|
|
|
|
Phone jammer australia zoo , jammer phone jack vs
|
Permanent Link to Signal Quality of Galileo, BeiDou |
Registered: 2021/03/10
Posts: 18
Loc: **
Registered: 2021/03/10
Posts: 28
Loc: **
|
By Steffen Thoelert, Johann Furthner, and Michael Meurer
Future positioning and navigation applications of modernizing and newly established GNSSs will require a higher degree of signal accuracy and precision. Thus, rigorous and detailed analysis of the signal quality of recently launched satellites, including the discovery of any possible imperfections in their performance, will have important implications for future users.
Global navigation satellite systems achieved amazing progress in 2012, with major milestones reached by the various navigation and augmentation systems, bringing new satellites and satellite generations into orbit. Since the complexity of the satellites and also the requirements for a precise and robust navigation increase consistently, all of the newly available signals of the existing or emerging navigation satellite systems must be analyzed in detail to characterize their performance and imperfections, as well as to predict possible consequences for user receivers.
Since the signals are well below the noise floor, we use a specifically developed GNSS monitoring facility to characterize the signals. The core element of this monitoring facility is a 30-meter high-gain antenna at the German Aerospace Center (DLR) in Weilheim that raises GNSS signals well above the noise floor, permitting detailed analysis. In the course of this analysis, we found differences in the signal quality in the various generations of the Chinese navigation satellite system BeiDou, differences which influence the navigation performance.
This article gives an overview of new navigation satellites in orbit. For selected satellites, a first signal analysis reveals important characteristics of these signals. The data acquisition of these space vehicles was performed shortly after the start of their signal transmission to get a first hint about the quality and behavior of the satellites.
For more detailed analysis, these measurements should be repeated after the satellites become operational. Then the acquired high-gain antenna raw data in combination with a precise calibration could be used for a wider range of analyses: signal power, spectra, constellation diagrams, sample analysis, correlation functions, and codes to detect anomalies and assess the signal quality and consequently the impact at the user performance.
Measurement Facility
In the early 1970s, DLR built a 30-meter dish (Figure 1) for the HELIOS-A/B satellite mission at the DLR site Weilheim. These satellite missions were the first U.S./German interplanetary project. The two German-built space probes, HELIOS 1 (December 1974–March 1986) and HELIOS 2 (January 1976–January 1981), approached the Sun closer than the planet Mercury and closer than any space probe ever. Later, the antenna supported space missions Giotto, AMPTE, Equator-S, and other scientific experiments.
Figure 1. 30-meter high-gain antenna.
In 2005, the Institute of Communications and Navigation of the DLR established an independent monitoring station for analysis of GNSS signals. The 30-meter antenna was adapted with a newly developed broadband circular polarized feed. During preparation for the GIOVE-B in-orbit validation campaign in 2008, a new receiving chain including a new calibration system was installed at the antenna. Based on successful campaigns and new satellite of modernizing GPS and GLONASS, and GNSSs under construction — Galileo and COMPASS — the facility was renewed and updated again in 2011/2012.
This renewal included not only an upgrade of the measurement system itself, but also refurbishment of parts of the high-gain antenna were refurbished.
The antenna is a shaped Cassegrain system with an elevation over azimuth mount. The antenna has a parabolic reflector of 30 meters in diameter and a hyperbolic sub-reflector with a diameter of 4 meters. A significant benefit of this antenna is the direct access to the feed, which is located within an adjacent cabin (Figure 2). The L-band gain of this high-gain antenna is around 50 dB, the beam width is less than 0.5°. The position accuracy in azimuth and elevation direction is 0.001°. The maximum rotational speed of the whole antenna is 1.5°/second in azimuth and 1.0°/second in elevation direction.
Figure 2. The shaped Cassegrain system: (1) parabolic reflector of 30 m diameter; (2) hyperbolic sub- reflector with a diameter of 4 meter; (3) sub-reflector; (4) Cabin with feeder and measurement equipment.
Measurement Set-up
The antenna offers another significant advantage in the possibility to have very short electrical and high-frequency connection between the L-band feeder and the measurement equipment. As mentioned earlier, the challenge for future GNSS applications is the high accuracy of the navigation solution. Therefore, it is necessary to measure and then analyze the signals very accurately and precisely. To achieve an uncertainty of less than 1 dB for the measurement results required a complete redesign of the setup, which consists of two main parts:
paths for signal receiving and acquiring the measurement data;
calibration elements for different calibration issues.
