Sharif Digital Repository

Vehicle localization and environment mapping are the most essential parts of the robot navigation in unknown environments. Since the problem of localization in indoor environments is directly related to the problem of online map generation, in this paper a new and efficient algorithm for simultaneous localization and map generation is proposed and novel results for real environments are achieved. This new algorithm interprets and validates the raw sonar measurements in first step, and applies them to the environment map in the next step. There are various adjustable parameters which make the algorithm flexible for different sonar types. This algorithm is efficient and is robust to sonar... 

The orientation of a conducting target was estimated with a generalized regression neural network (GRNN) network using back-scattered data. Steps made to provide the training data sets by a computer code using method of moments were investigated. Noisy data sets were provided to improve the system generalization. The GRNN target orientation estimation and its performance was evaluated and the robustness was verified against target scaling, target deformation, sensor misplacements and introduction of noise with different S/N into sensor measurements  

This paper, describes a solution for tracking multiple soccer players, simultaneously, in soccer ground. It adapts Kalman filter for tracking multiple players. Adapting Kalman filter is divided to four main tasks. The first task is defining the state vector for multiple object tracking. The second task is determining a motion model for estimating the position of soccer players in the next frame. The third task is defining an observation method for detecting soccer players in each frame. Finally, the fourth task is tuning the measurement noise covariance and estimating noise covariance. In the third task, a novel observation method for detecting soccer players is proposed. This method divides... 

In some well-known passive localization methods, when the number of equations equals the number of unknown object coordinates, there arise finite number of possible solutions. A localization disambiguation technique is required to identify the correct solution in these cases. As an example, the exact solution of time-difference-of-arrival (TDOA) based equations for four receiver sites, leads to a couple of solutions with only one of them being the true target position. This ambiguity, conventionally is resolved by using angle-of-arrival (AOA) measurements or using an additional receiver site which increase the cost and complexity of the system. In this paper a localization disambiguation... 

In some well-known passive localization methods, when the number of equations equals the number of unknown object coordinates, there arise finite number of possible solutions. A localization disambiguation technique is required to identify the correct solution in these cases. As an example, the exact solution of time-difference-of-arrival (TDOA) based equations for four receiver sites, leads to a couple of solutions with only one of them being the true target position. This ambiguity conventionally is resolved by using angle-of-arrival measurements or using an additional receiver site, which increase the cost and complexity of the system. In this paper, a localization disambiguation... 

Multi-turn resolvers are employed in the applications that high reliability; high accuracy and absolute position measurement are required, simultaneously. They are basically consisted of two individual resolvers in a common frame. In this paper a novel sinusoidal air-gap length multi-turn resolver is proposed. The rotor shape and the winding configuration are designed to achieve single-speed and multi-speed operations using a single rotor and a single stator core. Furthermore, some constraints are laid down and discussed in such a way that the performance of two resolvers has no interference with each other. All the mathematical calculations are validated using time stepping finite element... 

Bistatic passive radars have many advantages over the monostatic ones because they are undetectable and silent. In passive coherent location, the original source of energy is derived from a waveform of opportunity in the environment and the re-radiated energy from the target is processed to decide about the existence of the target. More over bistatic radars receive forward scatters from target in place of the backscatters in monostatics systems. As a result of the larger forward scattered RCS, the stealth targets can be detected easier. Passive radar does not need any frequency allocation so are very attractive for surveillance. Multipath effects and direct path interference are two problems... 

This letter investigates the problem of threedimensional (3-D) target localization in multiple-input multipleoutput (MIMO) radars with distributed antennas, using hybrid timedelay (TD) and angle of arrival (AOA) measurements. We propose a closed-form positioning method based on weighted least squares (WLS) estimation. The proposed estimator is shown theoretically to achieve the Cramer-Rao lower bound (CRLB) under mild noise conditions. Numerical simulations also verify the theoretical developments. IEEE  

In this letter, the problem of source localization using time difference of arrival (TDOA) is investigated. Then, a closedform two-stage solution is proposed based on estimation of the range nuisance parameter in the first stage and refinement of initial solution in the next stage. The proposed solution is shown analytically and verified by simulations to be an efficient estimate, which can attain the CRLB performance under mild Gaussian noise assumption. This method is able to locate the source with the minimum number of sensors required for N-dimensional localization. Numerical simulations demonstrate significant performance improvement of the proposed method compared with the... 

Multi-turn resolvers are consisted of two individual resolvers in one housing. Due to use of both single speed and multi-speed resolvers in one frame, multi-turn resolvers are supposed to provide the benefits of higher accuracy and absolute position measurement, simultaneously. In this paper, after presenting different configurations of wound-rotor (WR), multi-turn resolvers, their design considerations are discussed. Winding function (WF) method is used for finding appropriate slot-pole combinations, and winding configurations. Then time stepping finite element analysis is applied to evaluate the performance of the designed resolvers. Finally, experimental measurements validate the...