Wednesday, April 24, 2024
Ultra violet
UV is a form of radiation generated by atomic transitions in chemical reactions such as those present in the Sun and in man-made equipment such as engines (jet and rocket motors), and some lighting systems (carbon arc lamps and fluorescent lights).
Sunday, June 27, 2021
Monday, July 10, 2017
Ukraine Offers Radars, UAVs and Air Defense to Phillipines
http://defense-studies.blogspot.my/2017/05/ukraine-offers-radars-uavs-and-air.html?m=0
Saturday, September 15, 2012
PHOTOMETRIC STANDARDS
PHOTOMETRIC STANDARDS
The candela-The standard candle has been redefined as the new candle or candela (cd). One candela is the luminous intensity of 1/60 of 1 of the projected area of a black body radiator operating at the temperature of the solidification of platinum (2045 K). The candela emits one lumen per steradian (1 lm sr-1).
Note that the luminous intensity emanating from a source with a spectral distribution that differs from that of the standard candle may be evaluated by using a sensor whose relative spectral response is identical to that standardized for photopic vision.
The lumen-The lumen (lm) is defined in. terms of the candela. The luminous flux per steradian from a source whose luminous intensity is 1 candela is 1 lumen.
The candela-The standard candle has been redefined as the new candle or candela (cd). One candela is the luminous intensity of 1/60 of 1 of the projected area of a black body radiator operating at the temperature of the solidification of platinum (2045 K). The candela emits one lumen per steradian (1 lm sr-1).
Note that the luminous intensity emanating from a source with a spectral distribution that differs from that of the standard candle may be evaluated by using a sensor whose relative spectral response is identical to that standardized for photopic vision.
The lumen-The lumen (lm) is defined in. terms of the candela. The luminous flux per steradian from a source whose luminous intensity is 1 candela is 1 lumen.
Radar –what it was
Radar –what it was
Short (e.g. 50 ns) powerful pulses (up to 1 GW EIRP) to get range => signal BW up to 20 MHz
=> distance-resolution cell 150m (w/o FM)
Regular pulse patterns – purposeful chosen
Band spread techniques by FM (chirp)
LOS
Frequencies ~1 GHz .. 18 GHz (rarely to 40 GHz)
Frequency agility rarely used
TWT, e.g. average power 45W => 90 MW peek power
3' to 12' Antennas with 3dB width of 0.5 .. 2°
Short (e.g. 50 ns) powerful pulses (up to 1 GW EIRP) to get range => signal BW up to 20 MHz
=> distance-resolution cell 150m (w/o FM)
Regular pulse patterns – purposeful chosen
Band spread techniques by FM (chirp)
LOS
Frequencies ~1 GHz .. 18 GHz (rarely to 40 GHz)
Frequency agility rarely used
TWT, e.g. average power 45W => 90 MW peek power
3' to 12' Antennas with 3dB width of 0.5 .. 2°
Monday, July 2, 2012
Electronic Warfare
Electronic Warfare is definitely an ele- ment of combat power. It is a weapon, which can be used without being detected to bring destruction down upon enemy forces.
Electronic Warfare in itself, however, is non-lethal and can be utilized in many ways without endangering a single human life.
It is a source of essential planning and combat information regarding the disposition, firepower and intentions of the enemy forces. It provides a commander with a means for monitoring the activity on a area of operation and determining the effect of his tactics on en- emy forces.
It also provides the military commander with both covert and overt methods for dis-
rupting and suppressing the enemy's com- mand, control, communications and intelli- gence systems (C³I).
Electronic Warfare is also referred to as radio electronic combat. These terms are gen- erally accepted as including Electronic Sup- port Measures (ESM) and Electronic Counter Measures (ECM) for use on the battlefield.
In addition, we include Communications Intelligence (COMINT) and Electronic Intelli- gence (ELINT) in the overall term Electronic Warfare as well as Electronic Protection Measures (EPM); and the meaning of the term will be so used in this training.
Electronic Warfare in itself, however, is non-lethal and can be utilized in many ways without endangering a single human life.
It is a source of essential planning and combat information regarding the disposition, firepower and intentions of the enemy forces. It provides a commander with a means for monitoring the activity on a area of operation and determining the effect of his tactics on en- emy forces.
It also provides the military commander with both covert and overt methods for dis-
rupting and suppressing the enemy's com- mand, control, communications and intelli- gence systems (C³I).
Electronic Warfare is also referred to as radio electronic combat. These terms are gen- erally accepted as including Electronic Sup- port Measures (ESM) and Electronic Counter Measures (ECM) for use on the battlefield.
