# The Unknown Input Observer and its Advantages with Examples

arXiv: https://arxiv.org/abs/1504.07300 · HTML: https://mlsanity.com/paper/1504.07300/

## Key facts

- Cited by 2 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 27 Apr 2015.

## Built on by (most cited first, 2 of 2)

- [A Framework for 3D Tracking of Frontal Dynamic Objects in Autonomous Cars](https://mlsanity.com/paper/2103.13430/) (2021)
- [EMMA: Extracting Multiple physical parameters from Multimodal Data](https://mlsanity.com/paper/2605.24047/) (2026)

## Abstract (arXiv)

This brief memo reviews the theory of Unknown Input Observers (UIO) for state estimation in systems subject to disturbance inputs that are not known a priori. One main advantage of the UIO is that the observer structure naturally decouples the plant inputs from the state estimation process. This advantage is highlighted in three example dynamic systems commonly found in control theory. It is shown that the estimation error for all three systems asymptotically approaches zero by application of the UIO under the influence of dynamic disturbances.