Nghiên cứu nâng cao chất lượng thông tin đo bám mục tiêu trong đài điều khiển tên lửa thế hệ mới tt tiếng anh

MINISTRY OF EDUCATION AND TRAINING

MINISTRY OF NATIONAL DEFENSE

ACADEMY OF MILITARY SCIENCE AND TECHNOLOGY

LE VAN SAM

DEVELOPMENT A METHOD OF IMPROVING THE
INFORMATION QUALITY OF MEASURING AND TRACKING THE
TARGET IN A MODERN MISSILE GUIDANCE STATION

Major: Control Engineering and Automation
Code:

9 52 02 16

SUMMARY OF PhD THESIS IN ENGINEERING

HA NOI – 2019



The thesis was completed at
ACADEMY OF MILITARY SCIENCE AND TECHNOLOGY

Scientific Supervisors:
1. Assoc. Prof. Dr. Vu Hoa Tien
2. Dr. Tran Ngoc Quy

Review 1: Assoc. Prof. Dr. Pham Trung Dung

Military Technical Academy
Review 2: Assoc. Prof. Dr. Tran Duc Thuan
Academy of Military Science and Technology
Review 3: Dr. Tong Xuan Dai
Air force – Air defence Technical Institute

The thesis was defended in front of the Doctoral Evaluating Committee at Academy
level held at Academy of Military Science and Technology at ………/………, 2019

The thesis can be found at:
- The Library of Academy of Military Science and Technology
- Vietnam National Library


THE SCIENTIFIC PUBLICATIONS

1. Vu Hoa Tien, Tran Ngoc Quy, Le Van Sam, 2016, “Study
the ability of automatically stabilize the receiver dynamic range
of the new-generation fire-control radar systems”, JMST,
Academy of Military Science and Technology (Special issue9/2016), Pp. 57-66.
2. Vu Hoa Tien, Tran Ngoc Quy, Le Van Sam, 2017, “Studying
and proposing solutions to automatically control the receiver’s
input dynamic range of the new-generation fire-control radar
system”, JMST, Academy of Military Science and Technology
(49, 6-2017), Pp. 09-17.
3. Vu Hoa Tien, Le Van Sam, Tran Ngoc Quy, 2017,
“Development of the software algorithm for automatic
detection nonlinear distortions of a useful signal in the
receiving path in the fire control radar with a large dynamic
range”, “Natural and Engineering Sciences Journal” (ВАКRussian) №10 (112) , 2017, Pp. 91-96.

4. Le Van Sam, Vu Hoa Tien, Tran Ngoc Quy, 2018,
“Synthesizing the automatic overload prevention transmit receive system in fire-control radar”. JMST, Academy of
Military Science and Technology (55, 6-2018), Pp. 03-15.


1
INTRODUCTION
1. Urgency of the thesis
In missile guidance stations, accuracy of measuring coordinates of
target and missile is particularly important, which is one of the decisive
factors to destroy a target of a missile.
Input signals of the target and missile tracking systems obtained
from the corresponding receivers are video or digital signals. If the
input signals are distorted or unstable, the performance of the
tracking systems will be reduced.
Studying the ability of automated receiving and processing target
signals in front of the coordinates target tracking system based on
synthesizing the closed receive-transmit control system is the
urgency mater. Research results not only improve the input signals
quality for target tracking systems, but also upgrade the level of
automation for the fire control radar systems, which are particularly
important in the modern warfare.
2. Purpose of research
Research on the ability of enclosing the receive-transmit system
of fire - control radar to become the closed-loop control system
which automatically eliminating receiver overload problems based on
synthesizing the new overload discriminator and transmitter
controller.
3. Object and scope of research
The general object are air defence fire control radar systems and

the specific object is the receive-transmit target tracking systems of
air defence missile guidance stations