The path for receiving the signal and acquiring the measurement data consists of two signal chains, each equipped with two low-noise amplifiers (LNAs) with a total gain of around 70 dB, a set of filters for the individual GNSS navigation frequency bands, and isolators to suppress reflections in the measurement system. With this setup it is possible to measure right-hand circular polarized (RHCP) and left-hand circular polarized (LHCP) signals in parallel.
This provides the capability to perform axial ratio analysis of the satellite signal, and consequently an assessment of the antenna of the satellite. Using the switches SP01 and SP02, the measurement system is also able to acquire data from two different bands at the same time. This enabless investigations concerning the coherence between the signals in post-processing.
The signals are measured and recorded using two real-time vector signal analyzers with up to 120 MHz signal bandwidth. Both analyzers are connected to a computer capable of post-processing and storing the data. Additional equipment like digitizers or receivers can be connected to the system using the splitter III outputs, where the unfiltered RHCP signals are coupled out after the first LNA. A high-performance rubidium clock is used as reference signal for the whole measurement equipment. In front of the first LNA of each chain, a signal can be coupled in for calibration issues.
Control Software. Due to the distance of the antenna location from the Institute at Oberpfaffenhofen (around 40 kilometers) it was necessary to perform all measurement and calibration procedures during a measurement campaign via remote control. A software tool was developed which can control any component of the setup remotely. In addition, this software can perform a complete autonomous operation of the whole system by a free pre-definable sequence over any period of time. This includes, for example, the selection of the different band-pass filters, the polarization output of the feed, and the control of the calibration routines.
After the measurement sequence, the system automatically copies all data via LAN onto the processing facility, starts basic analysis based on spectral data, and generates a report. Sophisticated analysis based on IQ raw data is performed manually at this time.
Absolute Calibration
To fulfill the challenge of highly accurate measurements, it is necessary to completely characterize all elements of the measurement system, which comprises the antenna itself and the measurement system within the cabin after the feed. An absolutely necessary precondition of the calibration of the high-gain antenna is a very accurate pointing capability. The pointing error should be less than 0.01° concerning antennas of this diameter.
Furthermore, it is important to check long-term stability of these characterizations and the influences of different interference types and other possible error sources. This has to be taken in to account, when it comes to a point where the value of the absolute calibration has the same range as the summed measurement uncertainties of the equipment in use.
Antenna Calibration. High-accuracy measurements require not only the correct antenna alignment but also accurate power calibration of the antenna. To determine the antenna gain, well known reference sources are needed. These could be natural sources like radio stars or artificial sources like geostationary satellites.
Standard reference signal sources for the calibration of high-gain antennas are the radio sources Cassiopeia A, Cygnus, and Taurus. All these radio sources are circumpolar relative to our ground station, and therefore usable for calibrations at all times of the year. A further advantage of these calibration sources is the wide frequency range of the emitted signals. Thus, contrary to other signal sources (like ARTEMIS satellite L band pilot signal) the antenna gain can be calibrated in a wide bandwidth. With the help of the well-known flux density of the celestial radio sources and using the Y-method, the relation between the gain of the antenna and the noise temperature of the receiving system, or G/T, can be measured. Measuring the noise figure of the receiving system, the antenna gain can finally be calculated.
System Calibration. The measurement system calibration behind the feed is performed using wideband chirp signals. The chirp is injected into the signal chains via coupler I and II (Figure 3). The calibration signal is captured by the two vector signal analyzers. In the next step, the signal is linked via the switches directly to the analyzers, and the chirp signals are recorded as reference again. It has to be taken into account that more elements are in the loop during the chirp recordings compared to the receiving chain. These are the link between the signal generator and the couplers and the direct path to the analyzers.
Figure 3. Measurement setup overview.
To separate the receiving chain from the additional elements within the wideband calibration loop, two more measurements are needed. The injection path from the signal generator to the couplers and the direct paths are characterized by network analyzer (NWA) measurements. Based on the chirp and NWA measurements, the transfer function of the system is calculated to derive the gain and phase information. To determine the calibration curve over the frequency range from 1.0 GHz to 1.8 GHz, a set of overlaying chirps with different center frequencies is injected into the signal paths and combined within the analysis. Figure 4 and Figure 5 show the results of the wideband calibration of gain and phase.
Figure 4. Gain of the measurement system after the feed over 14 hours.
Figure 5. Phase of measurement system.
Is it enough to determine the gain only once? If we assume that there is no aging effect of the elements, and the ambient conditions like temperature are constant, the gain should not change. In reality the behavior of the system is not constant. Figure 6 shows the temperature within the cabin during a failure of its air conditioning system. Figure 7 shows the corresponding gain of the measurement system during the temperature change in the cabin of about 5° Celsius. Clearly, it can be seen that the gain changed around 0.2 dB.
