IEC TR 63385-1:2023

Transmitting and receiving equipment for radiocommunication - Short-range radar technologies and their performance standard - Part 1: System applications of short-range radars

IEC TR 63385-1:2023 provides a catalogue of the architecture and principles of measurement of short-range radars that are widely exploited in civil applications. The applications are related to the detection of the target for obstacle avoidance, motion sensing, or identification of devices. The mass civil use of radars sometimes creates compatibility issues among the services. The performance of each radar system is guaranteed in the field without any harmful interference but the frequency allocation using theoretical calculations does not consider the latest mitigation technologies. In order to increase the efficiency of the system usage without any degradation of the performance of the radars, this document provides clarification on the characteristics of the radar systems and additional information on applications in the field.

General Information

• Status: Published
• Publication Date: 06-Nov-2023
• ICS: 33.060.20 - Receiving and transmitting equipment
• Technical Committee: TC 103 - Transmitting and receiving equipment for radiocommunication
• Current Stage: PPUB - Publication issued
• Start Date: 07-Nov-2023
• Completion Date: 25-Aug-2023

Overview

IEC TR 63385-1:2023 is a Technical Report from the IEC that catalogs architectures, measurement principles and performance-related characteristics of short-range radar technologies used in civil applications. It clarifies system characteristics and practical field applications (detection, obstacle avoidance, motion sensing, device identification) to help improve spectrum efficiency and compatibility among mass civil radar services while avoiding harmful interference.

Key topics and technical content

• Measurement principles - clear explanations of how radars determine distance and motion, including time-of-flight methods and signal processing fundamentals.
• Radar architectures - coverage of common short-range radar types:
  • Pulsed radar (time-domain distance measurement)
  • FMCW / linear frequency-modulated continuous-wave (LFMCW) (beat-frequency ranging)
  • Digital processing with correlation (code-based time measurements)
  • Secondary surveillance radar (SSR) and passive radar concepts
• Performance fundamentals - discussion of the radar equation, received power, radar cross-section (RCS), and receiver noise considerations (S/N ratio, noise figure, bandwidth). The report explains how propagation time, signal attenuation and receiver sensitivity affect detection range and resolution.
• Measurement illustrations - waveform, timing, correlation and beat-frequency schematics to support practical understanding.

Practical applications and users

IEC TR 63385-1 describes real-world uses of short-range radars, making it relevant for multiple stakeholders:

• Automotive industry - adaptive cruise control, collision avoidance and parking assist (automotive radar applications).
• Mobile device designers - presence/motion sensing in smartphones and consumer electronics.
• Aviation and airport operations - airborne weather radars, radar altimeters, and foreign object debris (FOD) detection systems.
• Security and safety - people/entrapped-person detection and security inspection radars.
• Emerging THz radars - short-range imaging and high-resolution sensing.
• Who should use it: system architects, RF engineers, OEMs, spectrum managers, regulators, test labs and standards developers who need to understand short-range radar behavior, interference mitigation and performance claims.

Related standards (if applicable)

• Part of the IEC 63385 series - consult other parts of the series for complementary guidance on performance standards and measurement methods.
• For procurement, compliance and spectrum management, users should cross-reference national regulations and other IEC/ISO documents via the IEC Webstore and Electropedia.

IEC TR 63385-1:2023 is a practical, standards-oriented reference for understanding short-range radar system architectures, measurement principles and civil applications to support safer, more compatible and efficient radar deployments.

Standards Content (Sample)

IEC TR 63385-1 ®
Edition 1.0 2023-11
TECHNICAL
REPORT
colour
inside
Transmitting and receiving equipment for radiocommunication – Short-range
radar technologies and their performance standard –
Part 1: System applications of short-range radars

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IEC TR 63385-1 ®
Edition 1.0 2023-11
TECHNICAL
REPORT
colour
inside
Transmitting and receiving equipment for radiocommunication – Short-range

radar technologies and their performance standard –

Part 1: System applications of short-range radars

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.060.20  ISBN 978-2-8322-7752-2

– 2 – IEC TR 63385-1:2023 © IEC 2023
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 6
4 Considerations on measurement principles of radars . 7
4.1 General . 7
4.2 Pulsed radar system . 7
4.3 Frequency modulated (FM) radar system . 9
4.4 Digital processing radar system using signal correlation . 10
4.5 Secondary surveillance radar system . 10
4.6 Passive radar system . 12
5 Practical applications of short-range radars . 12
5.1 General . 12
5.2 Automotive radar applications . 12
5.3 Radars in mobile phones . 13
5.4 Radars for trapped-person detection . 13
5.5 Weather radars . 13
5.6 Short-range radars for civil aviation . 13
5.6.1 Airborne weather radar . 13
5.6.2 Radar altimeters . 14
5.7 Airport object detection radars . 14
5.8 Security inspection radars . 15
5.9 THz short-range radars . 16
Bibliography . 17

Figure 1 – Schematic diagram of radar system . 7
Figure 2 – Waveform and timing of transmission and reception for a pulsed radar
system . 7
Figure 3 – Frequency sweep pattern and beat frequency of transmission and reception
for linear FMCW radar . 9
Figure 4 – Time measurement using correlation calculation by digital codes . 10
Figure 5 – Principle of secondary surveillance radar system . 11
Figure 6 – Principle of passive radar system . 12
Figure 7 – Airborne weather radar . 14
Figure 8 – Foreign object and debris detection system . 15
Figure 9 – Imaging application scene . 16
Figure 10 – Results of radar images . 16

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TRANSMITTING AND RECEIVING EQUIPMENT FOR
RADIOCOMMUNICATION – SHORT-RANGE RADAR
TECHNOLOGIES AND THEIR PERFORMANCE STANDARD –

Part 1: System applications of short-range radars

FOREWORD
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IEC TR 63385-1 has been prepared by IEC technical committee 103: Transmitting and receiving
equipment for radiocommunication. It is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
103/235/DTR 103/257/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.

