Cognitive EW — that the threat library is complete and the threat behaves as catalogued. AI/ML emitter ID — that a classifier's label is a fact. NAVWAR — that you always know where you are. Space EW — that the satellites and links behind your support package are always there.
Sense — intercept and characterize the emitter (ES). Learn — model what the emitter does, without needing a library entry. Adapt — choose a response, then score it by what the emitter does next and feed that back. The feedback is what a library lookup lacks.
The library holds catalogued parametric signatures, per mode (L12). A radar whose waveform is software can present a mode nobody has catalogued, so the lookup finds no match or the wrong one — and the collect, analyze, reprogram cycle that fixes the library takes weeks, not seconds.
The same sense–learn–adapt loop run by the adversary: a radar that senses your jamming and changes its own waveform in reply. L15's electronic-protection menu stops being a design-time choice and becomes an in-flight one.
Rows are what each test emitter really was; columns are what the classifier said; the diagonal counts the correct calls. Every off-diagonal cell is one particular mistake, such as a tracking radar called an acquisition radar.
\(P_d\) along that class's row: the diagonal cell over the row total (true members caught). \(P_{fa}\) down its column, off the diagonal: the non-members called that class, over all non-members. In the lesson's example, TTR gives \(P_d = 88/100 = 0.88\) and \(P_{fa} = 10/200 = 0.05\).
The classifier outputs a score, and a threshold decides when it names a class. Lower the threshold for "TTR" and both \(P_d\) and \(P_{fa}\) rise; sweep it and the pairs trace L8's ROC. Because a missed tracking radar costs more than a false one, that threshold is set low.
Because the class is rare. If one intercept in twenty is a TTR, 1000 intercepts give \(0.88 \times 50 = 44\) true TTR calls and \(0.05 \times 950 \approx 48\) false ones. It is L8's many-cells lesson: a small false-alarm rate over many chances fills the display.
It still answers with one of the labels it knows — its matrix has no "unknown" column — often with high confidence. Unless it is built to reject unfamiliar inputs, it turns a library's "no match" into a confident, wrong match. Adversarial emitters, shaped to be mislabeled, exploit the same weakness.
The L1 C/A signal (1575.42 MHz) arrives from about 20,000 km at roughly \(-130\) dBm, about 20 dB under the thermal noise in its 2 MHz band (\(\approx -111\) dBm). The code's processing gain, \(G_p = 10\log_{10}(1.023\times10^6/50) \approx 43\) dB, collapses the signal back out of the noise (L16).
Despreading gives \((\text{J/S})_\text{after} \approx (\text{J/S})_\text{in} - G_p\), and the loops need a margin \(M\) on top, so \((\text{J/S})_\text{tol} = G_p - M\). With the notional \(M = 13\) dB that is about 30 dB — the jammer can arrive a thousand times louder than the signal.
Set J/S equal to the tolerable level and solve the one-way link for range: \(20\log_{10} R_\text{deny} = \text{ERP} - S - (\text{J/S})_\text{tol} - 20\log_{10} f_\text{GHz} - 92.45\), with ERP and \(S\) in dBm and \(R\) in km (L2's FSPL). A notional 10 W jammer denies about 150 km.
It doubles. The jammer's signal travels one way, so its power falls as \(1/R^2\) and the radius grows as \(\sqrt{\text{ERP}}\): 6 dB of power buys one doubling of range. A radar's echo pays \(1/R^4\) and would need sixteen times the power. Conversely, every 6 dB of receiver anti-jam halves the circle.
Jamming denies: it raises the noise until the loops lose lock, and the receiver knows. Spoofing deceives: counterfeit signals capture the loops and walk the position away, so the receiver reports a confident, wrong fix — L18's range-gate pull-off aimed at your position. Defenses: authentication, INS cross-checks, integrity monitoring.
With a notional constant drift rate, \(e \approx \dot{e}\,t\) with \(t = \ell/V\) for a chord \(\ell\) through the circle. A navigation-grade INS drifts about 1.5 km/h. A clearance past a MEZ is real only if it exceeds \(e\): inflate the MEZ, spend less time denied, or plan a fix before the leg that matters.
An uplink jammer attacks the satellite: from inside its receive beam, a relay satellite retransmits the jam to every user; from outside, the antenna barely hears it. A downlink jammer competes with the satellite's faint signal at one receiver at a time, so it denies only the terminals near it — which is why GPS denial is a circle.
Pick one trend and say what it would change in your route — a number or a line on the map, and by how much if you can. "GPS could be jammed" is a disclaimer; comparing the INS error on a denied leg with your smallest MEZ clearance is analysis.