Our team and mission

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

The Sentinel-1 Project is responsible for the development of the Sentinel-1 Next Generation (NG) mission concept, the spacecraft and the Synthetic Aperture Radar (SAR) and Automatic Identification System (AIS) payloads. In addition, the Sentinel-1 team has responsibility for the satellite launch and in-orbit commissioning, i.e. end-to-end system performance and calibration. This also involves the development of prototype SAR and SAR interferometry (InSAR) data processors and the Calibration and Performance Analysis Facility (CPAF).

Sentinel-1NG is the successor of the Earth Observation Copernicus Sentinel-1 SAR mission. Copernicus is the most ambitious Earth observation program to date. It is a cornerstone of Europe’s efforts to monitor the planet and its many ecosystems. Sentinel-1 enables an instantaneous mapping of wide-area surface deformation, caused, e.g., by tectonic processes or ground subsidence, as well as the monitoring of ice sheet and glacier dynamics.
The goal of Sentinel-1NG is to provide a long-term continuity of C-band SAR observations beyond the next decade (2030) in support of operational Copernicus services that are routinely using Sentinel-1 data. In addition, the enhanced capabilities of Sentinel-1NG, compared to Sentinel-1, along with novel imaging capabilities enable the further development and improvement of operational applications.

This improvement of the Sentinel-1NG imaging capabilities (i.e. a better spatial resolution, a shorter revisit time, a longer orbital SAR duty cycle, a better radar sensitivity and a shorter repeat-pass orbit interval for SAR interferometry) over the performance currently achievable with Sentinel-1 is possible by employing a new multi-channel SAR architecture that enables novel techniques, such as SCORE (Scan On Receive) and MAPS (Multiple Azimuth Phases). These new methods overcome the inherent limitations of conventional single channel SAR missions (e.g., Sentinel-1), and allow for a wide swath with high azimuth resolution.

A growing problem in SAR is Radio Frequency Interference (RFI). RFI signals are signals emitted by other systems in the same frequency band as Sentinel-1NG. These disturbance signals overlap with the SAR signal and introduce biases and artifacts in the SAR imagery. The Sentinel-1 SAR processor is capable of removing a part of the SAR signal in the time and frequency domain that is corrupted by RFI. However, this comes at the cost of a degraded imaging performance and is only feasible for strong RFI that is detected easily. It is therefore important to understand the expected RFI environment of Sentinel-1NG and the impact on the mission performance. In addition, future SAR systems with multiple channels, such as Sentinel-1NG, open up novel opportunities for spatially filtering RFI. This capability of spatially removing RFI comes at the cost of an increased system complexity, which, however, is already present in Sentinel-1NG due to the use of SCORE and MAPS.

For further information visit our web site: http://www.esa.int

Field(s) of activity for the internship

Topic: Multichannel Synthetic Aperture Radar Signal Simulation

You will familiarize yourself with the principle of Synthetic Aperture Radar (SAR) remote sensing and learn about future concepts for multichannel SAR systems, such as foreseen for the ESA missions Sentinel-1 Next Generation and ROSE-L. You will then apply this knowledge by implementing the foundation of a SAR signal simulation tool (preferably using Python).

As a SAR satellite flies along its orbit, it repeatedly transmits radar pulses and listens for the return echoes from the targets on the ground. The goal of this internship is the simulation of this received return signal over a small, distributed scene. The work can then be extended to be applicable to multichannel systems.

Depending on the duration of the internship, the developed signal simulator can be utilized for further research into the received signal properties in the presence of disturbances, such as Radio Frequency Interference (RFI). If this is the case, you will learn more about these disturbance signals in order to perform relevant analyses.

Behavioural competencies

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

Education

You must have student status and be enrolled at university for the entire duration of the internship. You should preferably be in your final or second to last year of a university course at master’s level in a technical or scientific discipline.

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.

Additional Requirements:

Specific competence in one of the following disciplines shall be considered an asset:

• Knowledge of signal processing, physics, electromagnetics, remote sensing
• Familiarity with development of data analysis tools using, e.g., Python or MATLAB