international telemetry consortium effects of diminishing spectrum resources on aeronautical...
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International Telemetry Consortium
Effects of Diminishing Spectrum Resources on Aeronautical
Telemetry
Jim Rizzo
Greg Strombo
AFFTC/ITC
Edwards AFB CA, 93534
25 October, 2001
DAB Issues
WRC-92 2310 – 2360 MHz» 2320 – 2345 Digital Audio Broadcast
– Affect began Summer 2000– Sirius Satellites First– XM Followed 2 months later– 1 Validated report of interference from Sirius– 2310 – 2320 & 2345 – 2360 Still not occupied
BBA-97 2385 – 2390– Still not occupied– Exasperating problems with DAB re-allocation
Initial Response to DAB
Formed ad hoc group in Aug 00» RCC TG and FMG Members
Discussed ramifications of DAB/TM Presentation by Gene Law of technical
ramifications Wrote policy letter: Strongly Urging all
member ranges to cease operations in 2320-2345 MHz
Predicted InterferenceTelemetry vs. DAB Rcvr
0
3
6
9
12
15
18
21
24
(I+
N)/N
(dB
)
0 200 400 600 800 1000 Range (TM XMTR to DAB RCVR) (km)
TM: 5W 5 Mb/s PCM/FM
Immediate Effects of Reduced Spectrum
Mission Profile Changes» Aircraft are routinely placed into standby and has
resulted in lost missions» Aircraft often operate outside of normal working
hours and on weekends – Note: Activity was specifically excluded from this
analysis to better enable comparison to predicted telemetry utilization levels
» Limitations on preflight ground testing» Limitations on Area of Operations
Telemetry Consumers at Edwards AFB
AFFTC Operations» 410th FLTS » 411th FLTS» 416th FLTS» 418th FLTS » 419th FLTS » 452nd FLTS » Test Pilot School
Significant Activities» Contractors
– Lockheed – Boeing– Northrop
» Phillips Laboratory» Miscellaneous
– Missiles– Special Scheduling
» NASA Ops (DFRC)
Spectrum Resources for Availability Analysis
Band DescriptionBand Start
Band End
Hrs/Day
Date Start
Date End
Total Days
MHz-Hrs Per Day
MHz-Hrs for Period
L-Band 1435 1525 8 08/05/01 10/04/01 40 720 28800
S-Band 2200 2290 8 08/06/01 10/05/01 40 720 28800Pre-DAB 2310 2390 8 08/05/01 10/04/01 40 640 25600
Upper S Pre BBA 2360 2390 8 08/05/01 10/04/01 40 240 9600
Upper S Post BBA 2360 2385 8 08/05/01 10/04/01 40 200 8000
83200
67200
65600
Total Pre DAB
Total Pre BBA
Total Post BBA
TM Utilization atEdwards AFB
OrganizationTotal Use MHz-Hrs Pre DAB Post DAB Post BBA
Projected 2001 Post DAB
410 FLTS/DOO 132.50 0.16% 0.20% 0.20% 0.16%411 FLTS/DOO 7255.50 8.72% 10.80% 11.06% 14.27%416 FLTS/DOO 2837.95 3.41% 4.22% 4.33% 1.10%418 FLTS/DOO 1105.50 1.33% 1.65% 1.69% 0.78%419 FLTS/DOO 5732.84 6.89% 8.53% 8.74% 17.88%452 FLTS/DOO 575.00 0.69% 0.86% 0.88% 2.91%LOCKHEED 532.50 0.64% 0.79% 0.81% 0.78%MISCELLANEOUS 15383.00 18.49% 22.89% 23.45% 29.91%NASA FLIGHT OPS 22259.20 26.75% 33.12% 33.93% 3.04%NORTHROP 142.00 0.17% 0.21% 0.22% 0.00%USAF TPS 81.67 0.10% 0.12% 0.12% 0.13%TOTALS 56037.66 67.35% 83.39% 85.42% 70.95%
TM Utilization atEdwards AFB
0.00%
10.00%
20.00%
30.00%
40.00%
50.00%
60.00%
70.00%
80.00%
90.00%
Pre DAB Post DAB Post BBA Projected 2001 PostDAB
Assumes: Full 8 hour flying dayNo other ranges operating100% Spectrum efficency
No Mission Slips
0
2000
4000
6000
8000
10000
12000
1999 2000 2001 2002 2003 2004 2005
MH
z/H
ou
rs p
er
we
ek
Projected Utilization Discrepancies
Delay of aircraft deliveries reduced spectrum consumption rates
Extended aircraft modifications Unanticipated new systems Cancellation of projects
Result; Train Wreck Delayed approximately 18 Months
Telemetry Spectrum Metrics
Use » Provides Actual Amount of Unoccupied Spectrum» Determines Efficiency of Spectrum Reuse
Availability» Characterizes Band Fragmentation» Projects Availability of Unoccupied Spectrum
– Probability that Standard mission types could schedule telemetry on short notice or reschedule after mission slips
» Effectiveness of Automated Tools being Integrated into IFDS Phase III Software Development
Increasing Spectrum Availability
Geographic Separation» Line-of-Sight Analysis» Propagation Analysis» Direction to Receiver Analysis
Operational Constraints» Restriction on pre-flight TM checks» Radio Frequency “Hats”
Temporal Techniques» 15 min Time Increments for Scheduling» Evening and Weekend Missions
Increasing Spectrum Availability
Spectrum Monitoring» Provides Actual Spectrum Utilization» Early Identification of Rogue Emitters
Interference Resolution» Reduction of Spectrum Piracy
Summary
Presence of DAB has increased number of “Lost Missions”
Worst Has Yet to Come Current Mitigation Efforts
» Mission Profile Adjustments» Implementation of IFDS Phase III» Development of IFDS Metrics» Greater Monitoring of Spectrum