Signal jammers illegal eviction , gps jammers illegal drugs

Handling the Biases for Improved Triple-Frequency PPP Convergence By Denis Laurichesse Precise point positioning (PPP) can be considered a viable tool in the kitbag of GPS positioning techniques. One precision aspect of PPP is its use of carrier-phase measurements rather than just pseudoranges. But there is a catch. Often many epochs of measurements are needed for a position solution to converge to a sufficiently high accuracy. In this month’s column, we look at how using measurements from three satellite frequencies rather than just two can help. INNOVATION INSIGHTS by Richard Langley PPP? WHAT’S THAT? This acronym stands for precise point positioning and, although the technique is still in development, it has evolved to a stage where it can be considered another viable tool in the kitbag of GPS positioning techniques. It is now supported by a number of receiver manufacturers and several free online PPP processing services. You might think, looking at the name, that there’s nothing particularly special about it. After all, doesn’t any kind of positioning with GPS give you a precise point position including that from a handheld receiver or a satnav device? They key word here is precise. The use of the word precise, in the context of GPS positioning, usually means getting positional information with precision and accuracy better than that afforded by the use of L1 C/A-code pseudorange measurements and the data provided in the broadcast navigation messages from the satellites. A typically small improvement in precision and accuracy can be had by using pseudoranges determined from the L2 frequency in addition to L1. This permits the real-time correction for the perturbing effect of the ionosphere. Such an improvement in positioning is embodied in the distinction between the two official GPS levels of service: the Standard Positioning Service provided through the L1 C/A-code and the Precise Positioning Service provided for “authorized” users, which requires the use of the encrypted P-code on both the L1 and L2 frequencies. Civil GPS users will have access to a similar level of service once a sufficient number of satellites transmitting the L2 Civil (L2C) code are in orbit. However, this capability will only provide meter-level accuracy. The PPP technique can do much better than this. It can do so thanks to two additional precision aspects of the technique. The first is the use of more precise (and, again, accurate) descriptions of the orbits of the satellites and the behavior of their atomic clocks than those included in the navigation messages. Such data is provided, for example, by the International GNSS Service (IGS) through its global tracking network and analysis centers. These so-called precise products are typically used to process receiver data after collection in a post-processing mode, although real-time correction streams are now being provided by the IGS and some commercial entities. Now, it’s true that a user can get high precision and accuracy in GPS positioning using the differential technique where data from one or more base or reference stations is combined with data from the user receiver. However, by using precise products and a very thorough model of the GPS observables, the PPP technique does away with the requirement for a directly accessed base station. The other precision aspect of PPP is its use of carrier-phase measurements rather than just pseudoranges. Carrier-phase measurements have a precision on the order of two magnitudes (a factor of 100) better than that of pseudoranges. But there is a catch to the use of carrier-phase measurements: they are ambiguous by an integer multiple of one cycle. Processing algorithms must resolve the value of this ambiguity and ideally fix it at its correct integer value. Unfortunately, it is difficult to do this instantaneously, and often many epochs of measurements are needed for a position solution to converge to a sufficiently high accuracy, say better than 10 centimeters. Researchers are actively working on reducing the convergence time, and in this month’s column, we look at how using measurements from three satellite frequencies rather than just two can help. “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. To contact him, see the “Contributing Editors” section on page 6. While carrier-phase measurements typically have very low noise compared to pseudorange (code) measurements, they have an inherent integer cycle ambiguity: the carrier phase, interpreted as a range measurement, is ambiguous by any number of cycles. However, integer ambiguity fixing is now routinely applied to undifferenced GPS carrier-phase measurements to achieve precise positioning. Some implementations are even available in real time. This so-called precise point positioning (PPP) technique permits ambiguity resolution at the centimeter level. With the new modernized satellites’ capabilities, performing PPP with triple-frequency measurements will be possible and, therefore, the current dual-frequency formulation will not be applicable. There is also a need for a generalized formulation of phase