Symapthies OP.
Our dog occasionally does this. It's usually when something has changed about her routine, or prior to being speyed, when she was coming into season.
What worked for us was treating it as a night waking for a naughty toddler. I worked out that she did because DH used to come down, look out of the window with her, stroke her to calm her down, then if that didn't work and she barked again, lay down on the sofa with her.
If I went down I would check to see if she was actually barking at a burglar or someone lurking around, let her out back to 'check', give her a fresh drink to settle her, then make her bed comfortable again.
So she was getting lots of fuss and attention.
So I stopped DH going down, I came down, shut the curtains so she couldn't look out, let her out for a wee with minimal fuss then just say 'bed'. If I had to come down again I just pointed to her bed looking cross.
It worked for us.
Also making sure she was really tired, so in the day a big, long walk. Then a shorter one at teatime, lots of garden time. And walking her different places as well.
It's very tough. They do learn that barking gets attention pretty quickly. Ours barks when she wants something. She's not yappy but if she thinks it's her walk time, she barks at me. If she wants fresh water (she likes it changed hourly it seems) she barks, wants some scraps from plates she barks. So for us the night time barking.was because she didn't want to be in bed, she wanted us with her.
She does occasionally bark at noise outside. We live opposite some shops so occasionally if they have workmen in at night we leave the tv on low to drown out the noise.