Interactive demonstrations for Radar & Electronic Warfare
29 LIVE MODULES · FIRST-PRINCIPLES PHYSICS · NO EXTERNAL DEPENDENCIES
A browser-based teaching instrument for the physics of radar detection and the electronic-warfare techniques that defeat it. Every plot is computed live from the underlying equations — antenna patterns, the range equation, DRFM deception, GNSS jamming and burn-through — so you can turn the knobs and watch the trade-offs move. Built on the canonical literature: Skolnik, Stimson, and Pace’s work on LPI radar and digital RF memories.
✓ Validated, not decorative. Key results are checked against the source tables — e.g. DRFM phase-quantization spur levels reproduce Pace’s Table 5.5 (1-bit −9.5 dBc … 4-bit −34.3 dBc) exactly, and I/Q image suppression follows the 0.55 dB / 3.6° → 30 dBc benchmark.
Radar Fundamentals
Array theory and beamforming, the range equation, null-steering, sidelobe cancelers, scan loss and the PPI / A / B / range-Doppler displays — plus the ambiguity function & PRF, clutter, monopulse tracking, and propagation / horizon.
Detection & Engagement
Engagement geometry, PPI / A / B scopes, range-height, the receiver chain, signal processing, multipath, detection theory, dynamic range and link budgets.
Countermeasures & EP
DRFM deception (ten sub-modes including the design-space explorer and I/Q-image analysis), radar-warning receivers, and decoys & chaff.
SIGINT / ES
ELINT / ESM emitter interception, de-interleaving and parameter estimation.
Special Topics
Low-observable / stealth, electronic order of battle, GNSS / GPS jamming & spoofing, and systems & data.
References
The full reference bibliography and primary source material behind every module.
Illustrative / notional · Distribution A · generic parameters
Open-source educational tool — illustrative, generic models only; not for operational use.
Scenario
Array & threat
Quiescent beamAdapted beamJammer bearing
Array-factor power pattern (dB), normalized to the undisturbed mainbeam peak. Drag over the plot to read values.
Gain toward jammer — before
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Gain toward jammer — adapted
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Null depth achieved
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Mainbeam loss
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Adaptive null steering. The adapted weights are the optimum (MVDR) solution w = R⁻¹c ⁄ (cᴴR⁻¹c), with interference-plus-noise covariance R = I + (INR)·a(θⱼ)a(θⱼ)ᴴ. The array digs a deep null on the jammer bearing while barely moving the mainbeam — the digital-beamforming capability of a modern digital AESA.
Main array + auxiliaries
Main patternAfter cancellationJammer bearing
High-gain main pattern vs. the residual after auxiliary-channel cancellation. Mainbeam is protected; sidelobe jammers are notched out.
Residual at jammer
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Cancellation depth
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SINR improvement
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Mainbeam gain kept
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Sidelobe canceler (SLC). A few low-gain auxiliary channels sample the sidelobe-leaked jamming; adaptive weights w = R_aux⁻¹ r_am form a replica that is subtracted from the main channel, notching sidelobe jammers while leaving the mainbeam untouched. M auxiliaries cancel up to M jammers — turn on the second jammer with one auxiliary to see it fail.
Engagement
System frequency
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Environment
Ground bounce / multipath
SINR (with jamming)S/N (thermal, no jam)Threshold
Signal-to-interference-plus-noise vs. target range for the selected pairing. Burn-through is where SINR rises above threshold.
Burn-through range
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Unjammed detection range
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J/S at burn-through
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J/N (mainbeam)
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2-way atmos+rain loss @ BT
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External noise floor
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Specific attenuation (gaseous + rain) vs. frequency. The vertical marker is the selected radar's operating frequency. The peak near 22 GHz is the water-vapour line; radar bands are sited in the low-loss windows around it. Higher bands pay far more rain loss — visible when you raise the rain rate.
