Investigation framework for L-band FCS EMC compatibility analysis AGCFG meeting Brussels 18/09/2006 Présented by Luc Deneufchatel] Investigation framework for L-band FCS EMC compatibility analysis Sous-titre facultatif de la diapositive

Agenda 1. Identification of system to be considered in the compatibility analysis Overall view of the L band system usage Type of compatibility analysis to be performed 2. Nature of the interference to be assessed In band interferences Spurious radiation interferences Out of band interferences 3. Characterisation of the FCI component to be analysed

System to be considered within the L band

Types of compatibility analysis to be performed Three types of compatibility analysis depending upon the frequency dependency between the system IN: in band system Systems operate in the same frequency range ADJ: in adjacent band Systems operate in different frequency bands which are directly adjacent or separated by a few MHz (i.e. FCI in 960-977 MHz and UAT at 978 MHz). CLS: in close band Systems operate in different frequency bands which are close but separated by more than a few MHz (i.e. FCI in 960-977 MHz and GNSS in 1164-1215 MHz). FCS Frequency Range GSM DME UAT SSR GNSS JTIDS 960-977 MHz ADJ CLS IN 960-1024 MHz 960-1164 MHz

Types of interferences Three types of interference must be considered depending on the FCI component characteristics: In band interferences: Assuming the FCS will be used, for instance, in frequencies above 977 MHz, in-band compatibility with DME will have to be studied. Some characteristics such as the temporal occupation of the transmitted signal (duty cycle) and the transmitted power will have an impact Out of band interferences: Out-of-band emissions are transmitted outside the necessary bandwidth but exclude spurious emissions. Out-of-band emissions from a transmitter will cause an increase of background noise in the victim receiver passband Spurious radiation interferences: Spurious emissions begin at +/- 250 % of the system bandwidth from the its center frequency

Essential system characteristics For the interferer system (the future FCI component): Transmission Filter (bandwidth, filtering slopes). These parameters will influence the levels of OOB and spurious emissions. Signal Modulation (useful bandwidth, spectrum fall off rate). These parameters will influence the levels of OOB emissions. Signal Polarization Time-domain Characteristics of Signals. Several separate cases have to be considered: a.      Pulsed emissions (transmitted power, length of pulses, duty cycle). Such emissions are transmitted by DME and JTIDS systems, for instance. b.      Bursted-Type emissions (transmitted power, length of bursts, duty cycle, time/amplitude profile of bursts). Such emissions are transmitted by UAT for instance. c.       Continuous emissions (transmitted power) For the victim system: Interference Susceptibilities: The currently available susceptibility values are provided within documents (ICAO Annex 10, EUROCAE and RTCA documents) They are limited to typical in-band or adjacent-band signals such as Continuous Wave, wideband noise and DME-like signal. Those values may not be directly valid for the candidate systems Reception Filter: The level of OOB and spurious emissions transmitted by an interferer and received by a victim receiver will depend on the characteristics of the reception filter Use of a Mutual Suppression Bus: The FCS may be connected onboard to a mutual suppression system in order to limit mutual interference with other systems

Compatibility analysis scenario Use of “source-path-receiver” methodology requires to identify: Potential interference sources Interference-victim receiver encounter scenario Receiver performance in presence of interference The following cases need to be investigated: Co-site compatibility onboard the aircraft Air-to-Ground compatibility Ground-to-Ground compatibility Ground-to-Air compatibility Air-to-Air compatibility