No abstract

The aim of so-called range-only target motion analysis (ROTMA) is to estimate the trajectory of a target by a single platform collecting range-only measurements. We focus on the observability analysis when the target is in constant-velocity motion. More precisely, the observability conditions are established when the observer's trajectory is composed of one or several legs. We establish a link between the Fisher information matrix (FIM), and the observability, after having proven the similarity of this matrix with the FIM encountered in bearingsonly target motion analysis (BOTMA). We compare observability statuses in BOTMA and ROTMA all along the paper.

Range-only target motion analysis (ROTMA) consists of estimating the trajectory of a target using a single platform collecting range-only measurements. Observability analysis is carried out when the target is in constant-velocity motion and the observer maneuvers gently (a constant turn motion or a constant acceleration motion). We compare observability in bearings-only target motion analysis (BOTMA) and ROTMA throughout the paper, together with the rank of the Fisher information matrix. In each case, we establish necessary and sufficient observability conditions and we identify the virtual (or ghost) targets giving the same measurements when the system is not observable.

No abstract

No abstract

In bearings-only target motion analysis (BOTMA), the common hypothesis is that the observer maneuvers while the source is traveling according to a constant speed and course. But there is no reason that the roles of each protagonist be not exchanged. In this paper, we consider an uncommon scenario: the trajectory of the target is composed of two legs (i.e. a target brutally changes its heading while keeping its speed) and the observer does not maneuver. We prove that the trajectory of the target is observable under non-restrictive conditions. A batch estimator is proposed and its performance is compared with the classic Cramèr-Rao lower bound (CRLB). Monte-Carlo simulations reveal the efficiency of the estimator. The robustness to a non brutal heading change is evaluated. Then an ad-hoc estimate taking the correct model into account isproposed and applied to simulated data. Again, its performance is compared to the CRLB and its robustness is evaluated when the speed of the target changes. Finally, the respective performances of the TMA made by each mobile are compared.

No abstract

The passive target motion analysis (TMA) of a source in constant turn motion by a platform moving with a constant velocity vector is addressed in this paper. The observer acquires either bearing measurements or bearing and frequency measurements. Firstly the bearings-only TMA is investigated. The observability conditions are established and the performance is analyzed with the Cramér-Rao lower bound. The behavior of the maximum likelihood estimator is evaluated using Monte-Carlo simulations, for various typical scenarios. The bearings and frequencies TMA is subsequently analyzed in the same way. Its performance is compared with that of the bearings-only TMA to evaluate the improvement brought about by frequency measurements, in some typical scenarios.Tactical aspects are also investigated.