OVERVIEW OF THE WORK ON THE CLASSIFICATION OF SAR 
SHIP IMAGERY PERFORMED AT DREO 
Robert Klepko 
Defence Scientist 
Defence Research Establishment Ottawa 
3701 Carling Avenue 
Ottawa, Ontario, K1A 0Z4 
KEYWORDS: Synthetic Aperture Radar, SAR Images, Ships, Classification, Computer-based tools, Operator- 
machine interface 
ABSTRACT 
The Airborne Radar and Navigation Section at the Defence Research Establishment Ottawa (DREO) has 
developed an airborne Synthetic Aperture Radar (SAR) that is capable of generating, in real-time, high- 
resolution radar images of ocean-going ships. The acquired SAR images of ships must be classified as to the 
type of ship, and this is performed by a Radar Operator. Classification must be done in real-time and with 
precision. Given that there are an abundance of images, and that these images can be generated at a high rate, 
it is difficult for a Radar Operator to maintain an accurate classification without the use of some aids. 
A. set of Operator aids, in the form of a computer-based graphics system, is currently being researched and 
developed. This system is called the Radar Operator Interactive Classification and Training System (ROICATS). 
ROICATS is composed of three main components: computer-based tools, operator-machine interface features, 
and automated target classification algorithms. This paper gives an overview of the work done on each of these 
three components. 
RÉSUMÉ 
La section du radar aéroporté et de la navigation du centre de recherches pour la défense à Ottawa a mis au 
point un Radar à ouverture synthétique (ROS) qui génére des images radars à haute résolution de navires de 
haute en temps réel. Un opérateur de radar doit classer les images ROS des vaisseaux en catégories. La 
classification doit étre faite en temps réel et avec précision. À cause de l'abondance d'images et parce qu'elles 
sont générées tres vite, l'opérateur du radar peut difficilement les classer correctement sans aide. 
Nous mettons au point un ensemble d'aides à l'opérateur, sous la forme d'un systéme informatique graphique. 
Ce systéme est appelé le Systéme d'entrainement et de classification interactive avec l'opérateur radar 
(SECIOR). Le SECIOR comprend trois composantes: outils informatiques, interface usager et algorithme de 
classification automatique de cibles. Ce rapport résume le travail accompli pour chacune des trois composantes. 
1.0 INTRODUCTION accomplish the main requirement for classification, 
which is to determine whether a ship is combatant or 
  
The Airborne Radar Section at DREO has developed 
an airborne SAR system, called SPOTlight SAR, which 
is capable of generating, in real-time, high-resolution 
radar images of land targets, and ships at sea. This 
SAR system is actually a new operational mode that 
will be incorporated into the AN/APS-506 Maritime 
Search radar on the CP-140. The AN/APS-506 radar, 
as it exists now, has three conventional modes of 
operation which are used for: periscope detection; 
weather watch and navigation; and long range detection 
of ships. It is possible to track a single target in all 
three modes. Because of the conventional search 
radar's coarse spatial resolution, it is not possible to 
noncombatant. Hence, the SAR mode was introduced 
to provide both this capability, and a capability for 
high-resolution land imaging. 
The SAR mode can be sub-divided into one of three 
sub-modes. In the first sub-mode, called the SPOTlight 
mode, the antenna is maintained fixed on a specific 
target, a certain amount of radar returns are 
accumulated, and a very high resolution radar image 1s 
generated from this data. With this image, detected 
targets can be classified. In an adaptive version of this 
mode, moving ship targets on the open ocean are 
tracked and compensated for their motion. In 
324 
  
nonadaptix 
of a small : 
analyzed f: 
particular] 
The seco 
Profiling ( 
maintaine« 
single rad. 
mode, a « 
images of 
the constr: 
less adapti 
Radar Op 
images Wi 
imaging. 
either stat 
In the thir 
mode, a c 
radar ima 
motion of 
for imagin 
of the ship 
applicatio: 
Because S 
a Radar C 
a high rat 
the image: 
be analyze 
location. 
immediate 
imagery f. 
likely, by 
image for 
these ima; 
especially 
To allevial 
encounter 
Operator 
consist of 
procedure 
The remai 
classificati 
of ships. 
The appe: 
function c 
type of s 
frequency, 
and type 
range res 
stationary 
type of s 
resolution