By Ruizhi Chen, Heidi Kuusniemi, Yuwei Chen, Ling Pei, Wei Chen, Jingbin Liu, Helena Leppäkoski, Jarmo Takala Currently, no single technology, system, or sensor can provide a positioning solution any time, anywhere. The key is to utilize multiple technologies. We are now exploring a multi-sensor multi-network (MSMN) approach for a seamless indoor-outdoor solution. Its hardware platform is described in the previous article. The digital signal processor (DSP) is embedded in the GPS module. All sensors are integrated to the DSP that hosts core software for real-time sensor data acquisition and real-time processing to estimate user location. A smartphone handset provides wireless network measurements. Positioning Algorithms The multi-sensor positioning platform enables a positioning solution with a combination of GPS and reduced inertial navigation system (INS), or GPS and pedestrian dead reckoning (PDR). The reduced INS consists of a 3D accelerometer and a 2D digital compass, as a low-cost alternative to augment GNSS positioning. The reduced INS combined with GPS uses a loosely coupled Kalman filter for data integration, while the combination of PDR and GPS uses algorithms for estimating the position change with pedestrian step-length estimation. PDR. The PDR solution uses human physiological characteristics, implemented in a local-level frame, with equations: where k denotes the current epoch, Y is the coordinate in East direction, X is the coordinate in North direction, S is step length, and φ is the heading. The PDR positioning algorithm includes step detection, step length estimation, determination of heading, and positioning. To achieve an accurate heading, compass measurements are corrected with an empirical online estimated error model, which requires some training data. WLAN and Bluetooth. Figure 1 describes the basic concept of the WLAN or Bluetooth locating solution using a fingerprint database approach. The circles around the access point (AP) in the figure represent the radio coverage area and the color the signal strength. This radio map is a simplified example representing measurements from just one AP. FIGURE 1. Sample WLAN or Bluetooth fingerprint map, in meters. For the fingerprinting approach, the received signal strength indicators (RSSIs) are the basic observables. The whole process consists of a training phase and a positioning phase. During the training phase, a radio map of probability distribution of the received signal strength is constructed for the targeted area. The targeted area is divided into a matrix of grids, and the central point of each grid is referred to as a reference point. The probability distribution of the received signal strength at each reference point is represented by a Weibull function, and the parameters of the Weibull function are estimated with the limited number of training observation samples. Based on the constructed radio map, the positioning phase determines the current location using the measured RSSI observations in real time. Given the observation vector , the problem is to find the most probable location (l) with the maximized conditional probability , maximized by Bayesian theorem as: We applied an assumption of Hidden Markov Models (HMM) to represent the pedestrian movement process. The locating problem is then translated into finding such a state sequence (locations) that is most likely to have generated the output sequence (the measured RSSIs) assuming the given HMM model. The Viterbi algorithm typically solves these kinds of problems efficiently. This study also utilizes the Viterbi algorithm to trace the user trajectory. MSMN. The general integration scheme combining the GPS output, sensor measurements, WLAN, or Bluetooth output, and their variance estimates is depicted in Figure 2. A simplified representation of the central filter combining different input sources can be described with typical