Synthetic Aperture Radar *SAR) and Inverse Synthetic Aperture Radar (ISAR)

choi

I have done extensive research on synthetic aperture radar (SAR).
(a) SAR
(i) The aperture is called synthetic, because it is man-made, by moving the radar for a distance (on, say, an airplane).
(ii) The English noun overture -- spelled the same in Middle English and when (earlier) first introduced from Anglo-French (spelled the same) into English "mid-13c, [then defined as] 'opening, aperture.' "  
https://www.etymonline.com/word/overture

Before that (Anglo-French), it was Vulgar Latin overtura, "alteration of Latin apertura."  Merriam-webster.com for overture.
(iii) What is Anglo-French language?

Jacquie Heys, French as a Mother-Tongue in Medieval England. In CE Percy (ed), he English Language(s): Cultural & Linguistic Perspectives. Department of English, University of Toronto, 2000
homes.chass.utoronto.ca/~cpercy/courses/6361Heys.htm
("Norman French was distinct from Parisian or Continental French, and, with time, the French spoken in England by the Norman landed gentry became distinct. Scholars refer to the particular dialect of French as spoken by England-dwelling native French speakers as Anglo-Norman or Anglo-French")

(b)
(i) SAR is a radar mounted on a moving (traveling) platform to discern a stationary object (target). On the other hand, inverse synthetic aperture radar (ISAR) uses a stationary radar to discern a moving object (target).
(ii) inverse
(adj): "[attributive]  opposite or contrary in position, direction, order, or effect  <numerous studies have shown an inverse relationship between exercise and the risk of heart disease>"  (brackets original; "attributive" means the adjective is before a noun, ie, not predicative)
(n): "[usually in singular]  something that is the opposite or reverse of something else  <power is the inverse of dependence>" ((brackets original)
https://en.oxforddictionaries.com/definition/inverse
(iii) Radar, especially earlier ones (in time), may detect an object. But many types of modern radars are sophisticated enough to include ISAR to have a reasonable 2-dimensional resolution of the object in question.

(c)
(i) Both Taiwan's 北斗干擾車 and "中国像竹竿一样插在地上的国产稀布阵综合脉冲孔径雷达" are in fact ISAR, because the the respective radar is stationary, with moving object/ target.
(ii) The best I can find about the latter is 张强, 米波雷达火眼金睛 隐身飞机无处遁形. 科技日报, Apr 4, 2018
http://www.xinhuanet.com/mil/2018-04/04/c_129844005.htm
(French acronym RIAS corresponds to English "Synthetic Antenna and Impulse Radar"

China, including its news media, has published nothing on this topic in English.
(iii) But "中国像竹竿一样插在地上的 * * * 雷达" is, in jargon, "antenna array."

(d)
(i) Synthetic Aperture Radar. In Radar Basics. Radartutorial.eu, undated
www.radartutorial.eu/20.airborne/ab07.en.html

Quote:

"The SAR works similar of a phased array, but contrary of a large number of the parallel antenna elements of a phased array, SAR uses one antenna in time-multiplex. The different geometric positions of the antenna elements [in SAR] are result of the moving platform now.

"SAR radar is partnered by what is termed Inverse SAR (abbreviated to ISAR) technology which in the broadest terms, utilizes the movement of the target rather than the emitter to create the synthetic aperture. ISAR radars have a significant role aboard maritime patrol aircraft to provide them with radar image of sufficient quality to allow it to be used for target recognition purposes.

* View Picture 1 where ISAR demonstrates a profile of a ship in movement.
(ii)
(A) phased array
https://en.wikipedia.org/wiki/Phased_array
("a computer-controlled array of antennas which creates a beam of radio waves that can be electronically steered to point in different directions without moving the antennas" with phase controlled by a device called phase shifter)

Click "array of antennas" will lead to a Wikipedia page for "antenna array."
(B) phase (waves)
https://en.wikipedia.org/wiki/Phase_(waves)