Position Estimation Comparison of a 3-D Linear Lateration Algorithm with a Reference Selection Technique

Multilateration system estimates emitter position using time difference of arrival (TDOA) measurement with a lateration algorithm. The position estimation (PE) accuracy of the system depends on several factors such as the number of ground receiving station (GRS)s deployed, the reference station used and the type of lateration algorithm. In this paper, the 3-D PE accuracy of a four-GRS linear lateration algorithm combined with a GRS reference pair selection (GREPS) technique is determined and compared with two different five-GRS linear lateration algorithms. The two five-GRS linear lateration algorithms chosen for comparison are based on single reference total least square (SF-TLS) and multiple reference least square (MF-LS) approaches. Monte Carlo simulation result comparison shows that the four-GRS linear lateration algorithm with the GREPS technique outperformed the SF-TLS and MF-LS with a reduction in horizontal coordinate PE error of about 50% and 30% respectively, and with a 90% reduction in the altitude error

Direct observation of dose distribution around a syringe-needle type proton-induced X-ray source using liquid scintillator and a CCD camera

This paper discusses a method to directly observe the dose distribution around a syringe-needle-type proton-induced monochromatic X-ray source proposed to avoid the risk that could exist in conventional brachytherapy. Images taken by using liquid scintillator and a high sensitivity CCD camera are presented and the dose distribution is qualitatively evaluated by comparing it with a Geant4 Monte Carlo simulation result.

Covariance Intersection Fusion Kalman Estimators

By the CI (Covariance Intersection) fusion algorithm, based on the ARMA innovation model, the two-sensor CI fusion Kalman estimators are presented for the systems with unknown cross-covariance. It is proved that their estimation accuracies are higher than those of the local Kalman estimators, and are lower than those of the optimal fused Kalman estimators. A Monte-Carlo simulation result shows that the actual accuracy of the presented CI fusion Kalman estimator are close to those of the optimal fused Kalman estimators with known cross-covariance.

A Study of the Microstructure and Grain Size at the Welding Heat Affected Zone of a Ferrite Stainless Steel

A method of Monte Carlo combined with welding experiments was adopted to study the grain size and microstructure in welding heat affected zone of the ferrite stainless steel. Firstly, the kinetic equation of grain growth was established with the experimental data . Then , a simulation procedure based on the kinetic equation was worked out. Agreement between Monte Carlo simulation result and the real experiment results was obtained.