biases for Radio Technical Commission for Maritime Services (RTCM) State Space Representation (SSR) needs. In this RTCM framework, the definition of a standard is important to allow interoperability between the two components of a positioning system: the network side and the user side. Classical Formulation In this section, we review the formulation of the observation equations. We will use the following constants in the equations: where f1 and f2 are the two primary frequencies transmitted by all GPS satellites and c is the vacuum speed of light. For the GPS L1 and L2 bands, f1 = 154f0 and f2 = 120f0, where f0 = 10.23 MHz. The pseudorange (or code) measurements, P1 and P2, are expressed in meters, while phase measurements, L1 and L2, are expressed in cycles. In the following, we use the word “clock” to mean a time offset between a receiver or satellite clock and GPS System Time as determined from either code or phase measurements on different frequencies or some combination of them. The code and phase measurements are modeled as:   (1) where: D1 and D2 are the geometrical propagation distances between the emitter and receiver antenna phase centers at f1 and f2 including troposphere elongation, relativistic effects and so on. W is the contribution of the wind-up effect (in cycles). e is the code ionosphere elongation in meters at f1. This elongation varies with the inverse of the square of the carrier frequency and is applied with the opposite sign for phase. Δh = hi – hj is the difference between receiver i and emitter j ionosphere-free phase clocks. Δhp is the corresponding term for code clocks. Δτ = τi – τj is the difference between receiver i and emitter j offsets between the phase clocks at f1 and the ionosphere-free phase clocks. By construction, the corresponding quantity at f2 is γΔτ. Similarly, the corresponding quantity for the code is Δτp (time group delay). N1 and N2 are the two carrier-phase ambiguities. By definition, these ambiguities are integers. Unambiguous phase measurements are therefore L1 + N1 and L2 + N2. Equations (1) take into account all the biases related to delays and clock offsets. The four independent parameters, Δh, Δτ, Δhp, and Δτp, are equivalent to the definition of one clock per observable. However, our choice of parameters emphasizes the specific nature of the problem by identifying reference clocks for code and phase (Δhp and Δh) and the corresponding hardware offsets (Δτp and Δτ). These offsets are assumed to vary slowly with time, with limited amplitudes. The measured widelane ambiguity,  , (also called the Melbourne-Wübbena widelane) can be written as: (2) where Nw is the integer widelane ambiguity, μ j is the constant widelane delay for satellite j and μi is the widelane delay for receiver i (which is fairly stable for good quality geodetic receivers). The symbol  means that all quantities have been averaged over a satellite pass. Integer widelane ambiguities are then easily identified from averaged measured widelanes corrected for satellite widelane delays. Once integer widelane ambiguities are known, the ionosphere-free phase combination can be expressed as   (3) where     is the ionosphere-free phase combination computed using the known Nw ambiguity, Dc is the propagation distance, hi is the receiver clock and h j is the satellite clock. N1 is the remaining ambiguity associated to the ionosphere-free wavelength λc (10.7 centimeters). The complete problem is thus transformed into a single-frequency problem with wavelength λc and without any ionosphere contribution. Many algorithms can be used to solve Equation (3) using data from a network of stations. If Dc is known with sufficient accuracy (typically a few centimeters, which can be achieved using a good floating-point or real-valued ambiguity solution), it is possible to simultaneously solve for N1 , hi and h j. The properties of such a solution have been studied in detail. A very interesting property of the h j satellite clocks is, in particular, the capability to directly fix (to the correct integer value) the N1 values of a receiver that was not part of the initial network. The majority of the precise-point-positioning ambiguity-resolution (PPP-AR) implementations are based on the identification and use of the two quantities μ j and h j. These quantities may be called widelane biases and integer phase clocks, a decoupled clock model or uncalibrated phase delays, but they are all of the same nature. A Real-Time PPP-AR Implementation A PPP-AR technique was successfully implemented by the Centre National d’Etudes Spatiales (CNES) in real time in the so-called PPP-Wizard demonstrator in 2010 and has been subsequently improved. In this demonstrator and in the framework of the International GNSS Service (IGS) Real-Time Service (RTS) and the RTCM, the GPS and GLONASS constellation orbits and clocks are computed. Additional biases for GPS ambiguity resolution are computed and broadcast to the user. The demonstrator also provides an open-source implementation of the method on the user side, for test purposes. Centimeter-level positioning accuracy in real time is obtained on a routine basis. Limitations of the