– 4 – IEC TR 63385-1:2023 © IEC 2023
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 63385 series, published under the general title Transmitting and
receiving equipment for radiocommunication – Short-range radar technologies and their
performance standard, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
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INTRODUCTION
Short-range radar systems are widely exploited in civil applications, such as automotive,
weather forecast, mobile, aviation, or security inspections applications. The performance of
each radar system is guaranteed in the field without any harmful interference but the frequency
allocation using theoretical calculations does not consider the latest mitigation technologies. In
order to increase the efficiency of the system usage without any degradation of the performance
of the radars, this document describes the principles of the radar systems and their performance
in applications.
This document summarizes the technological features of short-range radar systems. In addition,
some practical applications are also investigated and reported.

– 6 – IEC TR 63385-1:2023 © IEC 2023
TRANSMITTING AND RECEIVING EQUIPMENT FOR
RADIOCOMMUNICATION – SHORT-RANGE RADAR
TECHNOLOGIES AND THEIR PERFORMANCE STANDARD –

Part 1: System applications of short-range radars

1 Scope
This part of IEC 63385 provides a catalogue of the architecture and principles of measurement
of short-range radars that are widely exploited in civil applications. The applications are related
to the detection of the target for obstacle avoidance, motion sensing, or identification of devices.
The mass civil use of radars sometimes creates compatibility issues among the services. This
document provides clarification on the characteristics of the radar systems and additional
information on applications in the field.
2 Normative references
There are no normative references in this document.
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.2 Abbreviated terms
AoA angle of arrival
FFT Fast Fourier Transformation
FM frequency modulation or frequency modulated
FMCW frequency modulated continuous wave
PPM pule position modulation
radar radio detection and ranging
RCS radar cross-section
Rx receiver
S/N ratio signal to noise ratio
SSR secondary surveillance radar
ToA time of arrival
Tx transmitter
UWB ultra wide band
4 Considerations on measurement principles of radars
4.1 General
The Clause 4 introduces the measurement principle of each radar architecture. The radar
comprises equipment to measure the distance D to the objects by radio waves. A schematic
diagram of the radar principle is shown in Figure 1. The radars fundamentally measure the time
for the round trip of the radio propagation from the transmitter to the receiver returned by the
reflection at the surface of the object.

Figure 1 – Schematic diagram of radar system
The distance to the target D is calculated by multiplying the time and speed of radio waves.
Several methods to measure the distance are developed for the radar systems to obtain the
propagation time. The resolution of the distance measurement and sensitivity of the radar
systems depend on the measurement methods. This Clause 4 provides information on the
measurement methods and their characteristics for each radar system.
4.2 Pulsed radar system
Pulsed radar is one of the classic technologies and the simplest way to measure the distance
to the object. A schematic diagram of the time versus power for a pulsed radar is shown in
Figure 2. The attenuated signal is received at the receiver located at the same place or nearby
the transmitter when the pulsed waveform is transmitted from the radar transmitter.

Figure 2 – Waveform and timing of transmission
and reception for a pulsed radar system
The radar measures the propagation time Δt from the transmission to reception via the reflection
by the target. The distance to the target is simply calculated by the measured reciprocal
propagation time as follows:
– 8 – IEC TR 63385-1:2023 © IEC 2023
Δt
D=
(1)
2c
where
D is the distance to the target;
Δt is the propagation time;
c is the speed of the radio wave.
The distance is calculated from half of the propagation time for the reciprocal propagation
divided by the speed of the light.
The power of the attenuated received radio wave P is calculated by the radar equation [1] :
r
PG λσ
t
P AP
(2)
r t
4πD
( )
where
A is the total attenuation of the transmitting wave;
P is the transmitting power of the radar;
t
G is the isotropic gain of the antenna;
𝜆𝜆 is the transmitting power of the radar;
𝜎𝜎 is the radar cross-section (RCS) of the target, which is the index of relative reflectivity
assuming the cross-section of an ideal metallic sphere.
To detect the reflected signal, the receiver noise floor and the received power are compared.
The radar can detect the target when the received signal should be higher than a value
multiplying the thermal noise and the signal to noise (S/N) ratio as:
P > k k k BT
(3)
r SN NF B r r
where
k is the minimum S/N ratio for the detection;
SN
k is the noise figure of the receiver;
NF
k is the Boltzmann's constant;
B
B is the total bandwidth of the receiver;
r
T is the absolute temperature of the receiver.
r
Near the noise floor, the noise will cause frequent instantaneous spikes in power which will
mean that simple comparison between the noise and received signal will sometimes cause the
misdetection of the target. Therefore, the minimum S/N ratio is designed by considering the
requirement to deal with the sensitivity and error rates.
___________
Numbers in square brackets refer to the Bibliography.
==
4.3 Frequency modulated (FM) radar system
The FM radar system is another classic technology to measure the distance to the target. The
principle of the linear FMCW radar is illustrated in Figure 3.

Figure 3 – Frequency sweep pattern and beat frequency
of transmission and reception for linear FMCW radar
The vertical axis of the graph is the frequency and the horizontal axis is the time. The
transmitting waveform has the linear frequency sweep (slope) in the frequency domain. The
chirp rate of the transmitted wave is calculated as k = T/2B, where 𝑇𝑇 is the period of the
c
triangular waveform of the FM chirp
...