TLE uncertainty estimation using robust weighted differencing

Jacco Geul*, Erwin Mooij, Ron Noomen

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

24 Citations (Scopus)


Accurate knowledge of satellite orbit errors is essential for many types of analyses. Unfortunately, for two-line elements (TLEs) this is not available. This paper presents a weighted differencing method using robust least-squares regression for estimating many important error characteristics. The method is applied to both classic and enhanced TLEs, compared to previous implementations, and validated using Global Positioning System (GPS) solutions for the GOCE satellite in Low-Earth Orbit (LEO), prior to its re-entry. The method is found to be more accurate than previous TLE differencing efforts in estimating initial uncertainty, as well as error growth. The method also proves more reliable and requires no data filtering (such as outlier removal). Sensitivity analysis shows a strong relationship between argument of latitude and covariance (standard deviations and correlations), which the method is able to approximate. Overall, the method proves accurate, computationally fast, and robust, and is applicable to any object in the satellite catalogue (SATCAT).

Original languageEnglish
Pages (from-to)2522-2535
Number of pages14
JournalAdvances in Space Research
Issue number10
Publication statusPublished - 15 May 2015


  • Conjunction analysis
  • Error analysis
  • Pairwise differencing
  • SGP4 accuracy
  • Space debris
  • Space Situational Awareness (SSA)

Cite this