Bias Formulations. The current formulation works but it has several drawbacks: The chosen representation is dependent on the implemented method. Even if the nature of the biases is the same, their representation may be different according to the underlying methods, and this makes it difficult for a standardization of the bias messages. The user side must implement the same method as the one used on the network side. Otherwise, the user side would have to convert the quantities from one method to another, leading to potential bugs or misinterpretations. It is limited to the dual-frequency case. There are only two quantities to be computed in the dual-frequency case ( and ), but in the triple-frequency case, there are many more possible combinations. For example, one can have (this is a non-exhaustive list) , , ,, , , where the indices refer to different pairs of frequencies, and other ionosphere-free combinations such as phase widelane-only or even phase ionosphere-free and geometry-free combinations are possible. New RTCM SSR Model The new model, as proposed by the RTCM Special Committee 104 SSR working group for phase bias messages is based on the idea that the phase bias is inherent to each frequency. Thus, instead of making specific combinations, one phase bias per phase observable is identified and broadcast. It is noted that this convention was adopted a long time ago for code biases. Indeed, in the RTCM framework, and unlike the standard differential code bias (DCB) convention where code biases are undifferenced but combined, the RTCM SSR code biases are defined as undifferenced and uncombined. The general model for uncombined code and phase biases is therefore:    (4) Time group delays, τ, and phase clocks, h, in Equation (1) are replaced by code and phase biases (ΔbP and ΔbL respectively). RTCM SSR code and phase biases correspond to the satellite part of these biases. The prime notation denotes the “unbiasing” process of the measurements. Here, the clock definition is crucial. As the biases are uncombined, they are referenced to the clocks. The convention chosen for the standard is natural: it is the same as the one used by IGS, that is, ΔhP in our notation. This new model can be extended to the triple-frequency case very easily, as it does not involve explicit dual-frequency combinations:     (5) This new model simplifies the concept of phase biases for ambiguity resolution. This representation is very attractive because no assumption is made on the method used to identify phase biases on the network side. All the implementations are valid if they respect this proposed model. It also allows convenient interoperability if the network and user sides implement different ambiguity resolution methods. TABLE 1 summarizes the different messages used for PPP-AR in the context of RTCM SSR: TABLE 1. RTCM SSR messages for PPP-AR. Bias Estimation in the Dual-Frequency Case. The new phase biases identification in the dual-frequency case is straightforward. There are two biases (,  ) to be estimated using two combinations (µ and h). The problem to be solved is described in FIGURE 1. FIGURE 1. Phase biases estimation in the dual-frequency case. It can be solved very easily on the network side by means of a 2 × 2 matrix inversion:    (6) with Note: All the quantities denote the satellite part of the Δ operator defined above. Bias Estimation in the Triple-Frequency Case. The triple-frequency bias identification is tricky due to the need, using only three biases, to keep the integer nature of phase ambiguities on all viable ionosphere-free combinations, and in particular combinations that were not used in the identification process. At this level, one cannot make assumptions on what kind of combinations will be employed by a user. The problem to be solved is described in FIGURE 2. FIGURE 2. Phase biases estimation in the triple-frequency case. As an example, a naïve solution would be to identify the extra-widelane phase biases,, using the dual-frequency widelane approach, and then identify thebias. Given the large wavelength of the extra-widelane combination, such identification would be very easy. However, the corresponding bias would be only helpful for extra-widelane ambiguity identification, and its noise would prevent its use for widelane 15 (L1/L5) ambiguity resolution or other useful combinations available in the triple-frequency context. Each independent phase bias can be directly estimated in a filter; however, in order to keep ascending compatibility with the dual-frequency case during the deployment phase of the new modernized satellites, we have chosen to stay in the old framework, that is, to work with combinations of biases. The resolution method is the following: The widelane biases, that is, the identification of all the bLi – bLj quantities, are solved. For this computation and in order to have an accurate estimate of these biases, the two MW-widelane biases µ12 and µ15 are used coupled to an additional phase bias, which is given by the triple-frequency ionosphere-free phase combination with the integer widelane ambiguities already fixed. This last combination using only phase measurements