https://www.cso.nato.int/ACTIVITY_META.asp?ACT=2073 https://www.cso.nato.int/ACTIVITY_META.asp?ACT=2073 https://www.eurocontrol.int/sites/default/files/publication/files/surveillance-report-alternative-detection-techniques-to-supplement-psr-coverage-20070228.pdf https://www.eurocontrol.int/sites/default/files/publication/files/surveillance-report-alternative-detection-techniques-to-supplement-psr-coverage-20070228.pdf https://www.eurocontrol.int/sites/default/files/publication/files/surveillance-report-alternative-detection-techniques-to-supplement-psr-coverage-20070228.pdf https://www.eurocontrol.int/sites/default/files/publication/files/surveillance-report-multi-static-primary-surveillance-radar-an-examination-of-alternative-frequency-bands-200807.pdf https://www.eurocontrol.int/sites/default/files/publication/files/surveillance-report-multi-static-primary-surveillance-radar-an-examination-of-alternative-frequency-bands-200807.pdf https://www.eurocontrol.int/sites/default/files/publication/files/surveillance-report-multi-static-primary-surveillance-radar-an-examination-of-alternative-frequency-bands-200807.pdf https://www.eurocontrol.int/sites/default/files/publication/files/surveillance-report-multi-static-primary-surveillance-radar-an-examination-of-alternative-frequency-bands-200807.pdf https://www.cso.nato.int/pubs/rdp.asp?RDP=RTO-TR-SET-152 https://www.cso.nato.int/ACTIVITY_META.asp?ACT=2266 https://www.cso.nato.int/ACTIVITY_META.asp?ACT=2266