Hi, I hope someone can help me figure out the solution to this problem. I have four ultrasound receivers positioned along two axis. These are the black dots on the blue and orange lines. From these I get a pair of distance measurements a & b from the origin. From these I want to work out an intersection position x,y.

The axis of the receivers is fixed at the angle A= B from the X,Y plane. Should be easy, but my trig is so rusty and I'm so much more concerned with the electronics I hoped a maths guru could point me in the right direction!