Comparing the data reduction pipelines of FRIPON, DFN, WMPL, and AMOS: Geminids Case Study

TL;DR

This study cross-validates four meteor data-reduction pipelines (FRIPON, DFN, WMPL, AMOS) using 584 FRIPON Geminid fireballs and the Global Fireball Exchange (GFE) standard. Although radiants, velocities, and orbits generally agree with prior Geminid measurements, small systematic differences emerge: FRIPON shows a $\sim$0.3$^{\circ}$ RA radiant offset and $\sim$0.3 km s$^{-1}$ higher $v_g$, while DFN tends to yield lower velocities for poorer data; velocity uncertainties vary systematically across pipelines. The analysis highlights the need for consistent uncertainty propagation, explicit reference-frame handling, and standardized data-sharing practices to improve cross-network comparability. These findings have practical implications for multi-network meteor studies and the interpretation of meteoroid-stream dynamics, emphasizing transparency and collaboration in data reduction methods.

Abstract

Methods. We processed a dataset of 584 Geminid fireballs observed by FRIPON between 2016 and 2023. The single-station astrometric data is converted into the Global Fireball Exchange (GFE) standard format for uniform processing. We assess variations in trajectory, velocity, radiant, and orbital element calculations across the pipelines and compare them to previously published Geminid measurements. Results. The radiant and velocity solutions provided by the four data reduction pipelines are all within the range of previously published values. However, there are some nuances. Particularly, the radiants estimated by WMPL, DFN, and AMOS are nearly identical. Whereas FRIPON reports a systematic shift in right ascension (-0.3 degrees), caused by improper handling of the precession. Additionally, the FRIPON data reduction pipeline also tends to overestimate the initial velocity (+0.3 km s-1) due to the deceleration model used as the velocity solver. The FRIPON velocity method relies on having a well-constrained deceleration profile; however, for the Geminids, many are low-deceleration events, leading to an overestimation of the initial velocity. On the other end of the spectrum, the DFN tends to predict lower velocities, particularly for poorly observed events. However, this velocity shift vanishes for the DFN when we only consider Geminids with at least three observations or more. The primary difference identified in the analysis concerns the velocity uncertainties. Despite all four pipelines achieving similar residuals between their trajectories and observations, their velocity uncertainties vary systematically, with WMPL outputting the smallest values, followed by AMOS, FRIPON, and DFN.

Figures (16)

• Figure 1: Distribution of $v_{\infty}$ corrected for pre-luminous deceleration using the model of vida2018modelling. The dashed vertical line and corresponding value correspond to the median $v_{\infty}$.
• Figure 2: Pre-luminous deceleration estimated for the 584 Geminid FRIPON fireballs using the model of vida2018modelling, showing that $>$98% experienced less than 100 m/s of deceleration before detection. The dashed vertical line indicates the median value.
• Figure 3: Calculated geocentric radiant distribution for the Geminid meteor showers based on FRIPON observations between 2016-2023. The six black points with crosses indicate radiants identified from previous studies of the Geminids (A:jopek2003meteor, B:brown2008meteoroid, C:sonotaco2009meteor, D:brown2010meteoroid, E:jenniskens2016established). Nominal values for the four pipelines and previous results can also be found in Table \ref{['tab:geminids']}.
• Figure 4: Variation in the FRIPON-observed Geminid fireball radiants calculated by the DFN, AMOS, and WMPL data reduction pipelines relative to those calculated by the FRIPON automated pipeline.
• Figure 5: Median $1\sigma$ radiant uncertainties in (top) right ascension and (bottom) declination as a function of the trajectory-fit cross-track RMS residuals. Values are binned logarithmically in RMS; the solid line in each colour-coded curve is the median of all events in the bin, while the shaded region encloses the 5 -- 95 % percentile range (central 90 %) and illustrates the event-to-event spread. FRIPON, WMPL, and AMOS pipelines (nearly flat curves) report uncertainties that are largely independent of fit quality. In contrast, the DFN solution shows a clear positive trend, indicating that its formal errors scale with the residuals.