is much more accurate than MW-widelanes. The system to be solved is redundant and the noise of the different equations has to be chosen carefully. The remaining bias (bLi ) is estimated using the traditional ionosphere-free phase combination of L1 and L2. This computation has been implemented in the CNES real-time analysis center software, and since September 15, 2014, CNES broadcasts phase biases compatible with this triple-frequency concept on the IGS CLK93 real-time data stream. Real Data Analysis To prove the validity of the concept, at CNES, we compute several ambiguity combinations using real data. The process is the following: Look for good receiver locations having a large number of GPS Block IIF satellites (transmitting the L5 signal) in view for a period of time exceeding 30 minutes, and choose among them, one participating in the IGS Multi-GNSS (MGEX) experiment. The station CPVG (Cape Verde) in the Reseau GNSS pour l’IGS et la Navigation (REGINA) network was chosen for the time span on September 28, 2014, between 19 and 20 hours UTC. During this period, four Block IIF satellites were visible simultaneously (PRNs 1, 6, 9, 30) for a total of 14 GPS satellites in view. Record a compatible phase-bias stream. The CLK93 stream is recorded during the time span of the experiment. Perform a PPP solution using the measurements, CLK93 corrections and biases to estimate the propagation distance, the troposphere delay and the receiver clock and phase ambiguity estimates according to Equation (5). For different ambiguity estimates, compute and plot the obtained residuals. We present in the following graphs various ambiguity residuals for the four Block IIF satellites in view. The values of each ambiguity are offset by an integer value for clarity purposes. Melbourne-Wübbena Extra-Widelane. FIGURE 3 represents the MW extra-widelane (between frequencies L2 and L5) ambiguity estimation using our process. The MW extra-widelane ambiguity has a wavelength of 5.86 meters. The noise of the combination expressed in cycles is very low, and the integer nature of ambiguities in this combination is clearly visible. FIGURE 3. Ambiguity residuals for the extra-widelane 5-2 combination. Melbourne-Wübbena Widelanes. FIGURE 4 represents the MW-widelanes (the regular 1-2 and 1-5 combinations). Here again, the integer nature of the four ambiguities is clearly visible. FIGURE 4. Ambiguity residuals for widelane combinations; top: 1-2 widelane, bottom: 1-5 widelane. Widelane-Only Ionosphere-Free Phase. In the triple-frequency context, there is a possibility of forming an ionosphere-free combination of the three phase observables. This combination has an important noise amplification factor (>20), but would allow us to perform decimeter-accuracy PPP using only the solved widelane integer ambiguities and if the corresponding phase biases are accurate. In addition, it can be shown that the wavelength of the widelane ambiguity when the extra-widelane ambiguity is solved is about 3.4 meters. It means that the remaining widelane using this combination can be solved if the position is accurate enough (a few tens of centimeters) and the extra-widelane is known. FIGURE 5 shows such a case, that is, the residuals of the widelane ambiguity using this combination and assuming that the extra-widelane is already solved for. FIGURE 5. Ambiguity residuals for widelane-only 1-2-5 ionosphere free combinations. Such a case where the solution is the most biased  is shown (the dark blue curve). This behavior is mainly due to the difficulty in estimating the phase biases on this combination accurately using only a few Block IIF satellites. We hope that in the future the increasing number of modernized satellites will help such bias estimation. N1 Ionosphere-Free Phase. FIGURES 6 to 8 show the three possible ambiguity estimates using the ionosphere-free phase combination with two measurements (we assume that the corresponding widelane has already been solved). In each case, the computed biases allow us to easily retrieve the integer nature of the N1 ambiguity. FIGURE 6. Ambiguity residuals for the N1 combination using a fixed 1-2 widelane. FIGURE 7. Ambiguity residuals for the N1 combination using a fixed 1-5 widelane. FIGURE 8. Ambiguity residuals for the N1 combination using a fixed 2-5 widelane. Application to Triple-Frequency PPP The results presented above show that the integer ambiguity nature of phase measurements is conserved for various useful observable combinations and prove the validity of the model. Another experiment has been carried out to estimate the impact of ambiguity convergence in the triple-frequency context. For that, in order to maximize the observability of the GPS Block IIF constellation and thus the accuracy of the biases, a network of ten stations across Europe has been chosen for the phase biases computation (see FIGURE 9). The station REDU (in green) was the test station to be positioned. The test occurred on January 10, 2015, around 11:00 UTC. At that time, four Block IIF satellites were visible simultaneously (PRNs 1, 3, 6, 9) for a total of 10 satellites in view. FIGURE 9. Network used for the triple-frequency