A method of implementing a real-time screening process for phase scintillation, the method comprising: detecting a phase scintillation event in the ionosphere during a sample time period at a phase scintillation monitor based on satellite measurement data; excluding associated satellite measurement data from further use based on the detection of the phase scintillation event at the phase scintillation monitor; detecting an end to the phase scintillation event at the phase scintillation monitor; readmitting associated satellite measurement data collected after the end of the phase scintillation event as detected by the phase scintillation monitor; characterized in that the method further comprises: calculating satellite motion and SV clock corrected carrier rates (cr _corrected i, j ( k)) for reference receiver/satellite pairs (RR i /SV j) for which accumulated delta range data is available; compensating a SV motion and SV clock corrected carrier rate (cr_corrected ij (k)) of a reference receiver for clock of the reference receiver by subtracting an average of other SV motion and SV clock corrected carrier rates ( cr_corrected i,j (k)) of the reference receiver from the SV motion and SV clock corrected carrier rate (cr_ corrected i,j (k)); calculating a reference receiver de-trended SV motion and SV clock corrected carrier rate (rrCR detrend) i,j (k) for the reference receiver/satellite pairs RR i /SV j in a k th sample time period based on the reference receiver compensated, SV motion and SV clock corrected carrier rates; computing a carrier phase estimate (P2 ij (k)) using numerical integration of de-trended SV motion and SV clock corrected carrier rate; and calculating a variation in the carrier phase estimate (P2 ij (k)) for the reference receiver/satellite pairs (RR i /SV j) in the current (kth) sample time period. detecting a phase scintillation event in the ionosphere during a sample time period at a phase scintillation monitor based on satellite measurement data; excluding associated satellite measurement data from further use based on the detection of the phase scintillation event at the phase scintillation monitor; detecting an end to the phase scintillation event at the phase scintillation monitor; readmitting associated satellite measurement data collected after the end of the phase scintillation event as detected by the phase scintillation monitor; characterized in that the method further comprises: calculating satellite motion and SV clock corrected carrier rates (cr _corrected i, j ( k)) for reference receiver/satellite pairs (RR i /SV j) for which accumulated delta range data is available; compensating a SV motion and SV clock corrected carrier rate (cr_corrected ij (k)) of a reference receiver for clock of the reference receiver by subtracting an average of other SV motion and SV clock corrected carrier rates ( cr_corrected i,j (k)) of the reference receiver from the SV motion and SV clock corrected carrier rate (cr_ corrected i,j (k)); calculating a reference receiver de-trended SV motion and SV clock corrected carrier rate (rrCR detrend) i,j (k) for the reference receiver/satellite pairs RR i /SV j in a k th sample time period based on the reference receiver compensated, SV motion and SV clock corrected carrier rates; computing a carrier phase estimate (P2 ij (k)) using numerical integration of de-trended SV motion and SV clock corrected carrier rate; and calculating a variation in the carrier phase estimate (P2 ij (k)) for the reference receiver/satellite pairs (RR i /SV j) in the current (kth) sample time period. calculating satellite motion and SV clock corrected carrier rates (cr _corrected i, j ( k)) for reference receiver/satellite pairs (RR i /SV j) for which accumulated delta range data is available; compensating a SV motion and SV clock corrected carrier rate (cr_corrected ij (k)) of a reference receiver for clock of the reference receiver by subtracting an average of other SV motion and SV clock corrected carrier rates ( cr_corrected i,j (k)) of the reference receiver from the SV motion and SV clock corrected carrier rate (cr_ corrected i,j (k)); calculating a reference receiver de-trended SV motion and SV clock corrected carrier rate (rrCR detrend) i,j (k) for the reference receiver/satellite pairs RR i /SV j in a k th sample time period based on the reference receiver compensated, SV motion and SV clock corrected carrier rates; computing a carrier phase estimate (P2 ij (k)) using numerical integration of de-trended SV motion and SV clock corrected carrier rate; and calculating a variation in the carrier phase estimate (P2 ij (k)) for the reference receiver/satellite pairs (RR i /SV j) in the current (kth) sample time period.