ESM System Flashcards
What are the functions of the ESM system?
electronic support (ES), functioning as an electronic warfare (EW) search, surveillance, and corroboration sensor. The second is to provide the aircrew with situational awareness regarding EW threats to the helicopter via the Helicopter Threat Warning (HTW) function.
What equipment is a part of the ESM system?
the receiver processor and four antennas
What does the Receiver/Processor consist of?
- Two RF baseband down converters;
- Two analog baseband receivers;
- A digital frequency discriminator;
- A pulse processor;
- SBC (Single board computer);
- Synthesizer module.
What do the down converters do?
Each down converter provides the necessary antenna switching, preselection, attenuation, and first RF down conversion to an intermediate frequency (IF).
What do the baseband receivers do?
Each baseband receiver performs the second and final IF conversion, IF filtering, video filtering, and amplitude/phase measurements.
What does the digital frequency discriminator do?
The digital frequency discriminator provides a frequency measurement on each incoming pulse.
What does the pulse processor do?
The pulse processor generates descriptor words, called pulse descriptor words (PDW) for each pulse detected.
What does the single board computer do?
receives pulse descriptor words from the pulse processor for data processing to correlate specific emitter pulses into pulse trains. PDW data is then
used to form emitters and define their characteristics and to determine emitter parameters such as identification, threat level, bearing, and location.
What does the synthesizer module do?
The synthesizer module provides multiple frequency references used for the local oscillator (LO) and built-in test (BIT)/calibration signals. Calibration functions provide correction factors to compensate for amplitude and phase measurement drift.
What does the active calibration capability do?
it injects known RF signals from the synthesizer into the antenna RF chains, to correct for system measurement errors. These errors are a function of the system environment and fluctuate over time (mainly due to temperature).
Describe the ESM antennas
Each ESM antenna contains four separate, spiral antenna elements, two in low band and two in high band and passive RF electronics. The ESM receiver processor further subdivides the RF operating ranges into six sub-bands.
What is the field of view for an individual antenna?
100 degrees, giving us a 360 field of view around the helo with some overlap.
What is LBI
Long Baseline Interferometer measurements. The
ESM receiver processor selects two adjacent antenna elements, within a band, to perform LBI which is then used to determine emitter location.
What do blanking inputs do?
Blanking input ports are provided to minimize the interference effects of onboard transmitter signals. Four ports are dedicated to the radar, radar altimeter, interference blanker and the Link 16. The interference blanker provides combined blanking from the TACAN, IFF interrogator, and IFF transponder.
How long does it take ESM to Initialize?
5-6 minutes after initial power application
EOI Function
Choose 4 Emitters from the MDL to be Emitters of Interest (EOIs). Emitters of interest that are detected are displayed with “pointers”. Bearing lines to detected EOI emitters will add the NATO name.
How long to the bearing lines to detected EOIs remain illuminated?
15 seconds
Emitter (+EMTR 10/20/50/ALL) function
used to selectively declutter the ESM display of symbols by emitter mode. The operator can choose to display all emitters of interest or the top 10, 20 (default), or 50. Contacts are displayed in order of priority to ensure that highest priority emitters are retained on the display.
Scan Modulation Analysis
Scan modulation analysis (SMA) is a tool with which the operator can potentially break up ambiguities to precisely identify emitters.
What happens when you do a Scan Mod Analysis?
the receiver must “stare” at the emitter of interest for the defined dwell time in order to collect the data required to perform the analysis. During this time, the receiver is dedicated to the scan, monopolizing the receiver in order to collect the required data. Detection of new emitters is inhibited during Scan Mod.
Where should the aircraft be during a Scan Mod?
on the beam of the emitter you are trying to identify.
Dwell times for Scan Mod
the default is 10 seconds, the max is 300 seconds (5 min)
Warning about SMA and HTW
Use of SMA in a high threat environment may result in failure to detect HTW.
How to stop a Scan Mod in progress?
re-select the emitter, select the SCAN MOD function, and enter 0 seconds for the dwell time.
