Disclosed are techniques for wireless communication. In an aspect, a position determination entity (PDE) receives a request to schedule an on-demand PRS positioning session of a UE at a future time, wherein the request is configured to request a first set of parameters for the scheduled on-demand PRS positioning session, with an availability of one or more parameters of the first set of parameters at the future time being indeterminable when the request is received. PDE determines the availability of the one or more parameters at the future time. PDE determines a PRS configuration for the scheduled on-demand PRS positioning session in advance of the future time.