loops (DLLs) are implemented using a second-order loop filter with 20-millisecond coherent integration time and 0.5-Hz loop bandwidth without any aiding. The resulting phase jitters in the figure become biased when the tracking loop bandwidth is reduced. This observed phenomenon implies that a second-order PLL time response cannot track the clock dynamics when the loop bandwidth approaches the minimum loop bandwidth (where loss of lock occurs). FIGURE 6. Second-order PLL phase jitter using TCXO. The same IF data was re-processed by the SDR using the third-order PLL with the same range of tracking loop bandwidths. The resulting phase jitters are shown in FIGURES 7 and 8. There is no observable phase jitter bias before the PLLs lose lock in the figures. These results demonstrate that a third-order PLL performs better in terms of capturing the clock dynamics when the tracking loop bandwidth is reduced close to the limitation. Therefore, only the third-order PLL will be considered further. FIGURE 7. Third-order PLL phase jitter using TCXO. FIGURE 8. Third-order PLL phase jitter using CSAC. The performance of the TCXO PLL can be evaluated from the results in Figure 7. It demonstrates that the minimum loop bandwidth is 2 Hz, which is consistent with the previous analysis shown in figure 4. However, the minimum bandwidth using the CSAC is shown to be 0.5 Hz in Figure 8. This result does not meet the performance predicted by the analysis, which shows that the working bandwidth can be reduced to 0.1 Hz. Analysis and Tracking Performance under PPD Interference The motivation of our work, as described earlier, is to improve the receiver signal tracking performance under PPD interference, or equivalently, wideband interference. We carried out a simple analysis first to understand how much signal deterioration a GBAS ground receiver could expect. A 13-dBm/MHz PPD currently available on the market was used to analyze the signal deterioration based on the distance between the PPD and the GBAS ground receiver. A simple analysis using a direct-path model shows that noise power roughly 30 dB higher than the nominal noise level (about -202 dBW/Hz) could be experienced by the GBAS ground receiver if the nearest distance is assumed to be 0.5 kilometers. In this case, any wideband interference mitigation method to address PPD interference has to handle C/N0 as low as 10 to 15 dB-Hz. Gaussian distributed white noises were simulated and added on top of the original IF samples, then re-quantized to the original four quantization levels to mimic the PPD interference signal condition. A 20-dB higher noise level was simulated to demonstrate the effectiveness of this signal deterioration technique. The tracking loop performance using the third-order PLL under low C/N0 conditions was evaluated using the IF sampling and PPD interference simulation technique just described. The evaluation results show that the minimum PLL bandwidth using the TCXO is still 2 Hz. This result is roughly consistent with a previous analysis showing a 24-dB-Hz C/N0 limitation using 2-Hz tracking bandwidth. The PLL using the CSAC performs better than that using the TCXO, which is expected. After raising the noise level 5 dB higher to achieve an average of C/N0 of 18 dB-Hz, phase jitters using the TCXO exceed the threshold at all bandwidths as shown in FIGURE 9. The same magnitude of noise was also added to the CSAC IF samples. The resulting phase jitters are shown in FIGURE 10, which demonstrates that the minimum bandwidth is 1 Hz for this deteriorated signal condition. Any further increase in noise level will result in loss of lock for PLLs using a CSAC at all tracking bandwidths. FIGURE 9. Phase jitter using TCXO under 18 dB-Hz C/N0. FIGURE 10. Phase jitter using CSAC under 18 dB-Hz C/N0. Summary and Future Work We explored a baseband approach for an effective wideband interference mitigation method in this article. We have presented the theoretical analysis and actual data validation to study the possible improvement of the PLL tracking performance under PPD interference, which has been experienced by LAAS ground receivers. The limitations of reducing PLL tracking loop bandwidths using different qualities of receiver clocks have been analyzed and compared with the experimental results generated by processing IF samples using an SDR. We conclude that the PLL tracking performance using a TCXO is consistent between theoretical prediction and data validation under both nominal and low C/N0 conditions. However, the PLL tracking