different Radar settings - same detection range

[VTJS17_Fire]

Hi Zeus,

 

I did a test for internal evaluation of the M-2000C in our squadron and am bewildered. Because, no matter how I set my Radar, I get the same results in target detection. Here's the test:

 

What I testet:

Detection range on fighter sized targets, with constant speed at level (same altitude)

 

 

Target Data:

 

• target is a fighter-sizde target, here an F/A-18C
  
• target is closing with a constant speed (500 knots ground speed)
  
• target ist on the same altitude (here 25.000 ft. MSL)
  
• target doesn't maneuver, aspect-angle is 180° ("hot" or "high aspect")
  

 

How I testet:

All tests were testet with high PRF, scope at 80NM and TDC at 60NM.

 

 

• Azimuth 60°, 4 bar
  
• Azimuth 60°, 2 bar
  
• Azimuth 60°, 1 bar
  

 

• Azimuth 30°, 4 bar
  
• Azimuth 30°, 2 bar
  
• Azimuth 30°, 1 bar
  

 

• Azimuth 15°, 4 bar
  
• Azimuth 15°, 2 bar
  
• Azimuth 15°, 1 bar
  

The result is always the same, no matter with which setting I tested: 47NM.

 

 

But should not a tighter cone (Radar azimuth) and a higher scanning frequency(bar) increase the detection range? With a smaller cone, I concentrate more energy in a smaller field which increases the Radar returns of objects in that area. With the results above the different changes on the VTB are useless.

 

Even the F-15C simulates that differnces in Radar settings. There, I can't set the bars, but the Radar azimuth. And in the F-15C, it matters in terms of detection range.

[myHelljumper]

If this is realistic, it should be implemented. The radar is superb as it is but the bar and cone width selection are useless right now.

[microvax]

Well, kinda depends on how the radar works.

 

For PRF this is very much true, HPRF has a way bigger detection range then lower PRF, due to the much higher duty cycle.

 

For bars and azimuth it gets tricky and is largely dependant on the algorithms used by the Radar computer.

 

But let me cite the manual

"The manufacturers claim that RDI will detect 90% of 5m² RCS fighter-sized targets out to

66 nmi (122 km) in clear air using a four-bar search pattern over 120° in azimuth, and 60

nmi (111 km) with a single-bar pattern over 30° in azimuth, dropping to 50 nmi (93 km) in

pulse-Doppler look-down mode."

 

In general, less azimuth doesnt necessarily mean higher energy density in a way that matters for range.

If the antenna speed is decreased, then yes, the radar will paint the target for a longer time per echo, so the return will be bigger, which can possibly result in a higher range.

If its the same antenna movement speed is the same as with a bigger azimuth, well, the energy density is higher, but each return has the same strength as in a bigger azimuth setting, so you get higher refreshrate => better track.

But again, it highly depends on how the Radar Computer handels stuff. So we kinda have to depend on what le manufacturer claims unless someone can get a RDI radar Computer and reverse engineer its programming ! :D

Edited October 24, 2016 by microvax