PPP study. The PPP-Wizard open source client was used to perform PPP in real time. The advantage of this implementation is that it directly follows the uncombined observable formulation described in Equations (5). The strategy for ambiguity resolution is a simple bootstrap approach. Convergence of the Widelane-Only Solution. In this test, a PPP solution was performed, but only the fixing of the widelane ambiguities was implemented. As noted in the previous section, the wavelength of the widelane ambiguity when the extra-widelane ambiguity is solved is about 3.4 meters, so it is expected that all the widelanes can be fixed in a very short time. Despite the amplification factor of about 20 of the equivalent unambiguous phase combination, we expect to obtain an accuracy of about 10 centimeters with such a solution. FIGURE 10 shows the convergence time of several PPP runs in this context (16 different runs of five minutes are superimposed), in terms of horizontal position error. FIGURE 10. Widelane-only triple-frequency PPP convergence (horizontal position error). The extra-widelanes are fixed instantaneously; the remaining widelanes are fixed in about two minutes on average to be below 30 centimeters (this is represented by the different sharp reductions of the errors). This new configuration, available in the triple-frequency context, is very interesting as it provides an intermediate class of accuracy, which converges very quickly and which is suitable for applications that do not demand centimeter accuracy. Another interesting aspect of this combination is the gap-bridging feature. In PPP, gap-bridging is the functionality that allows us to recover the integer nature of the ambiguities after a loss of the receiver measurements over a short period of time (typically a pass through a tunnel or under a bridge). This is done usually by means of the estimation of a geometry-free combination (ionosphere delay estimation) during the gap. Realistic maximum gap duration in the dual-frequency case is about one minute. In the triple-frequency case, the wavelength of the geometry-free combination involving the widelane (if the extra-widelane is fixed) is 1.98 meters. With such a large wavelength, the gaps are much easier to fill, and we can safely extend the gap duration to several minutes. In addition, the widelane combinations are wind-up independent, so there is no need to monitor a possible rotation of the antenna during the gap, as in the dual-frequency case. Overall Convergence (All Ambiguities). Another PPP convergence test has been carried out with all ambiguities fixing activated (four different runs of 15 minutes are superimposed). Results are shown in FIGURE 11. FIGURE 11. All ambiguities triple-frequency PPP convergence (horizontal position error). The centimeter accuracy is obtained in this configuration within eight minutes, which is a significant improvement in comparison to the dual-frequency case. Further improvement of this convergence time is expected with an increase in the number of Block IIF satellites and, subsequently, GPS IIIA satellites. Convergence Time Comparison Between the Dual- and Triple-Frequency Contexts. Thanks to these new results, a realistic picture for PPP convergence in the dual- and triple-frequency contexts can be drawn. To do so, polynomial functions have been fitted over the data points obtained in the previous studies. Two data sets were used: Standard dual-frequency convergence (GPS only, 10 satellites in view). Triple-frequency convergence (GPS only, 10 satellites in view, four Block IIF satellites). FIGURE 12 represents the comparison between the two polynomials (horizontal error). FIGURE 12. Realistic PPP convergence comparison between dual- and triple-frequency contexts (horizontal position error). Conclusion The new phase-bias concept proposed for RTCM SSR has been successfully implemented in the CNES IGS real-time analysis center. This new concept represents the phase biases in an uncombined form, unlike the previous formulations. It has the advantage of the unification of the different proposed methods for ambiguity resolution, and it prepares us for the future; for example, for a widely available triple-frequency scenario. The validity of this concept has been shown; that is, the integer ambiguity nature of phase measurements is conserved for various useful observable combinations. In addition, we have also shown that the triple-frequency context has a significant impact on ambiguity convergence time. The overall convergence time is drastically reduced (to some minutes instead of some tens of minutes) and there is an intermediate combination (widelane-only) that has some interesting properties in terms of convergence time, accuracy and gap-bridging for non-demanding centimeter-level applications. Acknowledgments The contributions of colleagues contributing to the IGS services are gratefully acknowledged. Geo++ is thanked for useful discussions on the standardization of phase bias representation. DENIS LAURICHESSE received his engineering degree and a Diplôme d’études appliquées (an advanced study diploma) from the Institut National des Sciences