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AUGER, Anne sophie, 03/22/2015 10:25 AM
| 1 | 1 | AUGER, Anne sophie | h1. DESIGN OF A TM/TC LINK BETWEEN SMALL AIRCRAFT AND GROUND STATION |
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| 3 | 2 | AUGER, Anne sophie | h2. INTRODUCTION |
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| 5 | 6 | AUGER, Anne sophie | The aim of this project is the design of a Telemetry and Telecommand (TM/TC) link between small aircrafts (ie TB20) and an antenna on top of ISAE building. There are different aspects in this work: |
| 6 | 2 | AUGER, Anne sophie | * regulatory aspects : we must pay for rights of emission on a given frequency band |
| 7 | 2 | AUGER, Anne sophie | * link budget aspects : some parameters can be adjusted to reach the wanted performance |
| 8 | 6 | AUGER, Anne sophie | * flight constraints have to be considered in the choice of the equipment to allow a full time link |
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| 10 | 1 | AUGER, Anne sophie | To summarize the system design constraints, we can fill the mission statement below: |
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| 15 | 6 | AUGER, Anne sophie | |_.Transmission content|Data (uplink and downlink|Video (downlink)| |
| 16 | 6 | AUGER, Anne sophie | |_.Quality of transmission|50 flight parameter/frames |
| 17 | 6 | AUGER, Anne sophie | 1 transmission/sec|12 fps |
| 18 | 6 | AUGER, Anne sophie | 720p display| |
| 19 | 6 | AUGER, Anne sophie | |_.Minimum range|50 km - Line Of Sight !figure!| |
| 20 | 6 | AUGER, Anne sophie | |_.Fligh constraints|+/-15° for attitude +/- 45° for inclination| |
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| 22 | 1 | AUGER, Anne sophie | In order to define the video bit rate required for our application, knowing the quality of the encoded video (720p) and its frame cadence (12 fps) , we used the following formula : |
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| 24 | 4 | AUGER, Anne sophie | p=. Bit rate = FPS * 5,0692 * L ^1,391 / (1000 * AR) |
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| 26 | 1 | AUGER, Anne sophie | With AR = 1,78, FPS=12 and L=720 |
| 27 | 4 | AUGER, Anne sophie | So |
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| 29 | 4 | AUGER, Anne sophie | p=.Bit rate=322 Kbps |
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| 31 | 3 | AUGER, Anne sophie | As the link will allow data and video transmission, we choose to use the MPEG4 packet format, adapted for multiplexing different nature content. Therefore, we have to consider extra bits due to the encapsulation of data in MPEG4 frames, and we decide to define a bit rate of 500 kbps. |
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| 36 | 1 | AUGER, Anne sophie | h2. RESEARCH OF A FREQUENCY BAND |
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| 39 | 2 | AUGER, Anne sophie | h3. Issue of a free band |
| 40 | 1 | AUGER, Anne sophie | SYSTEM DESIGN CONSTRAINTS AND VARIABLES |
| 41 | 1 | AUGER, Anne sophie | SIMULATION OF THE LINK BUDGET PERFORMANCE |