Report ITU-R RA.2126-2 (03/2026) Mitigation techniques relating to radio frequency interference into radio astronomy
Foreword
Policy on Intellectual Property Right (IPR)
TABLE OF CONTENTS
1 Introduction
     1.1 Definition and characteristics of radio frequency interference
     1.2 Characteristics of astronomical signals
     1.3 Dealing with radio frequency interference
     1.4 ITU documentation
     1.5 Adoption of mitigation methods
     1.6 Effective observing techniques
2 RFI mitigation methodology – Layers of mitigation
3 Techniques for mitigating RFI
4 Pro-active measures – Changing the RFI environment
     4.1 Regulatory and coordination measures
     4.2 Local measures
     4.3 Pre-detection and post-detection measures
     4.4 Operational data sharing
          4.4.1 Boresight avoidance technique
5 Spatial excision (nulling)
     5.1 Multi-antenna systems
     5.2 Subspace projections
     5.3 Post-correlation beamforming
     5.4 Reference antennas and reference beams
6 Waveform subtraction
7 Anti-coincidence methods
8 Temporal and frequency data flagging
     8.1 Temporal blanking
     8.2 Antenna-based digital processing
     8.3 Digital excision at correlation
     8.4 Post-correlation – Before or during imaging
9 Implementation at the telescopes – A strategy
10 Summary
Annex 1  First results related to Boresight Avoidance method testing between the NRAO Green Bank Telescope and a non-geostationary orbit (non-GSO) satellite system
     A1.1 Executive summary
     A1.2 Introduction
     A1.3 Results
     A1.4 Discussion and summary
Annex 2  Example of operational data sharing record