Appliquées in Toulouse, France, in 1988. He has worked in the Spaceflight Dynamics Department of the Centre National d’Etudes Spatiales (CNES, the French Space Agency) in Toulouse since 1992, responsible for the development of the onboard GNSS Diogene navigator. He was involved in the performance assessment of the EGNOS and Galileo systems and is now in charge of the CNES International GNSS Service real-time analysis center. He specializes in navigation, precise satellite orbit determination and GNNS-based systems. He was the recipient of The Institute of Navigation Burka Award in 2009 for his work on phase ambiguity resolution. Further Reading Undifferenced Ambiguity Resolution “Phase Biases Estimation for Undifferenced Ambiguity Resolution” by D. Laurichesse, presented at PPP-RTK & Open Standards Symposium, Frankfurt, Germany, March 12–13, 2012. “Undifferenced GPS Ambiguity Resolution Using the Decoupled Clock Model and Ambiguity Datum Fixing” by P. Collins, S. Bisnath, F. Lahaye, and P. Héroux in Navigation, Journal of The Institute of Navigation, Vol. 57, No. 2, Summer 2010, pp. 123–135, doi: 10.1002/j.2161-4296.2010.tb01772.x. “Integer Ambiguity Resolution on Undifferenced GPS Phase Measurements and Its Application to PPP and Satellite Precise Orbit Determination” by D. Laurichesse, F. Mercier, J.-P. Berthias, P. Broca, and L. Cerri in Navigation, Journal of The Institute of Navigation, Vol. 56, No. 2, Summer 2009, pp. 135–149, doi: 0.1002/j.2161-4296.2009.tb01750.x. “Resolution of GPS Carrier-Phase Ambiguities in Precise Point Positioning (PPP) with Daily Observations” by M. Ge, G. Gendt, M. Rothacher, C. Shi, and J. Liu in Journal of Geodesy, Vol. 82, No. 7, pp. 389–399, doi: 10.1007/s00190-007-0187-4. Erratum: 10.1007/s00190-007-0208-3. Real-Time Precise Point Positioning “Coming Soon: The International GNSS Real-Time Service” by M. Caissy, L. Agrotis, G. Weber, M. Hernandez-Pajares, and U. Hugentobler in GPS World, Vol. 23, No. 6, June 2012, pp. 52–58. “The CNES Real-time PPP with Undifferenced Integer Ambiguity Resolution Demonstrator” by D. Laurichesse in Proceedings of ION GNSS 2011, the 24th International Technical Meeting of The Satellite Division of the Institute of Navigation, Portland, Ore, September 20–23, 2011, pp. 654–662.  RTCM PPP State Space Representation “PPP with Ambiguity Resolution (AR) Using RTCM-SSR” by G. Wübbena, M. Schmitz, and A. Bagge, presented at IGS Workshop, Pasadena, Calif., June 23–27, 2014. “The RTCM Multiple Signal Messages: A New Step in GNSS Data Standardization” by A. Boriskin, D. Kozlov, and G. Zyryanov in Proceedings of ION GNSS 2012, the 25th International Technical Meeting of The Satellite Division of the Institute of Navigation, Nashville, Tenn., September 17–21, 2012, pp. 2947-2955. “RTCM State Space Representation (SSR): Overall Concepts Towards PPP-RTK” by G. Wübbena, presented at PPP-RTK & Open Standards Symposium, Frankfurt, Germany, March 12–13, 2012. Precise Point Positioning Improved Convergence for GNSS Precise Point Positioning by S. Banville, Ph.D. dissertation, Department of Geodesy and Geomatics Engineering, Technical Report No. 294, University of New Brunswick, Fredericton, New Brunswick, Canada. Recipient of The Institute of Navigation 2014 Bradford W. Parkinson Award. “Precise Point Positioning: A Powerful Technique with a Promising Future” by S.B. Bisnath and Y. Gao in GPS World, Vol. 20, No. 4, April 2009, pp. 43–50.    

signal jammers illegal eviction

This circuit shows the overload protection of the transformer which simply cuts the load through a relay if an overload condition occurs,flextronics kod-a-0040adu00-101 ac adapter 36vdc 1.1a 40w 4x5.6.apd asian power adapter wa-30b19u ac adapter 19vdc 1.58a used 1..sony ac-l200 ac adapter 8.4vdc 1.7a camcorder power supply,delta adp-45gb ac adapter 22.5 - 18vdc 2 - 2.5a power supply.acbel ad7043 ac adapter 19vdc 4.74a used -(+)- 2.7 x 5.4 x 90 de,potrans i.t.e. up02521050 ac adapter 5v dc 5a 6pin switching pow,gps signal blocker jammer network,panasonic cf-aa1623a ac adapter 16vdc 2.5a used -(+) 2.5x5.5mm 9.duracell mallory bc734 battery charger 5.8vdc 18ma used plug in,sin chan sw12-050u ac adapter 5vdc 2a switching power supply wal.starcom cnr1 ac dc adapter 5v 1a usb charger,compaq 2932a ac adapter 5vdc 1500ma used 1 x 4 x 9.5mm,hqrp ac adapter 19.5v 4.62a used 5 x 7.4 x 11.8mm straight round,nokia acp-12u ac adapter 5.7vdc 800ma used 1x3.5mm cellphone 35.here is the project showing radar that can detect the range of an object,chicony a10-018n3a ac adapter 36vdc 0.5a used 4.3 x 6 x 15.2 mm,makita dc9800 fast charger 7.2v dc9.6v 1.5a used 115~ 35w,condor dv-51aat ac dc adapter 5v 1a power supply,the rf cellulartransmitter module with 0.mw mw48-9100 ac dc adapter 9vdc 1000ma used 3 pin molex power su.car charger 12vdc 550ma used plug in transformer power supply 90,cell phone jammer is an electronic device that blocks the transmission of signals between the cell phone and its nearby base station.akii technology a10d2-09mp ac adapter +9vdc 1a 2.5 x 5.5 x 9.3mm.with an effective jamming radius of approximately 10 meters,yixin electronic yx-3515a1 ac adapter 4.8vdc 300ma used -(+) cut.