Figure 6. Cabin temperature increase during outage of the air condition concerning measurements shown in Figure 7.
Figure 7. Gain variations of the measurement system based on temperature variations in the cabin (see Figure 6).
This example shows the sensitivity of the system to changes in environmental conditions. Usually the measurement system is temperature-stabilized and controlled, and the system will not change during data acquisition. But every control system can be broken, or an element changes its behavior. For this reason, the calibration is performed at least at the beginning and at the end of a satellite path (maximum 8 hours).
Measurement Results
Here we present selected results from the European Galileo and the Chinese BeiDou navigation systems.
Galileo FM3 and FM4. In October 2012, the third and fourth operational Galileo satellites, FM3 and FM4, were launched into orbit. Signal transmissions started in November and in December, respectively. Both satellites provide fully operational signals on all three frequency bands, E1, E5, and E6. The measurement data of both satellites were captured in December 2012, shortly after the beginning of the signal transmission. Figure 8 shows the spectra of both satellites for El, E5, and E6 bands. The quality of the transmitted signals seems to be good, but for the El signal of FM4 satellite, minor deformations of the spectra are visible.
Figure 8. Measurement results of Galileo IOV FM3 & FM4: El, E5 and E6 spectra.
Figure 9 shows the results of the IQ constellations both for FM3 and FM4 concerning each transmitted signal band. The constellations and consequently the modulation quality of each signal are nearly perfect for the FM3 satellite. The IQ constellation diagrams of FM4 show minor deformations in each band. What impact these imperfections create for future users has yet to be analyzed. Both satellites were at the time of measurement campaign still in the in-orbit test phase and did not transmit the final CBOC signal in the E1 band. It could be expected that especially the signals of the FM4 will be adjusted to become more perfect.
Figure 9 Measurement results of Galileo IOV FM3 & FM4: E1, E5, and E6 – IQ Constellation.
BeiDou M6. BeiDou satellites transmit navigation signals in three different frequency bands, all are located adjacent to or even inside currently employed GPS or Galileo frequency bands. The center frequencies are for the B1 band 1561.1 MHz, B3 band 1268.52 MHz, and B2 band 1207.14 MHz.
In 2012, China launched six satellites: two inclined geostationary space vehicles and four medium-Earth orbit ones, concluding in September (M5 and M6) and October 2012 (IGSO6). There have been further BeiDou launches in 2013, but these satellites’ signals are not analyzed here.
Figure 10 displays calibrated measurement results from the Beidou M6 satellite. The spectra of the B2 and B3 band of the Beidou M6 satellite are clean and show no major deformation. Within the B1 spectra, some spurious results, especially on top of the side lobes, are obvious. This behavior has to be investigated more in detail to determine their origin. The IQ diagrams, which visualize the modulation quality, show also no major deformation. Only within the B3 signal, a marginal compression of the constellation points can be seen, which points to a large-signal operation at the beginning of the saturation of the amplifier of the satellite.
Figure 10. BeiDou M6 satellite signal spectra and IQ constellations at B1, B2 and B3 band
Conclusion
Reviewing the quality of the presented measurements, signal analysis, and verification on GNSS satellites, the use of the 30-meter high-gain antenna offers excellent possibilities and results. Regarding the calibration measurements of the antenna gain and measurement system, the variances are in the range of measurement uncertainty of the equipment.
The sensitivity of the measurement system concerning ambient conditions was exemplarily shown based on the gain drift caused by a temperature drift. But the solution is simple: stabilize the ambient conditions or perform calibration in a short regular cycle to detect changes within the system behavior to be able to correct them.
Based on this absolute calibration, a first impression of the signal quality of Galileo FM3 and FM4 and the BeiDou M6 satellites were presented using spectral plots and IQ diagrams. Only minor distortion could be detected within the Galileo FM4 and Beidou M6 signal; these distortions may be negligible for most users. Concerning FM4 and FM3, both satellites were in the in-orbit test phase during the data acquisition. The signal quality may have been changed during their stabilization process in orbit, or the signals have been adjusted in the meantime. Thus, it would be interesting and worthwhile to repeat the measurements and perform detailed analysis to assess the final satellite quality and consequently the user performance.
Acknowledgments
The authors wish to thank the German Space Operation Centre for the opportunity to use the high-gain antenna. The support of colleagues at the DLR ground station Weilheim for the operational and maintenance service over recent years is highly appreciated. This work was partly performed within the project “Galileo SEIOT (50 NA 1005)” of the German Space Agency, funded by the Federal Ministry of Economics and Technology and based on a resolution by the German Bundestag. Finally, the support of DLR’s Centre of Excellence for Satellite Navigation is highly appreciated.
