D-RAPCON PSR Pd Study AFFSA

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D-RAPCON PSR Probability of Detection (Pd) Performance

Analysis

D-RAPCON Program Office

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Concerns

• D-RAPCON PSR will be capable of half of the peak output power of MASR and DASR– Approximately 11 kW vs. 22 kW– MASR PSR uses 8 High Power Amplifiers (HPA) – D-RAPCON existing baseline PSR uses only 4 HPAs– This directly affects Pd

• D-RAPCON will consist of a single channel PSR vs. fully dual redundant PSR f– Full Redundancy means 2 sets of transmitter AND receiver hardware – MASR employs 2 PSR channels

• 4 HPAs per transmission channel = 8 HPAs – In addition to increased Pd performance there are other advantages to

two separate transmitters and receivers

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Critical PSR SRD Target Detection Requirements

PSR Operating Frequency <<11>> The PSR shall include a backup transmitter system or redundant transmitter sub-systems, such as multiple high power amplifiers (HPAs), that will allow the entire system to meet the required system reliability. (T=O)

PSR Detection Probability in the Clear <<23>> In the clear, the PSR shall have a single scan Probability of detection (Pd) ≥ 80% (T), > 90% (O), for a one square meter RCS, Swerling-1 type target, within the detection volume as defined herein section 3.2.2.3, PSR Detection Probability Volume at a Probability of False Alarm (PFA) ≤10-6 over 92 percent of the target radial velocities between -700 and +700 knots.

PSR Detection Probability Volume <<24>> The PSR detection probability requirements shall extend: from 0.5 NM to 60 NM on the nose of the beam, from between 8,000 to 20,000 feet AGL at 50 NM, and from the local radar horizon to 30 degrees elevation angle for any PSR antenna pointing azimuth angle from 0 to 360 degrees. (T=O)

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Detection Volume

4

50 60

e = 30 d

egrees

20

8

Alti

tude

(kft)

e

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Range (NM)

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Raytheon’s Position“The solution that Raytheon has proposed for D-RAPCON contains multiple HPAs and therefore satisfies requirement #11. Raytheon feels that our proposal was very clear on this subject:

Our deployable EA16300 antenna integrates the performance of our NAS-certified ground based DASR PSR and LVA antennas with that of Australian TASR proven deployable EA5427 antenna, providing unsurpassed PSR and MSSR integrated antenna performance (see Figure II- 5(b)-(d)). Our air-cooled PSR single channel solid state transmitter is a proven in production item with Ao >0.999999, and expansion capability to dual-channel eight-module transmitter for PSR detection range >80 nmi.” *• Note that both DASR and TASR use 8 HPAs

* D-RAPCON_13_007 Raytheon Response CDRL A003-002_SRR Meeting Minutes – Backup PSR, 19 July 2013

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Raytheon Blake Chart

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• Raytheon claims that since multiple HPAs are being used that the baseline design satisfies Requirement 11

• Raytheon claims only 4 HPAs are required to meet required power to satisfy both requirements 23 and 24

• The Blake chart is correct but does not take into account the effects of multipath on Pd

• Multipath causes areas of low received SNR and thus lower Pd in the detection volume

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Analysis Focus

• This analysis quantitatively addresses Pd as a performance metric– 4 HPA vs. 8 HPA implementation

• D-RAPCON requirement for Pd is > 0.8 inside detection volume• D-RAPCON detection volume requirement

<<24>> The PSR detection probability requirements shall extend: from 0.5 NM to 60 NM on the nose of the beam, from between 8,000 to 20,000 feet AGL at 50 NM, and from the local radar horizon to 30 degrees elevation angle for any PSR antenna pointing azimuth angle from 0 to 360 degrees. (T=O)

• Other advantages of fully redundant PSR are also discussed

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Analysis Summary and Purpose• Purpose is to determine if Pd requirement is achievable within

the required detection volume– Realistic multipath environment

• Two cases• Zero HPA failure case

• Compare 4 HPA performance to 8 HPA performance using Pd as a metric• Land and Sea

• Single HPA failure case• Compare 3 HPA performance to 7 HPA performance using Pd as a metric• Land and Sea

• Two separate radar propagation models were used and results were compared– D-RAPCON MATLAB Radar Simulation*– AREPS used to validate the MATLAB model results– Both models assess effects of multipath on Pd

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*Based largely on Mahafza, Radar Systems Analysis and Design Using MATLAB

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Model Inputs and Assumptions

• Inputs taken from Blake chart in Raytheon SRR presentation– 10-6 Probability of False Alarm – 20 feet antenna height– 4.8 seconds antenna scan time– 34 dB antenna gain– 3 degree antenna tilt angle– 2.1 dB receiver noise figure– 89 microsecond radar pulse– 5 radar pulses per target dwell time– Dual frequency operation (2800 MHz and 2830 MHz)– Vertical polarized transmission signal– 7 dB signal miscellaneous signal loss– 1 square meter Swerling 1 target model– Flat Earth model (MATLAB), Spherical Earth multipath model (AREPS)– Ground reflection coefficient for water (worst case multipath)

