Using PRI Prediction to Improve ECM Effectiveness By Scott McDonald & Ken McRitchie Ottawa, Ontario, Canada Visit us at MC Countermeasures Inc.

Sept 042Visit us at Overview Introduction Benefits of Prediction PRED Features PRED Performance Timeshare Basics Applications Summary

Sept 043Visit us at PRI Prediction Prediction vs Tracking Typical radar environments are complex – Many emitters -scanning/non-scanning – Conventional pulse, pulse Doppler, etc. Focus is on DRFM-based ECM – other applications such as VCOs also possible – DRFM generally “single threat” device

Sept 044Visit us at Single Emitter

Sept 045Visit us at A Problem – Interleaved PRI Patterns

Sept 046Visit us at DRFM Enables Uprange FT

Sept 047Visit us at But Only for Constant PRI!

Sept 048Visit us at Benefits of PRI Prediction Works in many cases where trackers won’t Generate up-range false targets even with staggered PRI patterns Compensate for jammer throughput delay Fade + Fast re-acquisition on scanning radars Operate in dense environment –Pulse train sorting –DRFM write control

Sept 049Visit us at RGPI >> PRI, 4 el Stagger

Sept 0410Visit us at (5sec) Fade + Re-Acq

Sept 0411Visit us at PRED Series Features Fast “learning” –No a priori data used –Not susceptible to war modes 0.5 µs < PRI < 20 ms > 128 stagger positions Adaptive acquisition Prediction < 250 ns

Sept 0412Visit us at Features (2) 4 parallel predictor channels Real-time de-interleaving Automatic channel selection, timesharing, ECM selection Integrated coherent ECM –RGPI –CRBM (v.s. head-to-tail) –FT Range >> PRI Embedded user memory

Sept 0413Visit us at Jamming 1 of 6

Sept 0414Visit us at Head to Tail

Sept 0415Visit us at CRBM

Sept 0416Visit us at Performance

Sept 0417Visit us at PRED Block Diagram

Sept 0418Visit us at Operating Modes Acquisition –Adaptive process –One complete pattern frame max. –Multiple threads for more efficient pattern handling Verification –Ensures proper PRED lock –User defined # PRIs: usually >10

Sept 0419Visit us at Prediction Algorithm

Sept 0420Visit us at Operating Modes (2) Track –Monitors PRI, breaks if error > tolerance –DRFM Write command “gated” to prevent overwriting memory Fade mode –False target strobes generated for defined period –Fast reacquisition

Sept 0421Visit us at TGPre-trigger

Sept 0422Visit us at Integral FT Generator

Sept 0423Visit us at Adaptive Prediction Does not require a priori radar information Responds very quickly – great for long staggers or small illumination times Improved performance against scanning radars –Predictions can be accurate during acquisition of pattern –fast reacquisition – typically only a few PRI – increased ECM effectiveness. Multiple Adaptive Processes during acquisition –Refine prediction within PRI as needed

Sept 0424Visit us at Adaptive Prediction

Sept 0425Visit us at Dwell Shift

Sept 0426Visit us at Dwell Shift

Sept 0427Visit us at Challenges Missing pulses: fades, effective jamming, scanning radar modes, receiver blanking Extra pulses: interleaved pulse trains, jammer OOB response (spurs, harmonics) –Time gating and frequency sorting very effective Sine or wobbulated PRI patterns

Sept 0428Visit us at (25%) Missing Pulses

Sept 0429Visit us at Missing Pulses

Sept 0430Visit us at Dense Environment

Sept 0431Visit us at Sinusoidal PRI patterns

Sept 0432Visit us at Wobulation/Sine Pattern Tests >10,000 waveforms tested (variations about nominal parameters) On average, PRED locked on in ~100 PRI Overall accuracy during acq: ~40% Overall accuracy during track: ~99%

Sept 0433Visit us at RF & Time Gating Composite video sorted and RF windows assigned dynamically to each channel Active channel selected based on: –Signal activity –Scanning/non-scanning priority –ECM: channel not selected if NO_ECM specified Up to 8 RF reject bands defined by user, updated real-time

Sept 0434Visit us at Timesharing (IR&D) application of PRI Prediction Use a single DRFM to jam multiple radars simultaneously Encompasses both: –Real-time pulse de-interleaving –Real-time control of DRFM Read and Write Algorithm calculates optimal allocation

Sept 0435Visit us at Timeshare Architecture

Sept 0436Visit us at Timeshare, ECM Selection 1 of 8 ECM techniques assigned based on: –PRI range (low, medium, high) –PW range (narrow or wide) –Scanning or non-scanning Permits selective jamming of specific emitters or radar modes simply with time gating DFD/IFM.

Sept 0437Visit us at Signal Environment

Sept 0438Visit us at Signal Environment

Sept 0439Visit us at Timeshare & ECM Select

Sept 0440Visit us at Auto ECM Selection

Sept 0441Visit us at Jam 1 – 6 of the Emitters

Sept 0442Visit us at Benefit of RF Sorting

Sept 0443Visit us at Applications - Isolation Many antennas compete for little space in most EW installations –Leads to insufficient isolation to transmit and receive simultaneously –Precludes cover pulse ECM OR –Prevents DRFM contents from being updated Situation corrected with PRI prediction

Sept 0444Visit us at A Second Problem Situation Weapon Systems that use separate Acquisition and Track radars –(Generally) not good enough to jam just the tracker

Sept 0445Visit us at Timeshare Track & Acq

Sept 0446Visit us at RF Agility Many non-Coherent threats RF Agility can be implemented as: –Switching between preset channels –Spin tuned magnetron The process involved in attempting RF prediction is quite similar to PRI prediction

Sept 0447Visit us at RF Agile Sources

Sept 0448Visit us at RF Prediction

Sept 0449Visit us at Adding RF PRED

Sept 0450Visit us at Typical RF Agility 200 Hz or 5 ms cycle If PRI < 1ms, can get shape of curve RF made "random" by staggering the PRI Need to predict PRI first, then get next RF from curve

Sept 0451Visit us at Summary (1) PRI prediction greatly improves the effectiveness of a DRFM in modern EA applications –Prediction circuitry is not standard in most systems MC Countermeasures has developed a line of predictors that can be easily interfaced to existing systems –Can be integrated with existing TG –Provide additional TG capability –Work around insufficient antenna isolation

Sept 0452Visit us at Summary (2) PRI prediction channels can be used to selectively track or ignore specific emitters. PRI prediction reduces the effects of overlapping or missing pulses. Timesharing – jam multiple radars with a single ECM asset –Automatic ECM selection (mini-receiver)

Sept 0453Visit us at Summary (3) RF Prediction can be added to a PRI predictor in order to extend the capability of the jammer. Chipset to be available in 2005 for OEM requirements.

Questions For further information, please feel free to contact us at: MC Countermeasures Inc Robertson Road, Suite 256 Nepean, Ontario, K2H 8R2 Canada Tel: +1 (613) Fax: +1 (613)