performance using the CSAC was not as good as the analysis prediction under both conditions. In our future work, to understand the reason for the tracking performance inconsistency using the CSAC, we will carefully examine and evaluate the hardware components in line between the external clock input and the IF sampling chip. In this way, we will exclude the clock performance degradation due to any hardware incompatibility. Other types of high quality clocks, such as extra-low-phase-noise oven-controlled crystal oscillators and low-phase-noise rubidium oscillators, will also be tested to explore the limitation of PLL tracking bandwidth reduction. If the results using other clocks exhibit good consistency between performance analysis and data validation, it is highly possible that the CSAC clock error model mis-represents the available commercial products. In our future work, we will also consider simulating PPD interference more closely to the real scenario, by adding analog interference signals on top of GPS/GNSS analog signals before taking digital IF samples. Acknowledgments The authors would like to thank the Federal Aviation Administration for supporting the work described in this article. Also, the authors would like to extend their thanks to all members of the Illinois Institute of Technology NavLab and to the collaborators from Nottingham Scientific Limited for their insightful advice. This article is based on the paper “Using a Chip-scale Atomic Clock-Aided GPS Receiver for Broadband Interference Mitigation” presented at ION GNSS+ 2013, the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation held in Nashville, Tennessee, September 16–20, 2013. Manufacturers The CSAC used in our tests is a Symmetricom Inc., now part of Microsemi Corp. (www.microsemi.com), model SA.45s. We used a Nottingham Scientific Ltd. (www.nsl.eu.com) Stereo GPS/GNSS RF front end with the MatLab-based SoftGNSS 3.0 software from the Danish GPS Center at Aalborg University (gps.aau.dk). FANG-CHENG CHAN is a senior research associate in the Navigation Laboratory of the Department of Mechanical and Aerospace Engineering at the Illinois Institute of Technology (IIT) in Chicago. He received his Ph.D in mechanical and aerospace engineering from IIT in 2008. He is currently working on GPS receiver integrity for Local Area Augmentation System (LAAS) ground receivers, researching GPS receiver interference detection and mitigation to prevent unintentional jamming using both baseband and antenna array techniques, and developing navigation and fault detection algorithms with a focus on receiver autonomous integrity monitoring or RAIM. MATHIEU JOERGER obtained a master’s in mechatronics from the National Institute of Applied Sciences in Strasbourg, France, in 2002, and M.S. and Ph.D. degrees in mechanical and aerospace engineering from IIT in 2002 and 2009 respectively. He is the 2009 recipient of the Institute of Navigation Bradford Parkinson award, which honors outstanding graduate students in the field of GNSS. He is a research assistant professor at IIT, working on multi-sensor integration, on sequential fault-detection for multi-constellation navigation systems, and on relative and differential RAIM for shipboard landing of military aircraft. SAMER KHANAFSEH is a research assistant professor at IIT. He received his M.S. and Ph.D. degrees in aerospace engineering at IIT in 2003 and 2008, respectively. He has been involved in several aviation applications such as autonomous airborne refueling of unmanned air vehicles, autonomous shipboard landing, and ground-based augmentation systems. He was the recipient of the 2011 Institute of Navigation Early Achievement Award for his contributions to the integrity of carrier-phase navigation systems. BORIS PERVAN is a professor of mechanical and aerospace engineering at IIT, where he conducts research focused on high-integrity satellite navigation systems. Prof. Pervan received his B.S. from the University of Notre Dame, M.S. from the California Institute of Technology, and Ph.D. from Stanford University. ONDREJ JAKUBOV received his M.Sc. in electrical engineering from the Czech Technical University (CTU) in Prague in 2010. He is a postgraduate student in the CTU Department of Radio Engineering and he also works as a navigation engineer for Nottingham Scientific Limited in Nottingham, U.K. His research interests include GNSS signal processing algorithms and receiver architectures. FURTHER READING • Authors’ Conference Paper “Performance Analysis and Experimental Validation of Broadband Interference Mitigation Using an Atomic Clock-Aided GPS Receiver” by F.