Electromagnetic Compatibility Testing and Rectification Analysis of

Beidou Shipborne Terminal System

Wanru Chen, Yongxin

Qian

and Shanyi Jin

Shanghai Institute of Measurement and Testing Technology, Shanghai, China

Keywords: Beidou Navigation, Beidou Shipborne Terminal System, Electromagnetic Compatibility.

Abstract: The Beidou shipborne terminal is mainly composed of two parts: the antenna and the chart display and control

terminal. Its circuit includes both the transmitting part and the receiving part, which is prone to

electromagnetic compatibility problems. Due to the increasingly complex electromagnetic environment of the

actual working environment, the Beidou shipboard terminal must meet the electromagnetic compatibility

requirements in order to ensure its safety and stability during work. This paper introduces the electromagnetic

compatibility test standards and methods of Beidou shipborne terminals, and studies the path of rectification,

which is of great significance and application value to the research of electromagnetic compatibility of Beidou

navigation series products.

INTRODUCTION

With the globalization of the economy and the

development of world trade, maritime shipping has

become increasingly popular. In order to obtain the

position information, shipping status information,

route information, etc. of shipping ships in real time

and effectively, large shipping companies have

invested a lot of manpower and material resources to

develop ship remote control systems, thereby

improving the accuracy and efficiency of shipping

logistics monitoring(Xie Dinglong, 2020).

The Beidou satellite navigation system is a

satellite navigation system independently developed

by my country. It has been applied in many fields and

played an important role, including: communications,

water, disaster reduction, maritime affairs, marine

fisheries, transportation, exploration, forest fire

prevention, etc.(Lao Ji-Ding Chen). The Beidou

shipborne terminal system is a marine

communication and navigation equipment that uses

satellite positioning technology, wireless network

technology and other real-time positioning, tracking,

and remote dispatching of ships on the move (Wang

Ershen, 2008). Its electromagnetic compatibility

performance is closely related to the safe driving of

the ship.

Graduated from Shanghai University majoring in

automation. Currently, he is an engineer at Shanghai

THE NECESSITY OF

ELECTROMAGNETIC

COMPATIBILITY TESTING OF

BEIDOU SHIPBORNE

TERMINAL SYSTEM

The electromagnetic compatibility design of the

system means that each device in the same

electromagnetic environment will not cause

performance degradation due to electromagnetic

emissions from other devices, and at the same time, it

will not cause other devices in the same

electromagnetic environment to suffer from

electromagnetic emissions from this device. Use

performance degradation, even can not be used

(Ogunsola A, 2003). In order to ensure that the

shipborne terminal system will neither affect the

normal operation of other equipment on the ship nor

reduce its performance due to external interference

when in use, it is particularly important to conduct

electromagnetic compatibility performance testing of

the Beidou shipborne terminal system in the

development stage.

Institute of Measurement and Testing Technology, and his

research field is electromagnetic compatibility testing.

Chen, W., Qian, Y. and Jin, S.

Electromagnetic Compatibility Testing and Rectiﬁcation Analysis of Beidou Shipborne Terminal System.

DOI: 10.5220/0012280100003807

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 2nd International Seminar on Artiﬁcial Intelligence, Networking and Information Technology (ANIT 2023), pages 243-247

ISBN: 978-989-758-677-4

243

3 ELECTROMAGNETIC

COMPATIBILITY TEST ITEMS

The IEC 60945 standard is a test method for general

requirements for maritime navigation and radio

communication equipment and systems. It involves

ship electrical, navigation, integrated navigation

equipment, navigation equipment, and ship

communication equipment. Therefore, the test

requirements of this standard are selected for the

Beidou shipborne terminal system. EMC testing. The

electromagnetic compatibility of the Beidou

shipboard terminal system is divided into two parts:

one is the self-compatibility of the Beidou shipboard

terminal system; the other is the electromagnetic

compatibility between the Beidou shipboard terminal

system and other equipment in the same environment.

The testing items should include the launch part and

the immunity part of the Beidou shipborne terminal

system (Wang Shuping, 2012).

3.1 Electromagnetic Emission Test Items

In order to examine whether the external radiation

disturbance generated by the Beidou shipborne

terminal system when it is working meets the test

limit requirements, it is necessary to test the external

emission value of the Beidou shipborne terminal

system. This test differs from antenna emissions not

interfering with other equipment on board. During

normal use, the equipment will not affect other

equipment or systems in the same environment.，such

as a radio receiver. When its emission value is within

the limits specified in the standard, it means that the

Beidou shipborne terminal system meets the

requirements. The table 1 shows specific test limits.

Table 1: Beidou Shipborne Terminal System Radiated

Emission Test Limits.

