الاثنين، 16 يونيو 2008

CYBERCRIME


VON HARVIX said: We explore. We prevent. We revenge.
But how can understand this theory (securities theory)?!
First what do we mean with the crime as a legal concept?!!
                                                                                     
 Crime as absolute concept is a psychological, social and economic phenomenon and is as old as the human society. And maybe known as a legal wrong manner that can be followed by criminal proceedings which may result into consequential punishment.

But what’s the CyberCrime??
Let’s dive slowly in that term:
                                                   
CyberCrime is “may be said to be those communities, of which, genus is the conventional crime, and where either the computer is a subject of the conduct constituting and making crime”.


Do You Know!!!
Any criminal activity that uses a computer (PC) either as an instrumentality, target or a means for devoting more and more from the crimes comes within the ambit (مدي) of CyberCrime”.


REASONS FOR CYBERCRIME:
1. Capacity to store data in comparatively small space
The computer has unique characteristic and we considered the one of them for storing data in a very small space, Make it easier for using.

2. Easy to access
The problem encountered in protecting and preventing a computer system from unauthorised access is that there is every possibility of breach or get cracked not due to human error but due to the complex technology.
But HOW this happens???
By secretly implanted logic bomb, key loggers that can steal access codes, advanced voice recorders, retina imagers etc. that can fool biometric systems and bypass firewalls can be utilized to get past many a security system.

3. Complex
The computers work on Operating Systems (O.S) which are composed of millions of codes (0, 1).
The cybercriminals (hackers or crackers) take advantage of these lacunas (ثغرات) and penetrate into the computer system.

4. Negligence (الاهـــــمال)
Negligence is very closely connected with human conduct. It is therefore very probable that while protecting the computer system there might be any negligence, which in turn provides a cybercriminal to gain unauthorised access and control over the computer system (patch plant).

5. Loss of evidence
Loss of evidence is a very common & apparent problem as all the data are routinely destroyed. Further collection of data outside the territorial extent المدي الاقليمي)) also paralyses this system of crime investigation.

6. Motivation of Knowledge
Where the hi-tech revolution prompted many young people to enter and search for rules of the game, even if the consequences were painful. After learning its arts, that we can see will be risky on the crumbs of society and thus a loss of confidence among us.
The love of possession generated within these people, and keep up with others in various areas of knowledge and the means were not aware of a useful but the spirit of competition to create a new type of scientific research.
  
And after these all we want to know who these criminals are?
Are Programmers, Organized Professionals or Trained Intelligent???



CYBERCRIMINALS divided into three types:
1. Children and teenagers between the age group of 6 – 18 years
The simple reason for this type of behaviour pattern in children is seen mostly due to the inquisitiveness (الفضول) to know and explore many things. 

2. HACKERS/CRACKERS
-Organised hackers
This divided into 2 hacking types:
a. DARK SIDE
These kinds of hackers are mostly organised together to fulfil certain satisfaction objectives.
b. MALICIOUS
Who organised for some reasons may be to fulfil their political bias, fundamentalism....etc.
-Professional crackers
Their work is motivated by the color of money. These kinds of crackers are mostly employed to crack the websites of the rivals (المنافسين) and get credible, reliable and valuable information.

3. Discontented employees
This group include those people who have been either sacked by their employer or are dissatisfied with their employer.



MODE AND MANNER OF COMMITING CYBERCRIME:
1. Unauthorized access to computer systems or networks
This kind of offence (الجريمة) is generally referred as Hacking/Cracking in the generic sense.

2. Theft of information contained
This includes information processed and stored in computer hard disks, removable storage media…..etc. 
E.g. compute name, user name, windows folders, windows version and its serial No, etc.

3. Email bombing/freezing
Email bombing refers to sending huge numbers of mails to the victim, which may be an individual, a company or even mail-servers in there by ultimately resulting into crashing. 
E.g. ebomber ,Kaboom…etc
Email Freezing refers to prohibit the messenger worked and also its mail service to open.
E.g. freeze email…etc
  

4. Data diddling (التحريف والتزوير بقواعد البيانات)
This kind of an attack involves altering raw (الخام) data just before a computer processes it and then changing it back after the processing is completed.
The electricity board faced similar problem of data diddling while the department was being computerised.

