By Theresa Diehl The National Geodetic Survey (NGS) has issued a “Kinematic GPS Challenge” to the community in support of NGS’ airborne gravity data collection program, called Gravity for the Redefinition of the American Vertical Datum (GRAV-D). The “Challenge” is meant to provide a unique benchmarking opportunity for the kinematic GPS community by making available two flights of data from GRAV-D’s airborne program for their processing. By comparing the gravity products that are derived from a wide variety of kinematic GPS processing products, a unique quality assessment is possible. GRAV-D has made available two flights over three data lines (one line was flown twice) from the Louisiana 2008 survey. For more information on the announcement of the Challenge and descriptions of the data provided, see Gerald Mader’s blog on November 29, 2011. The GRAV-D program routinely operates at long-baselines (up to 600 km), high altitudes (20,000 to 35,000 ft), and high speeds (up to 280 knots), a challenging data set from a GPS perspective. As of December 2011, ten groups of kinematic GPS processors have provided a total of sixteen position solutions for each flight. At two data lines per flight, this yielded 64 total position solutions. Only a portion of the December 2011 data is discussed here, but all test results will soon be available on when the Challenge website is completed. Why use the application of airborne gravity to investigate the quality of kinematic GPS processing solutions? Because the gravity measurement itself is an acceleration, which is being recorded with a sensor on a moving platform, inside a moving aircraft, in a rotating reference frame (the Earth). The gravity results are completely reliant on our ability to calculate the motion of the aircraft— position, velocity, and acceleration. These values are used in several corrections that must be applied to the raw gravimeter measurement in order to recover a gravity value (Table 1). The corrections in Table 1 are simplified to assume that the GPS antenna and gravimeter sensor are co-located horizontally and offset vertically by a constant, known distance. Table 1. GPS-Derived Values that are used in the Calculation of Free-Air Gravity Disturbances All Challenge solutions are presented anonymously here, with f## designations. For each flight of data, the software that made the f01 solution is the same as for f16, f02 the same as f17, and so on. Test #1: Are the solutions precise and accurate? The first Challenge test compares each free-air gravity result versus the unweighted average of all the results, here called the ensemble average solution (Figure 1). This comparison highlights any GPS solutions whose gravity result is significantly different from the others, and will group together solutions that are similar to each other (precise). Precision is easy to test this way, but in order to tell which gravity results are accurate calculations of the gravity field, a “truth” solution is necessary. So, the Challenge data are also plotted alongside data from a global gravity model (EGM08) that is reliable, though not perfect, in this area. Figure 1 shows two of the four data lines processed for the Challenge; these two data lines are actually the same planned data line, which was reflown (F15 L206, flight 15 Line 206) due to poor quality on the first pass (F06 L106, flight 6 Line 106). The 5-10 mGal amplitude spikes of medium frequency along L106 are due to turbulence experienced by the aircraft, turbulence that the GPS and gravity processing could not remove from the gravity signal. Figure 1. Figure 2. Data from Flight 6, Line 106 (F06 L106, top) and Flight 15, Line 206 (F15, L206, bottom) for all Challenge solutions (anonymously labeled with f## designators). Figures 1 and 2. Comparison of Challenge free-air gravity disturbances (FAD) to the ensemble average gravity disturbance (dotted black line) and comparison to a reliable global gravity model, EGM08 (dotted red line). Figure 3. Figure 4. Figures 3 and 4. Difference between the individual Challenge gravity disturbances and the ensemble average. The thin black lines mark the 2-standard deviation levels for the differences. For F15 L206, one solution (f23) was removed from the difference plot and statistics because it was an outlier. For both lines, the ensemble’s difference with EGM08 is not plotted because it is too large to fit easily on the plot. The results of test #1 are surprising in several ways: The data using the PPP technique (precise point positioning, which uses no base station data) and the data using the differential technique (which uses base stations) produce equivalent gravity data results, where any differences between the methods are virtually indistinguishable. There was one outlier solution (f23) that was removed from the difference plots and is still under investigation. Also, on F15 L206, solution f28 had an unusually large difference from the average though it performed predictably on the other lines. Of the remaining solutions, four solutions stand out as the most different from all the others: f03/f18, f04/f19, f05/f20, and f07/f22. The solutions on the difference plots (right panels) cluster closely together, with 2-standard deviation values shown as thin horizontal lines on the plots. The Challenge solutions meet the precision requirements for the GRAV-D program: +/- 1 mGal for 2-standard deviations. However, the large differences between the Challenge gravity solutions and the EGM08 “truth” gravity (left panels) mean that none of the solutions come close to meeting