Frequency Range (MHz)

QP limit（dBμV/m）

0.15-0.3 80-52

0.3-30 52-34

30-2000 54

156-165

24(QP) or 32（PK）

The lower limit should apply at transition frequencies (0.3MHz

and 30MHz) and in the frequency range 156 MHz -165 MHz.

3.2 Conducted Disturbance Test Items

In order to test any signal generated by the Beidou

shipboard terminal system, such as the signal

appearing on its power port. The signal is conducted

into the ship's power supply, potentially disturbing

other equipment. It is necessary to test whether the

conducted disturbance generated by the Beidou

shipboard terminal system meets the test limit

requirements. If the disturbance exceeds the limit

value, it may be conducted in the ship power supply

system, which may affect the normal operation of

other equipment. The table 2 shows specific test

limits.

Table 2: Beidou shipborne terminal system conducted

emission test limits.

Frequency Range (MHz) QP limit value

（dBμV）

0.01-0.15 96-50

0.15-0.35 60-50

0.35-30 50

At the transition frequency (0.15MHz) a lower limit should be

use

Table 3: List of Beidou Shipborne Terminal System

Immunity Test Projects.

Test Items Portable Protected Ex

osed Underwater Test

oses

Conducted

RFI

150kHz-80MHz：3Vr.m.s.

e.m.f.

At a specific frequency point

(refer to 6.4 requirement b)：

10Vr.m.s. e.m.f.

AC and DC power ports, signal

and control ports, common mode

performance criterion A

Evaluate the effect

on equipment of

conducted

disturbance signals

induced by

electromagnetic

radiation.

Radiation

Interference

shell port：80MHz-2GHz

10V/m

Performance criterion A

Evaluate the impact

of radiated

disturbance signals

induced by

electromagnetic

radiation on

ment.

Fast

transient

(pulse

group)

AC Port: 2kV

Signal and control ports:1kV

Performance criterion B

Evaluate the impact

of fast transient

pulse bursts (such

as switching off

inductive loads,

relay shock bounce,

etc.

)

on e

ment.

Slow

Transient

(surge)

AC power port：Line to ground

1kV，Line to line 0.5kVPer

formance criterion B

Assess the impact

of equipment

exposed to lightning

sur

es.

Short term

change in

power

supply

AC power port:±20%V

1.5s，

±10% Frequency 5s

Performance criterion B

Evaluate the effects

of equipment when

subjected to short-

term changes in

power.

Power

Outage

AC and DC power ports：60s

Interrupt

Performance criterion C

Assess the impact

of equipment

experiencing a

power outage.

Electrostati

c Discharge

6kV Contact Discharge

8kv Air Discharge

Performance Criterion B

Evaluate the effects

of equipment when

subjected to

electrostatic

discharges directly

from the operator

and its operator to

acent ob

ects.

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244

3.3 Electromagnetic Immunity Testing

Project

The anti-interference ability of the Beidou shipborne

terminal system to external emission values should be

considered from the following aspects, including the

radiation signal effect of the ship's transmitter antenna,

direct or induced signals in the connecting cable, and

sinusoidal and instantaneous signals caused by the

ship's power supply or electrostatic discharge. State

interference effect, etc. The different types of

immunity test items and purposes that need to be

completed by the Beidou shipborne terminal system

are shown in Table 3.

4 ELECTROMAGNETIC

COMPATIBILITY TEST

RECTIFICATION ANALYSIS

The Beidou shipborne terminal system under

development can find out through testing the parts of

the electromagnetic compatibility performance of the

designed product that need to be improved.

4.1 Analysis of the Generation and

Transmission Pathways of

Electromagnetic Interference

The generation of electromagnetic interference must

have three elements, namely interference source,

interference propagation path and sensitive

equipment, as shown in Figure 1.

Figure 1: Electromagnetic Interference Propagation Path.

Interference sources are divided into natural

interference sources and man-made interference

sources according to the interference form. According

to the source, it can be divided into internal

interference and external interference. It can be seen

that to improve the electromagnetic compatibility

performance of the product, one of the three elements

of electromagnetic interference must be eliminated,

and the interference will be suppressed (

James Colotti,

2006

The Beidou shipborne terminal system has the

following common interference sources:

1） Radio interference sources

2） Interference sources formed by circuit ports

or interfaces, voltage or current changes

3） Interference of gas discharge on the system

4） Interference caused by external emissions

from the internal modules of the Beidou

shipborne terminal system

According to the above interference sources, the

propagation paths of the analysis interference mainly

include the following types:

1） radiation coupling

2） Conductive coupling

3） common impedance coupling

4） Line-to-line inductive coupling (Wang Ershen,

2008).