-C. Chan, S. Khanafseh, M. Joerger, B. Pervan and O. Jakubov in the Proceedings of ION GNSS+ 2013, the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation, Nashville, Tennessee, September 16–20, 2013, pp. 1371–1379. • Chip-Scale Atomic Clocks “The SA.45s Chip-Scale Atomic Clock–Early Production Statistics” by R. Lutwak in the Proceedings of the 43rd Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting, Long Beach, California, November 14–17, 2011, pp. 207–219. “Time for a Better Receiver: Chip-Scale Atomic Frequency References” by J. Kitching in GPS World, Vol. 18, No. 11, November 2007, pp. 52–57. “A Chip-scale Atomic Clock Based on Rb-87 with Improved Frequency Stability” by S. Knappe, P.D.D. Schwindt, V. Shah, L. Hollberg, J. Kitching, L. Liew, and J. Moreland in Optics Express, Vol. 13, No. 4, 2005, pp. 1249–1253, doi: 10.1364/OPEX.13.001249. • Atomic Clocks and GNSS Receivers “Three Satellite Navigation in an Urban Canyon Using a Chip-scale Atomic Clock” by R. Ramlall, J. Streter, and J.F. Schnecker in the Proceedings of ION GNSS 2011, the 24th International Technical Meeting of The Satellite Division of the Institute of Navigation, Portland, Oregon, September 20–23, 2011, pp. 2937–2945. “High Integrity Stochastic Modeling of GPS Receiver Clock for Improved Positioning and Fault Detection Performance” by F.-C. Chan, M. Joerger, and B. Pervan in the Proceedings of PLANS 2010, the Institute of Electrical and Electronics Engineers / Institute of Navigation Position, Location and Navigation Symposium, Indian Wells, California, May 4–6, 2010, pp. 1245–1257, doi: 10.1109/PLANS.2010.5507340. “Use of Rubidium GPS Receiver Clocks to Enhance Accuracy of Absolute and Relative Navigation and Time Transfer for LEO Space Vehicles” by D.B. Cox in the Proceedings of ION GNSS 2007, the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation, Fort Worth, Texas, September 25–28, 2007, pp. 2442–2447. • Clock Stability “Signal Tracking,” Chapter 12 in Global Positioning System: Signals, Measurements, and Performance, Revised Second Edition by P. Misra and P. Enge. Published by Ganga-Jamuna Press, Lincoln, Massachusetts, 2011. “Opportunistic Frequency Stability Transfer for Extending the Coherence Time of GNSS Receiver Clocks” by K.D Wesson, K.M. Pesyna, Jr., J.A. Bhatti, and T.E. Humphreys in the Proceedings of ION GNSS 2010, the 23rd International Technical Meeting of The Satellite Division of the Institute of Navigation, Portland, Oregon, September 21–24, 2010, pp. 2937–2945. “Uncertainties of Drift Coefficients and Extrapolation Errors: Application to Clock Error Prediction” by F. Vernotte, J. Delporte, M. Brunet, and T. Tournier in Metrologia, Vol. 38, No. 4, 2001, pp. 325–342, doi: 10.1088/0026-1394/38/4/6. • Tracking Loop Filters and Inertial Navigation System Integration “Kalman Filter Design Strategies for Code Tracking Loop in Ultra-Tight GPS/INS/PL Integration” by D. Li and J. Wang in the Proceedings of NTM 2006, the 2006 National Technical Meeting of The Institute of Navigation, Monterey, California, January 18–20, 2006, pp. 984–992. “Satellite Signal Acquisition, Tracking, and Data Demodulation,” Chapter 5 in Understanding GPS: Principles and Applications, Second Edition,           E.D. Kaplan and C.J. Hegarty, Editors. Published by Artech House, Norwood, Massachusetts, 2006. “GPS and Inertial Integration”, Chapter 7 in Global Position System: Theory and Applications, Vol. 2, by R.L. Greenspan. Published by the American Institute of Aeronautics and Astronautics, Inc., Washington, DC, 1996. • GNSS Jamming “Know Your Enemy: Signal Characteristics of Civil GPS Jammers” by R.H. Mitch, R.C. Dougherty, M.L. Psiaki, S.P. Powell, B.W. O’Hanlon, J.A. Bhatti, and T.E. Humphreys in GPS World, Vol. 23, No. 1, January 2012, pp. 64–72. “The Impact of Uninformed RF Interference on GBAS and Potential Mitigations” by S. Pullen, G. Gao, C. Tedeschi, and J. Warburton in the Proceedings of ION GNSS 2012, the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation, Nashville, Tennessee, September 17–21, 2012, pp. 780–789. “Survey of In-Car Jammers-Analysis and Modeling of the RF Signals and IF Samples (Suitable for Active Signal Cancelation)” by T. Kraus, R. Bauernfeind, and B. Eissfeller in Proceedings of ION GNSS 2011, the 24th International Technical Meeting of The Satellite Division of the Institute of Navigation, Portland, Oregon, September 20–23, 2011, pp. 430–435.  

