The transmission power and position of the primary user in cognitive radio(CR) is very precious information because these information of the primary user determines the spatial resource. This opportunistic spatial resource is available to secondary users to exploit it. To find position of the primary user, we try to use existing positioning or localization schemes based on ranging techniques but those require the primary user’s transmission. Since most primary users in CR are legacy system, and there are no beacon protocol to advertise useful information such as transmission power. Some of existing localization schemes don’t require the transmission power, but those don’t work in Outer case that the primary user is out of convex hull of secondary users’ coordinates. We propose the constrained optimization method to estimate transmission power and position without the prior information of the transmission power. Also, we do extensive simulations on two major cases of network deployments to prove that the proposed constrained optimization method increases performance in mean square error(MSE).