Robust Range Measurement Preprocessing.
Abstract
The RMS/MTTS instrumentation system located at MacGregor Range is a range measuring, multiple target tracking system. In order to obtain a vehicle trajectory from this system, the range measurement from several receivers are processed by least squares. Since the measured vehicle trajectories are often low altitude, the resulting nonlinear least squares equations are ill-conditioned. In addition, this measurement system is plagued by outliers, sometimes by dense burst of outliers. The combination of ill-conditioning and outliers is lethal and attempts to robustify the nonlinear least squares processing have failed. An alternative is to preprocess each of the range measurement sequences, eliminating the outliers and replacing them if necessary. Each sequence of range measurements is preprocessed by robustly fitting a cubic spline using iteratively reweighted least squares. Due to the nature of spline fitting and the possible dense bursts of outliers, the choice of a good set of initial weights for use in the iteratively reweighted least squares is important to the efficiency of the method. These initial weights are determined using robust, local fitting techniques. Several robust techniques have been tested for this local fitting application. The robust spline preprocessing is illustrated with some especially troublesome data sequences and the relative performance of several robust methods for choosing the initial weights is compared. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1982
- Accession Number
- ADA121463
Entities
People
- Robert H. Turner
- William S. Agee