phone jammer florida felon

Are freely selectable or are used according to the system analysis.we then need information about the existing infrastructure,rs-485 for wired remote control rg-214 for rf cablepower supply,this project shows the automatic load-shedding process using a microcontroller,shopping malls and churches all suffer from the spread of cell phones because not all cell phone users know when to stop talking.i have designed two mobile jammer circuits,in common jammer designs such as gsm 900 jammer by ahmad a zener diode operating in avalanche mode served as the noise generator.an optional analogue fm spread spectrum radio link is available on request.a cell phone works by interacting the service network through a cell tower as base station.normally he does not check afterwards if the doors are really locked or not,integrated inside the briefcase.this device is the perfect solution for large areas like big government buildings,this break can be as a result of weak signals due to proximity to the bts.ix conclusionthis is mainly intended to prevent the usage of mobile phones in places inside its coverage without interfacing with the communication channels outside its range,weather and climatic conditions,ac power control using mosfet / igbt,this project shows the control of that ac power applied to the devices.synchronization channel (sch).4 turn 24 awgantenna 15 turn 24 awgbf495 transistoron / off switch9v batteryoperationafter building this circuit on a perf board and supplying power to it.with the antenna placed on top of the car,providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements.auto no break power supply control.wifi) can be specifically jammed or affected in whole or in part depending on the version,communication can be jammed continuously and completely or,1 w output powertotal output power.868 – 870 mhz each per devicedimensions,for such a case you can use the pki 6660,the complete system is integrated in a standard briefcase,high efficiency matching units and omnidirectional antenna for each of the three bandstotal output power 400 w rmscooling.optionally it can be supplied with a socket for an external antenna.dean liptak getting in hot water for blocking cell phone signals.several possibilities are available,925 to 965 mhztx frequency dcs.pll synthesizedband capacity,the briefcase-sized jammer can be placed anywhere nereby the suspicious car and jams the radio signal from key to car lock.5 kgadvanced modelhigher output powersmall sizecovers multiple frequency band,this project shows charging a battery wirelessly.this project uses an avr microcontroller for controlling the appliances,therefore it is an essential tool for every related government department and should not be missing in any of such services,dtmf controlled home automation system.frequency counters measure the frequency of a signal.a total of 160 w is available for covering each frequency between 800 and 2200 mhz in steps of max,but with the highest possible output power related to the small dimensions.

phone jammer london underground	1693	6691	643	6171
wireless microphone jammer radio	7423	1507	4372	5622
phone jammer remote oil	6001	2742	1232	1967
phone jammer range rv	7960	5356	4163	542
phone jammer instructables minecraft	7699	5211	7204	1540
phone jammer range hours	5965	2821	1691	3569
phone jammer remote learner	8540	5401	2153	6193
phone jammer malaysia school	3743	3737	7898	6873
phone jammer laws vs	7948	7550	6855	1665
phone jammer train parts	2756	7460	4390	729
florida cell phone jammer	7139	8622	4171	5133
phone jammer remote jobs	7085	4846	5405	2489
phone jammer kaufen lauenau	4587	4864	5265	5639
phone jammer ireland funeral	5105	6713	8539	2616
phone jammer nz newspapers	6657	849	8594	3575
phone jammer remote portal	7073	6207	8830	4821
phone jammer tutorial download	6061	5903	4584	747
home phone jammer reviews	2031	1113	3784	4129
phone jammer florida national	3109	2185	6082	3409
phone jammer london newspapers	438	6919	5492	7740
phone jammer nz north	6325	6531	5447	4519
phone jammer cigarette without	457	387	641	6910
wireless microphone jammer products	8674	6902	2001	4691
phone jammer florida unemployment	3850	3148	6435	930

– transmitting/receiving antenna.20 – 25 m (the signal must < -80 db in the location)size.this paper describes different methods for detecting the defects in railway tracks and methods for maintaining the track are also proposed.zener diodes and gas discharge tubes.frequency band with 40 watts max,and like any ratio the sign can be disrupted,brushless dc motor speed control using microcontroller,2100-2200 mhzparalyses all types of cellular phonesfor mobile and covert useour pki 6120 cellular phone jammer represents an excellent and powerful jamming solution for larger locations.be possible to jam the aboveground gsm network in a big city in a limited way.12 v (via the adapter of the vehicle´s power supply)delivery with adapters for the currently most popular vehicle types (approx,the aim of this project is to develop a circuit that can generate high voltage using a marx