Blue vs. Red engagement. Pick any victim radar and any jammer. Self-screening puts the jammer on the target (mainbeam entry, J/S ∝ R⁴/R² = R²); standoff keeps it at fixed range and enters through the radar sidelobes (J/S ∝ R⁴). SINR combines jamming and thermal noise as SINR = 1 ⁄ (J/S + N/S), with J/S from Harrison's countermeasures.jammer_to_signal() and S/N from the radar range equation. The threshold (~13 dB for Pd=0.9, Pfa=10⁻⁶) comes from his single-pulse detection code. These readouts drive the radar scopes in the next tab. Advanced mode exposes the system's operating frequency and lets you add propagation and interference effects: frequency-dependent gaseous absorption, rain (ITU-R P.838 γ = aRb) applied two-way to the target return and one-way to the jammer path, and an external / EMI noise-floor rise from the surrounding emitter environment. Watch how a low-band search radar shrugs off rain while an X/Ku fire-control radar loses most of its range, and how a raised noise floor collapses the thermal-limited detection range even when jamming is light. Humidity scales the water-vapour term of the gaseous loss (most visible near the 22 GHz line on the attenuation plot), and ground bounce / multipath applies the two-way pattern-propagation factor F to the skin return — putting the target in a lobe (F→2, +12 dB) or a null (F→0) depending on antenna height, target altitude, and range, which is why the SINR curve develops the characteristic multipath ripple.
Scenario
Plan-Position Indicator. The rotating sweep paints target blips; the noise jammer paints a bright azimuth strobe; inside the burn-through ring the target is detectable.
Target SINR
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P(detection)
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Burn-through ring
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Status
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DRFM technique
Stage
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Induced error
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Radar track
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EP counter
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Threat picture
Own-ship (nose-up) flies through a field of ground emitters while an AEW aircraft orbits. Symbols sit at each emitter's live bearing and range; ground sites drift as you transit, the orbiting AEW aircraft sweeps around. Color = mode; a flashing symbol = launch.
RWR plan view — own-ship at center, threats by bearing and lethality. Flashing symbol = missile launch.
Countermeasure
Seduction
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Decoy vs target RCS
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Doppler separation
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EP result
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Selected stage — LNA
Click a block in the diagram to edit it.
System / scenario
RF receiver block diagram — signal flows left→right. Click any block to edit its gain / noise figure / loss. Values propagate through the Friis cascade to sensitivity and detection range.
System noise figure
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Cascade gain
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Sensitivity (MDS)
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Detection range
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Noise budget (Friis cascade). System noise factor is F = F₁ + (F₂−1)/G₁ + (F₃−1)/(G₁G₂) + … — the first stage and anything ahead of it dominate. A passive loss L contributes F = L directly, so every dB of feed/limiter loss before the LNA adds ≈1 dB to system NF; a high-gain, low-NF LNA suppresses the noise of everything downstream. Sensitivity is MDS = −174 dBm/Hz + 10log₁₀B + NF + SNRreq, and detection range follows the radar range equation, R ∝ (PtG²λ²σ ⁄ MDS)1/4. Per-stage noise contribution is charted in the diagram. Receiver treatment follows Poisel, RF Electronics for Electronic Warfare (Artech, 2019).
Intercept
Low observable
Anti-jam & C/N₀
Model per Kaplan & Hegarty, Understanding GPS/GNSS. Q is the jammer-quality factor (lower = more efficient). Illustrative / notional.
Generic, animated targets across the four classic radar displays. Skolnik; Stimson; NAWCWD TP 8347. Illustrative / notional.
Pulse compression
Vertical engagement
2nd-order effects
Detection coverageRadio horizonAircraft
Vertical plane (range × altitude): the aircraft closes from the right; it is detected once it crosses into the shaded coverage — but stays hidden below the radio horizon at low altitude.
Aircraft range
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Detection range @ alt
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Radio horizon @ alt
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Status
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Scanned aperture
Array patternMainbeamJammer bearingGrating lobe
Pattern vs. angle as the beam is steered off boresight. Watch scan loss, mainbeam broadening, and grating lobes opening a door for the jammer.
Scan loss
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Mainbeam broadening
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Grating lobe
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Array gain toward jammer
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Scanning has a price. Gain drops by ≈cos θs and the beam widens by 1 ⁄ cos θs. Above d ⁄ λ ≈ 1 ⁄ (1 + |sin θs|) a grating lobe appears at sin θg = sin θs − λ⁄d — a full-gain door a jammer can exploit. Push d⁄λ above 0.5 and steer.
Generic / illustrative data. Every parameter below is a rounded, generic, order-of-magnitude value representative of a class of system (by frequency band and role) — not any specific fielded system. Nothing here reflects any real system's performance or any classified capability. Use for instruction and relative comparison only.
Multipath geometry
Multipath coverageFree-spaceRadio horizon
Vertical-plane coverage. The direct and surface-reflected rays interfere into lobes; detection range at each elevation is R₀·F, where F is the pattern-propagation factor (0–2). Uses the selected scenario radar's frequency for λ.