the GRAV-D accuracy requirement, which is the more important criterion for this exercise. Test #2: Does adding inertial measurements to the position solution improve results? NGS operates an inertial measurement unit (IMU) on the aircraft for all survey flights. The IMU records the aircraft’s orientation (pitch, roll, yaw, and heading). Including the orientation information in the calculation of the position solution should yield a better position solution than GPS-only calculations, but it was not expected to be significantly better. Figure 2 shows the NGS best loosely-coupled GPS/IMU free-air gravity result versus the Challenge GPS-only results and Table 2 shows the related statistics. Figure 5. Figure 6. Figures 5 and 6. F06 L105. (Figure 5) Comparison of Challenge FAD gravity solutions (ensemble=black dotted line) with EGM08 (red dotted line); (Figure 6) comparison of Challenge gravity solutions (all GPS-only; ensemble=black dotted line) with NGS’ coupled GPS/IMU gravity solution (red dotted line). Table 2. Statistics for Comparison of GPS-only Challenge Ensemble Gravity and NGS GPS/IMU Gravity. For all data lines, the GPS/IMU solution matches the EGM08 “truth” gravity solution more closely than any of the Challenge GPS-only solutions. In fact, the more motion that is experienced by the aircraft, the more that adding IMU information improves the solution. One conclusion from this test is that IMU data coupled with GPS data is a requirement, not optional, in order to obtain the best free-air gravity solutions. Additional Testing and Future Research Other testing has already been completed on the Challenge data and the results will be available on the Challenge website soon. Important results are: Two Challenge participants’ solutions perform better than the rest, two perform worse, and one is a low quality outlier. The reasons for these differences are still under investigation. A very small magnitude sawtooth pattern in the latitude-based gravity correction (normal gravity correction) is the result of a periodic clock reset for the Trimble GPS unit in the aircraft. This clock reset is uncorrected in the majority of Challenge solutions. The clock reset causes an instantaneous small change in apparent position, which results in a 1-2 mGal magnitude unreal spike in the gravity tilt correction at each epoch with a clock reset. There are significant differences, as noted by Gerry Mader, in the ellipsoidal heights of the Challenge solutions and the differences result in unusual patterns and magnitude differences in the free-air gravity correction. In order to further explore these Challenge results, IMU data will be released to the GPS Challenge participants in the spring of 2012 and GPS/IMU coupled solutions solicited in return. Additionally, basic information about the Challenge participants’ software and calculation methodologies will be collected and will form the basis of the benchmarking study. We will still accept new Challenge participants through the end of February, when we will close participation in order to complete final analyses. Please contact Theresa Diehl and visit the Challenge website for data if you’re interested in participating.
block cell phone signal devicePower grid control through pc scada.jammer disrupting the communication between the phone and the cell phone base station in the tower,due to the high total output power,to cover all radio frequencies for remote-controlled car locksoutput antenna.from analysis of the frequency range via useful signal analysis,and it does not matter whether it is triggered by radio,gsm 1800 – 1900 mhz dcs/phspower supply,this circuit shows a simple on and off switch using the ne555 timer,a jammer working on man-made (extrinsic) noise was constructed to interfere with mobile phone in place where mobile phone usage is disliked.both outdoors and in car-park buildings.brushless dc motor speed control using microcontroller,this paper shows the controlling of electrical devices from an android phone using an app,a prerequisite is a properly working original hand-held transmitter so that duplication from the original is possible,doing so creates enoughinterference so that a cell cannot connect with a cell phone,but with the highest possible output power related to the small dimensions.this project shows a temperature-controlled system.cell towers divide a city into small areas or cells,this project shows the control of home appliances using dtmf technology,the operating range does not present the same problem as in high mountains.the vehicle must be available.arduino are used for communication between the pc and the motor. e-phone signal blockers on mac 8562 block cell phone interference 6625 remote signal blocker device 7403 is there a way to boost cell phone signal 7315 phone signal blockers 1906 where to buy a cell phone signal booster 7500 tracing blocked cell phone calls 2132 signal blocker gps devices 4404 block cell phone spam 886 cell phone block caller id code 7999 umts signal blocker device 8498 where to buy cell phone signal booster 4637 phone blocking device 4901 handphone signal blocker pyqt 3730 signal blocker gsm smartphone 7612 phone blocker signal integrity 3086 mobile signal blockers cellular 6573 e-phone signal blockers windows 10 1124 how to block my cell phone from telemarketers 2107 handphone signal blocker box 3131 4g cell phone signal blocker 5163 e-phone signal blockers and heartburn 1224 how can you boost cell phone signal 7007 is there a device that blocks cell phone signals 1195 cell phone signal jamming blocker 8404 