2
The result scope is synthesizing the closed loop receive-transmit
control system to automatically eliminating overload receiver
problem in the receive-transmit target tracking system of air defence
missile guidance stations.
4. Method of Research
- Theoretical methods: automatic control; modeling system;
modern signal processing…
- Method of calculating and synthesizing models on digital
computers.
- Verification method; empirical statistics; simulating processes
on digital computers; comparative control.
5. Practical and scientific significance
- The thesis has contributed the results of theoretical research to
synthesis

the

closed

loop

receive-transmit

control

system

automatically eliminating overload receiver problem for radar
systems in general and for the target tracking system of air defence
missile guidance stations in particular.
6. Structure of thesis
The entire of thesis consists of 131 pages, 4 chapters, 55 figures,
11 tables and 11Pps appendice.
Chapter 1
OVERVIEW OF FACTORS AFFECTING ON THE
PERFORMANCE OF TARGET COORDINATE MEASURING TRACKING SYSTEMS IN THE FIRE CONTROL RADAR
1.1. Overview of the air defence missile guidance stations, the
role of the tracking channel and the need to maintain the
performance of the target coordinates measuring-tracking systems


3
1.1.1. General overview of air defence missile guidance stations
The basic components of general missile control system are
shown in the Fig.1.1.
Transmitter system
Target

Receiver for target
tracking

Missile

Receiver for missile
tracking

Synchronous
system
(εmt,βmt,rmt)
Control command
block
(εtl,βtl,rtl)

Transmit control
command

(λε,λβ,K3)

Radio-frequency
transmission line

Fig 1.1. The basic components of general missile guidance station
In that system, the functions of coordinate-tracking systems are measuring
angular, distance coordinates of both objects (targets, missiles).

1.1.2. The role of target tracking chanel in missile guidance stations
The target tracking system is one of the main compornents of the
missile control system. Improving performance of processing the target
signal is directly related to improving the input signal of coordinate
tracking systems and the quality of control information in the missile
control system.
1.1.3. Influence of input signal quality to the precision of
determining the target coordinates of the tracking systems in a
missile guidance stations
Distortion and instability of input signals will directly decrease

the performance of the target tracking system.
1.1.3.1. Effect of unstable amplitude and distortion of input signal
to the performance of the range and speed target tracking system in
missile guidance stations
Acccuracy of tracking a target is mainly dependent on perfomrmance of
range and speed discriminators. From analyzing the effects of amplitude
instability and distortion of the input signal on accuracy of tracking target can
draw the following comments:
- Comment 1.1: If the amplitude of the Uv signal changes, it will lead
to a change of transmission coefficient (K ± ΔK) in discriminator. If the
signal is distorted, its center of energy is shifted (∆’τ) and delay error is:
∆τ=∆τ0±∆’τ.


4
In order to measure the Doppler frequency, a two-channel
frequency-difference discriminator (BPB-Vmt) is used.
Comment 1.2: Distortion and amplitude instability of input signal
can lead to distort the frequency characteristic of speed discriminator.
The distortion of discriminator characteristic depends on the
distortion of input signals.
1.1.3.2. Effect of unstable amplitude and distortion of input signal
to the performance of angle target tracking system
From the expressions of measuring angle errors, can draw the
comment: the distortion and unstable amplitude of input signal will
reduces the quality of the angle-tracking system.
1.2. Overview of the methods to stabilize amplitude and shape
of input signal of the target measuring – tracking system in the
fire control radar systems
1.2.1. Factors affecting on the instability and distortion of input

signal of the target coordinate tracking system in the fire control
radar
Two main factors are concerned:
- Amplitude of input signal is too large.
- Distortion of the output signal induced by receiver overload problem.
To visually display the signal distortion caused by overloading the
receiver, we consider the amplifier’characteristics of the receiver (Fig. 1.10)
Nonlinear
Uout amplitude

Uout

Uin
Uout

t
Nonlinear distort
signal

Linear amplitude range
t

Fig. 1.10. Amplifier’ characteristics of the receiver over signal distortion phenomenon


5
1.2.2. Overview of the methods to improve stability and decrease
distortion of input signals of the target coordinates measuringtracking system
1.2.2.1. Overview of methods to stabilize the amplitude, decrease
distortion of the input signal of the target coordinates measuringtracking system

The Receive-transmit system in target tracking chanel of fire control radar is
usually not a closed loop control system (Fig. 1.11).
To adjust K, use a combination of methods [25], [47] including:
Decrease the input signal (attenuator); automatic gain adjustment
(AGC); manual amplitude adjustment; switching power transmission.
AT