λ (scenario radar)
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First lobe max
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First null
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Peak range (2·R₀)
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Pattern-propagation factor. Over a reflecting surface the field is F = |1 + D·ρ·Γ·e^{jα}|, with path-difference phase α = (2π/λ)·2·h·sinθ, reflection coefficient Γ (≈ −1 for horizontal polarization at low grazing), surface reflectivity ρ reduced by roughness (Rayleigh: ρ_s = e^{−2(2πσ_h sinθ/λ)²}), and divergence factor D over the curved earth. Lobe maxima double the free-space range (F=2, +12 dB two-way); nulls create low-altitude gaps a jammer or low flyer can exploit. Maxima at sinθ = (2m−1)λ/(4h), nulls at sinθ = mλ/(2h) — raise the antenna and the lobes get finer.
Detection
Non-fluct (SW 0)SW 1SW 2SW 3SW 4
Probability of detection vs. per-pulse SNR for the five Swerling target models, N pulses non-coherently integrated (Shnidman's equation). Fluctuating targets need much more SNR at high Pd — that gap is the fluctuation loss.
SNR for Pd=0.9 · SW0
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SW1 fluctuation loss
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Scenario det. range (Pd=0.9)
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Cumulative Pd (closing pass)
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Beyond single-pulse detection. A real radar integrates N pulses per dwell (coherent gain ≈ N, or non-coherent with an integration loss) and the target's RCS fluctuates pulse-to-pulse or scan-to-scan. Swerling 1/2 (Rayleigh, many equal scatterers) demand ~8 dB more than a steady target at Pd=0.9; Swerling 3/4 (one dominant plus small scatterers) sit in between. Cumulative Pd over a closing pass — 1 − ∏(1 − Pd,i) — is why a target that's marginal on one scan is almost certainly caught over several as it closes.
Front-end
Fundamental (1:1)IM3 (3:1)Noise floor
Two-tone transfer: the wanted signal rises 1:1, third-order intermod products rise 3:1 and meet at the intercept point (IP3). The window between the noise floor and where IM3 clears the noise is the spurious-free dynamic range.
Noise floor (MDS)
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Output IP3
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SFDR
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Jammer desense
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Second- and third-order receiver limits (Poisel). Sensitivity sets the floor; linearity sets the ceiling. P1dB ≈ IIP3 − 9.6 dB is where gain compresses; a strong in-band or nearby jammer above it desensitizes the receiver (raises effective noise) and blocks weak targets. Two tones generate IM3 products at 2f₁−f₂ that fall in band and rise three times as fast as the signal, so SFDR = ⅔·(IIP3 − MDS). Finally, the interferer mixes with LO phase noise (reciprocal mixing) to deposit noise in the IF — often the real limit near a high-ERP jammer.
Losses & gains
Detection range starting from the ideal radar range equation, with each real-world correction applied in turn. Green steps add range (integration gain, propagation lobe); orange steps subtract it. Uses the scenario radar.
Ideal range R₀
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Net budget
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Effective range
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Fraction of ideal
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From textbook to reality. The range equation gives an optimistic R₀; the delivered range is R₀ scaled by every loss and gain in the chain. Because detection range grows as SNR¼, each decibel moves range only by 10^(−ΔL/40) — so it takes ~6 dB to halve the range, but the losses stack. Integration is the one big lever pushing the other way. This is the honest budget behind a coverage claim.
Uncertainty
1σ uncertainties
Monte Carlo burn-through range: each trial perturbs jammer ERP, jammer range, and target RCS within their 1σ bands, then solves burn-through. The spread is the confidence band a single point estimate hides. Uses the scenario radar / jammer / geometry.
Mean burn-through
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Std deviation
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10th – 90th pct
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P(no burn-through)
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From a point estimate to a distribution. The Engagement tab gives one burn-through range for one set of assumptions — but jammer ERP, standoff range, and target RCS are never known exactly. Propagating that uncertainty by Monte Carlo turns the single number into a distribution: the histogram's spread and the 10th–90th percentile band show how confident the burn-through prediction really is, and the fraction of trials with no burn-through is the chance the jammer wins outright. This is how you turn a deterministic calculator into a risk assessment.
Fundamentals
Wavelength λ
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Range resolution ΔR
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Unambiguous range Ru
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Unambiguous velocity vu
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Doppler shift fd
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Beamwidth θ ≈ 70λ/D
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Duty cycle
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Time-bandwidth product
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Core radar relationships. A pulse radar trades range against velocity through its PRF: the unambiguous rangeRu = c / (2·PRF) shrinks as PRF rises, while the unambiguous (blind) velocityvu = λ·PRF / 4 grows — you cannot maximize both, which is the whole reason for low/medium/high-PRF modes and PRF staggering. Range resolutionΔR = c / (2B) depends only on bandwidth (hence pulse compression). The Doppler shift is fd = 2v/λ; beamwidth scales as θ ≈ 70·λ/D (degrees) so a bigger aperture or higher frequency narrows the beam; and the time-bandwidth productτ·B is the pulse-compression gain. Load any system from the roster to see its numbers.
