{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,1]],"date-time":"2026-08-01T17:01:48Z","timestamp":1785603708327,"version":"3.56.0"},"reference-count":19,"publisher":"MDPI AG","issue":"15","license":[{"start":{"date-parts":[[2022,7,23]],"date-time":"2022-07-23T00:00:00Z","timestamp":1658534400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"NASA GPM Ground Validation program"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The accuracy of weather radar-measured products, such as reflectivity, plays a crucial factor in obtaining good quality, derived remote sensing products, such as hydrometeor classification. A slight mismatch of a few decibels in reflectivity may cause the hydrometeor classification to deviate from the actual truth. In order to obtain accurate remote-sensing measurements, calibration of weather radars should be carried out at regular intervals of time. The dual-frequency, dual-polarization, Doppler radar (D3R) is a well-established tool for measuring light rain and snow. There are various methods which are used for the calibration of weather radars, such as suspending a metallic sphere from a weather balloon or using corner reflectors on top of a tower or structure. In this work, we have shown the potential of using a UAV to suspend a calibration sphere, which is then used for calibrating the D3R radar. In this work, the advantages along with the practical aspects to be considered for calibration using UAV are discussed in detail. From the calibration results, it was observed that an offset of 2.2 dB was present in the Ku H-Pol reflectivity, Ku V-Pol was well calibrated and offsets within 2 dB were observed in the Ka H-Pol and V-Pol reflectivities.<\/jats:p>","DOI":"10.3390\/rs14153534","type":"journal-article","created":{"date-parts":[[2022,7,25]],"date-time":"2022-07-25T01:42:13Z","timestamp":1658713333000},"page":"3534","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Calibration of D3R Weather Radar Using UAV-Hosted Target"],"prefix":"10.3390","volume":"14","author":[{"given":"Shashank S.","family":"Joshil","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chandra V.","family":"Chandrasekar","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, CO 80523, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,7,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"377","DOI":"10.1175\/1520-0477-41.7.377","article-title":"Calibration of a weather radar by using a standard target","volume":"41","author":"Atlas","year":"1960","journal-title":"Bull. Am. Meteorol. Soc."},{"key":"ref_2","unstructured":"Williams, E., Hood, K., Smalley, D., Donovan, M., Melnikov, V., Forsyth, D., Zrnic, D., Burgess, D., Douglas, M., and Sandifer, J. (2013, January 16\u201320). End-to-end calibration of NEXRAD differential reflectivity with metal spheres. Proceedings of the 36th Conference on Radar Meteorology 2013 American Meteorological Society, Breckenridge, CO, USA."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"83","DOI":"10.1016\/j.jhydrol.2005.11.046","article-title":"Radar calibration by gage, disdrometer, and polarimetry: Theoretical limit caused by the variability of drop size distribution and application to fast scanning operational radar data","volume":"328","author":"Lee","year":"2006","journal-title":"J. Hydrol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1004","DOI":"10.1175\/JTECH1759.1","article-title":"Monitoring the reflectivity calibration of a scanning radar using a profiling radar and a disdrometer","volume":"22","author":"Williams","year":"2005","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1138","DOI":"10.1175\/JTECH1772.1","article-title":"Calibration issues of dual-polarization radar measurements","volume":"22","author":"Ryzhkov","year":"2005","journal-title":"J. Atmos. Ocean. Technol."},{"key":"ref_6","first-page":"34","article-title":"UPRM WEATHER RADARS AT THE CENTRAL AMERICAN AND CARIBBEAN GAMES AT MAYAG\u00dcEZ 2010","volume":"156","author":"Colom","year":"2010","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_7","unstructured":"Junyent, F., Chandrasekar, V., Brunkow, D., Kennedy, P.C., and McLaughlin, D.J. (September, January 28). Validation of first generation CASA radars with CSU-CHILL. Proceedings of the 32nd Conference on Radar Meteorology, Albuquerque, NM, USA."},{"key":"ref_8","first-page":"45","article-title":"Calibration procedures for global precipitation-measurement ground-validation radars","volume":"2015","author":"Chandrasekar","year":"2015","journal-title":"URSI Radio Sci. Bull."},{"key":"ref_9","unstructured":"Vega, M.A. (2017). Multi-Frequency Dual-Polarized Platform for Validation of Satellite Precipitation Measurements. [Doctoral Dissertation, Colorado State University]."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Qin, H., Cui, J.Q., Li, J., Bi, Y., Lan, M., Shan, M., Liu, W., Wang, K., Lin, F., and Zhang, Y.F. (2016, January 1\u20133). Design and implementation of an unmanned aerial vehicle for autonomous firefighting missions. Proceedings of the 2016 12th IEEE International Conference on Control and Automation (ICCA), Kathmandu, Nepal.","DOI":"10.1109\/ICCA.2016.7505253"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"281","DOI":"10.14358\/PERS.81.4.281","article-title":"Overview and current status of remote sensing applications based on unmanned aerial vehicles (UAVs)","volume":"81","author":"Pajares","year":"2015","journal-title":"Photogramm. Eng. Remote Sens."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"062014","DOI":"10.1088\/1757-899X\/490\/6\/062014","article-title":"A review: UAV-based Remote Sensing","volume":"Volume 490","author":"Yin","year":"2019","journal-title":"IOP Conference Series: Materials Science and Engineering"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"50","DOI":"10.5670\/oceanog.2019.212","article-title":"Deployment of the SEA-POL C-band Polarimetric Radar to SPURS-2","volume":"32","author":"Rutledge","year":"2019","journal-title":"Oceanography"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"2189","DOI":"10.1109\/TIM.2017.2687518","article-title":"Drone-based external calibration of a fully synchronized Ku-band heterodyne FMCW radar","volume":"66","author":"Suh","year":"2017","journal-title":"IEEE Trans. Instrum. Meas."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"10362","DOI":"10.1109\/TGRS.2019.2933912","article-title":"UAV-aided weather radar calibration","volume":"57","author":"Yin","year":"2019","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Paonessa, F., Virone, G., Sarri, A., Dell\u2019Omodarme, K., Fiori, L., Addamo, G., Matteoli, S., and Peverini, O.A. (2018, January 3\u20136). UAV-Mounted Corner Reflector for in-Situ Radar Verification and Calibration. Proceedings of the 2018 IEEE Conference on Antenna Measurements & Applications (CAMA), Vasteras, Sweden.","DOI":"10.1109\/CAMA.2018.8530616"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1087","DOI":"10.1002\/2014RS005529","article-title":"Salient features of the dual-frequency, dual-polarized, Doppler radar for remote sensing of precipitation","volume":"49","author":"Vega","year":"2014","journal-title":"Radio Sci."},{"key":"ref_18","unstructured":"Joshil, S.S. (2018). Salient Features of the D3R Radar Enhancements. [Doctoral Dissertation, Colorado State University]."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Bringi, V.N., and Chandrasekar, V. (2001). Polarimetric Doppler Weather Radar: Principles and Applications, Cambridge University Press.","DOI":"10.1017\/CBO9780511541094"}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/15\/3534\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:55:24Z","timestamp":1760140524000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/15\/3534"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,7,23]]},"references-count":19,"journal-issue":{"issue":"15","published-online":{"date-parts":[[2022,8]]}},"alternative-id":["rs14153534"],"URL":"https:\/\/doi.org\/10.3390\/rs14153534","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,7,23]]}}}