5. Salami attacks
This kind of crime is normally prevalent (شائعة) in the financial institutions and establishments or for the purpose of committing financial crimes.
 E.g. the Ziegler case wherein a logic bomb was introduced in the bank’s system, which deducted 10 cents from every account and deposited it in a particular account.

6. Denial (انكار) of Service attack
The computer of the victim is flooded with much more requests than it can handle which cause it to crash.
Distributed Denial of Service (DDS) attack is also a type of denial of service attack, in which the offenders are wide in number and widespread. E.g. AltaVista ,Yahoo ,Lycos …etc

7. Virus / worm attacks
Viruses are programs that attach themselves to a computer or a file in it and then circulate themselves to other files and to other computers on a network. They usually affect the data on a computer, either by altering or deleting it.
 E.g. love bug virus, which affected at least 5 % of the computers of the   globe. The losses were accounted to be $ 10 million.

Worms unlike viruses do not need the host to attach themselves to computer or maybe file in it.They merely make functional copies of themselves and do this repeatedly till they eat up all the available space on a computer's memory.
The world's most famous worm was the Internet worm let loose on the Internet by Robert Morris sometime in 1988. 

 8. Logic bombs
 These are event dependent programs. This implies that these programs are created to do something only when a certain event (known as a trigger event) occurs.
 E.g. even some viruses may be termed logic bombs because they lie dormant (مختفية)all through the year and become active only on a particular date (like the Chernobyl virus).

9. Trojan attacks
This term has its origin in the word ‘Trojan horse’. In software field this   means an unauthorized program, which passively gains control over another’s system by representing itself as an authorised harmful program. The most common form of installing a Trojan is through e-mail.
E.g. a Trojan was installed in the computer of a lady film director in the U.S. while chatting. The cyber criminal through the web cam installed in the computer obtained her nude photographs. He further harassed (مضايقات) this lady.

10. Internet time thefts
Normally in these kinds of thefts the Internet surfing hours of the victim are used up by another person. This is done by gaining unauthorised access to the login ID and the password of any account or maybe even the credit cards.

11. Web jacking (الاصطياد عبر الشبكة الالكترونية)
This term is derived from the term Hi-jacking. In these kinds of offences the hacker gains unauthorised access and control over the websites. He may even mutilate or change the information on the site. This may be done for fulfilling satisfaction objectives, for money or some political racism ideas.


CLASSIFICATION of CYBERCRIME:
The subject of cybercrime may be broadly classified under the following three groups:

1. Against Individuals 
a. their person .
b. their property(possession) of an individual.
 
2. Against Organization
a. Government.
c. Firm, Company and Group of Individuals.

3. Against Society at large 
 The following are the crimes, which can be committed against the followings group.
 

And take it in details to know its specific elements.
Against Individuals: –
- Harassment (الابتزاز) via e-mails.
- Cyber-stalking
(مطاردة).
- Dissemination
(نشر) of obscene (اباحية) material.
- Defamation
(التشهير).
- Unauthorized control/access over computer system.
- Indecent
(غير لائق) exposure.
- Email spoofing
(التحايل عبر البريد)
- Cheating & Fraud
(الغش والخداع)

Against Individual Property: - 
- Computer vandalism (التخريب).
- Transmitting virus.
- Unauthorized control/access over computer system.

- Intellectual Property
(الحقوق الفكرية) crimes.
- Internet time thefts.

Against Organization: -
- Unauthorized control/access over computer system
- Possession of unauthorized information.
- Cyber terrorism against the government organization.
- Distribution of pirated software etc.

Against Society at large: -
- Pornography (basically child pornography).
- Polluting the youth through indecent exposure.
- Trafficking
(الاتجار بالبشر)
- Financial crimes.
- Sale of illegal articles.

-.Online gambling(القمار).
- Forgery
(الغش).


The above mentioned offences may discuss in brief as follows:
       1. Harassment via e-mails
       Harassment through e-mails is not a new and different concept. It is very similar to harassing through letters.

