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Challenges of Testing Indoor Localization Systems



Person wearing a localizing backpack
Top view of a three-dimensional building
Heat map demonstrating areas that have strong transmission signal compared to areas with weak transmission signal.

Testing of indoor localization and tracking systems (LTSs) is complicated for several reasons:

  • There are many categories of such systems. Some rely on presence of electronic infrastructure in the environment (buildings/tunnels/caves/underground mines) to facilitate localization and tracking. Some systems require site-specific training and calibration before they can be used. Some systems need to have access to the floor plans of the building or need to know the global coordinates of its boundaries in order to operate. Therefore, one must be careful when comparing the performance of various systems to ensure the comparisons are fair.
  • LTSs often have RF components. RF wave propagation can vary considerably from one building to another depending on the construction material used in the building, its floor plans, and objects housed in it. Therefore, LTSs must be tested in a variety of buildings, including a high rise, because these systems typically have more difficulty in estimating the floor on which the entity to be localized or tracked (ELT) is than in estimating its horizontal location.
  • With the rapid proliferation of smartphones that are equipped with accelerometers, gyroscopes, and magnetometers as well as the use of these sensors in other LTSs, it is important to test the performance of such systems under various scenarios involving different modes of mobility. Given that these sensors suffer from "drift" that worsens over time, it is important to test the systems using long test scenarios, complex paths, and different modes (e.g., walking, running, sidestepping, walking backwards, and crawling) and speeds of movement. Therefore, the use of large buildings is a prerequisite for a well-designed testing procedure.

Given the complexities of indoor localization testing, more often than not vendors do not test their products in a thorough and comprehensive manner; hence the users are unable to ascertain whether a given system meets their needs.

These issues demonstrate the need for standardized testing procedures according to which systems can be tested and compared.

Created February 22, 2024, Updated March 11, 2024