Altitude for fixed wing ASW patrol

[donaldseadog]

Lets take something like a P8 Poseidon, it will fly 'low' to drop sonar bouy, but in between bouy drops will it normally remain low or climb to a medium alt to gain a better theatre eyes view? Any one know what the usual practice is here? I'm thinking of altering the Toolbox ASW patrol for fixed wing ac to give better detection of surface vessel.

[eeustice]

One of the limiting factors would be how far the Sonobuoy can transmit data to the processing equipment on the aircraft. To process data from a sonobuoy field the AC would have to fly at an altitude to receive data from all the buoy's.

An article I just came across says that a Sonobuoy from as high as 30,000 feet.

https://dosits.org/galleries/technology-gallery/locating-objects-by-listening-to-their-sounds/difar/

Here is another article on Sonobuoy's:

https://www.militaryaerospace.com/sensors/article/14283490/antisubmarine-warfare-asw-sonobuoys-underwater-sounds

Here is an article on how the whole process for detecting a sub works:

https://nps.edu/web/slamr/-/disrupting-anti-submarine-warfare-with-autonomous-systems

The lower the AC is to the water the easier it is for the sub to hear the aircraft.

Once a contact has been acquired and the general location of the contact is known only then the aircraft drops down to a lower altitude to get a precise location of the contact wit MAD.

I haven't been able to find out the transmission range to the aircraft of the buoy. That information may not be published for a good reason.

To detect a surface ship you would first look for any electronic emissions. The electronic emissions will be detected long before the ship will be able to detect the aircraft.

Since the noise a surface ship makes is trapped above the thermal layer of the ocean it can travel long distances. The only way to try an localize a surface contact is to use Time motion analysis. A good example for TMA was used in the Hunt for Red October by Sonar Technician Jonsey when he plotted the course of the weird sound. He was able to figure out what the course was of the Red October.

The one unknown factor is what can Harpoon do and can't do. That is the question for TE to try and answer.

[donaldseadog]

Some good points.

In hc the main restriction is that when looking generically at asw you need to be able to loiter\hover at low alt at periodic places in order to drop bouys, lower sonar etc. I haven't tested mad but i seem to think mad will work (when fitted) at medium alt, but this could easy be wrong (and perhaps should be?)

My asw patrols are based on a two ring octogon (or maybe hexagon, i forget) and at each node the unit loiters\hovers for 30 or 60 secs {probably it should be longer) so as to drop sensors. In between these it flies at low alt but I'm thinkng of having it fly medium alt for better electonic visual surveillance

 

[CV32]

On 9/18/2023 at 11:58 PM, eeustice said:

One of the limiting factors would be how far the Sonobuoy can transmit data to the processing equipment on the aircraft. ...

I haven't been able to find out the transmission range to the aircraft of the buoy. That information may not be published for a good reason.

 

Sonobuoys typically transmit via VHF, so there is a practical range of about 20 km.

Much of the fundamentals of ASW is covered by my Tactics 101 piece on the subject.