2. Cyber-stalking
Cyber stalking involves following a person's movements across the Internet by posting messages (sometimes threatening) on the bulletin boards frequented by the victim, entering the chat-rooms frequented by the victim, constantly bombarding the victim with emails…..etc.

3. Dissemination of obscene material/ Indecent exposure/ Pornography (basically child pornography)
Pornography on the net may take various forms. It may include the hosting of website containing these prohibited materials, Use of computers for producing these obscene materials, downloading through the Internet, obscene materials. These obscene matters may cause harm to the mind of the adolescent and tend to corrupt their mind.

4. Defamation
This is the communication of a statement that makes a claim, expressly stated or implied to be factual.

5. Unauthorized control/access over computer system
This activity is commonly referred to as hacking. So we will not use the term "unauthorized access" interchangeably with the term "hacking" to prevent confusion as the term used in the Act of 2000 is much wider than hacking.

         6. E mail spoofing
A spoofed e-mail may be said to be one, which misrepresents its origin. It shows it's origin to be different from which actually it originates recently.

7. Computer vandalism
Vandalism means destroying and genocide the property of another. Thus computer vandalism may include within its purview (نص) any kind of physical harm done to the computer of any person.
   
      8. Intellectual Property crimes (IPR)
Intellectual property consists of a bundle of rights. Any unlawful act by which the owner is deprived completely or partially of his rights is an offence. The common form of IPR violation may be said to be software piracy, copyright infringement (انتهاك), trademark and service mark violation, theft of computer source code….etc.

 9. Cyber terrorism against the government organization
 At this juncture a necessity may be felt that we need to distinguish between cybercrime and cyber-terrorism.
Both are criminal acts….But is the difference among them??
A cybercrime is generally a domestic issue (قضية داخلية), which may have international consequences.
A cyber-terrorism is a global concern, which has domestic as well as international consequences.  The common form of these terrorist attacks on the Internet is by distributed denial of service attacks, hate websites and hate emails, attacks on sensitive computer networks, etc.  Technology savvy (دهاء)terrorists are using 512-bit encryption, which is next to impossible to decrypt(فك تشفير).
The recent example may be cited of – Osama Bin Laden, the LTTE, attack on America’s army deployment system during Iraq war.
And a cyber terrorist is the person who uses the computer system as a means or ends to achieve the above objectives. Every act done in pursuance thereof is an act of cyber terrorism.

  10. Trafficking
Trafficking may assume different forms. It may be trafficking in   drugs, human beings, arms weapons etc. These forms of trafficking are going unchecked because they are carried on under pseudonyms 
(اسماء مستعارة).

11. Fraud & Cheating
    Online fraud and cheating is one of the most lucrative businesses that are developing and growing today in the cyber space. It may assume different forms. Some of the cases of online fraud and cheating that have come to light are those pertaining to credit card crimes, contractual crimes, offering jobs….etc.
   

CyberCriminals Exploring:
I. system information (Msinfo):
To start Msinfo.exe
     1. Click Start, and then click Run 
     2. Type Msinfo, and then click OK.
And we ll concentrate to two orders :
-Software Environment:
The status of the Operating System Wholly.
-Running Task (Also by pressing ctrl+Alt+Delete on the Keyboard):
And find the wired actions in your computer.
II. System Configuration Utility Start-Up (Msconfig):
Is a system tool that allows you to temporarily change the way Windows starts by disabling startup programs and services which making incorrect changes and damage your system.
To start Msconfig.exe
    1. Click Start, and then click Run 
    2. Type Msconfig, and then click OK.
     3. Then appears  System Configuration Utility list.
   4. Take Srartup.
Then we will see many files determined in arrangement, these files all we installed before on the system if you doubt about some files then delete it quickly from that list.
III. Registry Editor (RegEdit):
Enables you to view, search for, and change settings in your system registry, which contains information about how your computer runs. Although you can use Registry Editor to inspect and modify the registry, doing so is not recommended, as making incorrect changes can damage your system.
To start Regedit.exe
     1. Click Start, and then click Run. 
     2. Type Regedit, and then click OK.
    3. Press on HKEY_LOCAL_MACHINE.
      4. Choose SOFTWARE.
      5. Then MICROSOFT.
    6. After that WINDOWS.
     7. CurrentVersion.
    8. Finally get RUN.

