IRS 2020 Tutorials
You are invited to propose a tutorial for IRS-2020 attendees.
Please contact TPC Chair – Jacek Misiurewicz firstname.lastname@example.org with your proposal
– title, presenter name(s) and short bio(s), 1000 words abstract.”
Waveform optimization techniques for radar systems:
The main goal of the tutorial is to provide the audience with a bouquet of optimization techniques to address different challenging waveform design problems in classical and emerging Multiple Input Multiple Output (MIMO) radar systems, under practical constraints.
Waveform design plays a key role in enhancing classical radar tasks including target detection and parameter estimation. Further, waveform design is a key enabler of the emerging paradigm on joint radar- communications. Different applications warrant different performance metrics; this coupled with the advent of MIMO radar makes the waveform design more challenging. Particularly, in the emerging scenario of self-driving automotive applications, towards enhancing safety and comfort, high spatial resolution is achieved using the colocated MIMO virtual array by maintaining orthogonality between the transmit waveforms. Further, waveform diversity can also be used to obtain low-probability-of-intercept (LPI) radar properties. Nevertheless, the static use of a fixed waveform reduces efficiency due to limited or no adaptation to the dynamic environment as well as vulnerability to electronic attacks highlighting the need for multiple and diverse waveforms exhibiting specific features.
In this context, the tutorial focusses on key applications and highlights a variety of optimization approaches including coordinate descent (CD) and majorization minimization (MM), dealing with important applications in radar including 1) enhancing angular resolution using sets of orthogonal sequences, 2) SINR enhancement with joint design of space-time transmit and receive weights, 3) enabling a joint radar-communications paradigm through the transmit waveform design. To further bring the optimization closer to implementation and early adaptation in systems, practical constraints, such as finite energy, unimodularity (or being constant-modulus) and finite or discrete-phase alphabet are included in the optimization problem as constraints. The diversity of design metrics and signal constraints lays the groundwork for many interesting research projects in waveform optimization.
While several seminal works have been published, a few previous “IRS” tutorials have focused on the optimization algorithms dealing with the various applications of active sensing. After attending the tutorial, participants will be able to understand:
- An overview of relevant theoretical bases and algorithms from optimization theory considered in the state-of-the-art waveform
- Current challenges and design criteria associated with waveform design in classical and emerging radar
- Key hardware constraints of the practical radar systems and their consideration in the optimization formulation.
- An insight into formulation of waveform design optimization problems in modern radar systems and a few approaches towards finding a solution.
Mohammad Alaee-Kerahroodi, Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg.
Bhavani Shankar M. R., Interdisciplinary Centre for Security, Reliability and Trust (SnT), University of Luxembourg.
24 and 79 GHz Automotive Radar Systems and Applications:
Driving a car is a dangerous task! There are about 5000 fatalities on German streets every year, which are absolutely too many. Drivers have strong limitations in the ability to measure precisely the distance and the speed difference between cars, which is the reason for several accidents. The all-weather-capability as well as the capability of measuring target range and radial velocity simultaneously are some of the essential features, which make radar systems suitable for automotive applications.
Radio Detection and Ranging (RADAR) is a worldwide well-known sensor technique since more than 110 years. Collision avoidance between ships was the first application for this new technique. Today we come back to the collision avoidance application however now between cars in a normal road environment.
The general requirement on an automotive radar sensor in the 24 and 79 GHz frequency domain is to measure the target range R and radial velocity vr simultaneously and unambiguously with high accuracy and resolution even in multi target situations, which is a matter of the appropriate waveform design. Several new waveforms have been developed for this application in the last years. In any continuous wave (CW) radar the receive signal is directly down-converted into baseband by the instantaneous transmit frequency. The receive signal is then sampled and further processed for target detection and parameter estimation. The resulting beat frequency fB will be measured with high accuracy by an FFT procedure.
The aim of the tutorial is to introduce multiple CW waveforms and describe their performance figures. With a single chirp waveform for example the target range and radial velocity cannot be measured in multiple target situations. Therefore several alternatives have been developed to fulfill the given requirements. Chirp sequence waveforms show good performance figures in this respect. The computation complexity will also be discussed.
Prof. Dr. Hermann Rohling, Hamburg University of Technology.