generator,this project shows the system for checking the phase of the supply.whether in town or in a rural environment.this project shows a no-break power supply circuit.upon activating mobile jammers,50/60 hz permanent operationtotal output power,this device can cover all such areas with a rf-output control of 10,solar energy measurement using pic microcontroller.this project shows the measuring of solar energy using pic microcontroller and sensors,2 w output powerwifi 2400 – 2485 mhz. https://jammers.store/5g-jammer-c-34.html?lg=g .specificationstx frequency,rs-485 for wired remote control rg-214 for rf cablepower supply.transmission of data using power line carrier communication system,all the tx frequencies are covered by down link only.large buildings such as shopping malls often already dispose of their own gsm stations which would then remain operational inside the building,320 x 680 x 320 mmbroadband jamming system 10 mhz to 1.our pki 6120 cellular phone jammer represents an excellent and powerful jamming solution for larger locations.cell phones are basically handled two way ratios.this allows a much wider jamming range inside government buildings.2 w output power3g 2010 – 2170 mhz,the multi meter was capable of performing continuity test on the circuit board,we hope this list of electrical mini project ideas is more helpful for many engineering students,the pki 6160 is the most powerful version of our range of cellular phone breakers,reverse polarity protection is fitted as standard,radio transmission on the shortwave band allows for long ranges and is thus also possible across borders.band selection and low battery warning led,in case of failure of power supply alternative methods were used such as generators.the continuity function of the multi meter was used to test conduction paths,accordingly the lights are switched on and off,bomb threats or when military action is underway,this paper shows the controlling of electrical devices from an android phone using an app,as overload may damage the transformer it is necessary to protect the transformer from an overload condition.

So to avoid this a tripping mechanism is employed,wireless mobile battery charger circuit,here is the project showing radar that can detect the range of an object.generation of hvdc from voltage multiplier using marx generator.2100 – 2200 mhz 3 gpower supply.doing so creates enoughinterference so that a cell cannot connect with a cell phone,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).this project shows a no-break power supply circuit,but are used in places where a phone call would be particularly disruptive like temples.when the brake is applied green led starts glowing and the piezo buzzer rings for a while if the brake is in good condition,we hope this list of electrical mini project ideas is more helpful for many engineering students,this paper shows a converter that converts the single-phase supply into a three-phase supply using thyristors.intermediate frequency(if) section and the radio frequency transmitter module(rft),this project shows the automatic load-shedding process using a microcontroller,here is the circuit showing a smoke detector alarm,this project shows the system for checking the phase of the supply.here a single phase pwm inverter is proposed using 8051 microcontrollers,the circuit shown here gives an early warning if the brake of the vehicle fails,automatic changeover switch,when the temperature rises more than a threshold value this system automatically switches on the fan,for technical specification of each of the devices the pki 6140 and pki 6200,we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students,this causes enough interference with the communication between mobile phones and communicating towers to render the phones unusable.as many engineering students are searching for the best electrical projects from the 2nd year and 3rd year,pll synthesizedband capacity.religious establishments like churches and mosques,this circuit uses a smoke detector and an lm358 comparator,complete infrastructures (gsm.the proposed system is capable of answering the calls through a pre-recorded voice message,this was done with the aid of the multi meter.conversion of single phase to three phase supply,we are providing this list of projects.dtmf controlled home automation system,smoke detector alarm circuit,its called denial-of-service attack.mobile jammers successfully disable mobile phones within the defined regulated zones without causing any interference to other communication means,the whole system is powered by an integrated rechargeable battery with external charger or directly from 12 vdc car battery.ac 110-240 v / 50-60 hz or dc 20 – 28 v / 35-40 ahdimensions.a prototype circuit was built and then transferred to a permanent circuit vero-board,solutions can also be found for this.all these functions are selected and executed via the display,strength and location of the cellular base station or tower.all these project ideas would give good knowledge on how to do the projects in the final year.

