1、 Recommendation ITU-R M.2030(12/2012)Evaluation method for pulsed interference from relevant radio sources other than in the radionavigation-satellite service to the radionavigation-satellite service systems and networks operating in the 1 164-1 215 MHz, 1 215-1 300 MHz and 1 559-1 610 MHz frequency
2、 bandsM SeriesMobile, radiodetermination, amateurand related satellite servicesii Rec. ITU-R M.2030 Foreword The role of the Radiocommunication Sector is to ensure the rational, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including sate
3、llite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocommunication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supporte
4、d by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of Resolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are a
5、vailable from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent information database can also be found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Seri
6、es Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy
7、RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service systems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and rel
8、ated subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2012 ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec.
9、ITU-R M.2030 1 RECOMMENDATION ITU-R M.2030 Evaluation method for pulsed interference from relevant radio sources other than in the radionavigation-satellite service to the radionavigation-satellite service systems and networks operating in the 1 164-1 215 MHz, 1 215-1 300 MHz and 1 559-1 610 MHz fre
10、quency bands (Questions ITU-R 217-2/4 and ITU-R 288/4) (2012) Scope This Recommendation provides a method for use in the initial evaluation of the potential for relevant1radio sources other than in the radionavigation-satellite service (RNSS) to cause pulsed interference2to a radionavigation-satelli
11、te system or network operating in the 1 164-1 215 MHz, 1 215-1 300 MHz, and 1 559-1 610 MHz frequency bands. The evaluation method components are a set of equations and a table of recommended parameters and allowable degradation ratios3for each frequency band and RNSS receiver type. Although the eva
12、luation method equations are applicable to RNSS receivers in the 1 559-1 610 MHz band, further studies would be needed to determine the necessary table of recommended method parameters and allowable degradation ratios for that frequency band before the evaluation method is completely defined for the
13、 1 559-1 610 MHz band. The ITU Radiocommunication Assembly, considering a) that systems and networks in the radionavigation-satellite service (RNSS) provide worldwide accurate information for many positioning, navigation and timing applications, including safety aspects for some frequency bands and
14、under certain circumstances and applications; b) that radio transmitters generally emit a level of out-of-band emissions dependent on the conditions of their use; c) that while Radio Regulations (RR) Appendix 3 specifies the maximum permitted spurious emission power levels, it also notes that in som
15、e cases, these levels may not provide adequate protection for receiving stations in space services and more stringent levels might be considered in each individual case in the light of the geographical position of the stations concerned, and that these levels may not be applicable to systems using d
16、igital modulation techniques; d) that the bands 1 164-1 215 MHz, 1 215-1 300 MHz, 1 559-1 610 MHz and 5 010-5 030 MHz are also allocated on a primary or secondary basis to other services besides RNSS; e) that emissions from other RNSS systems and networks, and from other services and sources in the
17、bands allocated for RNSS, as well as unwanted emissions, may cause interference to an RNSS systems or RNSS networks receivers and should be included in an interference evaluation; 1The term “relevant” refers to radio sources that transmit RF pulses or that generate equivalent RF pulses at the RNSS r
18、eceiver by other means such as, for example, the use of a scanning antenna beam. 2Recommendation ITU-R M.1318-1 provides an analysis method for continuous interference sources. 3See Annex 1, 3 for the degradation ratio description and 4 for more information on the allowable degradation ratio values.