RF
transmitter

Impulse
modulator

Synchrounous

IF receiver

Video
processing

MT
RF receiver
AT

Target
tracking
systems

Fig. 1.11. The transmit/receive system as a opened loop control system

1.2.2.2. Some comments on methods of stabilizing the output
amplitude and eliminating overload receiver problem
- Use of both manual and automatic methods: AGC; MGC; ATT;
change the transmit power to stabilize and prevent signal distortion.
- The timing and magnitude of manual adjustments are subjective,
which causes an undesirable delay and signal distortion. Those
directly reduce the signal quality of input signal of the target
coordinate measuring- tracking system.
1.3. Determining the research problems of the thesis
Synthesizing algorithms and structure of the closed-loop transmit/receive
control system automatically eliminating overload receiver problem in fire
control radar system.
Four problems have been identified:


6
1. Surveying and building the power characteristic and amplitude
characteristic of reflected signal at the input of receiver over distance
and radar cross section (RCS) of the target.
2. Building the amplitude characteristic of receiver in terms of
target’distance and RCS changing in all its range.
3. Synthesizing the detection algorithm, control algorithm and
suitable structure for closed loop transmit/receive control system.
4. Simulating, surveying, evaluating the effectiveness of the system.
Antenna
Target

Antenna

RF

transmitter

RF receiver

Impulse
modulator

Controller

Receiver

Overload
discriminator

Tracking
systems

Fig 1.16. The structure of a transmit/receive automatically eliminating the overload
receiver problem

1.4. Conclusion of chapter 1
Stabilizing the input information of the tracking systems is
directly improving perfomance of the tracking systems.
The automatically preventing distortion and stabilizing amplitude of
input signal based on synthesizing the closed loop transmit/receive control
system is the effective method to improve the quality of input signal of the
target tracking system in the fire control radar system.
Chapter 2
PROPOSING A METHOD OF PREVENTING THE RECEIVER
OVERLOAD PROBLEM BASED ON ANALYSING SIGNAL

CHARACTERISTICS
2.1. Choosing the object and model to survey
2.1.1. The object for surveying, analysing
The object studied in this chapter is an transmit/receive system of the fire
control radar. Serveying is done with a tracking target chanel.


7
2.1.2. The structure of the coordinates target tracking chanel
The general structure diagram of the coordinate target tracking system
of fire control radar system is shown in Figure 2.1. [9],[11]. This is not a
closed loop transmit/receive control system. There are some VGA
and ATT with its parameters can be manually adjusted.
Antenna

RF
transmitter

Impulse
modulator

Synchronous
system

Center computer

Target
RF receiver
Antenna

IF
Filter
Gain-2
PPY
CИД
PPY

Mixer 2

IF Gain1

fns2
Attenuator

Mixer 3
fns3

IF
Gain-3
Tracking
systems

AGC
8dB 18dB 26dB

Fig. 2.1. Strcucture of the transmit/receive target tracking in the fire control radar
2.2. Surveying to determine the receiver characteristic and
amplitude characteristic of the input signal.
2.2.1. Determining the power characteristic of input signal
The power of signal reflected from target is determined (2.1):

P .G .G . . . . '
(2.1)
P 
 4  R L
2

ph

p

px

t

mt

3

4
mt

Based on (2.1), with the parameters of the real fire control radar and
MATLAB-SIMULINK software, the simulations are done. As a result,
the power characteristic of reflected signal at the input of antenna is shown
in Fig. 2.2 and Fig. 2.3. The dynamic range of receiver is determinated:
P
(2.2)
vao_max 
D
=10log 

MT

 Pvao_min 



Fig. 2.2. Changing range of the reflected signal
power at the receiving antenna input mt=0.02m2

Fig. 2.3. Changing range of the reflected signal
power at the receiving antenna input mt=100m2


8
The changing range of signal power at the input of receiver can be
calculated:
D

px


 Ppx_max 
. R 4max
 =10log  mt _max
 Ppx_min 

4


  mt _min .Rmin

=10log 






(2.3)

Putting the real parameters of fire control radar into (2.3), obtained:
D


.R 4
 mt _max max
=10log 
px
4
  mt _min .Rmin




4

 100.(300000)   110 dB
  10log 
4 


 0.02.(5000) 


When comparing this value (Dpx) with the nominal dynamic range of
the receiver (DMT = 50 dB), it is clear that Dpx is much larger than DMT
(Figure 2.4). Therefore, the receiver can be overloaded when the target is
near, or the target’RCS is very big.

