The ionospheric amplitude scintillation index \(\:{S}_{4c}\) has significance for ionospheric scintillation monitoring due to its applicability to common Global Navigation Satellite System (GNSS) geodetic receivers. However, due to the difference of tracking performance between various GNSS receivers, the magnitudes of \(\:{S}_{4c}\) derived from different receivers can show certain difference under the same scintillation level. This limits the application of \(\:{S}_{4c}\) index on the wider-area scintillation monitoring. Using the datasets from seven groups of collocated GNSS stations during 2010–2023, this study investigates the magnitude difference of \(\:{S}_{4c}\) for LEICA, TRIMBLE, SEPTENTRIO, and JAVAD receivers, and further determines their scintillation thresholds. Temporal coverage varies across stations from 2010 to 2023, and receiver types changed at these stations during this period. Statistical results indicate that the order of \(\:{S}_{4c}\) magnitudes from the highest to the lowest is TRIMBLE > JAVAD > LEICA > SEPTENTRIO. It also find that the conventional \(\:{S}_{4c}\) thresholds as 0.2 cannot be applied to different GNSS geodetic receiver types. We propose using the weighted average (WA) method to reconstruct the \(\:{S}_{4c}\) thresholds, referred to as WA thresholds, for the LEICA, TRIMBLE, SEPTENTRIO, and JAVAD, respectively. The values of 0.222 (LEICA), 0.302 (TRIMBLE), 0.178 (SEPTENTRIO), and 0.311 (JAVAD) are finally determined in this study. Experimental results indicate that based on WA thresholds, the error rates of scintillation detection are only 4.6% and 5.9% for the HNLW and STMC stations installed with ionospheric scintillation monitoring receivers. In addition, among 14 stations, the scintillation occurrence rates of WA thresholds for eight stations (57.1%) are closer to those of ROTI > 0.5 TECU/min. This work can provide valuable insights for detecting and monitoring ionospheric scintillation based on GNSS geodetic receivers at low-latitudes.
