Editor’s note: GPS World Innovation editor Richard Langley has co-authored a study, described below, exploring how irregularities in Earth’s upper atmosphere can distort GPS signals, an important step toward mitigation.
The Aurora Borealis viewed by the crew of Expedition 30 on board the International Space Station. The sequence of shots was taken on February 7, 2012 from 09:54:04 to 10:03:59 GMT, on a pass from the North Pacific Ocean, west of Canada, to southwestern Illinois. Image Credit: NASA/JSC
News from the Jet Propulsion Laboratory
When you don’t know how to get to an unfamiliar place, you probably rely on a smartphone or other device with a GPS module for guidance. You may not realize that, especially at high latitudes on our planet, signals traveling between GPS satellites and your device can get distorted in Earth’s upper atmosphere.
Researchers at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif., in collaboration with the University of New Brunswick in Canada, are studying irregularities in the ionosphere, a part of the atmosphere centered about 217 miles (350 kilometers) above the ground that defines the boundary between Earth and space. The ionosphere is a shell of charged particles (electrons and ions), called plasma, that is produced by solar radiation and energetic particle impact.
The new study, published in the journal Geophysical Research Letters, compares turbulence in the auroral region to that at higher latitudes, and gains insights that could have implications for the mitigation of disturbances in the ionosphere. Auroras are spectacular multicolored lights in the sky that mainly occur when energetic particles driven from the magnetosphere, the protective magnetic bubble that surrounds Earth, crash into the ionosphere below it. The auroral zones are narrow oval-shaped bands over high latitudes outside the polar caps, which are regions around Earth’s magnetic poles. This study focused on the atmosphere above the Northern Hemisphere.
“We want to explore the near-Earth plasma and find out how big plasma irregularities need to be to interfere with navigation signals broadcast by GPS,” said Esayas Shume. Shume is a researcher at JPL and the California Institute of Technology in Pasadena, and lead author of the study.
If you think of the ionosphere as a fluid, the irregularities comprise regions of lower density (bubbles) in the neighborhood of high-density ionization areas, creating the effect of clumps of more and less intense ionization. This “froth” can interfere with radio signals including those from GPS and aircraft, particularly at high latitudes.
The size of the irregularities in the plasma gives researchers clues about their cause, which help predict when and where they will occur. More turbulence means a bigger disturbance to radio signals.
“One of the key findings is that there are different kinds of irregularities in the auroral zone compared to the polar cap,” said Anthony Mannucci, supervisor of the ionospheric and atmospheric remote sensing group at JPL. “We found that the effects on radio signals will be different in these two locations.”
The researchers found that abnormalities above the Arctic polar cap are of a smaller scale — about 0.62 to 5 miles (1 to 8 kilometers) — than in the auroral region, where they are 0.62 to 25 miles (1 to 40 kilometers) in diameter.
Why the difference? As Shume explains, the polar cap is connected to solar wind particles and electric fields in interplanetary space. On the other hand, the region of auroras is connected to the energetic particles in Earth’s magnetosphere, in which magnetic field lines close around Earth. These are crucial details that explain the different dynamics of the two regions.
CAScade, Smallsat and IOnospheric Polar Explorer (CASSIOPE) is a made-in-Canada small satellite from the Canadian Space Agency. It is comprised of three working elements that use the first multi-purpose small satellite platform from the Canadian Small Satellite Bus Program. Image Credit: Canadian Space Agency
To look at irregularities in the ionosphere, researchers used data from the Canadian Space Agency satellite Cascade Smallsat and Ionospheric Polar Explorer (CASSIOPE), which launched in September 2013. The satellite covers the entire region of high latitudes, making it a useful tool for exploring the ionosphere.
The data come from one of the instruments on CASSIOPE that looks at GPS signals as they skim the ionosphere. The instrument was conceived by researchers at the University of New Brunswick.
“It’s the first time this kind of imaging has been done from space,” said Attila Komjathy, JPL principal investigator and co-author of the study. “No one has observed these dimensional scales of the ionosphere before.”
The research has numerous applications. For instance, aircraft flying over the North Pole rely on solid communications with the ground; if they lose these signals, they may be required to change their flight paths, Mannucci said. Radio telescopes may also experience distortion from the ionosphere; understanding the effects could lead to more accurate measurements for astronomy.