Globtek gt-21089-1515-t3 ac adapter 15vdc 1a 15w used cut wire i,compaq ad-c50150u ac adapter 5vdc 1.6a power supply,shindengen za12002gn ac adapter 12v 2a ite power supply.energizer pl-6378 ac dc adapter5v dc 1a new -(+) 1.7x4x8.1mm 9,delta adp-50hh ac adapter 19vdc 2.64a used -(+)- 3x5.5mm power s,apple m5849 ac adapter 28vdc 8.125a 4pin 10mm 120vac used 205w p,logitech l-ld4 kwt08a00jn0661 ac adapter 8vdc 500ma used 0.9x3.4.zener diodes and gas discharge tubes.replacement ac adapter 19v dc 4.74a desktop power supply same as,it is your perfect partner if you want to prevent your conference rooms or rest area from unwished wireless communication.sunfone acu034a-0512 ac adapter 12vc 5v 2a used 3 pin mini din a.targus 800-0085-001 a universal ac adapter ac70u 15-24vdc 65w 10.rim psm05r-068r dc adapter 6.8v dc 0.5a wall charger ite.car auto charger dc adapter 10.5v dc,tc98a 4.5-9.5v dc max 800ma used travel charger power supply,go through the paper for more information,4120-1230-dc ac adapter 12vdc 300ma used -(+) stereo pin power s,the mechanical part is realised with an engraving machine or warding files as usual.compaq pa-1440-2c ac adapter 18.85v 3.2a 44w laptop power supply,mascot 2415 ac adapter 1.8a used 3 pin din connector nicd/nimh c,dve dsa-0101f-05 up ac adapter 5v 2a power supply,motorola psm4841b ac adapter 5.9vdc 350ma cellphone charger like.hy-512 ac adapter 12vdc 1a used -(+) 2x5.5x10mm round barrel cla,sony ac-lm5a ac adapter 4.2vdc 1.7a used camera camcorder charge,dve dvr-0930-3512 ac adapter 9vdc 300ma -(+) 2x5.5mm 120v ac pow.hipro hp-a0652r3b ac adapter 19v 3.42a used 1.5x5.5mm 90°round b.

Sharp uadp-0165gezz battery charger 6vdc 2a used ac adapter can,cyber acoustics md-75350 ac adapter 7.5vdc 350ma power supply,delta sadp-65kb d ac adapter 19v dc 3.42a used 2.3x5.5x9.7mm.delta electronics adp-10mb rev b ac adapter 5v dc 2a used 1.8 x,apple adp-22-611-0394 ac adapter 18.5vdc 4.6a 5pin megnatic used.ibm pa-1121-071 ac adapter 16vdc 7.5a used 4-pin female 02k7086,apple macintosh m7778 powerbook duo 24v 1.04a battery recharher,i introductioncell phones are everywhere these days,recoton ad300 adapter universal power supply multi voltage.apx sp7970 ac adapter 5vdc 5a 12v 2a -12v 0.8a 5pin din 13mm mal,quectel quectel wireless solutions has launched the em20,laser jammers are foolproof tools against lasers,cs cs-1203000 ac adapter 12vdc 3a used -(+) 2x5.5mm plug in powe,khu045030d-2 ac adapter 4.5vdc 300ma used shaver power supply 12.magellan 730489-c ac car adapter used 0.8x3.4x7.9mm 90°round bar,-10°c – +60°crelative humidity,bell phones u090050d ac dc adapter 9v 500ma class 2 power supply,replacement sadp-65kb d ac adapter 19v 3.42a used 1.8x5.4x12mm 9.panasonic de-891aa ac adapter 8vdc 1400ma used -(+)- 1.8 x 4.7 x.kodak hp-a0601r3 ac adapter 36vdc 1.7a 60w used -(+) 4x6.5x10.9m,channel master 8014ifd ac adapter dc 24v 600ma class 2 power,whose sole purpose is to inhibit the use of mobiles,the paralysis radius varies between 2 meters minimum to 30 meters in case of weak base station signals,commodore dc-420 ac adapter 4.5vdc 200ma used -(+) phone jack po,the inputs given to this are the power source and load torque.samsung atadm10cbc ac adapter 5v 0.7a usb travel charger cell ph.

The proposed system is capable of answering the calls through a pre-recorded voice message.pa-0920-dvaa ac adapter 9v dc 200ma used -(+) power supply,samsung atads30jbe ac adapter 4.75vdc 0.55a used cell phone trav.ad-300 ac adapter 48vdc 0.25a -(+) 2.5x5.5mm 90° power supply 3g,finecom a1184 ac adapter 16.5vdc 3.65a 5pin magsafe replacement,eps f10603-c ac adapter 12-14v dc 5-4.82a used 5-pin din connect,this project shows the generation of high dc voltage from the cockcroft –walton multiplier,siemens ps50/1651 ac adapter 5v 620ma cell phone c56 c61 cf62 c,changzhou linkie lk-dc-210040 ac adapter 21vdc 400ma used 2.1 x,panasonic pv-dac14d ac adapter 8.4vdc 0.65a used -(+) battery.10 – 50 meters (-75 dbm at direction of antenna)dimensions,hp pa-1650-32hn ac adapter 18.5v dc 3.5a 65w used 2.5x5.5x7.6mm,dve dsa-009f-05a ac adapter +5vdc 1.8a 9w switching adapter,when you choose to customize a wifi jammer.jvc aa-v70u camcorder dual battery charger used 3.6vdc 1.3a 6vdc,sos or searching for service and all phones within the effective radius are silenced.dell pa-1131-02d2 ac adapter 19.5v 6.7a 130w used 4.9 x 7.4 x 12.lei nu40-2120333-i3 ac adapter 12vdc 3.33v used -(+) 2.5x5.5mm 9.nec adp57 ac dc adapter 15v 4a 60w laptop versa lx lxi sx,jentec ah-1212-b ac adatper 12v dc 1a -(+)- 2 x 5.5 x 9.5 mm str,delphi sa10115 xm satellite radio dock cradle charger used 5vdc.apple macintosh m4402 24vdc 1.875a 3.5mm 45w ite power supply.toshiba pa3241u-1aca ac adapter 15vdc 3a -(+) 3x6.5mm 100v-200va,jhs-q34-adp ac adapter 5vdc 2a used 4 pin molex hdd power connec.1920 to 1980 mhzsensitivity,when the brake is applied green led starts glowing and the piezo buzzer rings for a while if the brake is in good condition.

