GNSS reflections and GPS bistatic radar in particular, has become a popular topic in the GPS community mainly because of the multitude of new exciting applications it provides. The concept was discovered by accident by a French research group in the early 90's and since then researchers all over the world have exploited the fact that GPS signal reflections are strong enough to be useful for remote sensing applications. In the past GPS receivers have been converted to GPS Bistatic Radar Receivers capable of receiving the reflected GPS signals. Modern receivers for GPS bistatic radar are typically very expensive custom built instruments or fast sampling receivers which store digital samples for post-processing. Since there are no commercial off the shelf (COTS) receivers available, research groups either have to let someone else collect data for them or they are stuck with the challenging task of designing their own receivers. Most attempts to design a receiver fail because the task is outside the scope for most GNSS research groups. It is safe to say that designing a GPS bistatic radar receiver is a cross-disciplinary task which requires in-depth knowledge of the GPS system as well as digital receiver design. This paper is an attempt to give an overview on the GPS bistatic receivers that are currently in use and to discuss parallel re-configurable receiver architectures suitable for implementation in Field Programmable Gate Arrays (FPGA).