August 15, 2018

HPS-106 Radar Issues on the Japanese P-1 MPA

The nose of the Japanese P-1 maritime patrol aircraft houses the main Toshiba/TRDI HPS-106 active electronically scanned array (AESA) search radar. Source: j-hangarspace.jp

Photos and descriptions (above and below) are reproduced on a Thai Military and Asia Region article https://thaimilitaryandasianregion.wordpress.com/2015/10/15/japan-kawasaki-p-1-patrol-aircraft/


The HPS-106 side-looking radar array is housed beneath this panel just below the cockpit.  Source http://daisetsuzan.blogspot.com/2016/01/kawasaki-p-1-maritime-patrol-aircraft.html
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PETE COMMENT

Desmond Ball and Richard Tanter's, The Tools of Owatatsumi: Japan’s ocean surveillance and coastal defence capabilities, ANU Press, 2015 Chapter 10 Airborne Ocean Surveillance especially page 82 provides context on Japanese maritime search developments. This includes the HPS-106 search radar, which, when mounted on Japanese P-1 maritime patrol aircraft (MPAs) can search for surfaced submarines (maybe periscopes?) and surface ships, as well as find lost boats. Presumably the US built Poseidon P-8 MPA has radars of similar capabilities.

ARTICLE

wispywood2344 on his/her Japanese website, which translates as Remembrance of Chiba Silver Pigeon, has written a fine article, dated April 19, 2018, on the number of antennas and coverage of the HPS-106 search radar used on Japanese P-1 MPAsHere is part of the article:

"Currently, the Japanese Navy is proceeding with the deployment of the Kawasaki P-1
MPA as a successor to the P-3C Orion patrol aircraft. The P-1 was developed domestically at the same time as the Kawasaki C-2 transport aircraft

The "HPS-106" search radar was developed as a multifunctional radar system to be mounted on the 
P-1 patrol aircraft I was told.

This HPS-106 has multiple active electronically scanned array (AESA) antennas as antennas for 
transmitting and receiving radar waves. By sending the waves in separate and precise directions 
vessels can be located in a patrol area.

Regarding the number of equipments and coverage of the AESA antenna:

  A total of 4 AESA antennas are installed in each of the front, rear, left and right sides of the 
fuselage, and the entire circumference of 360 degrees in front, rear, right and left of the
fuselage can be scanned

  There are blind spots behind the aircraft because the AESA antenna is equipped only with a total of three sides and the rear of the aircraft is unable to be scanned

There are various ways to find more information, including the Internet:

(In an English-speaking website, it is common to see articles with "Wide area scan with 4 AESA equipments" as Wikipedia English version of P-1, but there are no articles with citations listed. The sources are unknown.)

Since the HPS-106 is an equipment of the Japanese Defense Force, in order to investigate further, it is nncessary to read official publications of the Ministry of Defense...[Several Tables with descriptions in Japanese follow]

WISPYWOOD2344's WHOLE ARTICLE (IN JAPANESE) IS HERE.

2 comments:

Josh said...

@Pete:

The USN actually uses a mechanically scanning radar, the APY-10. The reason for this is supposedly because rapid mechanical scanning was found to be superior specifically for periscope detection. The rotator moves so fast in its housing that it is actually stored inside a vacuum sealed sphere:

http://www.navyrecognition.com/images/stories/news/2015/june/Raytheon_AN_APY-10_radar_P-8A_Poseidon.jpg

https://en.wikipedia.org/wiki/AN/APY-10

This presumably means a degradation of most other radar modes compared to an AESA set like in the P-1. In the context of USN usage, this is probably an acceptable trade off for periscope detection, both because ASW of D/E boats is a high priority and because the USN envisions their MPAs working with a MQ-4C orbit which would handle long detection and ID of surface traffic.

The P-8 is also slated to be able to be fitted with the APS-149 Littoral Surveillance Radar System which previously was carried by a limited number of P-3Cs for overland use in Afghanistan. This sensor is more of a JSTARS level installation and in fact P-8/APS-149 is being pitched as an off the shelf JSTARS replacement.

Cheers,
Josh

Ztev Konrad said...

There seems to be some suggestion that the AESA radar can only cover 3 sides. However all sources say that there is 4 antennas which give 360 degree coverage. Close up photos show the side panels beneath the cockpit windows, however the front and rear antennae arent normally so visible. The forward is behind the nosecone fairing, which may contain other sensors and the rear antenna is under the tail just before the MAD boom. The need to consider aerodynamic effects means front and rear antenna dont have externally visible flat plates but they do exist behind the shaped die-electric covering
http://www.heinkel.jp/yspack/ysf_p1_eng.html
https://thaimilitaryandasianregion.wordpress.com/2015/10/15/japan-kawasaki-p-1-patrol-aircraft/
https://www.naval-technology.com/projects/kawasaki-xp-1-maritime-patrol-aircraft/

I have serached for but cant find a better close up of the rear AESA fairing