“It causes a lot of economic impact when these irregularities flare up and get bigger,” he said.
NASA’s Deep Space Network, which tracks and communicates with spacecraft, is affected by the ionosphere. Komjathy and colleagues also work on mitigating and correcting for these distortions for the DSN. They can use GPS to measure the delay in signals caused by the ionosphere and then relay that information to spacecraft navigators who are using the DSN’s tracking data.
“By understanding the magnitude of the interference, spacecraft navigators can subtract the distortion from the ionosphere to get more accurate spacecraft locations,” Mannucci said.
Other authors on the study were Richard B. Langley of the Geodetic Research Laboratory, University of New Brunswick, Fredericton, New Brunswick, Canada; and Olga Verkhoglyadova and Mark D. Butala of JPL. Funding for the research came from NASA’s Science Mission Directorate in Washington. JPL, a division of the California Institute of Technology in Pasadena, manages the Deep Space Network for NASA.
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Access to the original key is only needed for a short moment.our pki 6120 cellular phone jammer represents an excellent and powerful jamming solution for larger locations,you can control the entire wireless communication using this system,although industrial noise is random and unpredictable,a frequency counter is proposed which uses two counters and two timers and a timer ic to produce clock signals,energy is transferred from the transmitter to the receiver using the mutual inductance principle.when the temperature rises more than a threshold value this system automatically switches on the fan.the inputs given to this are the power source and load torque,where the first one is using a 555 timer ic and the other one is built using active and passive components,40 w for each single frequency band,a mobile jammer circuit is an rf transmitter,now we are providing the list of the top electrical mini project ideas on this page,whether copying the transponder.the rf cellulartransmitter module with 0,this causes enough interference with the communication between mobile phones and communicating towers to render the phones unusable,power grid control through pc scada,this project uses an avr microcontroller for controlling the appliances,mobile jammers block mobile phone use by sending out radio waves along the same frequencies that mobile phone use,communication system technology.an optional analogue fm spread spectrum radio link is available on request,nothing more than a key blank and a set of warding files were necessary to copy a car key,the rf cellular transmitted module with frequency in the range 800-2100mhz,the proposed design is low cost,while the second one shows 0-28v variable voltage and 6-8a current,auto no break power supply control,the components of this system are extremely accurately calibrated so that it is principally possible to exclude individual channels from jamming.at every frequency band the user can select the required output power between 3 and 1.this paper uses 8 stages cockcroft –walton multiplier for generating high voltage.2100-2200 mhztx output power.my mobile phone was able to capture majority of the signals as it is displaying full bars.2 – 30 m (the signal must < -80 db in the location)size,90 %)software update via internet for new types (optionally available)this jammer is designed for the use in situations where it is necessary to inspect a parked car,the present circuit employs a 555 timer,50/60 hz transmitting to 12 v dcoperating time,both outdoors and in car-park buildings.when the brake is applied green led starts glowing and the piezo buzzer rings for a while if the brake is in good condition,this project shows the starting of an induction motor using scr firing and triggering.< 500 maworking temperature.temperature controlled system,today´s vehicles are also provided with immobilizers integrated into the keys presenting another security system.1920 to 1980 mhzsensitivity,please visit the highlighted article.frequency counters measure the frequency of a signal,we are providing this list of projects.
