{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,31]],"date-time":"2025-10-31T07:49:55Z","timestamp":1761896995743,"version":"build-2065373602"},"reference-count":13,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2019,4,9]],"date-time":"2019-04-09T00:00:00Z","timestamp":1554768000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In order to improve the performance of Terrain Referenced Navigation (TRN), an Interferometric Radar Altimeter (IRA) has been developed as a more accurate altimeter. The IRA outputs not only the relative distance (slant range, R) but also the cross-track angle (look angle, \u03b8) of the closest point on the zero Doppler line by using the principle of interferometry and two or more antennas. To perform TRN using the IRA, the 3D relative position of the closest point should be calculated. There is a formula to calculate the relative position of the closest point using the Euler angles. However, in an actual flight environment in which the influence of wind exists, the angle of attack, the side slip angle and \u201cthe effective look angle\u201d should be used rather than the Euler angles. In this paper, a new formula for calculating the relative position of the closest point is proposed and mathematically derived. The proposed formula was verified with real data from actual flight. The flight test results show that the positions of the closest points calculated using the conventional method and the proposed method are different because of the wind effect. The TRN simulation results indicate that the proposed formula calculates the closest points more accurately than the conventional formula.<\/jats:p>","DOI":"10.3390\/s19071688","type":"journal-article","created":{"date-parts":[[2019,4,10]],"date-time":"2019-04-10T03:47:36Z","timestamp":1554868056000},"page":"1688","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":9,"title":["Accurate Measurement Calculation Method for Interferometric Radar Altimeter-Based Terrain Referenced Navigation"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4019-1580","authenticated-orcid":false,"given":"Juhyun","family":"Oh","sequence":"first","affiliation":[{"name":"Agency for Defense Development, Yuseong P.O.Box 35, Daejeon 34186, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Chang-Ky","family":"Sung","sequence":"additional","affiliation":[{"name":"Agency for Defense Development, Yuseong P.O.Box 35, Daejeon 34186, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9481-2864","authenticated-orcid":false,"given":"Jungshin","family":"Lee","sequence":"additional","affiliation":[{"name":"Agency for Defense Development, Yuseong P.O.Box 35, Daejeon 34186, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Sang Woo","family":"Lee","sequence":"additional","affiliation":[{"name":"Agency for Defense Development, Yuseong P.O.Box 35, Daejeon 34186, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9400-5157","authenticated-orcid":false,"given":"Sang Jeong","family":"Lee","sequence":"additional","affiliation":[{"name":"Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Myeong-Jong","family":"Yu","sequence":"additional","affiliation":[{"name":"Agency for Defense Development, Yuseong P.O.Box 35, Daejeon 34186, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2019,4,9]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Siouris, G.M. (2004). Missile Guidance and Control Systems, Springer Science & Business Media.","DOI":"10.1115\/1.1849174"},{"key":"ref_2","unstructured":"(2019, January 16). Available online: www.taurus-systems.de."},{"key":"ref_3","unstructured":"Groves, P.D. (2013). Principles of GNSS, Inertial, and Multisensor Integrated Navigation Systems, Artech House. [2nd ed.]."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1578","DOI":"10.1109\/36.718861","article-title":"The delay\/Doppler radar altimeter","volume":"36","author":"Raney","year":"1998","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_5","unstructured":"(2019, January 16). Honeywell. Available online: https:\/\/aerocontent.honeywell.com\/aero\/common\/documents\/ myaerospacecatalog-documents\/MilitaryAC\/PTAN.pdf."},{"key":"ref_6","unstructured":"Rosen, P.A., Hensley, S., Joughin, I.R., Li, F.K., Madsen, S.N., Rodriguez, E., and Goldstein, R.M. (2019, April 06). 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Proceedings of the 2018 IEEE\/ION Position, Location and Navigation Symposium (PLANS), Monterey, CA, USA.","DOI":"10.1109\/PLANS.2018.8373375"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"81","DOI":"10.5515\/KJKIEES.2015.26.1.81","article-title":"An Implementation of Interferometric Radar Altimeter Simulator","volume":"26","author":"Paek","year":"2015","journal-title":"J. Korean Inst. Electromagn. Eng. Sci."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/7\/1688\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T12:43:59Z","timestamp":1760186639000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/19\/7\/1688"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2019,4,9]]},"references-count":13,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2019,4]]}},"alternative-id":["s19071688"],"URL":"https:\/\/doi.org\/10.3390\/s19071688","relation":{},"ISSN":["1424-8220"],"issn-type":[{"type":"electronic","value":"1424-8220"}],"subject":[],"published":{"date-parts":[[2019,4,9]]}}}