Small arms localization

Date: 12.12.2015 Category: Military - Defense

Small arms localization

Introduction

With increased rate of crime by using fire-arms, it has become necessary for authorities to devise ways of dealing with the problem. Among the many potential systems of detection, acoustics is a technique that can help to build a solution. Acoustics method of localization of firearms, especially in sniper situations can be used alone or in conjunction with several other techniques like optics radar, or infrared. For accurate localization of small firearms by use of this method, several options are considered.

Conventional wave-front-curvature

First, is the use of the conventional wave-front-curvature, a passive ranging method that requires the differential time-of-arrival (DTOA) measurements of the gun muzzle blast wave; in an estimation of the source position. This is then modified to account for sensor positions, which in most cases are not collinear. The method is used in situations when only the muzzle blast wave is the only thing received.

Single-sensor-node ballistic model-based localization

The second step involves an existing single-sensor-node ballistic model-based localization method. This, again, makes use of both the DTOA and the differential angle-of-arrival (DAOA) measurements of the gun muzzle blast wave, as well as the ballistic shock wave. It is improved by the replacement of the basic external ballistics model with a model that is more rigorous. The look-up table ranging procedure is also replaced with a nonlinear equation-based ranging procedure.

Multiple-sensor-node ballistic model-based localization

The last step involves a multiple-sensor-node ballistic model-based localization method that makes use of the DTOA measurements of the ballistic shock wave in a localization of the point of fire. This model is formulated, and the firearm localized. It applies in situations where only the ballistic shock wave is received. The effectiveness of the three named methods needs to be verified by experts using an extensive set of real and accurate data that is recorded during a week’s field experiment.

Data fusion methods for small arms localization

Data fusion methods can always be used together with the acoustic methods to increase levels of accuracy. In this method, each one of the acoustic sensors is placed at a location with an assumption that the given systems may either return or not return estimated range of the gun shooter. The method also involves the use of various basic data fusion that is based on geometry. These methods are first proposed, experimented and their performance later evaluated. Models of localization disparities and errors are also brought forth, and they are used herein in the development of a maximum chance approach to data fusion. Real world data provides an estimate of the parameters of statistical distributions. Comparison of the results of the methods is done at the end.

Normally, the results show that the best results are brought about by use of the maximum likelihood-based approach. It is, however, arguable that decent and accurate result is expected when the simpler geometric based approach of localization is adopted. These are data based experiments, and the accuracy of data will determine the accuracy of the results. The data used need to be from credible sources to assure the validity of the conclusions.