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Probability of Detection (Pd) Results

• Percentage of Pd >0.8 in detection volume – No HPA Failures

• 8 HPAs 99.95 % MASR / DASR• 4 HPAs 98.93 % D-RAPCON

– 1.02% loss in relative performance– Single HPA Failure

• 7HPAs 99.79 % MASR / DASR• 3 HPAs 94.98 % D-RAPCON

– 4.81% loss in relative performance

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SRD Compliance Assessment• Raytheon’s Blake chart shows full compliance with the

SRD Pd requirement• The D-RAPCON multipath analysis shows

– 99% Pd compliance for no HPA failures (4 HPAs)– 95% Pd compliance for one HPA failure (3 HPAs)

• Note: There is no SRD requirement to meet performance with 3 HPAs– Very small areas where Pd is less than 0.8

• Due to nulls in antenna pattern caused by multipath• Small expected effect on operational effectiveness

– Better expected performance under 10,000 feet and for approach and landing

– Quick replacement of single failure insures operational effectiveness and availability (sparing)

– Radar optimization and/or greater antenna height will further reduce effects of multipath

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Performance Relative To MASR

• Relative Pd Performance – Going from 8 to 4 HPAs degrades performance only about 1% – Loss of one HPA increases difference in relative performance

• Going from 8 to 7 HPAs (MASR) does not significantly degrade performance (99.95% to 99.79% compliance)

• Going from 4 HPAs to 3 HPAs (D-RAPCON) degrades performance significantly (98.93% to 94.98% compliance)

– D-RAPCON 4 HPA system must rely heavily on sparing and quick replacement to match MASR Pd performance

• Additional D-RAPCON performance degradation– 4 HPAs Will not support 80 NM range extension

• Multipath effects increase with range– No automatic online weather optimization without loss of PSR– Lower reliability and availability than MASR– Potential “Qualification By Similarity” issues

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Recommended Trade Off Studies

• Performance Trade Off– Importance of the ability to fully replace the MASR/DASR

must be determined• Dually redundant PSR has marginal performance improvement

over MASR/DASR• D-RAPCON performance close to MASR assuming higher level of

sparing to compensate for loss in performance with 3 HPAs– Use model to assess Pd and range/azimuth accuracy

performance for typical landing trajectory• Life Cycle Cost Trade Off

– Extra cost for dually redundant PSR is estimated to be $1.1M per system

– Dually redundant PSR may translate to less spares– Trade off should be done to look at the relative life cycle

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Backup Slides

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Pd Performance Delta for 2800 MHZ, 2830 MHz and Combined 2800/2830 MHZ

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Land SeaNo Fail 8 4 Delta No Fail 8 4 Delta2800 99.59 97.5 2.09 2800.00 100.00 99.17 0.832830 99.59 97.55 2.04 2830.00 100.00 99.14 0.86comb 99.89 98.44 1.45 comb 100.00 99.42 0.581 Fail 7 3 Delta 1 Fail 7 3 Delta2800 99.02 93.56 5.46 2800.00 100.00 94.35 5.652830 99.03 93.52 5.51 2830.00 100.00 94.12 5.88comb 99.57 94.97 4.60 comb 100.00 94.99 5.01

Total Performance Gain 2.91%No Failures 1.02%One Failure 4.81%Land 3.03%Sea 2.80%Land No Failures 1.45%Sea No Failures 0.58%Land One Failure 4.60%Sea One Failure 5.01%

Less than 3.0% Pd performance gain for dually redundant PSR

D-RAPCON very nearly meets the Pd > 0.8 requirement for 100% of the detection volume • Average Pd = 0.92 (3 HPAs) vs 0.96 (7 HPAs)

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Pd Over Land (3, 4, 7, and 8 HPAs)

2800 MHz 3 HPAs

2830 MHz 3 HPAs

2800/2830 MHz 3 HPAs

2800 MHz 4 HPAs 2800 MHz 7 HPAs 2800 MHz 8 HPAs

2830 MHz 8 HPAs2830 MHz 7 HPAs2830 MHz 4 HPAs

2800/2830 MHz 4 HPAs

2800/2830 MHz 4 HPAs2800/2830 MHz 3 HPAs 2800/2830 MHz 7 HPAs 2800/2830 MHz 8 HPAs

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100% Compliance 100% Compliance

Pd Over Sea (3, 4, 7, and 8 HPAs)

2800 MHz 3 HPAs

2830 MHz 3 HPAs

2800/2830 MHz 3 HPAs

2800 MHz 4 HPAs 2800 MHz 7 HPAs 2800 MHz 8 HPAs

2830 MHz 8 HPAs2830 MHz 7 HPAs2830 MHz 4 HPAs

2800/2830 MHz 4 HPAs 2800/2830 MHz 7 HPAs 2800/2830 MHz 8 HPAs