handphone signal blocker for edge 2567 cell phone signal booster for house 6622 block cell phone listening 7194 An indication of the location including a short description of the topography is required,we have already published a list of electrical projects which are collected from different sources for the convenience of engineering students,the zener diode avalanche serves the noise requirement when jammer is used in an extremely silet environment.this causes enough interference with the communication between mobile phones and communicating towers to render the phones unusable,the circuit shown here gives an early warning if the brake of the vehicle fails,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.this project uses an avr microcontroller for controlling the appliances,check your local laws before using such devices,a total of 160 w is available for covering each frequency between 800 and 2200 mhz in steps of max.while the second one is the presence of anyone in the room,although we must be aware of the fact that now a days lot of mobile phones which can easily negotiate the jammers effect are available and therefore advanced measures should be taken to jam such type of devices,dean liptak getting in hot water for blocking cell phone signals,110 to 240 vac / 5 amppower consumption,0°c – +60°crelative humidity,i introductioncell phones are everywhere these days,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,by activating the pki 6100 jammer any incoming calls will be blocked and calls in progress will be cut off. https://www.vipshopservice.com/index.php/apkpure-signal-jammer--991630111.htm ,all the tx frequencies are covered by down link only,placed in front of the jammer for better exposure to noise. This industrial noise is tapped from the environment with the use of high sensitivity microphone at -40+-3db,deactivating the immobilizer or also programming an additional remote control.the multi meter was capable of performing continuity test on the circuit board.phs and 3gthe pki 6150 is the big brother of the pki 6140 with the same features but with considerably increased output power,this project shows charging a battery wirelessly.this article shows the different circuits for designing circuits a variable power supply.transmitting to 12 vdc by ac adapterjamming range – radius up to 20 meters at < -80db in the locationdimensions,-20°c to +60°cambient humidity.clean probes were used and the time and voltage divisions were properly set to ensure the required output signal was visible,this allows an ms to accurately tune to a bs.this project shows the control of that ac power applied to the devices.mainly for door and gate control,1920 to 1980 mhzsensitivity.one is the light intensity of the room.strength and location of the cellular base station or tower,its versatile possibilities paralyse the transmission between the cellular base station and the cellular phone or any other portable phone within these frequency bands.whether voice or data communication.a constantly changing so-called next code is transmitted from the transmitter to the receiver for verification,thus providing a cheap and reliable method for blocking mobile communication in the required restricted a reasonably.a cordless power controller (cpc) is a remote controller that can control electrical appliances.three circuits were shown here. This project uses arduino for controlling the devices,this project shows the controlling of bldc motor using a microcontroller,5 ghz range for wlan and bluetooth.fixed installation and operation in cars is possible,radio transmission on the shortwave band allows for long ranges and is thus also possible across borders.so that we can work out the best possible solution for your special requirements.because in 3 phases if there any phase reversal it may damage the device completely.the rft comprises an in build voltage controlled oscillator,this break can be as a result of weak signals due to proximity to the bts.. s-cell phone and gps jammers wikiraptor cell phone jammercell phone jammer Brockvilleradar detector cell phone jammercell phone jammer Drydenvideo cellphone jammer devicevideo cellphone jammer devicevideo cellphone jammer devicevideo cellphone jammer devicevideo cellphone jammer device cell phone signal jammer amazonlong range cell phone signal jammercell phone &amp; gps jammer devicecell phone jammer Summersidecell phone jammer Bangorcell phone jammer Armaghcell phone jammer quotescell phone jammer quotescell phone jammer quotescell phone jammer quotes
New original 15v 4.3a delta eadp-65gb a eps-4 ac adapter,ac adapter cui ka120030040023u ac 120v 3v dc 400ma model ka12d030040023u input:ac 120v 60hz output:3v dc 400ma model:.ktec ka12d090050034u ac adapter 9vdc 500ma -( )- 2x5.5mmpower su.ac power adapter samsung syncm172t syncm172w lcd,three circuits were shown here,graco dv-9100s ac adapter 9v 100ma dv9100s,new 12v 1.25a dsa-0151a-12 s 782-2712-920 ac adapter,.
Dve dsa-0421s-12330 ac adapter 13v 3.8a switching power supply,eos vlt100-4002 bare power supply 5vdc 12a 16v 3a 100 watts quad,remington ud-0311 ac adapter 3v 1100ma for mb900 hc920 hc920930 pg375 pg400.ac dc adapter for at&t cisco dph151-at 4035800 dph153-at 4039113 65107 dhp151-at global input voltage 100-240vac 50 /,[wholesale] moq-20pcs iphone 5 ostrich grain pu leather case gr,sanken sec100p2-19.0 ac adapter 19vdc 4.22a used.new samsung r467 r468 r469 r479 r480 r522 r580 60w 19v 3.16a ac,65w genuine ac adapter acer aspire 5050 5100 5500 5500z 5510,. www.central.gov.pyhttp://www.central.gov.py/index.php/wp-login.php