Fig. 2.4. The receiver dynamic range and the changing range of input signal power
2.2.2. Surveying amplitude and attenuation characteristic
during stabilizing signal amplitude and eliminating the receiver
overload problem (fig. 2.6)
Input
[dBW]
-100
-110
-120
-130
-140

Input
[dBW]

ATT;
adjusting
transmit
power

-100
-110

-120
-130

-150

-140
-150

-160

-160

Output [dBV]
Receiver
dynamic
range

Adjusting K
(AGC, MGC)

Output
range

0.3
0.17
0

Fig. 2.6. The principle of adjuting the signal power in combination
with the dynamic range and eliminating receiver overload

9
Comment 2.3 (from fig. 2.6): In receiver dynamic range, the signal
amplitude varys from U-min to U-max, (fig. 2.7b). Changing K by ΔUra
is interpreted as changing the slope of the receiver amplitude
characteristic (hình 2.7a). From that, Ura is always approximated
Ura=Ura0-Ura(t)≈0 (Ura=Ura0), fig. 2.7c.
Ura
Ura
Nonlinear
amplitude

AGC
saturation

AGC
threshold (a)

(c) t
UV
Uv

Uvào-min

Ura-min

APY range

Uvào-max

Ura-max
danh định

Nolinear distortion

t (b)

Fig. 2.7. Principle of adjusting the K

2.3. Surveying effect of changing the signal amplitude range on
the input receiver by adjusting the transmitter power and
attenuator parameters.
2.3.1. Some databased for survey
We have:

P  UI 

U

2

Rt

From (2.4) it follows: U  P . R t

(2.4)
(2.5)

Take 20log both side (2.5) with Rt=50:

20log U  20log P  20log 50
By definition of dBV, dBW and from (2.6), we have:
dBV = dBW +17

(2.6)
(2.7)

Based on the surveying of the changing range of signal power at the
input of the receiver (Figure 2.4) and formulas (2.4)  (2.7), the
dependence of receiver input signal amplitude on the target’s distance
and target’s RCS is constructed in (fig. 2.8).


10

Fig. 2.8. The changing range of the receiver's input signal amplitude
according to the target’s distance and target’s RCS
2.3.2. Surveying the changing of amplitude characteristic of
input receiver signal over adjusting the transmitter power and
attenuator parameters.
2.3.2.1. Adjusting the transmit power
Following the real parameters of the fire control radar [11], highfrequency generator can work in the following power modes: maximum
P0 = 75kW; average P01 = 7.5kW; Low P02 = 750W. Thus, the
transmitter power can be adjust twice: P0P01 and P01P02.
a) First adjusting transmitter power survey: Reduce P0P01 when the
receiver overloads, the amplitude of receiver input signal was reduced, as
shown in Figure 2.10.
b) Second adjusting transmitter power survey: (P01P02) : The results are
shown in Fig. 2.11).

Fig. 2.10. The changing of
receiver signal amplitude at the
first adjusting P ph

Fig. 2.11. The changing of receiver
signal amplitude at the second
adjusting Pph


11
2.3.2.2. Using the receiver input attenuator (ATT)
The ATT used for the survey has 3 attenuation levels: 8dB; 18dB;
26dB. The simulating attenuation levels including:
a) 1st level (SG1- point 4 fig. 2.12)
b) 2nd level (SG2- point 5 fig 2.13)
c) 3rd level (SG3 - point 6 fig. 2.14).

