1. AAE 450 Spring 2008 Justin M. Rhodes 02.07.2008 Avionics - Telecommunications Analysis Code - Integration and Automation Webmaster Signal Frequency and Data Rate Analysis

2. AAE 450 Spring 2008 Telecommunications: Signal Frequency Assumptions  8.5 x 10 7 bps  20 m receiving antenna  35 degree beamwidth Equipment cost and complexity rises with frequency magnitude. Avionics 1

3. AAE 450 Spring 2008 Telecommunications: Data Rate Analysis Same assumptions at path length = 5,000 km Avionics 2 Reducing the data rate results in: Higher link margins Simpler equipment Cheaper systems

4. AAE 450 Spring 2008 Telecommunications: Signal Frequency Same assumptions at path length = 5,000 km Avionics 3 Higher Frequency Signal = Higher Doppler Shift High Doppler shift can result in loss of signal

5. AAE 450 Spring 2008 Doppler Shift Avionics 4 f = transmitted frequency v = velocity at which the vehicle is travelling away from the ground station c = speed of light λ = wavelength of transmitted wave

6. AAE 450 Spring 2008 Link Budget Analysis: Sample, Part 1 Avionics 5 ItemSymbolUnitsSourceValue frequencyfGHzinput parameter0.137 frequencyfMHzconversion137 wavelengthlamdamlamda = c/f2.188266117 transmitter powerPWattsinput parameter5 transmitter powerPdBW10logP6.989700043 transmitter line lossLfdBWinput parameter antenna gain towards vehicleη input parameter0.55 transmit antenna beamwidthθtθtdeginput parameter30 peak transmit antenna gainGptDbieq. 314.75757491 transmit antenna diameterDtmeq. 45.109489051 transmit antenna pointing offsetetdeginput parameter27 transmit antenna pointing lossLptdBeq. 5-9.72 transmit antenna gain (net)GtDbiGpt + Lpt5.037574906 Continued, next slide.

7. AAE 450 Spring 2008 Link Budget Analysis: Sample, Part 2 Avionics 6 ItemSymbolUnitsSourceValue equiv isotropic radiated powerEIRPDBWP + Lf + Gt11.02727495 propagation path lengthSkminput parameter4500 space lossLsdBeq. 6-148.2486616 propagation & polarization lossLadBfig. 1-0.3 receive antenna diameterDrminput parameter20 peak receive antenna gain (net)GrpdBieq. 726.56863815 receive antenna beamwidthθrθrdegeq. 47.664233577 receive antenna pointing errorerdeginput parameter0.2 receive antenna pointing lossLprdBeq. 5-0.008171537 receive antenna gainGrdBiGrp + Lpr26.56046661 system noise tempTsKfig. 2135 data rateRbpsinput parameter9600 Eb/No (1)Eb/NodBeq. 856.50 carrier to noise density ratioC/NodB-Hzeq. 1096.33 bit error rateBER input parameter0.00001 required Eb/No (2)REQ Eb/NodBfig. 39.6 implementation loss dBestimate-2 final margin dB(1) - (2) + (3)44.90485839