<?xml version="1.0" encoding="utf-8" standalone="yes"?><rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom"><channel><title>State Estimation | Md Abu Sayed</title><link>https://sayedcseku.github.io/tags/state-estimation/</link><atom:link href="https://sayedcseku.github.io/tags/state-estimation/index.xml" rel="self" type="application/rss+xml"/><description>State Estimation</description><generator>Hugo Blox Builder (https://hugoblox.com)</generator><language>en-us</language><lastBuildDate>Wed, 15 Apr 2026 00:00:00 +0000</lastBuildDate><image><url>https://sayedcseku.github.io/media/icon_hu_bf4b945a42c519b1.png</url><title>State Estimation</title><link>https://sayedcseku.github.io/tags/state-estimation/</link></image><item><title>Maritime Trajectory Prediction &amp; State Estimation</title><link>https://sayedcseku.github.io/project/trajectory-prediction/</link><pubDate>Wed, 15 Apr 2026 00:00:00 +0000</pubDate><guid>https://sayedcseku.github.io/project/trajectory-prediction/</guid><description>&lt;p>&lt;strong>Maritime Trajectory Prediction &amp;amp; Bayesian State Estimation&lt;/strong> forms the foundational empirical benchmarking contribution of Md Abu Sayed&amp;rsquo;s doctoral dissertation (&lt;strong>Chapter 6&lt;/strong>; &lt;em>TrajectoryKF&lt;/em>).&lt;/p>
&lt;p>Before deploying complex deep generative models, operational autonomy systems require establishing the exact performance boundary of classical Bayesian filters and kinematics estimators. This project provides a comprehensive, fine-grained empirical study comparing six canonical filter architectures across multi-vessel encounter dynamics.&lt;/p>
&lt;h2 id="evaluated-filter-architectures">Evaluated Filter Architectures&lt;/h2>
&lt;ol>
&lt;li>&lt;strong>Constant Velocity (CV) Baseline&lt;/strong>: Linear state propagation under Gaussian motion assumption.&lt;/li>
&lt;li>&lt;strong>Standard Unscented Kalman Filter (UKF-4D)&lt;/strong>: Nonlinear sigma-point propagation with standard 4D kinematic state &lt;code>[x, y, v_x, v_y]&lt;/code>.&lt;/li>
&lt;li>&lt;strong>UKF with 5D Constant-Velocity State (UKF-5D-CV)&lt;/strong>: Augments the state with heading (θ) for coordinated forward extrapolation.&lt;/li>
&lt;li>&lt;strong>Asymmetric UKF with Acceleration State (UKF-CA-6D)&lt;/strong>: Models constant acceleration &lt;code>[a_x, a_y]&lt;/code> to capture rate changes during maneuvering.&lt;/li>
&lt;li>&lt;strong>Extended Kalman Filter with Constant Turn Rate &amp;amp; Velocity (EKF-CTRV)&lt;/strong>: Analytic Jacobian linearization of circular arc kinematics &lt;code>[x, y, v, θ, ω]&lt;/code>.&lt;/li>
&lt;li>&lt;strong>UKF-CTRV&lt;/strong>: Deterministic sigma-point propagation through exact CTRV nonlinear dynamics.&lt;/li>
&lt;/ol>
&lt;h2 id="key-findings--research-questions">Key Findings &amp;amp; Research Questions&lt;/h2>
&lt;ul>
&lt;li>&lt;strong>Nonlinear Dynamics &amp;amp; Sigma-Point Propagation&lt;/strong>: When motion models are linear, sigma-point propagation collapses to the closed-form Kalman update; UKF provides clear benefits only when unprojected heading or turn rates are actively estimated.&lt;/li>
&lt;li>&lt;strong>Observability &amp;amp; Covariance Divergence&lt;/strong>: Because turn rate (ω) is not directly measured by radar/AIS and must be inferred from sequential coordinates, UKF-CTRV covariances diverge during long-horizon predict-only phases (T_pred ≥ 10), whereas EKF-CTRV remains numerically bounded.&lt;/li>
&lt;li>&lt;strong>Horizon Limits of Kinematic Models&lt;/strong>: Across four experiment horizons (T_obs ∈ {20, 40}, T_pred ∈ {5, 10, 20}), classical CTRV models maintain competitive performance on benign and crossing encounters (ADE &amp;lt; 1.5 m) but diverge sharply on adversarial maneuvers (herding, ramming), proving that pure kinematic filters cannot substitute for tactical intent understanding.&lt;/li>
&lt;li>&lt;strong>Foundation for Chapter 7&lt;/strong>: Directly motivates the multi-task intent-conditioned generative architecture (MTITP GAN) developed in Chapter 7.&lt;/li>
&lt;/ul></description></item></channel></rss>