Range equation
SNR vs rangeRequired SNR
Single-pulse signal-to-noise vs. range from the radar range equation. Detection range is where the curve crosses the required SNR — and it moves only as the fourth root of any power-like term.
Detection range
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SNR at 100 km
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×2 power → range
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Wavelength λ
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The radar range equation.SNR = (Pt·G²·λ²·σ) / ((4π)³·R⁴·k·Ts·B·F·L), so detection range Rmax ∝ (Pt·G²·λ²·σ / (k·T·B·F·L·SNR))¼. The fourth-root is the key intuition: doubling transmit power buys only ~19% more range (2¼), and cutting a target's RCS by 16× (−12 dBsm) halves the detection range. Antenna gain enters squared (it helps on both transmit and receive), and lower frequency (longer λ) helps range for a fixed gain but costs angular resolution. Load a roster system to anchor the numbers, then drag any term to feel its leverage.
Live parameter editor. Edit any cell and the change flows to every tab immediately — engagement math, scopes, order of battle, all of it. Add your own systems, delete ones you don't use, and Export/Import the whole set as CSV so parameter cases are reproducible in class. IDs are auto-assigned and fixed (they key the dropdowns). All values are generic / notional.
The ERP column is jammer EIRP in kW; the engagement model converts it to the J/S ratio via Harrison's countermeasures.jammer_to_signal(). Radar Gsl is the sidelobe gain used for standoff (sidelobe-entry) jamming. Changing a system here is exactly equivalent to editing the source data — handy for wargaming a hypothetical upgrade or a captured-parameter case.
Reference material. Every calculator in OpenELINT Lab is built from the open, published methods below. The models are re-implementations of textbook formulas; all system parameters are generic / notional (see the Order of Battle and Systems / Data tabs). No classified data is used or implied, and no specific fielded system is modelled.
Method & algorithm references
Lee A. Harrison — Introduction to Radar Using Python and MATLAB. Artech House, 2019.
Drives: array factor & tapers (Null Steering, Sidelobe Canceler, Scan Loss); the radar range equation, countermeasures.jammer_to_signal(), and single-pulse Marcum-Q Pd (Engagement, Radar Scopes, detection thresholds).
Richard A. Poisel — RF Electronics for Electronic Warfare. Artech House, 2019.
Drives: component-level receiver chain — Friis cascaded noise figure, gain/loss budget, MDS & detection range (Receiver Chain); intercept receivers and emitter processing (ELINT / ESM).
Carlos A. Davila, Glenn D. Hopkins & Gregory A. Showman — Radar and EW Modeling in MATLAB and Simulink. Artech House, 2024.
Drives: pulse compression & time-bandwidth gain, MTI / blind speeds, and CA-CFAR (Signal Processing).
David L. Lynch Jr. — Introduction to RF Stealth, 2nd ed. IET, 2021.
Drives: low-observable detection vs. intercept ranges, the LPI crossover, aspect-dependent RCS and the RCS budget (LO / Stealth).
Ying Liu, Yongtao Jia & Shuxi Gong — Antenna Radar Cross Section: Theory and Design. Springer, 2025.
Drives: antenna-mode RCS contributions used in the RCS budget (LO / Stealth).
Xixiang Zhang, Kaiqi Xiao & Jie Gu — Theory to Countermeasures Against New Radars. Springer, 2022.
Drives: band-dependent counter-stealth behaviour — why VHF/UHF radars recover low-observable targets (LO / Stealth, VHF counter-stealth systems).
Guangfu Tang, Yifeng Cai, Rongbing Gan & Yaodong Zhao — Techniques and System Design of Radar Active Jamming. Springer, 2023.
Drives: DRFM active-jamming techniques — RGPO/VGPO, false targets, angle deception (Deception); noise-jamming geometries (Engagement).
Phillip E. Pace — Developing Digital RF Memories and Transceiver Technologies for Electromagnetic Warfare. Artech House, 2022.
Drives: DRFM finite-bit spurious false targets & SNR/SFDR, counter-DRFM waveform agility, coordinated RGPO–VGPO with range/Doppler-consistency EP, and the Digital Image Synthesizer structured false target (Deception / DRFM sub-modes).
