I would have to think it is an early Hagglunds bandvagn given the articulated steering. You can see that the "trailer" or rear carrier is an integral part of the machine. You can see there is a driveshaft connecting it to the front carrier Volvo power unit that powers the rear set of tracks. Also the cables you can see in the photos provide the articulation that steers the unit as a whole.
The more modern hagglunds, eg. BV-206 have a very similar articulated steering system, the main difference being that the steering unit uses hydraulic cylinders to force articulation of the two carrier sections as opposed to cables. Maybe someone more knowledgable can tell you for sure what it is, but my money is on Hagglunds. Looks like a neat piece of snowcat history to me.
Cheers - Paul