Master's Thesis, 30 hp, ECTS: Orbit Information-Based Motion Compensation for Satellite-Based Passive Radar

Are you a student eager to apply your theoretical knowledge and fresh perspectives to real-world challenges? At Saab, we believe that innovation thrives on new ideas, and your master thesis project could be the spark that ignites our next technological breakthrough.

Your role

We recognize the immense value that students bring to our company. Your academic rigor, combined with your enthusiasm for cutting-edge technology, allows you to approach problems with a unique and insightful lens. At Saab, you'll have the opportunity to collaborate with experienced engineers and specialists, gaining invaluable practical experience while making a tangible contribution to our growth and development.

Background

Passive radar using Low Earth Orbit (LEO) satellites employs signals transmitted by the satellite and their reflections from objects to detect targets. The satellite's high velocity causes signal propagation paths and Doppler shifts to vary throughout the observation period. Without adequate compensation, the energy from a target may be spread across multiple range and Doppler bins, making detection more challenging.

Knowledge of the satellite's orbit and the illuminated area can be used to predict some of these variations and constrain which signal delays are physically possible. Various approaches can be explored to exploit this information and reduce the search space, including methods inspired by the window-grid framework proposed for LEO sensing. However, alternative motion-compensation and search-space reduction techniques may also be considered.

In passive radar, the exact transmitted waveform is generally not available. Instead, a reference signal is obtained from measurements of the satellite's direct-path signal. Consequently, the signal processing chain must account for measurement noise, uncertainties, and potential interference in the reference channel.

Description of the Project

The objective of this thesis is to develop and compare signal processing methods for passive radar systems using a moving satellite as the signal source and a ground-based receiver.

A simulation model will be created to describe the satellite, target, and receiver, as well as the differences between the propagation paths of the direct-path signal and the reflected echo signal. The model will be used to generate reference and surveillance signals with controllable levels of noise and uncertainty.

The project includes the following tasks:

• Model signal delay and Doppler shift for representative satellite and target trajectories.
• Develop compensation methods for changes in signal path length and Doppler shift during the integration period.
• Evaluate sensitivity to errors in orbit information.
• Compare conventional range-Doppler processing with more advanced approaches (for example, a window-based method).

The overall goal is to identify when motion compensation and geometric constraints provide improved detection performance, and to compare the achievable performance when orbit information is known versus when parameters are estimated directly from the reference signal. The work should also investigate when external orbit information is necessary and when it can be replaced by signal-based estimation methods.

The results should include a reproducible simulation environment and a comparison of detection probability at a specified false alarm rate, estimation accuracy, and computational cost.

Your Profile

This project is suitable for a student in the final stage of a Master of Science program in Electrical Engineering, Engineering Physics, Applied Mathematics, or a related field, who is undertaking a 30 ECTS master's thesis project.

You have an interest in signal processing, modeling, and algorithm development, as well as solid programming skills in MATLAB or Python. A basic understanding of probability theory, statistics, and communication systems is beneficial. Experience with radar systems, satellite geometry, or OFDM is considered an advantage.

We provide the support and guidance you need to translate your theoretical knowledge into practical solutions. Join us and become a driving force behind Saab's technological advancements!

This position requires that you pass a security vetting based on the current regulations around/of security protection. For positions requiring security clearance additional obligations on citizenship may apply.

Kindly observe that this is an ongoing recruitment process and that the position might be filled before the closing date of the advertisement.

Contact information

Andreas Berntsson, Manager

+46 31 7948944

andreas.berntsson@saabgroup.com

Robert Kandel, Master Thesis Supervisor

+46 102796457

robert.kandel@saabgroup.com

Andréas Sundström, Master Thesis Supervisor

+46 102161876

andreas.sundstrom1@saabgroup.com

What you will be a part of

Explore a wealth of possibilities. Take on challenges, create smart inventions, and grow beyond. This is a place for curious minds, brave pioneers, and everyone in between. Together, we achieve the extraordinary, each bringing our unique perspectives. Your part matters.

Saab is a leading defense and security company with an enduring purpose, to help nations keep their people and society safe. Empowered by its 28,000 talented people, Saab constantly pushes the boundaries of technology to create a safer and more sustainable world.

Saab designs, manufactures and maintains advanced systems in aeronautics, weapons, command and control, sensors and underwater systems. Saab is headquartered in Sweden. It has major operations all over the world and is part of the domestic defense capability of several nations. Read more about us here.