REPORT M.2032-2003 Tests illustrating the compatibility between maritime radionavigation radars and emissions from radiolocation radars in the band 2 900-3 100 MHz
ITU-R - International Telecommunication Union/ITU Radiocommunication Sector
Scope
Introduction Tests have been performed to assess the effects of emissions representative of radiolocation radars having a secondary allocation in the 2 900-3 100 MHz band on two representative maritime radionavigation radars having a primary allocation in that band. The maritime radionavigation radars used for these tests are identified as Radars A and B in this Report1. The tests were performed in two separate efforts. In the first effort@ the radiolocation emissions were simulated by means of signal generators@ using pulses with no intra-pulse modulation and were roughly representative of emissions from P0N type radiolocation radars described in Recommendation ITU-R M.1460 ?C Technical and operational characteristics and protection criteria of radiodetermination and meteorological radars in the 2 900-3 100 MHz band. In the second effort@ tests were performed with longer pulse width and higher duty cycle P0N type emissions@ which are not typical of those radars identified in Recommendation ITU-R M.1460. Analog reconstructions of digitally recorded emissions from a stepped-frequency radiolocation radar that operates with the characteristics and parameters similar to that of Radar 2 in Recommendation ITU-R M.1460 were also used as unwanted stimuli to one of the maritime radars. This Report describes the conduct of these two test efforts and their findings. 1 These tests addressed pulsed maritime radionavigation radars having pulse widths@ pulse repetition frequencies (PRFs)@ bandwidths@ noise figures@ and antenna beamwidths typical of those identified in Recommendation ITU-R M.1313. Those radars typically employ interference mitigation techniques/processing methods identified in Recommendation ITU-R M.1372 to allow them to operate in the presence of other radionavigation and radiolocation radars. Mitigation techniques of that kind are relatively inexpensive to provide now that powerful digital signal processing circuitry is available at low cost and is in wide use for other navigation radar functions. Older and less sophisticated maritime radionavigation radars may not have the same level of interference rejection capabilities as those typically provided in the International Maritime Organization (IMO)-category radars identified in Recommendation ITU-R M.1313 ?C Technical characteristics of maritime radionavigation radars.