High Frequency Motion Residuals: Identification and Estimation

Significant Sources of Wobble: Integration errors evolve with vessel motion

Driven by ocean waves with characteristic periods

Erred Georeference Model

𝜃𝑇𝑥 𝜃𝑅𝑥 𝜔𝑅𝑥 𝜓𝑅𝑥 𝜅𝑅𝑥 𝜔𝑇𝑥 𝜓𝑇𝑥 𝜅𝑇𝑥

𝐧𝑇𝑥 𝐧𝑅𝑥

𝐧𝐺𝑒𝑜

𝜃𝑁𝑂 𝐱′ 𝐲′ 𝐳′

𝐧𝐿𝐿

𝜃 𝜙

𝐧𝐺𝑒𝑜𝑅

𝐆𝐍𝐒𝐒𝑇𝑥 𝐋𝑀𝐵 𝐆𝐍𝐒𝐒𝑅𝑥

𝐌𝐁𝑇𝑥 𝐌𝐁𝑅𝑥

𝑆𝑆𝑃 𝑇𝑊𝑇𝑇

𝜙𝑅

𝑠

Δ𝑆𝑆𝑆 Δ𝜅 Δ𝑡 Δ𝜌 Δ𝐿(𝑥)𝑀𝐵 Δ𝐿(𝑦)𝑀𝐵

𝐗

Simulated Swath Corridor:

Forced Integration Errors:

Sensitivity Analysis:

RISC: Rigorous Inter-Sensor Calibrator

A Closer Look: Real Motion + Rolling Bathymetry L = 600m A = 30m L = 200m A = 10m

“Asymptotic” Results:

L = 200m A = 10m L = 600m A = 30m

Just How “Asymptotic” Should You Be?

L = 600m A = 30m

L = 200m A = 10m

Conclusions:

• Errors solvable once: 1. vessel undergoes dynamic motion

2. seafloor suitably fit

• Identifying suitable seafloor–vessel motion combinations essential

• Worth attempting on field data using more sophisticated: 1. statistics (input uncertainties, regression model)

2. sounding model (non-concentric)

Pathological case: Motion-induced spurious regression exaggerated by poor seafloor fit

Mitigated Exaggerated