# Effective Target Aware Visual Navigation for UAVs

## TL;DR

This paper introduces a vision-based navigation method for UAVs that maintains target focus during fast maneuvers by optimizing trajectories with non-linear optimization and real-time NMPC, outperforming standard techniques.

## Contribution

It presents a novel trajectory optimization and control framework that ensures continuous target focus during UAV navigation, addressing limitations of existing visual servoing methods.

## Key findings

- The proposed method effectively maintains line of sight during fast UAV maneuvers.
- It outperforms standard visual servoing techniques in real and simulated experiments.
- The approach successfully integrates non-linear optimization with real-time NMPC for UAV control.

## Abstract

In this paper we propose an effective vision-based navigation method that allows a multirotor vehicle to simultaneously reach a desired goal pose in the environment while constantly facing a target object or landmark. Standard techniques such as Position-Based Visual Servoing (PBVS) and Image-Based Visual Servoing (IBVS) in some cases (e.g., while the multirotor is performing fast maneuvers) do not allow to constantly maintain the line of sight with a target of interest. Instead, we compute the optimal trajectory by solving a non-linear optimization problem that minimizes the target re-projection error while meeting the UAV's dynamic constraints. The desired trajectory is then tracked by means of a real-time Non-linear Model Predictive Controller (NMPC): this implicitly allows the multirotor to satisfy both the required constraints. We successfully evaluate the proposed approach in many real and simulated experiments, making an exhaustive comparison with a standard approach.