Surface Radar and Visual Ranges - Excessively Short

[Elouda]

I've noticed that the detection ranges for both Visual detection and Surface capable radars are VERY short, even in clear conditions.

This is most apparent in the Radar tutorial test mission. Instead of launching the helicopter, send the Halifax to hunt for the fishing boats on the surface.

I routinely get visual detection ranges of 1-2nm, and the SeaGiraffe array gets maybe 15nm.

I can say from personal experience at sea that these are both completely borked; in clear weather you can easily spot things WITHOUT binoculars from a semi-elevated position (say 8m above water) out to 8, even 12nm in the case of large targets. Identification is harder, though rough classification at about 3/4 of that is certainly possible (warship, cargo, passenger liner). With a good set of handheld binoculars spotting range goes up a little, and classification is possible almost as soon as you spot something. I have no experience with large, fixed and stabilised binoculars, but would imagine those to be even better.

Radar is similarly out of whack. Commercial radar sets in the 25-30kW range I've worked with (Furuno FAR-21x7 S/X for reference) can pick out medium/large surface targets (cargo ships, large fishing boats, etc) reliably at over 20-25nm, even in slightly rougher weather (though operator skill and experience plays into being able to pick them out amidst clutter). While I've never had the chance to work with a military grade radar system, I know their capabilities are significantly greater. Not only are they generally much more powerful transmitters, but their signal processing gear is much more sophisticated, and they operate on a range of wavelengths granting greater flexibility. I wont even mention the capabilities of a Phased Array like the SPY-1 with several MW of power.

Now, I've tried to correct both of these through modding, but while I can happily increase the radar detection range on air targets, or from the air to the ground, surface to surface radar and visual in all cases remains extremely limited. I can only guess that something is wrong with the radar horizon/curvature modelling, which is beyond our ability to remedy as modders. I can only assume the game is modelling all radars as being mounted at sealevel, and ignoring radar wave curvature and instead only using line of sight horizon or something, but whatever the cause, this is a pretty serious issue.

EDIT: Interesting, if I swap the SensorType of the 'Visual' sensor to infrared, it suddenly makes detections at sensible ranges (10-11nm). Nothing I do seems to get radars to beyond ~16nm, though I did notice that increasing ship height increased their ranges somewhat, so clearly theyre modelled at some fraction of this. Unfortunately that isnt really a solution since this means larger RCS on targets too. =/

 

[Marder2075]

I think the distance you can see until the beam reaches the horizon is not as far as you think.
http://wiki.answers.com/Q/How_far_from_the_shore_can_you_see_until_the_horizon

 

[Geredis]

Actually, doing the maths, Marder according to that link you sent...I'm pretty sure that the numbers he's given are relatively accurate.

Let's say we go with his 8 metres. That's 8*39 to get 312 inches. Divided by 12 to get feet comes to 26 feet. Add to that six feet for the average person, let's say...32 feet total. That comes to 7 statute miles, give or take according to the formula. Now, 1.15 nautical miles are in one statute mile. Provided I've done my math right, that comes to just shy 8 nautical miles (7.96nm to be exact). Which is the lower end of his range, but still at it. And then once you take into his other factors, 10-12nm for visual identification from various points on a warship (which I'm almost certain are taller than 26 feet) sounds perfectly reasonable with the inevitable visual aids a watchman might have.

 

[Elouda]

When it comes to visual ranges, dont forget that you dont need to see the waterline of the ship youre looking at. Many times at those ranges you might only see half the freeboard on a large cargo ship, but its still enough to tell what it is. At even longer ranges you might only see the bridge or masts on a large vessel, but you know that something is there. In both these cases it looks kind of cool since the ships seem to be 'floating' above the water a little.

The 1-2nm for current visual detection clearly has something wrong with it.

With regards to Radar, I think theres a similar issue; as with visual you dont need to hit the waterline to get a detection. Obviously freeboard is an excellent reflector, but so are most superstructures and masts. So possibly the game is not taking the height of the target into account properly, except for RCS calculations. This is where the difference between a military several hundred kW system and a civilian 30kW one should appear; the civilian system might not be able to get a strong enough return just from the masts or top of the superstructure on a target (or might filter it as clutter), while a military system would, meaning longer ranges. In addition, the curvature seems to be underestimated, especially considering north atlantic conditions which generally result in more deflection due to the temperature gradients.

 

[avee]

Actually, doing the maths, Marder according to that link you sent...I'm pretty sure that the numbers he's given are relatively accurate.

Let's say we go with his 8 metres. That's 8*39 to get 312 inches. Divided by 12 to get feet comes to 26 feet. Add to that six feet for the average person, let's say...32 feet total. That comes to 7 statute miles, give or take according to the formula. Now, 1.15 nautical miles are in one statute mile. Provided I've done my math right, that comes to just shy 8 nautical miles (7.96nm to be exact). Which is the lower end of his range, but still at it. And then once you take into his other factors, 10-12nm for visual identification from various points on a warship (which I'm almost certain are taller than 26 feet) sounds perfectly reasonable with the inevitable visual aids a watchman might have.

I`m sorry for offtopic, but that`s why people invented metric scale.
Meters -> inches -> feet -> statute miles -> nautical miles conversion is ridiculous.

 

[Geredis]

I know, Avee. Sadly, I didn't feel like converting the instructions on the site into metrics. And I know it is quite ridiculous; but again, just following the instructions given once I realised everything was in Imperial.

 

[unmerged(255172)]

The detection algorithm actually uses the top of the spotter and the top of the target, so it should be more in the optimistic side.

 

[Elouda]

Interesting. Still getting horrid ranges with any sensors using the Visual <SensorType> (including non visual methods like electro-optical systems). Swapping to IR rectifies the problem and gives good surface visual ranges. So I would guess something is amiss with the Visual <SensorType>.

 

[unmerged(255172)]

Visual and IR uses the same distance-to-horizon. Make sure you test it in a scenario that has full daylight

 

[Elouda]

I've run the Radar Test Tutorial repeatedly to test this. I swapped the closest fishing boat for a Tanker. I tested it at both 1300 UTC and 1700 UTC as I wasnt sure if you guys account for timezones/daylight differences.

In both cases cases (with Radar off), first detection is by ESM at ~20nm, followed by 'IR Visual' at ~12nm and lastly 'Visual Visual' at 2nm. Radar generally gets a detection at ~17-18nm.

I can post screenshots if you'd like.

 

[unmerged(255172)]

Thanks. We'll go through the details and check it out more carefully.

The "visual" sensor all non-sub units have are meant to simulate the eyes of the crew. There are clear limitations to what size objects humans can see against the sea. We haven't added any electronic optical sensors, though obviously that is a good idea to add.

 

[Elouda]

Thanks. We'll go through the details and check it out more carefully.

The "visual" sensor all non-sub units have are meant to simulate the eyes of the crew. There are clear limitations to what size objects humans can see against the sea. We haven't added any electronic optical sensors, though obviously that is a good idea to add.

Thanks for the response. I understand thats what their meant to represent, but the ranges on big targets just dont match with personal experience doing precisely that. Not to mention that most navies have vision test requirements for deck crew, and anyone who fails to spot a 332m Tanker (siruisstar) until 2nm most certainly does NOT meet those requirements. I could understand a Skjold or Hamina maybe being hard to spot, but a tanker or large warship? Those are going to be visible the instant they cross the visual horizon to any dedicated watchman.

 

[unmerged(255172)]

Clearly. Will check what is going on