Daniel Medina

Dr. Daniel Medina

German Aerospace Center (DLR), Germany
orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 March 2021 in Journal of Field Robotics
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Journal Article
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LMLukas Meyer
Lukas Meyer
MSMichal Smíšek
Michal Smíšek
AVAlejandro Fontan Villacampa
Alejandro Fontan Villacampa
LMLaura Oliva Maza
Laura Oliva Maza
Daniel MedinaDaniel Medina
Daniel Medina
RTRudolph Triebel
Rudolph Triebel
Planetary rovers increasingly rely on vision‐based components for autonomous navigation and mapping. Developing and testing these components requires representative optical conditions, which can be achieved by either field testing at planetary analog sites on Earth or using prerecorded data sets from such locations. However, the availability of representative data is scarce and field testing in planetary analog sites requires a substantial financial investment and logistical overhead, and it entails the risk of damaging complex robotic systems. To address these issues, we use our compact human‐portable DLR Sensor Unit for Planetary Exploration Rovers (SUPER) in the Moroccan desert to show resource‐efficient field testing and make the resulting Morocco‐Acquired data set of Mars‐Analog eXploration (MADMAX) publicly accessible. The data set consists of 36 different navigation experiments, captured at eight Mars analog sites of widely varying environmental conditions. Its longest trajectory covers 1.5 km and the combined trajectory length is 9.2 km. The data set contains time‐stamped recordings from monochrome stereo cameras, a color camera, omnidirectional cameras in stereo configuration, and from an inertial measurement unit. Additionally, we provide the ground truth in position and orientation together with the associated uncertainties, obtained by a real‐time kinematic‐based algorithm that fuses the global navigation satellite system data of two body antennas. Finally, we run two state‐of‐the‐art navigation algorithms, ORB‐SLAM2 and VINS‐mono, on our data to evaluate their accuracy and to provide a baseline, which can be used as a performance reference of accuracy and robustness for other navigation algorithms. The data set can be accessed at https://rmc.dlr.de/morocco2018.

16 November 2020 in IEEE Robotics and Automation Letters
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Journal Article
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Francisco PastorFrancisco Pastor
Francisco Pastor
JGJorge Garcia
Jorge Garcia
Juan M. GandariasJuan M. Gandarias
Juan M. Gandarias
Daniel MedinaDaniel Medina
Daniel Medina
Pau ClosasPau Closas
Pau Closas
Jesus Gomez-De-GabrielJesus Gomez-De-Gabriel
Jesus Gomez-De-Gabriel

8 December 2020 in IEEE Transactions on Signal Processing
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Journal Article
Closed access
HLHaoqing Li
Haoqing Li
Daniel MedinaDaniel Medina
Daniel Medina
Jordi Vilà-VallsJordi Vilà-Valls
Jordi Vilà-Valls
Pau ClosasPau Closas
Pau Closas
State estimation is a fundamental task in many engineering fields, and therefore robust nonlinear filtering techniques able to cope with misspecified, uncertain and/or corrupted models must be designed for real-life applicability. In this contribution we explore nonlinear Gaussian filtering problems where measurements may be corrupted by outliers,and propose a new robust variational-based filtering methodology able to detect and mitigate their impact. This method generalizes previous contributions to the case of multiple outlier indicators for both independent and dependent observation models. An illustrative example is provided to support the discussion and show the performance improvement.

13 August 2020 in IET Radar, Sonar & Navigation
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Daniel MedinaDaniel Medina
Daniel Medina
LOLorenzo Ortega
Lorenzo Ortega
JVJordi Vilà‐Valls
Jordi Vilà‐Valls
PCPau Closas
Pau Closas
FVFrancois Vincent
Francois Vincent
ECEric Chaumette
Eric Chaumette
The derivation of tight estimation lower bounds is a key tool to design and assess the performance of new estimators. In this contribution, first, the authors derive a new compact Cramér–Rao bound (CRB) for the conditional signal model, where the deterministic parameter's vector includes a real positive amplitude and the signal phase. Then, the resulting CRB is particularised to the delay, Doppler, phase, and amplitude estimation for band‐limited narrowband signals, which are found in a plethora of applications, making such CRB a key tool of broad interest. This new CRB expression is particularly easy to evaluate because it only depends on the signal samples, then being straightforward to evaluate independently of the particular baseband signal considered. They exploit this CRB to properly characterise the achievable performance of satellite‐based navigation systems and the so‐called real‐time kinematics (RTK) solution. To the best of the authors’ knowledge, this is the first time these techniques are theoretically characterised from the baseband delay/phase estimation processing to position computation, in terms of the CRB and maximum‐likelihood estimation.

7 December 2019 in Sensors
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Journal Article
Open access
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Daniel MedinaDaniel Medina
Daniel Medina
HLHaoqing Li
Haoqing Li
Jordi Vilà-VallsJordi Vilà-Valls
Jordi Vilà-Valls
Pau ClosasPau Closas
Pau Closas
Navigation problems are generally solved applying least-squares (LS) adjustments. Techniques based on LS can be shown to perform optimally when the system noise is Gaussian distributed and the parametric model is accurately known. Unfortunately, real world problems usually contain unexpectedly large errors, so-called outliers, that violate the noise model assumption, leading to a spoiled solution estimation. In this work, the framework of robust statistics is explored to provide robust solutions to the global navigation satellite systems (GNSS) single point positioning (SPP) problem. Considering that GNSS observables may be contaminated by erroneous measurements, we survey the most popular approaches for robust regression (M-, S-, and MM-estimators) and how they can be adapted into a general methodology for robust GNSS positioning. We provide both theoretical insights and validation over experimental datasets, which serves in discussing the robust methods in detail.

17 June 2020 in Remote Sensing
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Daniel MedinaDaniel Medina
Daniel Medina
Jordi Vilà-VallsJordi Vilà-Valls
Jordi Vilà-Valls
AHAnja Hesselbarth
Anja Hesselbarth
RZRalf Ziebold
Ralf Ziebold
Jesus GarciaJesus Garcia
Jesus Garcia
Global Navigation Satellite Systems’ (GNSS) carrier phase observations are fundamental in the provision of precise navigation for modern applications in intelligent transport systems. Differential precise positioning requires the use of a base station nearby the vehicle location, while attitude determination requires the vehicle to be equipped with a setup of multiple GNSS antennas. In the GNSS context, positioning and attitude determination have been traditionally tackled in a separate manner, thus losing valuable correlated information, and for the latter only in batch form. The main goal of this contribution is to shed some light on the recursive joint estimation of position and attitude in multi-antenna GNSS platforms. We propose a new formulation for the joint positioning and attitude (JPA) determination using quaternion rotations. A Bayesian recursive formulation for JPA is proposed, for which we derive a Kalman filter-like solution. To support the discussion and assess the performance of the new JPA, the proposed methodology is compared to standard approaches with actual data collected from a dynamic scenario under the influence of severe multipath effects.