Training Slides

1. Training Slides Code 5774 Naval Research Laboratory Washington DC, 20375 202-404-7616 (DSN) 754-7616 builder@enews.nrl.navy.mil builder@nrl-dc.navy.smil.mil https://builder.nrl.navy.mil https://builder.nrl-dc.navy.smil.mil

2. Tips • Heights: Altitudes are a huge factor when estimating propagation loss. If a plot looks weird, or before you send the information off, double check that height fields are set appropriately. • Platform height • Make sure aircraft are at a reasonable altitude • Check whether terrain is being added to the altitude (AGL) • Antenna height • Make sure the antenna height reflects the expected conditions • Plot height • Make sure the plot is being calculated at the correct height • Make sure the plot is being positioned with desired respect to terrain height • Wrapping over terrain (AGL) • Constant altitude when terrain is encountered (MSL) • If you calculated across a range of heights, you can open up the VPS and see which slice is being drawn on the main display • Sampling rate • Before taking the final screenshot, or replying with your final results, take a few minutes to generate the plot again at a high sampling rate. Sample at least along each degree and every 500 meters. Remember that two sampling points •  Target Detectability Plot • Min/Ideal values (Min/Ideal PD's) • Radars can show an arbitrary Min/Ideal SNR, can use the device's defined Min/Ideal SNR's, or can show Target Probability of Detection values. Make sure the plots is showing the values you're interested in. • Target Platform (or RCS) • Detectability is heavily dependent on a platform's RCS (Radar Cross Section)

3. Tips • SNR Plots • Rx Function • Do you know the capabilities of your expected receiver? You should model them in a function, then select that function as the Rx function in the Visualization tab of the function you're visualizing. • Min. Discernable SNR and Ideal SNR • These two values control how a plot is colored. Make sure they apply to the situation you're modeling. If they're not set appropriately, your plot won't be much use. • Take additional care to check these if switching between Rx functions or between propagation types (signal strength plot), because these values are sometimes switched during the selection process. • Signal Strength Plots • Min. Discernable and Idea Signal levels… • Like the Min & Idea SNR values, these control a plot's coloration when Signal Strength propagation is being modeled. • Signal strength (dBW) and SNR (dB) will be very different numbers. While SNRs are usually low (5-15dB), signal levels are represented by much greater (though smaller) values (-90 -> -140 dBW). • The noise floor is around -150dBW. It makes sense that the signal levels at the edge of receive range approach that value as they drop off from the transmitter.

4. Day 1 Exercise • The USS Afloat needs to operate near an oil platform in the Suez Canal. • A known launch site for ASM missiles is nearby. It will launch ASM’s against the Afloat if it shows up on the radar. • An EA-6B will fly a “race track” pattern along the far coast, jamming the enemy radar site.

5. ASM Site Intel. • Latitude: 28.62848940297 • Longitude: 33.29916208894 • Altitude: 10ft (AGL) • Antenna: • 7 ft high • 8 dB gain • Frequency: 3 GHz • Power: 5 kW

6. USS Afloat Info. • RCS: 10,000 m*m, centered 50 ft over surface • Latitude: 28.60673273678 • Longitude: 33.15317304352

7. EA-6B Settings • Latitude: 28.5507793657 • Longitude: 33.05172487184 • Altitude: 2,000 ft • Velocity: 500 kts • Antenna Gain: 5dBi • Peak Power: 1 kW • RCS: 500 m*m

8. 45o 15o 30o EA-6B Capabilities • One jamming pod on each wing, pointing away from the body. • Each jamming pod should be 5 ft out on the wing • Scan patterns cover about 45 degrees • Antennas are angled 15 degrees below the wings, and cover 30 degrees beneath that during scanning.

9. EA-6B Race Track… • Begin: • Latitude: 28.54402694052 • Longitude: 33.04648785751 • First Bank: • 28.59920982346 • 33.01343595989 • Second Bank • 28.50235318097 • 33.06638056853

10. Questions • Without jamming… • Can the radar site detect the EA-6B? • Can the radar site see the USS Afloat? • How does jamming change this (ignore EA-6B movement)? • During which sections of the jammer’s track is the Afloat most vulnerable? • How can we eliminate these vulnerabilities? • Are there any sections other than the turns with questionable coverage?

11. Solutions • Without jamming… • Can the radar site detect the EA-6B? (No) Plot probability of detection for the enemy radar at the EA-6B’s height (2000 ft), and RCS (500sqm) • Can the radar site see the USS Afloat? (Yes) Plot probability of detection for the enemy radar at theAfloat’s height (2000 ft), and RCS (500sqm) • How does jamming change this? • With jamming, the enemy radar can no longer detect the Afloat. • During which sections of the jammer’s track is the Afloat most vulnerable? • The banks are the most vulnerable. There are also a few spots as the EA approaches the first bank. How can these be eliminated?

12. USS Afloat Radar • Frequency: 5 GHz • Power: 2 kW • Gain: 15 dBi • Height: 60 ft • Spotting missiles • 5 m*m RCS • 10-20ft above sea

13. Questions • At what distance can the Afloat expect to detect missile threats with the expected characteristics? • How does the EA-6B’s jammer affect the USS Afloat’s threat-detection capabilities? • How much of the surrounding region is affected by the EA-6B’s signal (assume effects range from negligible at -120dBW to significant at -100 dBW) ? • Ignoring the coverage lost when banking, how much could the EA-6B lower their power and still provide effective cover for the Afloat?

14. Questions • At what distance can the Afloat expect to detect missile threats with the expected characteristics? • About 3 nm • How does the EA-6B’s jammer affect the USS Afloat’s threat-detection capabilities? • It doesn’t, because the EA is only jamming the 3GHz band • How much of the surrounding region is affected by the EA-6B’s signal (assume effects range from negligible at -120dBW to significant at -100 dBW) ? • Effects can be seen up to about 20nm out • Ignoring the coverage lost when banking, how much could the EA-6B lower their power to reduce unnecessary effects while providing effective cover for the Afloat?

15. Questions • If our intel about the threat site is less specific, we might not know the exact frequency that the enemy radar is operating at. • Assume we get a range of expected frequencies, say from 3GHz to 8GHz. • How does a greater signal frequency change detection distances? • How can we change the jammer to cover the range of expected frequencies? • Set Tx Frequency to 5.5GHz (between 3GHz and 8GHz) • Set Tx Bandwidth to 5GHz

16. Questions • How does the EA-6B’s jammer affect the USS Afloat’s threat-detection capabilities? • Plot the USS Afloat’s PD for a 10 sqm target 20 ft AGL • How much of the surrounding region is affected by the EA-6B’s signal? • Answer this with a signal strength plot for the EA-6B’s jammer. • What would happen if the Afloat’s radar operated at a higher frequency (say 5 GHz)? • No interference from jamming, but range is reduced. • How much could the EA-6B lower their power and still provide effective cover for the Afloat? • Maybe…find the place on the EA’s track with poorest jamming coverage and reduce power until that is –just– effective. Then play through the loop to make sure sufficient coverage occurs.