{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T18:56:48Z","timestamp":1774292208623,"version":"3.50.1"},"reference-count":20,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2011,9,29]],"date-time":"2011-09-29T00:00:00Z","timestamp":1317254400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/3.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The localization of persons in indoor environments is nowadays an open problem. There are partial solutions based on the deployment of a network of sensors (Local Positioning Systems or LPS). Other solutions only require the installation of an inertial sensor on the person\u2019s body (Pedestrian Dead-Reckoning or PDR). PDR solutions integrate the signals coming from an Inertial Measurement Unit (IMU), which usually contains 3 accelerometers and 3 gyroscopes. The main problem of PDR is the accumulation of positioning errors due to the drift caused by the noise in the sensors. This paper presents a PDR solution that incorporates a drift correction method based on detecting the access ramps usually found in buildings. The ramp correction method is implemented over a PDR framework that uses an Inertial Navigation algorithm (INS) and an IMU attached to the person\u2019s foot. Unlike other approaches that use external sensors to correct the drift error, we only use one IMU on the foot. To detect a ramp, the slope of the terrain on which the user is walking, and the change in height sensed when moving forward, are estimated from the IMU. After detection, the ramp is checked for association with one of the existing in a database. For each associated ramp, a position correction is fed into the Kalman Filter in order to refine the INS-PDR solution. Drift-free localization is achieved with positioning errors below 2 meters for 1,000-meter-long routes in a building with a few ramps.<\/jats:p>","DOI":"10.3390\/s111009393","type":"journal-article","created":{"date-parts":[[2011,9,29]],"date-time":"2011-09-29T11:34:46Z","timestamp":1317296086000},"page":"9393-9410","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":49,"title":["PDR with a Foot-Mounted IMU and Ramp Detection"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9771-1930","authenticated-orcid":false,"given":"Antonio R.","family":"Jim\u00e9nez","sequence":"first","affiliation":[{"name":"Centre for Automation and Robotics (CAR), Consejo Superior de Investigaciones Cientificas (CSIC)-UPM, Ctra. Campo Real km 0.2, La Poveda, Arganda del Rey, Madrid, 28500, Spain"}]},{"given":"Fernando","family":"Seco","sequence":"additional","affiliation":[{"name":"Centre for Automation and Robotics (CAR), Consejo Superior de Investigaciones Cientificas (CSIC)-UPM, Ctra. Campo Real km 0.2, La Poveda, Arganda del Rey, Madrid, 28500, Spain"}]},{"given":"Francisco","family":"Zampella","sequence":"additional","affiliation":[{"name":"Centre for Automation and Robotics (CAR), Consejo Superior de Investigaciones Cientificas (CSIC)-UPM, Ctra. Campo Real km 0.2, La Poveda, Arganda del Rey, Madrid, 28500, Spain"}]},{"given":"Jos\u00e9 C.","family":"Prieto","sequence":"additional","affiliation":[{"name":"Centre for Automation and Robotics (CAR), Consejo Superior de Investigaciones Cientificas (CSIC)-UPM, Ctra. Campo Real km 0.2, La Poveda, Arganda del Rey, Madrid, 28500, Spain"}]},{"given":"Jorge","family":"Guevara","sequence":"additional","affiliation":[{"name":"Centre for Automation and Robotics (CAR), Consejo Superior de Investigaciones Cientificas (CSIC)-UPM, Ctra. Campo Real km 0.2, La Poveda, Arganda del Rey, Madrid, 28500, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2011,9,29]]},"reference":[{"key":"ref_1","unstructured":"Jim\u00e9nez, A, Seco, F, Prieto, J, and Roa, J (2005, January 14\u201316). Tecnolog\u00edas sensoriales de localizaci\u00f3n para entornos inteligentes. I Congreso espa\u00f1ol de inform\u00e1tica\u2014Simposio de Computaci\u00f3n Ubicua e Inteligencia Ambiental. 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