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CHAPTER 1. INTRODUCTION
decrease the effect of the deployed sensor to the vehicle’s aerodynamics and
appearance. The Frequency Modulated Continuous Wave (FMCW) radar is
a type of radar that offers more advantages compared to the others. It ensures
the range and velocity information of the surrounded objects to be detected
simultaneously. This information is very crucial for the control system of the
self-driving vehicle to provide a safe and collision-free cruise control.
A radar system installed in a car should be able to provide the neces-
sary information to the control system in real-time. It requires to have a
base-band processing system which is capable of providing enough comput-
ing power to meet the real-time system requirements. The processing system
performs digital signal processing on the received signal to extract the use-
ful information such as range and velocity of the surrounded objects. One
of the platforms that can achieve this task is a multiprocessor system-on-
chip (MPSoC) which uses multiple processors to increase the computational
power.
The Starburst multiprocessor system has been developed at the Com-
puter Architecture for Embedded Systems (CAES) group of the University
of Twente. This system is used to carry out research on real-time design and
analysis. It is prototyped on a Xilinx ML605 development board which hosts
a Virtex-6 FPGA and several peripheral devices such as DDR3 SDRAM,
Ethernet and UART interface. The main processing element of the Star-
bust is Xilinx’s soft processor core - MicroBlaze. A number of MicroBlaze
cores are connected through Network-on-Chip (NoC) with a ring topology
which provides arbitration for all the processing elements connected to it.
The platform also supports hardware accelerator integration to improve it’s
computing capabilities [4].
The aim of this thesis is to analyze the Starburst platform from the per-
spective of the requirements of the FMCW radar signal processing and pro-
pose an alternative architecture if it fails to meet the real-time requirements.
First, a theoretical study on the MIMO FMCW radar signal processing will
be performed, second, computational requirements of the algorithm will be
analyzed and based on the requirements a platform for the implementation
will be chosen, third, a signal processing architecture will be designed and
implemented, finally, the tests will be performed and the results will be an-
alyzed.
1.2
FMCW Radar Fundamentals
This section introduces the basics of radar systems and gives a brief intro-
duction to the FMCW type radar. In addition, the basic working principle
1.2. FMCW RADAR FUNDAMENTALS
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of the FMCW radar is discussed and some application examples are given.
Radar which stands for Radio Detection and Ranging, is a system that
uses electromagnetic waves to detect and locate objects. A typical radar
system consists of a transmitter, receiver and a signal processing module.
Initially, the transmitter antenna radiates electromagnetic energy in space.
If there is an object within the range of the antenna, it will intercept some of
the radiated energy and reflect it in multiple directions. Some of the reflected
electromagnetic waves will be returned and received by the receiver antenna.
After amplification and some signal processing operations, target information
such as distance, velocity and direction can be acquired [2].
Nowadays, radars are used for many different purposes. The applications
of radars include but are not limited to surveillance, object detection and
tracking, area imaging and weather observation. Each type of radar requires
the radar sensor to have specific features which can deliver useful information
to the user [2]. In case of automotive radars, the radar sensor should provide
the range and the relative velocity information of the surrounded objects to
the driver with a high accuracy and resolution. In addition, the sensor is
desirable to be smaller in size and lower in cost. Currently, FMCW radar is
the most common radar type used for this purpose [5].
FMCW radar is a type of Continuous Wave (CW) radars in which fre-
quency modulation is used. The first practical application of this type of
radar emerged in 1928, when it was patented by J.O.Bentley to be used
on airplane altitude indicating system. Industrial applications of this radar
started to appear at the end of the 1930s, after exploitation of the ultra-high
frequency band. In the following years, FMCW radar had been applied in the
number of civilian and military applications in which estimation of the range
with a very high accuracy was crucial. Few examples of these systems are
vehicle collision avoidance systems, radio altimeters and the systems to mea-
sure the small motion changes caused by vibrations of various components
of machines and mechanisms [6].
The theory of operation of FMCW radar is simple. FMCW radar sends
a continuous wave with an increasing frequency. A transmitted wave after
being reflected by an object is received by a receiver. Transmitted and re-
ceived signals are mixed (multiplied) to generate the signal to be processed
by a signal processing unit. The multiplication process will generate two sig-
nals; one with a phase equal to the difference of the multiplied signals, and
the other one with a phase equal to the sum of the phases. The sum signal
will be filtered out and the difference signal will be processed by the signal
processing unit [7]. The block diagram of the radar sensor can be seen in the
Figure 1.1.
FMCW radar offers a lot of advantages compared to the other types of