How Russia is avoiding detection with its strikes from the skies above Ukraine

There's a veneer of normality to life in Ukraine's major cities if you ignore the air raid sirens, the booming sounds of anti-aircraft fire, the threatening buzz of drones passing overhead, and the darkened streets of neighbourhoods taking their turn as part of rolling power cuts affecting all of Ukraine.

As I say, if you ignore all of the above it's fine, and many people do.

Kyiv appears particularly normal. Shops and restaurants are open, I'm told theatre performances are sometimes sold out, and at times you can still see families taking photos in front of the capital's exquisite churches and cathedrals.

Late at night though, the city starts to change.

In the past few days, mostly throughout the night, air raid apps have been lighting up with warnings to "seek shelter", while the sound of the sirens pierces the still and freezing air of the city.

From different directions I watched the anti-aircraft batteries tracking and following Russian drones swarming over Kyiv in unprecedented numbers - the tracers from their machine guns shooting into the night skies and ominous orange glows in the distance from possible missile strikes.

The capital is being targeted as never before, so much so that the military has assigned special anti-air units particularly for the defence of Kyiv.

Attacking this city is partly a Russian tactic to wear its population down and create fear and uncertainty.

But many of its drones and missiles are targeting the country's energy infrastructure. Russia wants to switch the lights out here and, if possible, literally freeze this people's resistance.

A necessity, rolling blackouts are the norm now while engineers repair power stations and supply lines. Power producing capacity is already limited after years of targeting, and as the temperature drops the authorities must save wherever they can.

For families the threat of attack from the skies never goes away

I drove through the streets of Kyiv's left-bank suburbs, darkened apartment blocks silhouetted against the city's skyline.

The dimly lit lights inside apartments are provided by generators or car batteries hooked up to makeshift electrical circuits tacked on to walls and ceilings.

Alona emerged from the doors of her apartment building into a pitch-black car park, her torch glinting off the remains of the first snows of winter, now turned into ice.

I followed her up three flights of stairs into her apartment and was introduced to her husband, Yevhen, and their two-year-old, Oles.

For families in particular, the threat of attack from the skies never goes away. In many ways it is psychological warfare, and Alona said it's taking its toll on her and her little boy Oles.

"The hardest part, by far, is at night when you're putting your child to sleep in the bathroom or when you have to rush to the shelter in the middle of the night. It's really tough because it disrupts the child's routine," she explained.

"He doesn't get proper sleep, everything is upside down for him, he's terrified and he had started to become scared of the alarms."

'It's still deeply frightening to be in the open'

Alona talked me through how her family tries to work out the risk of a strike in their area when the air raid sirens go off, and then they make a decision whether or not to seek shelter accordingly.

This family is typical of thousands here - scared to stay at home and scared to go out.

"I saw a missile being shot down and let me tell you, it was terrifying," Alona said.

"It's a haunting experience, even though I'm standing here now, telling you about how we 'measure' the scale of the danger, it's still deeply frightening to be in the open."

The soldiers who do their best to track Russian drones

After travelling to see the family, I went to meet an air defence mobile group belonging to the National Guard. I followed them on to a frozen field where they set up to man their position in the dark of night and sub-zero temperatures.

They are just a handful of hundreds, even thousands, of soldiers across the country doing the same.

These men, led by their commander Serhii, do their best to track the incoming drones with radar and use large spotlights to search the skies when they believe a Russian drone is nearby.

'The enemy is changing tactics'

Russian tactics have changed though. As many as half are harmless decoys designed to waste time and bullets. The other half are deadly.

"The enemy is changing tactics, trying out different manoeuvres," Serhii told me.

"They are attempting to approach in groups at low altitudes to avoid detection by radar, some targets fly high and are visible on radar, while another group flies low and slips past air defence systems."

He showed me a Ukrainian-developed program on a tablet that tracks and monitors the movement of drones and missiles.

"Here it shows the movement of aerial targets in real-time within our zone of engagement," he explained, pointing at a swarm of drones on his screen flying over Ukrainian territory.

People try to carry on as normal as attacks increase

Whether Russia's main tactic is to target energy infrastructure or to sow fear, or both, nobody really knows. What they do know is that the attacks have increased.

"I cannot say the specific [reason for] that, whether it's just the terror to make people feel unsafe and create [an] unstable situation or it's some kind of facilities they're trying to target, but they are operating, it's like regular," Pavlo Yurov of the National Guard's "Hurricane" brigade told me.

Beneath the National Guards' rudimentary dome of protection, people try to carry on with life as staff in restaurants and shops dress Christmas trees and hang fairy lights, but this war is grindingly depressing for everyone.

Young men fear being drafted, many hide out of sight. The news from the eastern front lines is never good, the Russians are taking more land.

Another Christmas is coming and like the last two it will likely pass without any sign of peace.