Beamforming with directional sensors
Given the horizontal and vertical component of the distance vector from the source to the sensor array be X and Y, then the angle between the sensor array and the source is given by:
$$ \theta = \tan^{-1} (Y/X) $$ 

If the linear distance between each sensor is $d$, each sensor should experience a delay:
$$ \delta t = d \sin(\theta)/c $$

Now if you can measure the delays (high precision measurement will lead to higher accuracy), and have the knowledge of $d$, you can find the angle $\theta$. 

Warning: Practical errors and considerations are not taken into account in this approach.