Now we looking at the right of present window that we seeing the many files and its values under the names of names and data respectively, so when we don’t find the value of any file just space or arrow pointing only this means patch file found or hacking program executed on our computer .so we delete it from our system with ALT+DELETE+ENTER.

 IV. Network Statistics (NetStat):
   
To start NetStat.exe
1.   Click Start, and then click Programs> Accessories >Command Prompt.
2.   Type NetStat , and then click OK.
 And from foreign address we the port linked to the hacking              program to your computer which is usually start from port 50000-to-port 60000.
3. After checking and determining the patch of hacking:
Disconnect the cable of networking and reboot the computer then get wholly (كليا) scan for your system.

V. By MS-DOS:
    1. Click Start, and then click Programs> Accessories >Command Prompt.
    2. Write C:\Windows\patch.exe,
                   C:\Windows\system32\patch.exe,
                   C:\Program files\%subfolder%\patch.exe or
                   C:\patch.exe.
  And all of the previous orders written depends on our system.
3. And if we find the patch file we delete by write this statement:   
             c:\windows\delete patch.


CYBERCRIME PREVENTION:
Prevention is always better than cure. It is always better to take certain precaution while operating the net.
So we should keep in mind the following things-
1. to prevent cyber stalking avoid disclosing any information pertaining to oneself(anyone). This is as good as disclosing your identity to strangers in public place.
2. always avoid sending any photograph online particularly to strangers(unknowns) and chat friends as there have been incidents of misuse of the photographs.
3. always use latest and up date antivirus software to guard against virus attacks and get scanning periodically to the system.
4.  always keep back up volumes so that one may not suffer data loss in case of virus contamination
5. never send your credit card number to any website that is not secured, to guard against frauds.
6. always keep a watch on the sites that your children are accessing to prevent any kind of harassment or depravation in children.
7. it is better to use a security programme that gives control over the cookies and send information back to the site as leaving the cookies unguarded might prove fatal, and better if you delete it all from your system every time you sit to work with your computer preventing it from theft.
8. websites owners should watch traffic and check any irregularity on the site. Putting host-based intrusion detection devices on servers may do this.
9. use of firewalls may be beneficial.
10. web-servers running public sites must be physically separate protected from internal corporate network.
11. Eliminating the websites Advertisements those jumping whenever and wherever you are by some special programs.
E.g. Optout program from grc.com company.
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AL-BIK...

الثلاثاء، 10 يوليو 2007

RADAR Engineering- YLC-6M Radar System IlI


       Battle Operation of YLC-6M Radar System

The battle operation of YLC-6M radar refers to activities that operators adjust radar’s operation modes, cancellation area, display setting, signal processing setting, communication setting, and etc. according to various conditions such as target, display, landmark, weather and jamming.
YLC-6M radar generally operates in normal operation state. It operates in anti-weather operation state when there is weather interference. It uses different anti-jamming operation modes if there is hostile active jamming. Now, we describe the battle operation of YLC-6M radar respectively.

Normal Operation
 Operation modes
The normal operation of YCL-6M radar refers to operation in the condition of weak weather echo and without electromagnetic jamming. In this case, there is only fixed ground clutter, so the radar adopts MTD operation mode, i.e., normal non-weather operation mode.

 Operation range and antenna rotation rate
When YLC-6M radar is being used for air surveillance, its operation range can be adjusted to 200km, 150km and 120km according to different air surveillance volumes and data rates. For general air surveillance task, 200km and 150km range can be selected. Its corresponding antenna rotation rate is 6rpm. If 12rpm is used in the two ranges, the number of echoes in a single beam of the radar system will be decreased by a factor of 2. It will greatly increase the processing loss of the radar system so as to have a certain effect on the radar coverage range. Thus, it is not suggested that 12rpm is used in the operation range of 150km and 200km. 120km operation range corresponds to 12rpm antenna rotation rate. In this operation mode, radar’s data rate will be increased by a factor of 2. It is mainly used for the search and surveillance of low altitude fast targets so as to rapidly form tracks and provide the command and control system with more target information.

