Submarine Detection

[StrikeHard]

Hi,

Anyone can tell me how to calculate submarine ESM and Early Warning RADAR detection ranges for nil, low, medium, heavy rain condition and also for different sea tide conditions ? if you can give equation or any link which helps to find out this will be great . I have another basic doubt how the ships are detecting targets for away (beyond radar horizon)?

Thank you.

[Deamon]

A book on electronic warfare would be the way to go!

[StrikeHard]

I have just got Introduction to Radar Systems by skolnk and i am reading it. Thank you for your advice, i will have a look on electronic warfare books too.

[Deamon]

The one that i have is "Introduction to Electronic Defence Systems" by Filippo Neri

About 530p. Goes through pretty much all subjects, is well illustrated and also comes with lots of formulas. I think there are even more comprehensive treatments of this subject than this. But it's a very good start.

Originally Posted by StrikeHard

I have another basic doubt how the ships are detecting targets for away (beyond radar horizon)?

Well, different radio frequencies are being reflected by one of the upper atmosphere layers of the earth. So what you do is to direct the radar antena somwhat upwards and use the upper atmosphere(i think it was the ionosphere or something) as a mirror for the radio waves to get behind the horizon. But i think this requires special radars or something.

[StrikeHard]

Originally Posted by Deamon

The one that i have is "Introduction to Electronic Defence Systems" by Filippo Neri

About 530p. Goes through pretty much all subjects, is well illustrated and also comes with lots of formulas. I think there are even more comprehensive treatments of this subject than this. But it's a very good start.

Thanks for reference. i will try to have look.

Well, different radio frequencies are being reflected by one of the upper atmosphere layers of the earth. So what you do is to direct the radar antena somwhat upwards and use the upper atmosphere(i think it was the ionosphere or something) as a mirror for the radio waves to get behind the horizon. But i think this requires special radars or something.

I am read some where like they use low frequency waves to detect long range targets because low frequency wave can bend across the earth more than the high frequency signals.

[Deamon]

Originally Posted by StrikeHard

I am read some where like they use low frequency waves to detect long range targets because low frequency wave can bend across the earth more than the high frequency signals.

Never heard of that.

[CTarana]

Originally Posted by Deamon

Never heard of that.

Wikapedia:" The most common method of constructing an OTH radar is the use of ionospheric reflection. Given certain conditions in the atmosphere, radio signals broadcast up towards the ionosphere will be reflected back towards the ground. After reflection off the atmosphere, a small amount of the signal will reflect off the ground back towards the sky, and a small proportion of that back towards the broadcaster. Only one range of frequencies regularly exhibits this behaviour: the High Frequency (HF) or Shortwave part of the spectrum from 3 – 30 MHz. Given certain conditions in the atmosphere, radio signals in this frequency range will be reflected back towards the ground. The "correct" frequency to use depends on the current conditions of the atmosphere, so systems using ionospheric reflection typically employ real-time monitoring of the reception of backscattered signals to continuously adjust the frequency of the transmitted signal. Given the losses at each reflection, this "backscatter" signal is extremely small, which is one reason why OTH radars were not practical until the 1960s, when extremely low-noise amplifiers were first being designed."

ChristopherT