Doggie Kruger is DekaMaster, the mentor of the 28th Super Sentai team, the Tokusou Sentai Dekaranger. As mentioned in the pamphlet for the 35th anniversary movie, Gokaiger Goseiger Super Sentai 199 Hero Great Battle, Doggie is good friends with Gavan.
The friendship betweeen Doggie and Gavan is presumably a reference to the fact that Dekaranger had several homages to Metal Heroes. The "Tokusou" in the name, the narrator who repeats the same description every single episode (and was once self-parodied in the show), and a birdman in charge of the organization are all references to Metal Heroes, especially the Space Sheriff shows.
- Doggie Kruger at the Power Rangers/Super Sentai Wiki