 Selection of MTD filter bank
In MTD operation mode, filter bank I, filter bank II and filter bank III on the master monitoring console respectively represent four different filter banks as follows:
          Filter bank I (clutter area):
                   Filter zero depth£-60dB (±14Hz bandwidth)
Sidelobe level£-30dB
Zero frequency filters are shut off.
Filter bank II (clutter area)
Filter zero depth £-60dB (±12Hz bandwidth)
Sidelobe level £-30dB
Zero frequency filters are shut off.
Filter bank III (clutter area)
Filter zero depth £-60dB (±30Hz bandwidth)
Sidelobe level £-13dB
Zero frequency filters are shut off.
Filter 0 (non-clutter area)
8 best matching filters (covering the whole range of all the filters, filter I, filter II and filter III)
Filter bank I and filter bank II have similar functions. They are used in the case that there is ground clutter around the radar and the clutter spectrum is narrow. If there is light weather clutter, filter bank III can be selected. This filter bank has better spectrum rejection performance in frequency domain (30Hz).
The specific operation method is to respectively push down the three buttons for filter bank I, II and III on the master monitoring console, which are interlocked one another. In this case, the corresponding MTD filter bank (i.e., filter bank I, or filter bank II or filter bank III) operates. Filter 0 operates when all the three buttons are bounced up.

 Selection of dynamic/static clutter map
In the signal processor subsystem, there are 8 kinds of preset static dynamic clutter maps (static STC control). 0# means there is no STC control (i.e., full 0 for STC). STC control amount (theory value) increases successively from 1#~7# clutter map.
When the radar arrives at some site, power it on to observe the landmark around the radar. If the landmark occupies a smaller area and has a weaker strength, the static clutter map with smaller STC control amount will be selected (such as 1# and 2#). Otherwise, the static clutter map with larger STC control amount (such as 6# and 7#) will be selected. If the landmark range is large and beyond the control range of the static clutter control map (for example, there is stronger ground clutter at a range of 80km.) and the strength of the landmark is strong, both a proper static clutter map and a dynamic clutter map will be used in order to reject ground clutter better.

 Selection of dynamic/static clutter contour map
Clutter contour map is a map to control the cancellation of ground clutter, i.e., to control whether filter 0 in the filter bank of the signal processor subsystem is switched on or not. There are 4 kinds of static clutter contour maps in the radar signal processor subsystem. 0# clutter contour map refers to non-cancellation in full range (i.e., when cancellation is carried out in all the coverage, 0# filter is switched off.). 1# to 3# clutter contour maps respectively correspond to the cancellation within the range out to 50km, 100km and full range.
When the radar arrives at some site, turn it on to observe the landmark around the site. Different static clutter contour maps are selected based on the range of the landmark away from the radar site. For example, when the ground echo is in a range of 87km away from the radar or the main radar observation direction, the static clutter contour map within 100km should be selected. In order to make a further rejection on the ground clutter, dynamic clutter contour map might be selected, which can automatically establish clutter contour map in two dimensions (azimuth and range) based on the static clutter contour map and make cancellation processing within it.
PPI picture without cancellation on some radar site


PPI picture after a clutter contour map is selected


PPI picture after a dynamic clutter contour map is selected
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AL-BIK...

الجمعة، 6 يوليو 2007

RADAR Engineering- YLC-6M Radar System II

schematic drawing of YLC-6M radar’s location
YLC-6M Radar System II

Main Features of YLC-6M Radar System
YLC-6M radar has the following five outstanding features:
(1) High mobility
YLC-6M radar adopts many advanced techniques such as accurate automatic hydraulic leveling, hydraulic folding and deploying of the antenna edge blocks, automatic north alignment and location, and etc.
The whole radar system is installed on a 6-meter-long carrier vehicle platform. Its setting-up and disassembling are conducted automatically.The operation is simple and rapid.
 For the whole radar system, the setting-up time is 8 minutes/4 men and the disassembling time is 6 minutes/4 men.