In addition, we include Communications Intelligence (COMINT) and Electronic Intelli- gence (ELINT) in the overall term Electronic Warfare as well as Electronic Protection Measures (EPM); and the meaning of the term will be so used in this training.
IEDs
"Shampoo bottles, bicycle seats, tiffins. A plastic container or an LPG cylinder. A parcel of books. A clock, a teddy bear. In the Kashmir Valley, any one of these innocuous objects can be fatal. They are all commonly used by militants to fashion bombs and improvised explosive devices (IEDs). But the most lethal of all is the remote controlled explosive device, hidden in a ditch, a drainpipe or a parked vehicle."
- "Lethal Weapons", Indian Express Newspaper (Bombay), August 24, 2000
General
While terrorists will use conventional weapons, such as rocket-propelled grenades and assault rifles to achieve their goals, they also have the ability to assemble and employ a wide variety of lethal improvised explosive devices (IEDs). Explosives are a popular weapon with terrorists and are covered in the al Qaeda training manual. The manual states, "Explosives are believed to be the safest weapon for the Mujahideen. Using explosives allows them to get away from enemy personnel and to avoid being arrested." It goes on to say that, "In addition, explosives strike the enemy with sheer terror and fright." 183
IEDs are a common tool of terror used by non-state actors. These devices have been fabricated in an improvised manner and incorporate highly destructive lethal and dangerous explosives or incendiary chemicals, which are designed to kill or destroy the target. The materials required for these devices are often stolen or misappropriated from military or commercial blasting supplies, or made from fertilizer and other readily available household ingredients.184 IEDs basically include some type of explosive, fuse, detonators and wires,
shrapnel and pieces of metal, and a container to pack the explosives and shrapnel.
The use of IEDs by terrorists is a constant threat. Terrorist groups are continuously developing new techniques and tactics in response to defenses and countermeasures established by their opponents. They will disguise IEDs to hinder recognition and will often booby-trap the devices to detonate if disturbed.
The most simple of the IEDs used is the one initiated by closing of a battery circuit, similar to turning on a battery operated light. When turning on the switch closes the circuit, electricity flows to the light so it can be illuminated. As shown in Figure E-1, a clothespin- triggering device in this IED replaces the light switch and when it is activated, the electricity flows to the charge, thus detonating the explosive.
183 Ben N. Venzke and Aimee Ibrahim, Al Qaeda Tactic/Target Brief (Alexandria: IntelCenter/Tempest Publishing, 2002), 11.
184 Conventional Terrorist Weapons (New York: United Nations Office for Drug Control and Crime Prevention,
2002), 4; available from http://www.undcp.org/odccp/terrorism_weapons_conventional.html; Internet; accessed 12 November 2002.
- "Lethal Weapons", Indian Express Newspaper (Bombay), August 24, 2000
General
While terrorists will use conventional weapons, such as rocket-propelled grenades and assault rifles to achieve their goals, they also have the ability to assemble and employ a wide variety of lethal improvised explosive devices (IEDs). Explosives are a popular weapon with terrorists and are covered in the al Qaeda training manual. The manual states, "Explosives are believed to be the safest weapon for the Mujahideen. Using explosives allows them to get away from enemy personnel and to avoid being arrested." It goes on to say that, "In addition, explosives strike the enemy with sheer terror and fright." 183
IEDs are a common tool of terror used by non-state actors. These devices have been fabricated in an improvised manner and incorporate highly destructive lethal and dangerous explosives or incendiary chemicals, which are designed to kill or destroy the target. The materials required for these devices are often stolen or misappropriated from military or commercial blasting supplies, or made from fertilizer and other readily available household ingredients.184 IEDs basically include some type of explosive, fuse, detonators and wires,
shrapnel and pieces of metal, and a container to pack the explosives and shrapnel.
The use of IEDs by terrorists is a constant threat. Terrorist groups are continuously developing new techniques and tactics in response to defenses and countermeasures established by their opponents. They will disguise IEDs to hinder recognition and will often booby-trap the devices to detonate if disturbed.
The most simple of the IEDs used is the one initiated by closing of a battery circuit, similar to turning on a battery operated light. When turning on the switch closes the circuit, electricity flows to the light so it can be illuminated. As shown in Figure E-1, a clothespin- triggering device in this IED replaces the light switch and when it is activated, the electricity flows to the charge, thus detonating the explosive.