4.2 Analysis and Verification of Beidou

Shipborne System Conducted

Disturbance Test

In the working mode of the Beidou shipborne

terminal system, the position data collected by the

antenna is mainly transmitted to the signal receiving

encoding module. The signal receiving encoding

module decodes the received signal, and the decoded

data is transmitted to the signal processing module.

The final processed data is transmitted to the

electronic chart display and control terminal and

displayed to the user through the screen.

The Beidou shipborne terminal system was tested

for the first time without any processing, as shown in

Figure 2. The test chart is shown in Figure 3, (0.5 ~ 2)

MHz range exceeds the standard seriously.

Figure 2: Beidou shipborne terminal system conducted

disturbance test layout diagram.

Electromagnetic Compatibility Testing and Rectiﬁcation Analysis of Beidou Shipborne Terminal System

245

Figure 3: The frequency spectrum of the conducted

disturbance test of the Beidou shipborne terminal system

exceeding the standard

By observing the spectrum diagram, it is found

that the signal frequency in the spectrum shows a

certain pattern, which is manifested in the

fundamental frequency of 0.63MHz and its multiples.

After analysis, the antenna and electronic chart

display and control terminal are potential sources of

electromagnetic interference. A step-by-step

investigation was carried out for further positioning.

First, after turning off the electronic chart display

and control terminal, we tried to reduce the external

conduction disturbance of the electronic equipment.

The excessive part of the disturbance changed slightly,

but there was no significant improvement. After

further investigation, the spectrum obtained after

turning off the antenna power was shown in Figure 4.

Figure 4: Spectrum diagram of the conducted disturbance

test of the Beidou shipboard terminal system (turn off the

antenna power supply).

After the antenna power is turned off, the portion

exceeding the standard (0.5~2) MHz decreases

significantly. After analysis, the antenna power

supply is likely to generate (0.5-2) MHz frequency

conduction disturbance. In order to reduce the

disturbance and make the product meet the standard

requirements, as shown in Figure 5, add magnetic

rings at both ends of the power line to increase the

impedance of the common-mode current and

suppress the common-mode current. The effect of

current and the conduction disturbance generated by

it is obvious.

Figure 5: Electromagnetic compatibility rectification

method-adding magnetic ring.

In order to more significantly reduce the

disturbance value, a magnetic ring and filter are added

to the antenna power supply. The test results are

shown in Figures 6 and 7. It can be seen from the test

chart that excessive conductive disturbance is well

suppressed.

Figure 6: Conducted disturbance test power supply positive

spectrum.

Figure 7: Negative spectrum diagram of conducted

disturbance test power supply.

100

10k 20 30 50 100k 200 300 500 1M 2M 3M 5M 10M 20 30M

Level dB¦ÌV

Frequency in Hz

CE TEST

BD PK Preview Result 1-PK+ Final Result 1-PK+

BD PK

100

10k 20 30 50 100k 200 300 500 1M 2M 3M 5M 10M 20 30M

Level dB¦ÌV

Frequency in Hz

CE TEST

BD PK Preview Result 1-PK+ Final Result 1-PK+

BD PK

ANIT 2023 - The International Seminar on Artiﬁcial Intelligence, Networking and Information Technology

246

5 CONCLUSION

During the research and development stage of the

Beidou shipborne terminal system, there are often

phenomena that the products do not meet the

standards. The conventional rectification methods

include grounding, electromagnetic shielding and

adding filters. When encountering the phenomenon

that the electromagnetic compatibility test of the

product does not meet the standards, such as

conductive harassment exceeding the standard, you

can check the addition or deletion of the components

one by one through the on/off status of the plugged

and unplugged components. Combined with the

circuit characteristics and device characteristics of the

system, the spectrum can be analyzed and rectified. ,

gradually find the emission source and rectification

path. With the rapid development of the shipbuilding

industry, more and more electrical and electronic

devices are equipped on modern ships, and they are

becoming more and more intelligent and complex.

The space where the PCB is located is relatively small,

and these devices will interact with each other. Cause

electromagnetic interference (Rajeshwar K, 2005).

Practice has shown that the electromagnetic

compatibility design and PCB design issues of the

Beidou shipborne terminal system circuit are also

very important for system performance. It not only

affects the operating performance of the equipment,

but also causes serious accidents (Wang Bingqie,

2006), and the wiring strategy, integrated chip

decoupling, Shielding, software anti-interference and

other methods can improve the anti-interference

ability of the system. The electromagnetic

compatibility detection and rectification of the

Beidou shipborne terminal system studied in this

article is of great significance to the improvement of

the quality of Beidou marine equipment developed

with independent intellectual property rights and the

development of the marine electronics industry.

FUND NUMBER

Establishment and problem diagnosis of lithography

machine and sub-system on-site radiation emission

test system (Shanghai Market Supervision and

Administration Project 2023-20 J00RJ2307).

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