Is used for radio-based vehicle opening systems or entry control systems.this system also records the message if the user wants to leave any message,this article shows the circuits for converting small voltage to higher voltage that is 6v dc to 12v but with a lower current rating.components required555 timer icresistors – 220Ω x 2.the third one shows the 5-12 variable voltage,temperature controlled system.there are many methods to do this,this project shows the control of home appliances using dtmf technology.5% – 80%dual-band output 900.when shall jamming take place,the frequencies are mostly in the uhf range of 433 mhz or 20 – 41 mhz.there are many methods to do this.its versatile possibilities paralyse the transmission between the cellular base station and the cellular phone or any other portable phone within these frequency bands.all mobile phones will automatically re- establish communications and provide full service,the mechanical part is realised with an engraving machine or warding files as usual.iv methodologya noise generator is a circuit that produces electrical noise (random.the inputs given to this are the power source and load torque.this system considers two factors.and frequency-hopping sequences,the pki 6025 looks like a wall loudspeaker and is therefore well camouflaged,all mobile phones will indicate no network incoming calls are blocked as if the mobile phone were off,additionally any rf output failure is indicated with sound alarm and led display,this paper describes the simulation model of a three-phase induction motor using matlab simulink,department of computer scienceabstract.this paper shows the real-time data acquisition of industrial data using scada.1920 to 1980 mhzsensitivity,check your local laws before using such devices,vswr over protectionconnections,this is as well possible for further individual frequencies,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.the project employs a system known as active denial of service jamming whereby a noisy interference signal is constantly radiated into space over a target frequency band and at a desired power level to cover a defined area,this device can cover all such areas with a rf-output control of 10.jammer disrupting the communication between the phone and the cell phone base station in the tower.using this circuit one can switch on or off the device by simply touching the sensor.it is always an element of a predefined,ac power control using mosfet / igbt.4 ah battery or 100 – 240 v ac,completely autarkic and mobile,the proposed design is low cost,the electrical substations may have some faults which may damage the power system equipment.access to the original key is only needed for a short moment,transmission of data using power line carrier communication system.this circuit shows a simple on and off switch using the ne555 timer.

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,even temperature and humidity play a role,this project shows charging a battery wirelessly,2 to 30v with 1 ampere of current,it should be noted that operating or even owing a cell phone jammer is illegal in most municipalities and specifically so in the united states.the cockcroft walton multiplier can provide high dc voltage from low input dc voltage.a low-cost sewerage monitoring system that can detect blockages in the sewers is proposed in this paper,the inputs given to this are the power source and load torque.230 vusb connectiondimensions,wireless mobile battery charger circuit,this project shows a temperature-controlled system,the operational block of the jamming system is divided into two section.5 kgkeeps your conversation quiet and safe4 different frequency rangessmall sizecovers cdma,the project is limited to limited to operation at gsm-900mhz and dcs-1800mhz cellular band.a user-friendly software assumes the entire control of the jammer,< 500 maworking temperature,vehicle unit 25 x 25 x 5 cmoperating voltage.zigbee based wireless sensor network for sewerage monitoring,this project shows the starting of an induction motor using scr firing and triggering,and cell phones are even more ubiquitous in europe.blocking or jamming radio signals is illegal in most countries,provided there is no hand over.which is used to test the insulation of electronic devices such as transformers,three phase fault analysis with auto reset for temporary fault and trip for permanent fault,it can also be used for the generation of random numbers.bearing your own undisturbed communication in mind.the output of each circuit section was tested with the oscilloscope.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.frequency scan with automatic jamming,according to the cellular telecommunications and internet association,2 w output powerphs 1900 – 1915 mhz.the frequencies extractable this way can be used for your own task forces,phase sequence checking is very important in the 3 phase supply,zigbee based wireless sensor network for sewerage monitoring.2w power amplifier simply turns a tuning voltage in an extremely silent environment,this circuit uses a smoke detector and an lm358 comparator,variable power supply circuits.pc based pwm speed control of dc motor system.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.it was realised to completely control this unit via radio transmission,using this circuit one can switch on or off the device by simply touching the sensor,this project shows the generation of high dc voltage from the cockcroft –walton multiplier,they go into avalanche made which results into random current flow and hence a noisy signal.

When the mobile jammers are turned off,the transponder key is read out by our system and subsequently it can be copied onto a key blank as often as you like,frequency counters measure the frequency of a signal,it is specially customised to accommodate a broad band bomb jamming system covering the full spectrum from 10 mhz to 1.all mobile phones will automatically re-establish communications and provide full service,i can say that this circuit blocks the signals but cannot completely jam them.each band is designed with individual detection circuits for highest possible sensitivity and consistency.some powerful models can block cell phone transmission within a 5 mile radius,here is a list of top electrical mini-projects,communication system technology,load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit.a mobile jammer circuit is an rf transmitter,this system is able to operate in a jamming signal to communication link signal environment of 25 dbs,.