Our team and mission

This position is based at the European Space Research and Technology Centre (ESTEC) - Noordwijk, Netherlands

LEO-PNT is an In Orbit Demonstration project within the FutureNAV Programme of ESA’s Directorate of Navigation. This project includes the definition, development, launch, operations, and experimentation of a reduced constellation of In-Orbit Demonstration satellites in Low Earth Orbit (LEO) for demonstrating innovative Positioning, Navigation and Timing (PNT) services, as complement and augmentation of existing Global Navigation Satellites Systems (GNSS) such as Galileo and GPS. LEO-PNT encompasses space, ground and user technologies and services, and aims to demonstrate capabilities and that would serve to meet the future challenging user demands on PNT domain and accelerate the readiness of European industry in this domain. LEO-PNT aims to adopt ‘New Space’ approaches for a fast-track implementation.

Some of the possible advantages of LEO-PNT is enabling faster high-accuracy positioning, enhanced services in harsh environment, more robust PNT services, geometry and frequency diversity, additional PNT data and 2-way PNT links. Those features would support a wide range of applications in different market sectors / verticals, including for instance, autonomous vehicles – road / UAVs - and digital mobility in general, railway, maritime, critical infrastructure, 5G/6G networks, Internet-of-Things, among others.

The LEO-PNT Project Team is responsible of the definition and implementation of the In Orbit Demonstration and the identification of directions, conclusions and lessons-learned towards a future European LEO-PNT operational system. 
 

Candidates interested are encouraged to visit the ESA website: http://www.esa.int

Field(s) of activity for the internship

Global Navigation Satellite Systems (GNSS) provide essential PNT services for critical infrastructure and consumer devices. However, current GNSS constellations face limitations, with blind spots in indoor environments, urban areas, valleys and the poles. To address these limitations and meet emerging applications’ needs, the PNT systems of the future will require unprecedented accuracy, resilience, and new frameworks. These needs can be addressed by a multi-layer architecture where MEO and GEO systems are augmented by a LEO layer, integrating (beyond) 5G, and extending to spectrum beyond L-band.

You can choose between the following topics:

1) Topic 1: Developing positioning concepts for LEO-PNT based on 5G NTN technology
LEO-PNT (Position, Navigation, and Timing) as an alternative to GNSS for backup, and Non-Terrestrial Networks (NTN) as part of 5G's satellite infrastructure are two emerging satellite technologies that are poised to change the way positioning and connectivity services are being offered. This task will focus on assessing how these two systems can complement each other and exploring the integration of a positioning concept-based NTN technology into LEO-PNT.           

Possible areas of work on Topic 1:

• System aspects: Starting from NTN layer 2 and layer 3 aspects, evaluate the potential integration of  an NTN concept for positioning and short messaging into ESA’s LEO-PNT concept;
• Physical layer aspects (NTN layer 1): 
  • Explore signal propagation when using NTN waveform in LEO-PNT systems; develop simulation models to assess the ranging and positioning accuracy with these waveforms, with focus on FR1 bands. Investigate factors such as signal attenuation, multipath effects, Doppler shifts, and delay variations due to satellite movement;
  • Trade-off analysis of various signal transmission schemes based on the intended use and satellite constellation configuration. Assess the impact of these schemes on bandwidth efficiency, robustness to interference, and overall positioning performance.

During your internship you will learn about integration of NTN concepts and waveforms into LEO-PNT systems, and in particular.

2) Topic 2: On-board Signal Processing for LEO-PNT Navigation Payloads

Very good synchronization of the satellites’ clocks and an accurate knowledge of the satellites’ orbits are key requirements in any satellite navigation system. The orbit determination and time synchronization of LEO satellites can be done with an onboard GNSS receiver. This information is then used by the LEO payload to generate a ranging signal whose signal quality needs to be kept to adequate levels as signal distortions translate into ranging errors.

The focus of Topic 2 is on advance signal processing techniques applied to the navigation signals:

• On the space GNSS receiver side, to ensure an adequate quality of the received GNSS signals used for orbit determination and time synchronization;
• On the transmitting side, to ensure the proper quality of the LEO-transmitted ranging signals to be used by final user receivers.

During your internship you will work on the implementation in Matlab of such signal processing techniques and will assess the achieved performance in terms of the signal quality under different conditions.  

During your internship you will learn about satellite navigation systems, and in particular:

• Signal processing of GNSS signals by GNSS receivers on board LEO satellites;
• Signal processing of LEO-PNT signals;
• Signal processing techniques to ensure signal quality.

3) Topic 3: LEO-PNT constellation management strategy

LEO-PNT requires large constellation of 250+ satellites which shall be deployed, maintained and disposed of. The focus of this internship is to conduct constellation management systems trade-off such as constellation deployment (including analysis of partial service provided during deployment), constellation maintenance/replenishment, solar power generation and system disposal strategies.

The list of tasks include:

• State of the art of typical single satellite and constellations orbit control strategies, applied to the LEO-PNT constellation study case;
• Consolidation of LEO-PNT constellation management strategies, including:
  • Deployment and orbit raising;
  • Autonomous orbit control strategies;
  • Autonomous Collision Avoidance Manoeuvres (CAM) strategies;
  • Maintenance strategies (replenishment, contingencies in the event of space segment anomalies/failures);
  • End of life disposal strategies.
• Evolution of internal ESA LEO-PNT system simulator to include the constellation control analysis;
• Consolidation of the analysis campaign and trade-off between proposed strategies;
• Consolidation of the LEO-PNT constellation design (ex: orbits design, hardware trade-off, concepts feasibility analysis) including definition of mission/system requirements.

Behavioural competencies

Result Orientation
Operational Efficiency
Fostering Cooperation
Relationship Management
Continuous Improvement
Forward Thinking

For more information, please refer to ESA Core Behavioural Competencies guidebook

Education

You must be a university student, preferably in your final or second-to-last year of a university course at Master’s level and you need to remain enrolled at your University for the entire duration of the internship.

Additional requirements

The working languages of the Agency are English and French. A good knowledge of one of these is required. Knowledge of another Member State language would be an asset.

Topic 1. Developing positioning concepts for LEO-PNT based on 5G NTN technology

The candidates are required to have a good knowledge in:

• Programming in Matlab or Python;
• Time-based positioning techniques;
• Link budget.

Knowledge on the following topics are considered an asset:

• Knowledge of NTN potential architectures and protocol stacks with focus on layer 1 to 3;
• 5G, and positioning systems in general;
• Digital signal processing for telecommunication signals.

Topic 2. Signal Processing for LEO-PNT Navigation Payloads

The candidates are required to have a good knowledge in:

• Digital signal processing for navigation/telecommunication signals;
• Programming in Matlab or Python.

Knowledge on the following topics are considered an asset:

• GNSS receiver processing;
• Navigation signals;
• RF Front End architectures and effects on signals.

Topic 3. LEO-PNT constellation management strategy

The candidates are required to have a good knowledge in:

• Satellite Engineering. Flight Dynamics. Mission Analysis;
• Programming in Matlab or Python.

Knowledge on the following topics are considered an asset:

• GNSS / SatNav / LEO-PNT / Radionavigation Systems;
• Satellite constellations.