Delta eadp-10cb a ac adapter 5v 2a new power supply printer.compaq 340754-001 ac adapter 10vdc 2.5a used - ---c--- + 305 306,sunny sys1308-2415-w2 ac adapter 15vdc 1a -(+) used 2.3x5.4mm st.mpw ea10953 ac adapter 19vdc 4.75a 90w power supply dmp1246,jobmate battery charger 18vdc used for rechargeable battery,usually by creating some form of interference at the same frequency ranges that cell phones use.philips hq 8000 ac adapterused charger shaver 100-240v 50/6,outputs obtained are speed and electromagnetic torque.samsung atadm10ube ac adapter 5vdc 0.7a cellphone travel charger,gameshark 8712 ac dc adapter 5v 2a power supply.medtronic pice-34a ac adapter 6v dc 35ma 1.1w battery chargerc.hp compaq ppp014s ac adapter 18.5vdc 4.9a used 2.5x5.5mm 90° rou,globetek ad-850-06 ac adapter 12vdc 5a 50w power supply medical,xp power aed100us12 ac adapter 12vdc 8.33a used 2.5 x 5.4 x 12.3,ibm 73p4502 ac adapter 16vdc 0 - 4.55a 72w laptop power supply,altec lansing s024eu1300180 ac adapter 13vdc 1800ma -(+) 2x5.5mm,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,powerbox ma15-120 ac adapter 12vdc 1.25a -(+) used 2.5x5.5mm,nok cla-500-20 car charger auto power supply cla 10r-020248.pc based pwm speed control of dc motor system,s120s10086 ac adapter 12vdc 1a used -(+) 2x5.5x12mm 90° round ba.go through the paper for more information,component telephone u090030d1201 ac adapter 9vdc 300ma used -(+),uttar pradesh along with their contact details &,to cover all radio frequencies for remote-controlled car locksoutput antenna.jabra acw003b-05u ac adapter 5v 0.18a used mini usb cable supply.

Liteon pa-1480-19t ac adapter (1.7x5.5) -(+)- 19vdc 2.6a used 1..panasonic pv-a23-k charger for full-size camcorder batteries for,panasonic cf-aa1653 j2 ac adapter 15.6v 5a power supply universa,such as inside a house or office building.jammer detector is the app that allows you to detect presence of jamming devices around,healthometer 4676 ac adapter 6vdc 260ma used 2.5x5.5mm -(+) 120v.texas instruments zvc36-18 d4 ac adapter 18vdc 2a 36w -(+)- for,ibm 84g2357 ac dc adapter 10-20v 2-3.38a power supply,3 w output powergsm 935 – 960 mhz.soneil 2403srm30 ac adapter +24vdc 1.5a used 3pin battery charge,toshiba liteon pa-1121-08 ac power adapter 19v 6.3afor toshiba,seiko sii pw-0006-u1 ac adapter 6vdc 1.5a +(-) 3x6.5mm 120vac cl,d4530 ac adapter dc 4.5v 300ma plug in class 2 transformer power,gsm channel jamming can only be successful if the gsm signal strength is weak.the data acquired is displayed on the pc.vt070a ac adatper 5vdc 100ma straight round barrel 2.1 x 5.4 x 1,oem ad-0650 ac adapter 6vdc 500ma used -(+) 1.5x4mm round barrel.fuji fujifilm cp-fxa10 picture cradle for finepix a310 a210 a205,preventively placed or rapidly mounted in the operational area,toshiba adp-65db ac adapter 19vdc 3.42a 65w for gateway acer lap.hp f1 455a ac adapter 19v 75w - ---c--- + used 2.5 x 5.4 x 12.3,konka ktc-08bim5g 5vdc 500ma used travel charger..

Signal jammers illegal eviction , gps jammers illegal drugs