1.5m across the base will mean you only have around 75cm height (if, indeed, it is a semicircle); is that enough?
Another option is one of them pop up style tents.
No to the pop up tent.
Firstly, they are vile, horrible, things.
Secondly, they are a waste of money - I already have a poncho.
Thirdly, a bloody nightmare to put away at the best of times and even less so in bad weather.
Fourthly, I doubt their waterproof abilities.
Fifthly, they are heavier and bulkier than a poncho and a separate pole.
Sixthly, a poncho can also function as a waterproof when I am walking.
Seventhly, (because it's worth repeating for emphasis) they are vile, horrible, things.
Point made.
as in post #18 you mean?
But, I think, it is worth repeating