(2) Fully solid state transmitter

In YLC-6M radar system, a fully solid state centralized transmitter is used so as to achieve low peak power, high reliability, good maintainability, long life cycle and high full-life-cycle efficiency-cost ratio.
 The radar system can be powered up or shut down rapidly. It also can continue to operate for a long time to assume operational tasks.

(3) Good ECCM capability

l       Digital Moving Target Detection (MTD) processing technique is adopted to make the radar system have good anti-ground clutter and anti-chaff capability.
l       A full-coherent, fully solid state system is used to make the radar system have a very high frequency stability, a rapid adaptive pulse burst to pulse burst frequency agility, pulse to pulse frequency agility and pseudo-random pulse burst to pulse burst frequency agility, thus the anti-clutter capability of the radar system is assured. Pseudo-random frequency agility can be achieved compatible with MTI.
l       Digital pulse compression technique is used. A frequency modulation (FM) signal with a large product of time width and bandwidth is used to increase resolution and decrease meteorological interference. It is also helpful to anti-active jamming.
l       Low side-lobe antenna, wide band and circular polarization techniques are used, which are helpful to both anti-active jamming and anti-passive jamming.

(4) High reliability

In the radar system, a fully solid state transmitter and a two-channel, redundant thermal switching receiver are used to largely increase their reliability.
The use of miniaturization and integration techniques greatly reduces the quantities of components and plug-in boards, so a further increase of system reliability is achieved.

(5) High automatization

The radar system has BIT, extraction and tracking functions, provides an information network data communication interface, and can report data to the higher level command and control posts via wire/radio communication equipment.


 Composition of YLC-6M Radar System
YLC-6M radar equipment vehicle is mainly composed of sidelobe reflector antenna, transmitter, servo, hydraulic leveling, electronic cabin and platform. Inside of the electronic cabin, there are 3 electronic equipment cabinets (i.e., receiving and signal processor cabinet, display and data processor cabinet, and servo control cabinet), in which receiver, signal processor, radar terminal, timing and master control, target extraction, anti-jamming, servo hydraulic leveling control and other electronic equipment are installed. In addition, there are documentation cabinets and spare parts cabinets in it.
In order to decrease the setting-up time, disassembling time and number of operators, radar antenna, transmitter and other electronic equipments are all installed on one carrier vehicle platform.
Diesel generator power station is installed on a trailer, which can be towed by the radar vehicle. So there is only one transportation unit for the whole radar system.
YLC-6M radar equipment consists of carrier vehicle, operation cabin, antenna and pedestal, hydraulic platform and transmitter. The hydraulic platform is a platform to support the whole radar system. It provides a space for operators to operate the whole radar system. The carrier vehicle is a carrier with which the radar is transported. The transmitter is installed on the rear of the hydraulic platform, where there are also air cooling cabin and power cabin. Inside of the former, there are two high power centrifugal blowers. Inside of the latter, there are power amplification modules of each level for the transmitter, power supply modules, BITE and other electronic equipment. Antenna and its pedestal are in the middle of the whole hydraulic platform. In the small cabin below the pedestal, there are hydraulic subsystem’s driving circuit and control circuit, feedline, receiver’s RF equipment, and etc. Inside of the pedestal, there are feedline’s rotary joints, sliding ring and etc. The antenna includes its reflector, feed horn and etc. The antenna’s reflector is composed of three blocks. In transportation state, the two edge blocks can be lowered respectively to the two sides of the transmitter. In the operation cabin, there are servo control cabinet, display and data processor cabinet, receiver and signal processor cabinet, documentation cabinets and spare parts cabinets.
In the operation cabin, there are three cabinets. They are respectively servo control cabinet, terminal cabinet, as well as receiver and signal processor cabinet. The names and locations of units in each cabinet are shown in :

Servo control cabinet
Display and data processor cabinet
Receiver and signal processor cabinet
Power distribution unit
A/R display unit
Signal processor unit
Leveling control, north alignment unit
Raster display unit
Control unit
Receiver unit
Servo control unit
Master console
Local oscillator
Operator panel
Power supply unit
Terminal processing unit
Power supply unit I
Stand-by power supply unit
Power supply unit II
Blower
Communication switching unit
Switching unit
Switching unit