19、 2 Rec. ITU-R M.2030 f) that further work is needed to adequately characterize the interference effects on RNSS receivers from emissions of pulsed RF sources operating in and near the bands 1 559-1 610 MHz and 5 010-5 030 MHz, noting a) that several ITU-R Recommendations provide technical data and p
20、rotection criteria for RNSS system and network operations; b) that Recommendation ITU-R RS.1347 also provides a pulsed interference evaluation methodology for interference to an RNSS receiver from synthetic aperture radars and measurement test results in the band 1 215-1 300 MHz; c) that Report ITU-
21、R M.2220 provides a method to calculate certain parameters used by this Recommendation along with supporting material and examples, recognizing that RR No. 4.5 states “the frequency assigned to a station of a given service shall be separated from the limits of the band allocated to this service in s
22、uch a way that, taking account of the frequency band assigned to a station, no harmful interference is caused to services to which frequency bands immediately adjoining are allocated”, recommends 1 that the analytic method in Annex 1 to this Recommendation should be used for the preliminary evaluati
23、on of the potential for pulsed interference from relevant radio sources other than in the RNSS to an RNSS system or network operating in the bands 1 164-1 215 MHz or 1 215-1 300 MHz; 2 that if the application of this method indicates that there is potential for pulsed interference that would impair
24、the ability of RNSS systems or networks to function, then a more detailed analysis should be performed; 3 that studies should be performed to develop the parameters to be included in the analytic method for the preliminary evaluation of the potential for pulsed interference from relevant radio sourc
25、es other than in the RNSS to an RNSS system or network operating in the frequency band 1 559-1 610 MHz (see Note). NOTE The analytic method equations in Annex 1 are applicable to the 1 559-1 610 MHz band. Rec. ITU-R M.2030 3 Annex 1 Analytic method for the preliminary evaluation of the potential for
26、 pulsed interference from relevant radio sources other than in the RNSS to an RNSS system or network operating in the bands 1 164-1 215 MHz, 1 215-1 300 MHz and 1 559-1 610 MHz 1 Introduction An evaluation model for continuous RF interference4(RFI) to RNSS receivers has been developed in Recommendat
27、ion ITU-R M.1318-1, but ITU-R has also recognized the need to address pulsed RF interference. This Annex derives from basic concepts a general pulsed RFI evaluation method for use with RNSS receivers. Report ITU-R M.2220 contains background material and a methodology to calculate composite pulsed in
28、terference parameters used in the interference evaluation. Section 2 below provides some background and describes RFI degradation equations for two basic types of RNSS receivers. Section 3 describes how the degradation equations could be used to assess the impact of additional pulsed RFI. Section 4
29、lists recommended baseline RFI method parameters and allowable degradation ratios for the pulsed RFI evaluation. 2 Characterization of pulsed RFI effects on RNSS receivers Studies by two aviation standards organizations5have shown that the highest levels of pulsed RFI impacting RNSS air-navigation r
30、eceivers operating in the 1 164-1 215 MHz band at or above Flight Level 200 (6 096 m above mean sea level (MSL) occur in several localized regions around the world. Those studies have developed a model of a general RNSS receiver signal processing method used to mitigate strong pulsed RFI and an asso
31、ciated equation6to express the amount of degradation to the post-correlator signal quality measure (C/N0,EFF) of that receiver. One study7also developed the comparable degradation equation for conventional receivers without special pulsed RFI mitigation. Both degradation equations handle continuous
32、RFI present along with the pulsed RFI. As such, they can be useful for determining RFI protection criteria as well as for analysing the effects of any new pulsed or continuous RFI beyond an initial baseline case. Sections 2.1 and 2.2 below describe details of the RFI degradation equations. 2.1 Effec
33、tive noise density calculation method (receiver pulse blanking) An effective means for mitigating strong pulsed RFI in, for example, an air navigation receiver, is the pulse blanker. One aspect of the blanker is that pulsed RFI signals with peak power levels below the blanker threshold combine with
34、the receiver noise and the un-blanked components of the continuous RFI. The other main aspect is that the blanker “zeros” the signal and noise into the 4Continuous interference is used here to mean interference from sources of fairly constant power that is generally present at all times. This is dis