Kalman filter equations. The measurement model is zk= Hkxk+vk where the state estimate vector is , with X, Y, and φ as previously defined, and S the user horizontal velocity (speed). The measurement vector is given as where g refers to GPS, W to WLAN/Bluetooth, acc to accelerometer, and dc to digital compass. The matrix Hk is the design matrix of the system and the vector vk is the measurement error vector. FIGURE 2. Integration scheme for multi-sensor, multi-network positioning approach The recursive sequence includes prediction and update steps. The prediction step includes the typical equations of and while the update step includes Indoor Test Results A field test has been carried out on a sports field, described in the accompanying article (see Going 3D). An indoor test was carried out in an office-building corridor, but the test started and ended in an outdoor terrace area. During the test, the indoor corridor was covered with eight WLAN and three BT APs. Figure 3 shows the positioning results of the GPS-only (red), Bluetooth-only (black), and WLAN-only (magenta) solutions; Figure 4 shows that of the integrated multi-sensor multi-network (MSMN) solution (blue) for an outdoor-indoor-outdoor test. A reference trajectory is in green in both figures and building outlines in grey. The position update rate achievable by the WLAN and Bluetooth fingerprinting approach is only 0.1 Hz whereas the GPS-only and the integrated MSMN solutions are obtained every second and thus have a higher availability. FIGURE 3. Pedestrian test results with GPS-only, BT-only, and WLAN-only positioning approaches with respect to a reference trajectory FIGURE 4. Pedestrian test result with the multi-sensor multi-network positioning approach with respect to a reference trajectory Figure 5 shows the horizontal errors obtained with the different positioning solutions over time in the indoor test. A mean horizontal error of 2.2 meters was achieved with the WLAN solution. The Bluetooth solution is not as accurate as the WLAN solution, due to the smaller amount of BT APs; it achieved a mean horizontal error of 5.1 meters. When moving inside the corridor, the GPS solutions are used for the MSMN integration only with very low weights due to their poor quality. GPS is mainly used as a source of location outdoors where the test starts and ends. The mean horizontal error of the GPS-only solutions during the whole test is 8.4 meters. WLAN- and Bluetooth-derived locations and the self-contained sensors are the main sources used inside the building for the MSMN positioning solution: the mean horizontal accuracy o btained with MSMN is 2.7 meters with a solution availability of 1 Hz. FIGURE 5. Horizontal errors of GPS-only, BT-only, WLAN-only and the MSMN positioning approaches with respect to time in the pedestrian indoor test The MSMN solution obviously performs much better than a GPS-only solution indoors. The track of the pedestrian walking inside the corridor can be identified clearly, which is not the case with typical approaches of GPS-only or GPS/low-cost sensors. WLAN fingerprinting provides good position accuracy indoors, but the MSMN solution provides the best result when taking into account positioning accuracy and the solution availabilities in both time and space domains. Conclusions Further development is needed for indoor areas to be able to obtain fully seamless outdoor-to-indoor location, though GPS initialization followed by sensor and WLAN/BT combination already provide very good initial results. Additional sensors and more refined pedestrian-specific algorithms will be added to further improve the positioning accuracy.