183 Ben N. Venzke and Aimee Ibrahim, Al Qaeda Tactic/Target Brief (Alexandria: IntelCenter/Tempest Publishing, 2002), 11.
184 Conventional Terrorist Weapons (New York: United Nations Office for Drug Control and Crime Prevention,
2002), 4; available from http://www.undcp.org/odccp/terrorism_weapons_conventional.html; Internet; accessed 12 November 2002.
Cryptography
Nearly two thousand years ago, Julius Caesar sent hand written orders for an attack to several of his legions. The messages were hand carried by runner. One of the runners was subsequently captured but the enemy could not make any use of the message because they could not understand it. The enemy soldiers encouraged the runner to explain the meaning of the message, however he did not know its contents and subsequently died at the hands of his captors. All Caesar had done was transpose each letter in the message by a predetermined number of places and the message was therefore unintelligible. Caesar won a great victory that day and the era of encoded messages was born. Historically, this would appear to be the first use of codes on the battlefield and the process became known as the Caesar Code. It was only a matter of time however before all armies were using codes and the emphasis was then placed on code breaking.
Transposition codes of Caesar's type were used for more than two thousand years and became more sophisticated as time progressed but it has only been since the start of WW11 that machines have been used for encoding and encryption. Today, every developed country in the world uses a combination of encoding and encryption to protect sensitive information. It was not until the early 1970s however that civilian businesses began using encryption – up until then, it had been the sole purview of the military.
These days, we can buy encryption software for use on our own PCs to encrypt email to our friends or business colleagues, and large business houses such as the banks routinely use encryption to secure transaction details. The quality of the protection provided by encryption varies widely and is largely dependent on the type of encryption algorithm used as well as the length of the encryption key.
Transposition codes of Caesar's type were used for more than two thousand years and became more sophisticated as time progressed but it has only been since the start of WW11 that machines have been used for encoding and encryption. Today, every developed country in the world uses a combination of encoding and encryption to protect sensitive information. It was not until the early 1970s however that civilian businesses began using encryption – up until then, it had been the sole purview of the military.
These days, we can buy encryption software for use on our own PCs to encrypt email to our friends or business colleagues, and large business houses such as the banks routinely use encryption to secure transaction details. The quality of the protection provided by encryption varies widely and is largely dependent on the type of encryption algorithm used as well as the length of the encryption key.
Saturday, June 30, 2012
Communication system history
1837 –Samuel Morse invented telegraph.
1858 –First telegraph cable across Atlantic (Canada – Ireland) 1876 – Alexander Graham Bell invented telephone.
1888 – Heinrich Hertz introduce electromagnetic field theory. 1897 – Marconi invented wireless telegraph.
1906 –Radio communication system was invented. 1923 –Television was invented.
1938 –Radar and microwave system was invented for World War II. 1950 –TDM was invented.
1956 –First telephone cable was installed across Atlantic. 1960 –Laser was invented
1962 – Satellite communication 1969 – Internet DARPA
1970 – Corning Glass invented optical fiber. 1975 – Digital telephone was introduced. 1985 – Facsimile machine.
1988 – Installation of fiber optic cable across Pacific and Atlantic. 1990 –World Wide Web and Digital Communication. 1998 – Digital Television.
1858 –First telegraph cable across Atlantic (Canada – Ireland) 1876 – Alexander Graham Bell invented telephone.
1888 – Heinrich Hertz introduce electromagnetic field theory. 1897 – Marconi invented wireless telegraph.
1906 –Radio communication system was invented. 1923 –Television was invented.
1938 –Radar and microwave system was invented for World War II. 1950 –TDM was invented.
1956 –First telephone cable was installed across Atlantic. 1960 –Laser was invented
1962 – Satellite communication 1969 – Internet DARPA
1970 – Corning Glass invented optical fiber. 1975 – Digital telephone was introduced. 1985 – Facsimile machine.
1988 – Installation of fiber optic cable across Pacific and Atlantic. 1990 –World Wide Web and Digital Communication. 1998 – Digital Television.
Vehicle-Protection Jammers (VPJs) against radio-controlled improvised explosive devices (`RCIEDs ´)
• Responsive VPJ (VPJ-R)
– With sufficiently fast reaction time upcoming RCIED-trigger signal can be detected and jammed before RCIED can be detonated
Advantages:
(i) Jamming signals are directly al located to potential trigger signals
(ii) Wide bands can be covered without excessive energy consumption
(iii) Even trigger signals at unexpected frequencies can be corrupted
Friday, June 29, 2012
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