Fig. 2.12. The changing of the signal
amplitude with SG8dB attenuated

Hình 2.14. The changing of the signal
amplitude with SG26dB attenuated

Fig. 2.13. The changing of signal
amplitude with SG18dB attenuated

Comment 2.6: After 5 times
controlling receiver signal amplitude (2
times of reducing the transmitter power,
3 times of increasing the attenuation

levels, the receiver can be maintained
not overloading, in term of the target’s
RCS is 100m2 and target’s range is

300km (Figure 2.14).
2.4. Synthesizing the algorithm to prevent overloading of receiver
2.4.1. Synthesizing the control algorithm (fig. 2.15)
2.4.2. Control characteristic to prevent overloading of receiver
With schematic diagram 2.15; MATLAB-SIMULINK software; real
parameter of fire control system [9], [11] and the target as described in
Section 2.3 .2.1, the simulating of synthesized control algorithm (Section
2.4.1) was performed. The results show that the signal amplitude of
receiver input can be automatically controlled into the receiver dynamic


12

Fig. 2.15. Flowchart of algorithms to
control transmitter power and attenuator

Fig 2.16. Characteristic of the signal
amplitude applying the control
algorithm

range, and overloading receiver problem is automatically eliminated
(Figure 2.16). This algorithm only applies to a specific target, as shown in
the example.
2.5. Conclusion of chapter 2
In Chapter 2, essential characteristics were investigated, which are
necessary for synthesizing the proposed detectors and controllers. However,

the synthesized algorithm can only applied to a specific target. The algorithm
applied to any arbitrary target was synthesized in Chapter 3.
Chapter 3
SYNTHESIZING ALGORITHM AND STRUCTURE FOR THE
OVERLOAD DISCRIMINATOR AND CONTROLLER OF
AUTOMATICALLY PREVENTING RECEIVER OVERLOAD
3.1. Synthesizing algorithm and structure for the receiver overload
discriminator


13
3.1.1. Basis for Synthesizing the algorithm for the receiver
overload discriminator
3.1.1.1. The nonlinear distortion of signal causes its spectral distortion
a) Nonlinear distortion of the signal due to overloading of the receiver
If receiver is overloaded, its output signal will be nonlinear
distortion. [13],[42] (fig. 3.1).

Fig 3.1. Explain the nonlinear distortion of the signal in a receiver

b) Portrait pectrum of a signal before and after nonlinear distorted
3.1.1.2. Surveying spectrum characteristic of receiver output signal
Results of survey:
1. Characteristic of the signal spectrum before the overloaded receiver (fig. 3.3).
2. Characteristic of the signal spectrum after the overloaded receiver (fig. 3.4).

Fig. 3.3. Spectrum of the receiver
output signal when not overloaded

Fig. 3.4. Spectrum of the receiver

output signal when overloaded

3.1.1.3. The evaluating of survey results and comments
Evaluate: When the receiver is not overloaded, the amplitude of
the spectrum lines far from the center frequency is very low and
stable. The amplitude of the side lobes will increase corresponding to
the level of overload.


14
Comment: It is possible to use the feature of changing the
amplitude of high frequency spectra lines for detecting the timing
when the receiver is overloaded. That based on constructing the
relationship between the amplitude of the "mth" line and power (Ppx)
of the receiver input signal, ie:
(3.16)
Smt (mf)=G[10log(p px )]
3.1.2. The reliability of the receiver overload detection method
based on monitoring the amplitude of a defined spectral line
This was evaluated based on the factors influencing the signal
spectrum (in the thesis).
3.1.3. Synthesizing the algorithm detecting receiver overload:
Including the function of preventing receiver overload and
rejecting function.
* Condition for overload signal "j=1":
- The amplitude of "mth" spectrum line is bigger than the threshold level (NG).
- Receiver output voltage: Ura>Ungương_max=Ura_0.
* Condition for “Q”(Rejecting one level of preventing receiver
overload methods which was using):
- The AGC voltage decreases down to: UAPY

The flow chart of receiver overload discriminator (shown in fig. 3.6)
3.1.4. Synthesizing the structure of the receiver overload
discriminator
3.1.4.1. The structure of the overload discriminator(fig. 3.8)

Fig. 3.8. The structure of the receiver overload discriminator
3.1.4.2. Operational principle of receiver overload discriminator
The input signals of the receiver overload discriminator include: the
reflected pulses beams Smt(t,nTx); The envelope of pulses beams which


