{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,12]],"date-time":"2026-05-12T16:47:21Z","timestamp":1778604441426,"version":"3.51.4"},"reference-count":25,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2020,2,24]],"date-time":"2020-02-24T00:00:00Z","timestamp":1582502400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Key R&amp;D Program of China for National Quality Infrastructure","award":["2017YFF0205006"],"award-info":[{"award-number":["2017YFF0205006"]}]},{"name":"National Key Scientific Instrument and Equipment Development Program of China","award":["2012YQ090208"],"award-info":[{"award-number":["2012YQ090208"]}]},{"name":"National Institute of Metrology","award":["22-AKYGH1801"],"award-info":[{"award-number":["22-AKYGH1801"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>The 24 GHz continuous-wave (CW) Doppler radar sensor (DRS) is widely used for measuring the instantaneous speed of moving objects by using a non-contact approach, and has begun to be used in train-borne movable speed measurements in recent years in China because of its advanced performance. The architecture and working principle of train-borne DRSs with different structures including single-channel DRSs used for freight train speed measurements in railway freight dedicated lines and dual-channel DRSs used for speed measurements of high-speed and urban rail trains in railway passenger dedicated lines, are first introduced. Then, the disadvantages of two traditional speed calibration methods for train-borne DRS are described, and a new speed calibration method based on the Doppler shift signal simulation by imposing a signal modulation on the incident CW microwave signal is proposed. A 24 GHz CW radar target simulation system for a train-borne DRS was specifically realized to verify the proposed speed calibration method for a train-borne DRS, and traceability and performance evaluation on simulated speed were taken into account. The simulated speed range of the simulation system was up to (5~500) km\/h when the simulated incident angle range was within the range of (45 \u00b1 8)\u00b0, and the maximum permissible error (MPE) of the simulated speed was \u00b10.05 km\/h. Finally, the calibration and uncertainty evaluation results of two typical train-borne dual-channel DRS samples validated the effectiveness and feasibility of the proposed speed calibration approach for a train-borne DRS with full range in the laboratory as well as in the field.<\/jats:p>","DOI":"10.3390\/s20041230","type":"journal-article","created":{"date-parts":[[2020,2,25]],"date-time":"2020-02-25T04:21:26Z","timestamp":1582604486000},"page":"1230","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Speed Calibration and Traceability for Train-Borne 24 GHz Continuous-Wave Doppler Radar Sensor"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2560-5722","authenticated-orcid":false,"given":"Lei","family":"Du","sequence":"first","affiliation":[{"name":"Division of Mechanics and Acoustics, National Institute of Metrology, Beijing 100029, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qiao","family":"Sun","sequence":"additional","affiliation":[{"name":"Division of Mechanics and Acoustics, National Institute of Metrology, Beijing 100029, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jie","family":"Bai","sequence":"additional","affiliation":[{"name":"Division of Mechanics and Acoustics, National Institute of Metrology, Beijing 100029, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Xiaolei","family":"Wang","sequence":"additional","affiliation":[{"name":"Division of Mechanics and Acoustics, National Institute of Metrology, Beijing 100029, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tianqi","family":"Xu","sequence":"additional","affiliation":[{"name":"Division of Mechanics and Acoustics, National Institute of Metrology, Beijing 100029, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"6788","DOI":"10.1109\/JSEN.2017.2747137","article-title":"A Survey of Train Positioning Solutions","volume":"17","author":"Otegui","year":"2017","journal-title":"IEEE Sens. 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