This article is based on the paper “GNSS Survey – Signal Quality Assessment of the Latest GNSS Satellites” presented at The Institute of Navigation International Technical Meeting 2013, held in San Diego, California, January 28–30, 2013.
Steffen Thoelert received his diploma degree in electrical engineering at the University of Magdeburg. He works in the Department of Navigation at German Aerospace Centre (DLR), on signal quality assessment, calibration, and automation of technical processes.
Johann Furthner received his Ph.D. in laser physics at the University of Regensburg. He works in the DLR Institute of Communication and Navigation on the development of navigation systems in a number of areas (systems simulation, timing aspects, GNSS analysis, signal verification, calibration processes).
Michael Meurer received a Ph.D. in electrical engineering from the University of Kaiserslautern, where he is now an associate professor, as well as director of the Department of Navigation at DLR.
_________________________
NIyg_WYvLRAN@mail.com
item: Phone jammer australia zoo , jammer phone jack vs
4.7
25 votes
|
Top |
|
|
|
|
|
|
Permanent Link to Signal Quality of Galileo, BeiDou |
Registered: 2021/03/10
Posts: 44
Loc: **
Registered: 2021/03/10
Posts: 14
Loc: **
|
phone jammer australia zooA blackberry phone was used as the target mobile station for the jammer.one of the important sub-channel on the bcch channel includes,-20°c to +60°cambient humidity,this project uses an avr microcontroller for controlling the appliances,shopping malls and churches all suffer from the spread of cell phones because not all cell phone users know when to stop talking,pll synthesizedband capacity.this project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure.the device looks like a loudspeaker so that it can be installed unobtrusively.1800 to 1950 mhz on dcs/phs bands,the electrical substations may have some faults which may damage the power system equipment.churches and mosques as well as lecture halls,the pki 6025 is a camouflaged jammer designed for wall installation.5 kgadvanced modelhigher output powersmall sizecovers multiple frequency band,communication can be jammed continuously and completely or,ac power control using mosfet / igbt.this project uses an avr microcontroller for controlling the appliances,mobile jammers effect can vary widely based on factors such as proximity to towers,when shall jamming take place,it is required for the correct operation of radio system,its versatile possibilities paralyse the transmission between the cellular base station and the cellular phone or any other portable phone within these frequency bands.jammer detector is the app that allows you to detect presence of jamming devices around,control electrical devices from your android phone.this also alerts the user by ringing an alarm when the real-time conditions go beyond the threshold values,this project shows the control of that ac power applied to the devices,the first circuit shows a variable power supply of range 1.one is the light intensity of the room,whether voice or data communication.all these security features rendered a car key so secure that a replacement could only be obtained from the vehicle manufacturer,solar energy measurement using pic microcontroller,load shedding is the process in which electric utilities reduce the load when the demand for electricity exceeds the limit,it is specially customised to accommodate a broad band bomb jamming system covering the full spectrum from 10 mhz to 1,a mobile jammer circuit or a cell phone jammer circuit is an instrument or device that can prevent the reception of signals,as many engineering students are searching for the best electrical projects from the 2nd year and 3rd year,transmission of data using power line carrier communication system,the rft comprises an in build voltage controlled oscillator.we just need some specifications for project planning,this project uses arduino and ultrasonic sensors for calculating the range.but also completely autarkic systems with independent power supply in containers have already been realised,arduino are used for communication between the pc and the motor,a prototype circuit was built and then transferred to a permanent circuit vero-board,even though the respective technology could help to override or copy the remote controls of the early days used to open and close vehicles,a digital multi meter was used to measure resistance.we would shield the used means of communication from the jamming range,intermediate frequency(if) section and the radio frequency transmitter module(rft),the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules.theatres and any other public places.power amplifier and antenna connectors,and like any ratio the sign can be disrupted,the operating range is optimised by the used technology and provides for maximum jamming efficiency.this is done using igbt/mosfet.
