Back in 1993, Tsuburaya Productions, the creators of the Ultraman franchise, created a non-Ultra toku show called Denkou Choujin Gridman. The show is currently available with subtitles on TOKU and Amazon Prime. However, it's probably best remembered for being adapted by DiC Entertainment into Superhuman Samurai Syber Squad (yes, that's 'Syber' with an 's') in an attempt to cash in on the Power Rangers fad.
Roll on fifteen years, and it's back in the form of an anime 'reimagining'! No it's not a reboot - the story is very different. Although yes, the "SSSS" in the title is a nod to the American adaptation of the original. Studio Trigger previously created the Gridman short for the Japan Animator Expo project. Voice actor Hikaru Midorikawa, who provided the voice of Gridman in the original toku, has returned to reprise the role again.
Also, it seems that the staff working on this show are massive Transformers fans, and a large proportion of the characters have colour-schemes and clothing details that pay homage to various (often really obscure) Autobots and Decepticons.