cdma lte gsm 3g 4g jammerTelergy sl-120150 ac adapter 12vdc 1500ma used -(+) 1x3.4mm roun.soneil 2403srd ac adapter 24vdc 1.5a 3pin xlr connector new 100-.this paper shows the controlling of electrical devices from an android phone using an app,amx fg426 ac adapter pcs power current sensor 4pin us 110vac.recoton ad300 adapter universal power supply multi voltage.ihomeu150150d51 ac adapter 15vdc 1500ma -(+) 2.1x5.5x10mm roun.energizer jsd-2710-050200 ac adapter 5vdc 2a used 1.7x4x8.7mm ro,its total output power is 400 w rms.type websploit(as shown in below image).compaq pa-1600-01 ac adapter 19v dc 3.16a used 2.5x5.5x12.2mm.ibm thinkpad 760 ac adapter 49g2192 10-20v 2-3.38a power supply.jvc ga-22au ac camera adapter 14v dc 1.1a power supply moudule f,motorola fmp5202c ac adapter 5v 850ma cell phone power supply.hipro hp-a0653r3b ac adapter 19vdc 3.42a 65w used,dell pa-1650-05d2 ac adapter 19.5vdc 3.34a used 1x5.1x7.3x12.7mm,nyko aspw01 ac adapter 12.2vdc 0.48a used -(+) 2x5.5x10mm round,finecom ac dc adapter 15v 5a 6.3mmpower supply toshiba tec m3.edac ea12203 ac adapter 20vdc 6a used 2.6 x 5.4 x 11mm.insignia e-awb135-090a ac adapter 9v 1.5a switching power supply,this project shows automatic change over switch that switches dc power automatically to battery or ac to dc converter if there is a failure,shun shing dc12500f ac adapter 12vdc 500ma used -(+) 2x5.5x8mm r. Cyber acoustics d41-09-600 ac adapter 9vdc600ma 3h33 e144991,cs-6002 used ac grill motor 120vac 4w e199757 214624 usa canada.panasonic eyo225 universal battery charger used 2.4v 3.6v 5a,rs-485 for wired remote control rg-214 for rf cablepower supply,d-link dir-505a1 ac adapter used shareport mobile companion powe.targus pa104u ac power inverter used auto air charger dell 12vdc,main business is various types of jammers wholesale and retail,0335c2065 advent ac dc adapter 20v 3.25a charger power supply la,a frequency counter is proposed which uses two counters and two timers and a timer ic to produce clock signals, ,replacement 1650-05d ac adapter 19.5v 3.34a used -(+)- 5x7.4mm r,cui stack sa-121a0f-10 12v dc 1a -(+)- 2.2x5.5mm used power supp,oem ad-1590n ac adapter 15vdc 900ma - ---c--- + used 1.1 x 3.5 x,normally he does not check afterwards if the doors are really locked or not.apd wa-18g12u ac adapter 12vdc 1.5a -(+)- 2.5x5.5mm 100-240vac u.4089 ac adapter 4.9vac 300ma used c-1261 battery charger power s,this paper describes the simulation model of a three-phase induction motor using matlab simulink,backpack bantam ap05m-uv ac adapter 5v dc 1a used.hon-kwang hk-c112-a12 ac adapter 12vdc 1a dell as501pa speaker,automatic telephone answering machine,please visit the highlighted article. Powerup g54-41244 universal notebook ac adapter 90w 20v 24v 4.5a.netmedia std-2421pa ac adapter 24vdc 2.1a used -(+)- 2x5.5mm rou,black&decker ua-0602 ac adapter 6vac 200ma used 3x6.5mm 90° roun,hp hstnn-la01-e ac adapter 19.5vdc 6.9a 135w used -(+) 0.6x5x7.5,some people are actually going to extremes to retaliate,seh sal115a-0525u-6 ac adapter 5vdc 2a i.t.e switching power sup,rio tesa5a-0501200d-b ac dc adapter 5v 1a usb charger,this project shows the control of home appliances using dtmf technology,. 4g lte 4g wimax cell phone jammer4g cell phone jammer amazoncell phone gsm jammers-cell phone and gps jammers wikiraptor cell phone jammerlow cost cell phone 3g 4g jammers chinalow cost cell phone 3g 4g jammers chinalow cost cell phone 3g 4g jammers chinalow cost cell phone 3g 4g jammers chinalow cost cell phone 3g 4g jammers china
Hipro hp-ol060d03 ac adapter 12vdc 5a used -(+)- 2.5x5.5power su,makita dc9800 fast charger 7.2v dc9.6v 1.5a used 115~ 35w,jabra ssa-5w-09 us 075065f ac adapter 7.5vdc 650ma used sil .7x2,compaq pa-1071-19c ac adapter 18.5v dc 3.8a power supply,a&d tb-233 ac adapter 6v dc 500ma used -(+) 2x5.5mm barrel 120va,brother ad-20 ac adapter 6vdc 1.2a used -(+) 2x5.5x9.8mm round b.th 5vdc 11v used travel charger power supply 90-250vac phone,. gps blocker
Ikea yh-u050-0600d ac adapter 5vdc 500ma used -(+) 2.5x6.5x16mm.akii techa25b1-05mb ac adapter +5vdc 5a power supply,macintosh m3037 ac adapter 24vdc 1.87a 45w powerbook mac laptop,. www.zicac.com
