how is it different to TOA (e.g Blitzortung)
Apparently not at all.
I would suggest quire a bit of difference... Blitzortung uses GPS timing and location, is controlled and sampled digitally, after Wide Band impulse energy reception and filtering.
Sfericc location is by TOA and TOGA calculations, not triangulation... Today's system controller comes mostly assembled utilizing SMD technology,
The system is NOT plug'n'play and not for dilettantes. It's a serious citizen science network, though classed as 'hobbyist' and 'experimental'.
Here's a wall of three production series Blitzortung Controllers operating in various modes with up to 14 channels of information 3 to 300kHz
E, H(M), Positive, Negative with various H (M)antenna types and E Probe sensing.