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‘igure 5. The true and the estimated trajectory with only four aligned satellites. The selective availability is disabled..

Figure 5 ‘igure 5. The true and the estimated trajectory with only four aligned satellites. The selective availability is disabled..

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Figure 1. To estimate the user position we need at least four visible emitters from at leat one positioning system N-Dimension require N+1-equations. In case we have only three visible satellites, the goal of our work is that the positioning may be without any interruption. Indeed, we complete the set of GPS equations by AP equations. In the case of three visible satellites we need supplementary AP equation. So the set of equations become as following: Concerning the AP equations we need at least three equations from three APs in order to estimate the user position. In fact, 3 equations are required when positioning one user outdoor, on the ground. When positoning indoor requires determining altitude, we add another equation.
Figure 1. To estimate the user position we need at least four visible emitters from at leat one positioning system N-Dimension require N+1-equations. In case we have only three visible satellites, the goal of our work is that the positioning may be without any interruption. Indeed, we complete the set of GPS equations by AP equations. In the case of three visible satellites we need supplementary AP equation. So the set of equations become as following: Concerning the AP equations we need at least three equations from three APs in order to estimate the user position. In fact, 3 equations are required when positioning one user outdoor, on the ground. When positoning indoor requires determining altitude, we add another equation.
Figure 3. The accuracy depends on the configuration of the combined position system We initiate our algorithm with tracking signals from both AP and GPS satellites. If the number of visible satellites is less than four or the number of visible AP is less than four then we combine them so that the number of visible AP and satellites is more than four.
Figure 3. The accuracy depends on the configuration of the combined position system We initiate our algorithm with tracking signals from both AP and GPS satellites. If the number of visible satellites is less than four or the number of visible AP is less than four then we combine them so that the number of visible AP and satellites is more than four.
we consider that @; was obtained through Signal Strength We don't introduce the 6 f,, in the AP equations because
we consider that @; was obtained through Signal Strength We don't introduce the 6 f,, in the AP equations because
This section presents some results from our proposal simulations. Performance of the position estimation technology was tested with different number of satellites in view and different number of Access Points in view. In our case, the more appropriate formulation of this GDOP that can help us to choose the best configuration of our combined position system at the time “f’ in the situation “yg 29 = is the following:
This section presents some results from our proposal simulations. Performance of the position estimation technology was tested with different number of satellites in view and different number of Access Points in view. In our case, the more appropriate formulation of this GDOP that can help us to choose the best configuration of our combined position system at the time “f’ in the situation “yg 29 = is the following:
Figure 4. All satellites in view. The user is in an open environment. The selective availability is activated. Mean error =36.4022 m. The mean error is equal to 25m when we use additional APs The following curves present simulation results from each scenario.
Figure 4. All satellites in view. The user is in an open environment. The selective availability is activated. Mean error =36.4022 m. The mean error is equal to 25m when we use additional APs The following curves present simulation results from each scenario.
When we compare combined positionning system based on GPS and cellular networks with our proposition that combines GPS and Wi-Fi networks, we conclude that the accuracy of our proposition stay always under a threshold of 100 meter. This quality guaranty to the user the knowledge of an approximate location even if the condition deplorable. The Table 1. Shows that the estimated position with gpsOne can reach 345 meters in poor conditions such as only one satellite in view when, with the same conditions noted proposal remains below the 100 meter. This accuracy is sufficient in the case of application that seeks only indicate eg restaurants are near the user. The simulation done, shows that the accuracy is less than 100 meter in the case of having two satellites and two Access Points in view instead of 253 meter [5] using gpsOne. The simulations shows also that when the number of satellites is equal to four or above, and when the angle of the satellites
When we compare combined positionning system based on GPS and cellular networks with our proposition that combines GPS and Wi-Fi networks, we conclude that the accuracy of our proposition stay always under a threshold of 100 meter. This quality guaranty to the user the knowledge of an approximate location even if the condition deplorable. The Table 1. Shows that the estimated position with gpsOne can reach 345 meters in poor conditions such as only one satellite in view when, with the same conditions noted proposal remains below the 100 meter. This accuracy is sufficient in the case of application that seeks only indicate eg restaurants are near the user. The simulation done, shows that the accuracy is less than 100 meter in the case of having two satellites and two Access Points in view instead of 253 meter [5] using gpsOne. The simulations shows also that when the number of satellites is equal to four or above, and when the angle of the satellites
Figure 7. The true and the estimated trajectory with only one aligned satellites and visible APs. The selective availability is disabled. Figure 6. The true and the estimated trajectory with four aligned satellites and two APs. The selective availability is disabled..
Figure 7. The true and the estimated trajectory with only one aligned satellites and visible APs. The selective availability is disabled. Figure 6. The true and the estimated trajectory with four aligned satellites and two APs. The selective availability is disabled..
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Computer ScienceWireless Communications and NetworkingTime measurementAntenna measurements
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