35、tinguished from pulsed interference which requires an analysis based on pulse duration, peak power and duty cycle. 5RTCA, headquartered in the United States, and EUROCAE in Europe. 6SC-159, “Assessment of radio frequency interference relevant to the GNSS L5/E5A frequency band”, RTCA Document No. RTC
36、A/DO-292, Washington, DC, 29 July 2004, Section 2.6.2.3. 7ibid RTCA/DO-292, Appendix D.2.2. 4 Rec. ITU-R M.2030 correlators during the time duration of strong pulses with power levels above the blanker threshold. The equation described below estimates an effective noise-plus-interference density (N0
37、,EFF) at the output of the signal correlators due to the pulse blanker. N0,EFFis quite general and can be applied to all RFI environments for an RNSS receiver because the equation input variables quantify the RFI environment as it changes. The effective post-correlator noise-plus-interference densit
38、y, N0,EFF, is defined as: ()+=IWBBEFFRNIPDCNN0,00,011(1) where: =NiiiIdcPBWNR101(2) In the above equations: RI: is the post-correlator power density ratio of total aggregate below-blanker threshold average pulsed RFI to receiver thermal noise (unitless ratio) PDCB: (pulse duty cycle of the blanker)
39、is the net aggregate duty cycle of all pulses exceeding the blanker threshold (unitless fraction) N0: is the RNSS receiver system thermal noise power spectral density in W/Hz (= kTsys) I0,WB: is the total wideband equivalent continuous RFI power spectral density (W/Hz) for the particular RNSS receiv
40、er application8BW: is the pre-correlator RF/IF bandwidth (Hz) Pi: is the received peak power (W) of the i-th pulse source (referenced to antenna output) with peak level below the blanker threshold dci: is the duty cycle (unitless fraction) of the i-th below-blanker pulse source N: is the total numbe
41、r of emitters that generate received pulses with peak level below the blanker threshold. As defined above, N0,EFFcombines all the pulsed RFI effects on thermal noise density, wideband continuous RFI density, and RNSS signal loss.9All noise and interference parameters in equations (1) and (2) are ref
42、erenced to the receive system passive antenna terminals. Note in equation (1) that without the pulsed RFI (i.e. RIand PDCB = 0), the N0,EFFequation reduces to the simpler expression used in continuous RNSS RFI analyses (N0,EFF= N0+ I0,WB). The aggregate pulsed RFI parameter, PDCB, is built out of co
43、mponents from the separate heterogeneous pulsed tranmitter systems “a”, “b” and “c” as follows: ()()()cbaBPDCPDCPDCPDC = 1111 (3) where: PDCa: above-blanker threshold pulse duty cycle for system “a” pulses (e.g. Distance Measuring Equipment/Tactical Air Navigation (DME/TACAN) 8See Report ITU-R M.222
44、0 for more details about this parameter. 9See Report ITU-R M.2220 for more details on N0,EFF. Rec. ITU-R M.2030 5 PDCb: above-blanker threshold pulse duty cycle for system “b” pulses (e.g. a Communication Navigation Identification (CNI) system); and PDCc: above-blanker threshold pulse duty cycle for
45、 system “c” pulses (e.g. Aeronautical Radionavigation Service/Air Traffic Control (ARNS/ATC). For each individual source, i, of a system, x, the above-blanker threshold pulse duty cycle PDCx,iis given in general by: PDCx,i= (PWx,i+ REC)PRFx,i(3a) where: PWx,i: is the effective received above-blanker
46、 threshold pulse width (s) REC: is the receiver overload recovery time (s); and PRFx,i: is the pulse repetition rate (Hz). The aggregate pulsed RFI parameter RIis built out of components from the separate heterogeneous pulsed transmitter systems “a”, “b” and “c” as follows: cbaIRRRR += (4) where Ra,
47、 Rband Rcare the below-blanker signal-to-receiver noise density ratio for systems “a”, “b” and “c” respectively. These ratios are calculated without regard to the presence of any other pulses that overlap in time from the various individual pulsed RFI sources. The pulse duty cycle of an individual s
48、ource, j, of a system, y for below-blanker threshold received pulses, dcy,j, is defined by: dcy,j= PWy,jPRFy,j(4a) where the equation right side terms are defined similar to (3a) except they are with respect to below-blanker threshold pulse characteristics. 2.2 Effective noise density calculation (r
49、eceiver pulse saturation) Certain RNSS receivers operating in the RNSS bands in, for example, ground-based applications may not be subjected to large amounts of in-band and adjacent band pulsed RFI as air navigation or similar receivers are. As such, they may not contain pulse blanking circuitry as described in 2.1 above but rather will be saturated briefly by RFI pulses from a nearby source. The presence of pulsed RFI reduces the amount of continuous RFI that the RNSS receiver can tolerate. The effects of both pulsed and continuous RFI for a sat