Setting-up Operation of YLC-6M Radar System
Requirements for Radar Site:


YLC-6M radar is highly mobile radar. All the radar equipments (excluding diesel generator power station) are installed on a 6m-long carrier vehicle platform. Therefore, it has lower requirements for its site and environment around the site. The specific requirements are as follows:
                          (1)Environments around the site
In the main observation direction, the blanking angle should be less than 0.2° and the ground surface should be flat. In order to decrease the interference as much as possible, the radar site should be away from broadcasting & TV station, large factory, transforming plant, high voltage line and etc. Around it, there shouldn’t be facilities that absorb electromagnetic wave such as high-speed railway, high bridge, mass of resident buildings, and etc.
                          (2) Radar setting-up site
In order to get better low altitude detection performance, a terrain with higher elevation should be selected as the radar setting-up site. The ground for the setting-up and adjustment of radar antenna should be a flat and solid area measuring 5´10(m2). On a temporary site, there is no need for staking; On a permanent site, one stake for grounding is needed.
                         (3) Lightning arrester
If the radar site is permanently used, a lightning rod should be installed. It shouldn’t be located in no main observation area. It should be 7~8m away from the antenna center. The grounding resistance shouldn’t be more than 3W. If the radar site is temporarily used, whether a mobile lightning rod is used will be decided by the weather condition in which the radar operates.
                         (4) Schematic drawing of radar site location
This represented the infrastructure of the being to the RADAR operation.
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AL-BIK...

الأحد، 1 يوليو 2007

RADAR Engineering- YLC-6M Radar System I


YLC-6M Radar System I


In the future war, rapid forces transferring and highly mobile operation will be a common-used tactical means.
 Low altitude and ultra low altitude attack now have become a common-used tactical means for air forces to avoid being detected. Additionally, in the future battlefield, there will be a variety of geographic and electromagnetic environments, many kinds of enemy electronic countermeasures.
All of these demand for a high performance radar that has the following performances: it can be disassembled, transported and set up rapidly; it has excellent electric performances, especially for detecting low altitude and ultra-low altitude targets; it has good ECCM performance and high reliability, and can be transported by land, sea and air; it can be powered on/powered off rapidly.

YLC-6M radar is a highly mobile, fully solid state, medium/low altitude surveillance radar developed in 1990s’ based on the operation demands by radar forces.
YLC-6M radar is a vehicle-carried, highly mobile, fully solid state, 2D, medium/low altitude surveillance radar in S band. It used fully solid state, full coherent, pulse compression and MTI detection techniques.

 The radar is characterized by good performances such as high mobility, high reliability, high Automatization and etc.
The radar is mainly used for highly mobile air surveillance, and detection of low altitude/ultra low altitude flying targets. It is also used to provide the operation and command system as well as aviation force with numerous synthetic information such as azimuth, range, foe/friend attribution of air targets. The acquired information can be introduced into the radar chain in real time. So it can be used as a highly mobile, medium/low altitude gap radar in the air intelligence radar chain. It can also be used as a stand-by radar to replace the destroyed radar. Its supplementary tactical function is to provide the air traffic control system in the airport with primary radar information of approaching control.


The radar has high maneuverability and strong ECM capability as well as higher survivability. Its main operation missions are:
a.     Suitable for rapid transfer in the battlefield and emergency mobile operation, to provide theater air situation surveillance so as to assure the operations and guidance of aviation forces;
b.     To detect low/ultra low altitude hostile targets and to prevent low/ultra low altitude sudden attacks;
c.      To rapidly enhance the deployment of the original radar chain and rapidly supplement the original radar chain so as to increase the local air situation provision capability.
d.     To play an unexpected role in the beginning of the war due to its mobile deployment capability and parameter shielding capability.
YLC-6M radar is mainly used to detect air targets such as kinds of fighters, attackers, bombers, EW aircraft, reconnaissance planes, transportation aircraft and civil flight planes. It has good detection capability for 
medium/low altitude targets, especially for low/ultra low altitude targets.
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AL-BIK...