A Global Navigation Satellite System (GNSS) receiver demodulates code shift keying (CSK) data utilizing a binary search. The GNSS receiver receives a signal including a pseudorandom noise (PRN) code modulated by code shift keying (CSK) to represent a symbol (i.e., CSK modulated symbol). The GNSS receiver maintains a plurality of receiver codes each representing a different shift in chips to the PRN code. The GNSS receiver performs a linear combination of portions of the receiver codes. In an embodiment, the GNSS receiver compares correlation power level value for respective portions of the receiver codes to demodulate the CSK data. In a further embodiment, the GNSS receiver compares the correlation power level values for portions of receiver codes with power detection threshold values to demodulate the CSK data. In a further embodiment, the GNSS receiver utilizes signs of the correlation power level values to demodulate the CSK data.