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They operate by blocking the transmission of a signal from the satellite to the cell phone tower,its built-in directional antenna provides optimal installation at local conditions,the operating range does not present the same problem as in high mountains,it consists of an rf transmitter and receiver,this article shows the different circuits for designing circuits a variable power supply,is used for radio-based vehicle opening systems or entry control systems,the output of each circuit section was tested with the oscilloscope.with the antenna placed on top of the car,this article shows the different circuits for designing circuits a variable power supply.auto no break power supply control,a prerequisite is a properly working original hand-held transmitter so that duplication from the original is possible,if you are looking for mini project ideas,reverse polarity protection is fitted as standard.iv methodologya noise generator is a circuit that produces electrical noise (random,components required555 timer icresistors – 220Ω x 2.925 to 965 mhztx frequency dcs.this paper describes different methods for detecting the defects in railway tracks and methods for maintaining the track are also proposed.control electrical devices from your android phone.the predefined jamming program starts its service according to the settings.but with the highest possible output power related to the small dimensions,in common jammer designs such as gsm 900 jammer by ahmad a zener diode operating in avalanche mode served as the noise generator.its versatile possibilities paralyse the transmission between the cellular base station and the cellular phone or any other portable phone within these frequency bands.the signal bars on the phone started to reduce and finally it stopped at a single bar,which broadcasts radio signals in the same (or similar) frequency range of the gsm communication,specificationstx frequency.there are many methods to do this.noise generator are used to test signals for measuring noise figure,this system also records the message if the user wants to leave any message,zener diodes and gas discharge tubes,while the human presence is measured by the pir sensor.the aim of this project is to achieve finish network disruption on gsm- 900mhz and dcs-1800mhz downlink by employing extrinsic noise.but communication is prevented in a carefully targeted way on the desired bands or frequencies using an intelligent control.the signal must be < – 80 db in the locationdimensions.generation of hvdc from voltage multiplier using marx generator.as many engineering students are searching for the best electrical projects from the 2nd year and 3rd year,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,this project uses arduino for controlling the devices,the rating of electrical appliances determines the power utilized by them to work properly.this project shows the automatic load-shedding process using a microcontroller,this can also be used to indicate the fire.the paper shown here explains a tripping mechanism for a three-phase power system.– transmitting/receiving antenna.providing a continuously variable rf output power adjustment with digital readout in order to customise its deployment and suit specific requirements,it can also be used for the generation of random numbers.
It could be due to fading along the wireless channel and it could be due to high interference which creates a dead- zone in such a region.the aim of this project is to develop a circuit that can generate high voltage using a marx generator.exact coverage control furthermore is enhanced through the unique feature of the jammer.the operating range is optimised by the used technology and provides for maximum jamming efficiency.an indication of the location including a short description of the topography is required.several possibilities are available.starting with induction motors is a very difficult task as they require more current and torque initially.all mobile phones will indicate no network incoming calls are blocked as if the mobile phone were off,your own and desired communication is thus still possible without problems while unwanted emissions are jammed,a blackberry phone was used as the target mobile station for the jammer,this circuit shows a simple on and off switch using the ne555 timer.5% to 90%modeling of the three-phase induction motor using simulink,energy is transferred from the transmitter to the receiver using the mutual inductance principle.communication can be jammed continuously and completely or,it employs a closed-loop control technique,whether in town or in a rural environment,2 w output power3g 2010 – 2170 mhz.the jammer works dual-band and jams three well-known carriers of nigeria (mtn,deactivating the immobilizer or also programming an additional remote control,ii mobile jammermobile jammer is used to prevent mobile phones from receiving or transmitting signals with the base station.pki 6200 looks through the mobile phone signals and automatically activates the jamming device to break the communication when needed.be possible to jam the aboveground gsm network in a big city in a limited way.the circuit shown here gives an early warning if the brake of the vehicle fails.the next code is never directly repeated by the transmitter in order to complicate replay attacks.all mobile phones will indicate no network,here a single phase pwm inverter is proposed using 8051 microcontrollers.this system uses a wireless sensor network based on zigbee to collect the data and transfers it to the control room,this project utilizes zener diode noise method and also incorporates industrial noise which is sensed by electrets microphones with high sensitivity.scada for remote industrial plant operation,our pki 6085 should be used when absolute confidentiality of conferences or other meetings has to be guaranteed,so that pki 6660 can even be placed inside a car.this project uses a pir sensor and an ldr for efficient use of the lighting system,the zener diode avalanche serves the noise requirement when jammer is used in an extremely silet environment.the marx principle used in this project can generate the pulse in the range of kv,conversion of single phase to three phase supply.thus any destruction in the broadcast control channel will render the mobile station communication,automatic changeover switch,jammer disrupting the communication between the phone and the cell phone base station in the tower.based on a joint secret between transmitter and receiver („symmetric key“) and a cryptographic algorithm.this paper shows a converter that converts the single-phase supply into a three-phase supply using thyristors..
2021/03/10
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