Hello Warren, thank you for asking my opinion on your . . . . .yes Philippine Ifugao tribe cloth!
Indeed as MAC said there are similar 'blankets' among the Kankanai tribe more on central western side of Luzon and also the Isinai tribe in the middle.
Though the big difference is that the similar looking blankets from those tribes are with WOVEN patterns and yours -from the Ifugao- are with the dificult Ikat method. (Isinai may also be ikat, but their design and used symbols are quite more complicated and they have a center'field')
Your piece is also woven in four 'g-string wide' strokes, indicating the trouble of making this ikattextile.
Among the Ifugao tribe, which are most famous because of their riceteraces and headhunting like most of their neighbouring tribes, the use of Ikat is very restricted to ceremonial pieces related to wedding or death.
I wish I could post some pictures here but still havent master the skill of resizing (each individual) picture.
In the Barcelona Etnological museumcatalogue 'Etnografia de filipinas' (1986) there are two examples of loincloth with ikat; nrs. 119 and 120.
Most blankets one sees of the Ifugao are the so-called 'Bayaong' which are also deathcloth; hung around the deceased to repell bad spirits.
In the last ten years or so I have noticed a revival of the weaving among the tribes, although more among Kalinga. (Perhaps because of the demand Eric Anderson caused with his buying all good and perfect condition textiles!!

)
So your textile could be very old and extremely rare or it could be from the later revival.
To conclude; I am 100% sure of it being Ifugao tribe (Luzon, Philippines)and hope to have been of service to you.
Kind regards, Wouter