15
are obtained from input signal; AGC voltage signal. The discriminator
operates following the predefined algorithm. "j" or "Q" signal is “1”
when its conditions are met. If “j” change from 0 to 1 – a method to
prevent receiver overload will be used. If “Q” change from 0 to 1 – a
method to prevent receiver overload will be rejected. There are four
rules to select the methods of preventing receiver overload:
- Rule 1 (QL1): P01P02SG1SG2SG3, for Rmt≤Rmt_max;
- Rule 2 (QL2): P02SG1SG2SG3, for Rmt≤0.5Rmt_max;
- Rule 3 (QL3): (P02+SG1)SG2SG3, for Rmt≤0.25Rmt_max;
- Rule 4 (QL4): (P02+SG2)SG3, khi Rmt≤0.1Rmt_max;
3.2. Synthesizing the algorithm and structure of the controller
to prevent receiver overload
3.2.1. The terms used for synthesizing the control algorithm of
transmitter power
- Following the principle of dividing target/misile channels by time series in
the modern missile guidance stations.
- The operation of the modern missile guidance stations based on the
control of the computer.

3.2.2. Control algorithm to prevent receiver overload
This is shown in Figure 3.10 of the thesis.

Fig. 3.10a)

Fig. 3.10b)

Fig. 3.10c)

Fig. 3.10d)


16

Fig. 3.10e)

Fig.
Fig.3.10e)
3.10e)

Fig. 3.10. Control algorithm to prevent receiver overload
3.2.3. Synthesizing the structure of the controller preventing
receiver oveload
The controller can be built in the form of logic circuits or as a control
software installed in the computer. It performs following the
algorithms described in Figure 3.10.
3.2.3.1. The structure of the controller: The components of the
controller are shown in Figure 3.11.

Control word

block

Mode computer

Control rule

Center computer

The controller of automatically preventing receiver overload
To
decoder of
transmiter
To
decoder of
ATT

Fig 3.11. Structure diagram of cotroller automatically preventing receiver overload

3.2.3.2. Structure diagram of control rule block
There are many ways to actualize the structure of the control rule
block, such as: Building the logical circuits by hardware; use of
microprocessor chips with a software control program.
a) The control rule of the control rule block (plan 1)
Structure of control rule block in hardware model showed in
fig.3.12.


17
The structure of the control rule block

“L”
coder
“J”
coder

Control
rule
circuit

To
center
computer

“Q”
coder

Fig. 3.12. The structure of the control rule block
The ouput signal of coders are 3bite of binary code signals. They are
used to discriminate: the times of overloads; the times of rejecting the
preventing overload methods and the rule of using preventing overload
methods. The control rule of ouputs (P0;P01;P02;SG1;SG2;SG3) will be
made in control rule circuit block which can be satisfy with any
parameters of target, such as: target’s appearing range; target’RCS;
target’s flying direction…
b) The controller of preventing receiver overload created by
Solfware program (plan 2)
Programming follows the steps:
Step 1 – Test the target distance information to select the receiver
overload preventing rule in accordance with the rule of changing the
signal amplitude according to the target’s distance (2.1).

Step 2 – Implement the rule of preventing receiver overload or
rejecting the method of preventing receiver overload following to
step 1 with two target cases: flying into the station - creating the "j"
code; Fly out of the station – creating the "Q" code. The "Q" is
created based on the control rulers (QL1;QL2:QL3:QL4) and the
current method of preventing receiver overload
Step 3 – Reseting “j” or “Q” signal and stopping the program.
The efficiency of the controller will be investigated in Chapter 4.


18
3.2.3.3. Principle of operation of the controller
The controller is capable of automaticall preventing all cases of
receiver overload problems, throughout the target range, based on the
algorithm synthesized.
3.3. Synthesizing the transmit - receive target tracking system
automatically preventing receiver overload in the fire-control radar
3.3.1. Basic elements of the control system
General diagram of the automatic control system is shown in figure 3.13.
3.3.2. Schematic structure of the transmit/receive system automatically
preventing receiver overload

Schematic structure of the transmit/receive system automatically
preventing receiver overload is shown in figure 3.14.

Fig. 3.14. Schematic structure of the transmit/receive system
automatically preventing receiver overload
3.3.4. Block dynamic diagram of the transmit/receive system
automatically preventing receiver overload
Block dynamic diagram of the transmit/receive system automatically

preventing receiver overload is shown in figure 3.15.

