Digital radar
A digital radar (Digital Radar) is the radar which does not need mechanical swing movement in the thing with a large number of small antennas on the plane, and the signal of all antenna elements is processed by digital control.
It is the radar which composes an electric wave by controlling phase of the electric wave to emit from the small antenna of the majority who set it not moving an antenna in top and bottom right and left like a conventional radar physically into a plane and a curved surface form each by a digital circuit, and scans space.
Table of contents
Good and bad points
Good point
- Mechanical driving means is not necessary
- Reliability increases
- Maintenance becomes relatively easy
- I am not bound by physical movement speed
- I can scan space at high speed
- I can scan plural aims, scanning level at the same time
- I can choose a variety of movement modes by software
- There is long-windedness to the unit of the antenna element unit
- Can just use even several trouble without loud degradation; is reliable
- The exchange repair by the unit unit is possible
- The unification with other digitized battle information appliances becomes easy (if for military affairs)
- Future development allows the placement of the antenna element to the curved surface
- The placement place of the antenna part does not spoil = (by warplane) stealth bomber characteristics becoming relatively free (by plane)
- Antenna placement to point to all 360-degree laps (by plane) including the rear becomes relatively easy (conformal array antenna)
- A nose part becomes available for other uses (by plane)
Bad point
- A high development technology is necessary.
- It becomes high-priced, and the damage to an antenna extends to an active voice element and the passive element.
- I am at risk of the reliability drop due to the complexity including the bug of the software.
Classification of the array-type radar
The digital radar is a kind of the array-type radar and shows below the classification of those array-type radars.
- Phased-array radar
- Passive expression
- Active expression = active electronic scanning array (AESA, Active Electronically Scanned Array)
- Digital radar
The theory of the array-type radar is reference in Huygens principle.
- Passive expression (phased-array radar)
- Each backside of the small antenna is provided with the mechanism called the phase converter (Phase shifter) adjacent to the wave guide of the role to distribute an electric wave and moves phase of the thing that I put together to each antenna while these distribute the electric wave from only one electric wave transceiver. The reception of the passive expression only becomes the opposite direction of the transmission.
- Active expression (phased-array radar, AESA)
- Each of the small antenna possesses exclusive frequency changer or a transceiver. The individual digital control of the transceiver is not performed.
Digital radar and AESA separate a transmission wave and a reception wave by a circulator (Circulator). MMIC (Monolithic Microwave Integrated Circuit) is used in a digital radar and a high frequency generator and a high frequency receiving device of AESA and frequency-converts it. A digital radar possesses digital - analog and a converter of analog - digital every each unit [1].
High function
You must receive it during uniformity during the reception time for electric wave reflection from the space targeted for exploration to detect it by one radar wave beam even if it is a phased-array radar. For example, you must maintain the reception state of the uniformity direction only at the time when a 200km electric wave goes ahead through the large in gas to receive a reflection wave to 0m - 100km ahead and cannot perform the reception from other directions during 200km ÷ 297,600km/sec = 0.672 msec. The transmission is possible the other day. By the digital radar, I make use of high flexibility by the digital control and am said to be it when I can realize a high function not to be able to perform in other phased-array radars.
Use of division
I divide the antenna element which there is a lot into the group of two and three by the digital radar and can let the different direction point to each, and reception, one of the emission signal from an enemy aim are appropriated to the use such as the instruction of plural friend missiles with wide area exploration, one with one at the same time. However, if the antenna number of elementses to create one radar wave beams decrease, only it opens without being able to narrow down a beam, and detection precision decreases.
Communication
I can perform the communication with friendly forces by submitting abnormality by the electronic intelligence to a radar wave.
Attack by the high output radar wave
It is said that I transmit a radar wave of the big electric wave output to the electric wave sensor of the enemy and sometimes the human body by controlling the transmission output and can give you an obstacle.
Conformal array antenna
The conformal array antenna (Conformal array antenna) is an array antenna located along the curved surfaces such as the body shells of the plane.
The emission, reception properties of the antenna element are array antennas using plural antenna elements to vary according to an angle and they change the electric wave gain (gain) by the installation angle of each antenna element and must calculate.
Source
- ^ military affairs study September, 2007 issue "U.S. air force "next-generation aerospace force" new model LRS bomber & pole super sonic speed weapon P.123-p.146 of the 21st century"
Allied item
This article is taken from the Japanese Wikipedia Digital radar
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