A signal based algorithm resulting in increased depth resolution is presented for medical ultrasound. It relies on multiple foci beamforming that is enabled by current ultrasound imaging systems. The concept stems from optical microscopy and is translated here into ultrasound using the Field II simulation software. A 7 MHz linear transducer is used to scan a single point scatterer phantom that can move in the axial direction. Individual beamformer outputs from 3 different foci are post-processed using the highly-dependent on focusing errors, metric of sharpness to estimate the position of the point scatter. A 37.8 μm uncertainty in depth estimation is achieved, which attains an almost 3-fold improvement compared to conventional ultrasound imaging axial resolution. Future work on the development of this algorithm requires experimental validation in tissue-like materials that provide strong aberrations.