Fig. 3.15. The dynamic transmit-receive system automatically
preventing receiver oveload


19
3.3.5. Operation characteristics of the transmit/receive system
automatically preventing receiver overload
- System works in discrete mode;
- System works following to the codes of output detector;
- The controller work as a logic switch;
- The time to work of controller is before that of transmiterreceiver system.
At this time, the closed loop automatic control system will perform to
eliminate the receiver overload problem.
3.4. Conclusion of chapter 3
Chapter 3 deals with two basic problems 3 and 4 that were identified at
the end of Chapter 1.
The closed loop transmit/receive control system is actually allowed to
increase the level of automation compared to the current system.
Accodingly, the peformance of the target coordinate tracking systems in
missile guidance stations are improved.
Chapter 4
EVALUATING THE EFFICIENCY OF THE CLOSED LOOP
TRANSMIT/RECEIVE CONTROL SYSTEM AUTOMATICALLY
PREVENTING RECEIVER OVERLOAD
4.1. Experimental simulation and simulation conditions
4.1.1. Simulation purpose
Evaluating the efficiency automatically cotrolling the receiver input
signal amplitude into receiver’s actual dynamic range, in terms of RCS,

distance appearances, flight velocity, direction of the target is not known,
and in terms of parameters of the target change in the wide range.
4.1.2. Conditions and data for simulation
4.1.2.1. Parameters of the fire control radar
Use the actual parameters a fire control radar [11].
4.1.2.2. Model and motion parameters of the target
Modeled using the Matlab-Simulink tools.
4.1.3. System model and elements used in the survey
Use the built-in Matlab-Simulink software


20
4.2. The survey and simulation plan
4.2.1. Surveyings of overload characteristics over the nature of
the target
Surveying the invariance of the receiver overload detection
characteristic ΔSmt (mf,kFch )=Φ(σ mt ,Vmt ) by the changing the σmt and
Vmt, with m=13 and x=0.75s.
Transmit
Anten (Px)

Transmitter

Controller
(QL1÷QL4)
j; Q; L

Target

Receive

Anten (Ppx)

Receiver
(Uv,UAPY, Ura, D,
KΣ, Ung-max,min)

Overload
discriminator (STT,
Sm, “j”, “Q”)

Target
trackings

The receiving and processing signal for tracking system

Fig. 4.1. Model used to simulate the transmit/receive system
4.2.2. Surveying the changing range of receiver input voltages
accoding to distance, RCS, distance appear and flying direction of
target
a) Plan 1 – checking the creating “j”. Target with different RCS, flying
in, from Rmax=300km to Rmin=5km. Simulation data is given in Table 4.2.
b) Plan 2 – checking the creating “Q”. Target with different RCS,
flying out, from Rmin=5km to Rmax=300km, (all of range gate).
Simulation data is given in Table 4.3.
c) Plan 3 – checking QL2÷QL4 – for the target flying in
Target with different RCS, appearing randomly in range gate of
the radar, flying in to Rmin=5km.
d) Plan 4 – check QL2÷QL4 - Target flying out
Target with different RCS, Appearing randomly in radar range
gate, flying out to Rmax=300km.

21
4.3. Results of survey and evaluation
4.3.1. Results of survey and evaluation about
overload characteristic

detection

Fig. 4.3. Changing spectrum line
Fig. 4.2. Changing spectrum line
amplitude
S13(13f,kFch) by target’s speed
amplitude S13(13f,kFch) by target’s RCS
mục tiêu

Comment 4.1: Changing amplitude of spectrum line 13th dependent on

target’s RCS and speed clearly (fig. 4.2 and fig. 4.3).
Evaluate : detection overload characteristic synthesized based on spectrum
analysis method has shown good quality (fig. 4.4).
4.3.2. The result of surveying the control characteristic for
signal amplitude
4.3.2.1. Results of the surveying plan 1
- The rule of preventing receiver over load: P0→P01→P02→SG1→SG2→SG3.
a)

b)

c)

d)

Fig. 4.5. Effects against receiver overload in cases of changing target’s
RCS: a) (σmt=90m2); b) (σmt=10m2); c) (σmt=1m2); d) (σmt=0.02m2)