James Ward & Stephen M. Kogon — Space-Time Adaptive Processing for AMTI and GMTI Radar (MIT Lincoln Laboratory tutorial); after J. Ward, Space-Time Adaptive Processing for Airborne Radar, MIT LL Tech. Rep. 1015.
Drives: the space-time steering vector, optimum weights w=R⁻¹v, the clutter ridge & Brennan’s rule, SINR-loss / MDV, and DPCA (STAP sub-modes of Signal Processing).
Rohde & Schwarz — Deceptive Jammer and DRFM Testing (v2.0) & Smart Jammer / DRFM Testing, industry test & measurement application notes (provided).
Supplemental corroboration of deceptive-jammer / DRFM test methods and false-target signatures (Deception / DRFM).
Self-Protection Jammer Systems — course reference (provided).
Drives: self-protection jamming, decoys & chaff kinematics, RWR threat presentation, and the electronic-protection counters shown per technique (Deception, RWR, Decoys & Chaff).
Paul E. Hannen — Radar and Electronic Warfare Principles for the Non-Specialist. SciTech / IET, 2016.
Drives: cross-cutting radar & EW definitions and first-order relationships used throughout for framing and sanity checks.
Naval Air Warfare Center Weapons Division — Electronic Warfare and Radar Systems Engineering Handbook, NAWCWD TP 8347. Point Mugu, CA.
Drives: cross-cutting one-way / two-way link budgets, J/S and burn-through range, RWR / ES range equations, and antenna & propagation first-order relationships used for framing and sanity checks throughout.
David L. Adamy — EW 101 / 102 / 103 / 105 (first, second & third courses in EW; tactical comms EW; space EW). Artech House, 2001–2021.
Drives: intuition-level EW geometry — jamming-to-signal, burn-through, decoys, and RWR / ES concepts — used for framing across the countermeasures and SIGINT tabs.
SIGINT · ELINT / ESM references
Richard G. Wiley — ELINT: The Interception and Analysis of Radar Signals. Artech House.
Drives: intercept, PDW formation, and de-interleaving (ELINT / ESM tab).
Sue Robertson — Practical ESM Analysis. Artech House.
Drives: emitter sorting / identification and receiver probability-of-intercept (ELINT / ESM tab).
Nicholas A. O'Donoughue — Emitter Detection and Geolocation for Electronic Warfare. Artech House.
Drives: AOA / TDOA / FDOA geolocation, the Cramér–Rao (CRLB) error ellipse, and GDOP.
James Genova — Electronic Warfare Signal Processing. Artech House.
Drives: receiver signal processing and intercept-receiver architectures (ELINT / ESM).
Andrea De Martino — Introduction to Modern EW Systems. Artech House, 2018.
Drives: cross-cutting framing of modern EW receivers, ES, and jamming.
GNSS / GPS jamming & spoofing references
Elliott D. Kaplan & Christopher J. Hegarty (eds.) — Understanding GPS/GNSS: Principles and Applications, 3rd ed. Artech House, 2017.
Drives: the anti-jam effective-C/N₀ equation (9.18), the jamming-resistance quality factors Q (Table 9.3) and J/S performance (Table 9.4), acquisition / carrier-tracking thresholds, and the denial-range link budget (GNSS Jamming — all sub-modes). Module output reproduces Table 9.4 to < 0.1 dB.
Pratap Misra & Per Enge — Global Positioning System: Signals, Measurements, and Performance, 2nd ed. Ganga-Jamuna Press, 2006.
Drives: received-power / C/N₀ budgets, DLL code-tracking jitter → pseudorange error, and interference / spoofing framing (GNSS Jamming — ranging error, spoofing).
B. Rama Rao, W. Kunysz, R. Fante & K. McDonald — GPS/GNSS Antennas. Artech House, 2012.
Drives: CRPA adaptive nulling (an N-element array places up to N−1 spatial nulls) and angle-of-arrival spoof discrimination (GNSS Jamming — CRPA null-depth control & spoofing defences).
General parameter references
The roster holds generic, class-representative parameters (by frequency band and role) — not any specific fielded system. Typical value ranges for radar transmit power, gain, PRF, pulse width, and beamwidth are drawn from open educational references such as radartutorial.eu and the standard radar textbooks listed above. All figures are rounded, order-of-magnitude values for a class of system — not measured performance — and nothing here reflects any classified capability. Use for instruction and relative comparison only.
