INTRODUCTION TO BASIC
This chapter discusses radar principles and basic
radar systems. As a Fire Controlman, and a possible
work-center supervisor, you must understand basic
radar principles and safety requirements for radar
You will find valuable supporting
information in the Navy Electricity and Electronics
Training Series (NEETS), especially Module 18,
Radar Principles, NAVEDTRA 172-18-00-84, and in
Electronics Installation and Maintenance Book,
Radar, NAVSEA SE000-00-EIM-020. By referring to
these publications on a regular basis, you can increase
your understanding of this subject matter.
This chapter is not designed to teach you every
radar system the Navy uses, but simply to familiarize
you with the radars and their general characteristics.
Because there are so many different models of radar
equipment, we will describe only the radars and radar
accessories that will be around for several years. We
will not discuss older radar systems that are scheduled
for replacement in the near future.
Refer to your
s p e c i fi c t e c h n i c a l p u b l i c a t i o n s f o r d e t a i l e d
descriptions of the operation and maintenance of your
specific radar system.
BASIC RADAR CONCEPTS
The term radar is an acronym made from the
words radio, detection, and ranging.
It refers to
e l e c t r o n i c
e q u i p m e n t
t h a t
u s e s
r e f l e c t e d
electromagnetic energy to determine the direction to,
h e i g h t o f , a n d d i s t a n c e o f d e t e c t e d o b j e c t s .
Electromagnetic energy of the frequency used for
radar is unaffected by darkness. However, it can be
affected by weather to some degree, depending on its
frequency. It permits radar systems to determine the
positions of ships, planes, and land masses that are
invisible to the naked eye because of distance,
darkness, or weather. Radar systems provide only a
limited field of view and require reference coordinate
systems to define the positions of detected objects.
Radar surface angular measurements are normally
made in a clockwise direction from true north, as
shown in figure 1-1, or from the heading line of the ship
or aircraft. The radar is located at the center of this
Table 1-1 defines the basic terms used in figure 1-1.
You must know these terms to understand the
Upon completing this chapter, you should be able to do the following:
1. Explain the terms range, bearing, and altitude as they are associated with radar.
2. Explain the two basic methods for detecting objects with radar.
3. Identify and explain the use of equipment found in basic radar.
4. Identify and state the use of the four basic types of military radar systems.
5. Identify and explain the three phases of fire-control radar.
6. Identify the radar systems currently used in the U. S. Navy.