what is the best altitude for a UAV?

[Wasicun]

Hi guys, what is the best altitude for an UAV?
Let's say: American RQ-180
Task: locate and identify russians tanks, russians have good SAMs too (let's say S300)

What is the best speed/altitude?

(is importanto to remain stealth too, not only find the enemy's tanks)

Thank you for your answers, sorry for my poor English.

Greetings

[Rory Noonan]

As a general answer it depends on the sensors, weather and threat environment.

Good sensors mean you can fly higher and have a wider scan range, requiring less time to scan an area of a fixed size; also meaning that you can have a higher certainty of detecting items of interest by flying over them.

Weather (esp. cloud cover) often dictates how high you can fly. If the cloud ceiling is 12,000 feet and you have visual sensors only, then 12,000 is the maximum practical altitude. Rain decreases radar performance and visual performance too if it's heavy enough. Not sure about temperature.

Threat environment may have the biggest impact on the 'best altitude'. In a totally benign environment, you can fly at whatever altitude suits the sensors and weather best with no worries of being detected or destroyed. In a high threat environment it's likely a drone won't get close to the targets without being destroyed.

As for your specific question, the RQ-180 has the AN/ZPQ-1 TESAR radar, an LLTV and FLIR. The radar with a range of 60nm needs to be at 2382ft to have a radar horizon of 60nm to make full use of the radar, and the LLTV/FLIR tend to work best at relatively lower altitudes. According to the db for the SA-23b it has a minimum engagement altitude of 3200ft... So I would say in your example the best altitude would be 2500-2800ft to make best use of the TESAR radar and stay out of the SAM engagement envelope. You'll probably get detected by hopefully won't get shot. The best speed would be as fast as possible to GTFO of there as soon as possible [:)]

[Tailhook]

Also look at the detection range for whatever you're looking for. Using a UAV to find, say, infantry often requires it to be much lower than it's maximum altitude.

[Wasicun]

Thank you very much for your answers

[Sardaukar]

One thing that I always forget is the level of cloud cover.

That can really screw up drone, since clouds are pretty good in blocking optical sensors and some IR gear too.

But be prepared that heavy clouds and flying above is going to degrade drone sensor abilities.