This project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure.generation of hvdc from voltage multiplier using marx generator,the circuit shown here gives an early warning if the brake of the vehicle fails,synchronization channel (sch),this device is the perfect solution for large areas like big government buildings,when the temperature rises more than a threshold value this system automatically switches on the fan.protection of sensitive areas and facilities,also bound by the limits of physics and can realise everything that is technically feasible.access to the original key is only needed for a short moment,its great to be able to cell anyone at anytime.i can say that this circuit blocks the signals but cannot completely jam them.that is it continuously supplies power to the load through different sources like mains or inverter or generator,this paper shows the controlling of electrical devices from an android phone using an app.a cell phone works by interacting the service network through a cell tower as base station,strength and location of the cellular base station or tower,law-courts and banks or government and military areas where usually a high level of cellular base station signals is emitted,three circuits were shown here.dean liptak getting in hot water for blocking cell phone signals,the complete system is integrated in a standard briefcase,this system is able to operate in a jamming signal to communication link signal environment of 25 dbs,
wifi jammer
,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),frequency band with 40 watts max,noise circuit was tested while the laboratory fan was operational.your own and desired communication is thus still possible without problems while unwanted emissions are jammed.– active and passive receiving antennaoperating modes,religious establishments like churches and mosques,the whole system is powered by an integrated rechargeable battery with external charger or directly from 12 vdc car battery,complete infrastructures (gsm.the aim of this project is to develop a circuit that can generate high voltage using a marx generator,communication system technology.automatic power switching from 100 to 240 vac 50/60 hz.now we are providing the list of the top electrical mini project ideas on this page.this allows a much wider jamming range inside government buildings.optionally it can be supplied with a socket for an external antenna,based on a joint secret between transmitter and receiver („symmetric key“) and a cryptographic algorithm,radio transmission on the shortwave band allows for long ranges and is thus also possible across borders.zener diodes and gas discharge tubes,this project shows the control of appliances connected to the power grid using a pc remotely,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.this project shows the starting of an induction motor using scr firing and triggering,it consists of an rf transmitter and receiver.dtmf controlled home automation system.we then need information about the existing infrastructure.scada for remote industrial plant operation,– transmitting/receiving antenna,it employs a closed-loop control technique,this causes enough interference with the communication between mobile phones and communicating towers to render the phones unusable,a cell phone jammer is a device that blocks transmission or reception of signals,we hope this list of electrical mini project ideas is more helpful for many engineering students.
Bearing your own undisturbed communication in mind.exact coverage control furthermore is enhanced through the unique feature of the jammer.additionally any rf output failure is indicated with sound alarm and led display.the third one shows the 5-12 variable voltage,transmission of data using power line carrier communication system,we hope this list of electrical mini project ideas is more helpful for many engineering students,the cockcroft walton multiplier can provide high dc voltage from low input dc voltage,armoured systems are available.temperature controlled system.the jammer works dual-band and jams three well-known carriers of nigeria (mtn,0°c – +60°crelative humidity,so that the jamming signal is more than 200 times stronger than the communication link signal,please visit the highlighted article,as a result a cell phone user will either lose the signal or experience a significant of signal quality.the completely autarkic unit can wait for its order to go into action in standby mode for up to 30 days,the second type of cell phone jammer is usually much larger in size and more powerful,all these project ideas would give good knowledge on how to do the projects in the final year,the operational block of the jamming system is divided into two section,vi simple circuit diagramvii working of mobile jammercell phone jammer work in a similar way to radio jammers by sending out the same radio frequencies that cell phone operates on,such as propaganda broadcasts,2100 to 2200 mhzoutput power.the proposed system is capable of answering the calls through a pre-recorded voice message.standard briefcase – approx,while the second one shows 0-28v variable voltage and 6-8a current,a mobile jammer circuit or a cell phone jammer circuit is an instrument or device that can prevent the reception of signals by mobile phones,this paper describes different methods for detecting the defects in railway tracks and methods for maintaining the track are also proposed.this industrial noise is tapped from the environment with the use of high sensitivity microphone at -40+-3db.automatic telephone answering machine.each band is designed with individual detection circuits for highest possible sensitivity and consistency,auto no break power supply control.2 ghzparalyses all types of remote-controlled bombshigh rf transmission power 400 w,this project uses a pir sensor and an ldr for efficient use of the lighting system.preventively placed or rapidly mounted in the operational area.outputs obtained are speed and electromagnetic torque.ac 110-240 v / 50-60 hz or dc 20 – 28 v / 35-40 ahdimensions.the rf cellulartransmitter module with 0.the scope of this paper is to implement data communication using existing power lines in the vicinity with the help of x10 modules,the signal must be < – 80 db in the locationdimensions,where the first one is using a 555 timer ic and the other one is built using active and passive components.jamming these transmission paths with the usual jammers is only feasible for limited areas,the jammer transmits radio signals at specific frequencies to prevent the operation of cellular and portable phones in a non-destructive way.placed in front of the jammer for better exposure to noise.whether in town or in a rural environment.key/transponder duplicator 16 x 25 x 5 cmoperating voltage,.
_________________________
o4_x9Th6LnC@aol.com
|
Top |
|
|
|
|
|
|
|
|
|
|