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Avionics, Software, and Simulation. Doug Astler Alex Krajewski Chris O’Hare Dennis Sanchez. Crew Capsule Selection. Team C4’s crew capsule was selected because it has no external elements, which leaves room for sensors
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Avionics, Software, and Simulation Doug Astler Alex KrajewskiChris O’HareDennis Sanchez
Crew Capsule Selection • Team C4’s crew capsule was selected because it has no external elements, which leaves room for sensors • It also has the highest mass margin, we therefore have the most available sensor mass total to work with
Link Budget Communications link budgets were created for the following links. A safety factor of 2 (3 dB) is used for determining transmitter size and power.
Link Budget - Receivers • The spacecraft will make use of different receivers during the mission; • Deep Space Network • Provides continuous possible coverage from three stations • Large dishes can pick up weak signals • Has some no-coverage spots within 30,000 km altitudes • TDRSS • TDRSS can relay transmissions to grounds stations • Useful if DSN is not available • No atmospheric concerns for signal • L2 Relay satellite • A theoretical satellite in the L2 Lagrangian point will help maintain continuous communication during orbital and lunar surface times on the dark side of the moon • This will be modeled as a TDRSS satellite • EVA suits • Communication must be maintained with crew during all EVA missions
Link Budget - Receivers This table represents the relevant statistics of the various receivers used in this mission.
Link budget - Diagrams Spacecraft to DSN Spacecraft to TDRSS Spacecraft to L2 relay satellite L2 Relay sat to DSN/TDRSS
Link Budget - Spacecraft • To minimize transmitter mass and size, one transmitter dish will be used for all three bands considered • This will limit communications to only one link at a time • Size and power requirements will be dictated by the band with the greatest requirements (in bold)
Link Budget – Relay Sat • The L2 relay sat antenna size is being modeled on TDRSS • We assume that it must reach earth from the L2 Lagrangian position
Link Budget - UHF Omni • UHF omni antenna will be used for both space and lunar EVA • Maximum EVA distance is 10 km (Apollo legacy)
Link Budget – Final Stats These are the final stats, that will drive the size and maximum power draw of the transmitters.
Different Bands of Frequency Microwave Frequency Band
Transmitter Due to the small transmitter being used, signal beams will be narrow. This necessitates accurate transmitter pointing.
Transmitter • Transmitter will be mounted on a 2 DOF rotational mount • Provides 2πsteradian coverage • Spacecraft will contain 2 transmitters at opposite sides • Minimizes spacecraft attitude maneuvers to send a transmission • Provides redundancy in the event of a transmitter failure
Different Bands of Frequency EU, NATO, US ECM frequency designations
DS18B20 Programmable Resolution 1-Wire Digital Thermometer • Provides 9-bit and 12-bit Celcius temperature measurements • Accuracy of ± 0.5°C in range of -10°C to 85°C • Accuracy of ± 2°C in range of -55°C to 125°C • Operating temperature range • -55° to 125°C • Power Supply • 3.0 – 5.5 Volts DC • Current Consumption • 1 to 1.5mA DC
DS18B20 Programmable Resolution 1-Wire Digital Thermometer • Sampling Rate • Temperature conversion times • 9 bit resolution = 93.75ms • 10 bit resolution = 187.5ms • 11 bit resolution = 375ms • 12 bit resolution = 750ms • Signal Band • Max can be is 1.3 GHz for signal output • Criticality • Used to check internal temperature of crew system vehicle to make sure it is around room temperature for crew • Ensures astronauts are safe
MPL115A Digital barometric pressure sensor • Measures an absolute pressure range of • 0 – 115 kpa • Accuracy of ± 1kpa in range of -20°C to 85°C • Operating temperature range • -40°C to 105°C • Power Supply • 2.4 – 5.5 Volts • Current Consumption • Sleep Mode = 1μA • Active = 5μA at one measurement per second
MPL115A Digital barometric pressure sensor • Sampling Rate • 1 measurement per second • Signal Band • Max can be is 8 MHz for SPI timing component • Criticality • Used to check internal pressure of crew system vehicle to make sure it is safe for crew • Ensures astronauts’ safety during the mission
TR250Z Oxygen Sensor • Measures O2 in a range of 0 to 25% or 0.1 to 95% • Accuracy of ± 0.5% (2% full scale) • Operating temperature range • -10°C to 70°C • Power Supply • 24 V DC ± 10% • Current Consumption • 600 mA @ 24V DC
TR250Z Oxygen Sensor • Sampling Rate • Sampling is done by diffusion with (ZrO2) Zirconium dioxide • 4 sec max diffusion time • Signal Band • 13.8 GHz to 14.7 GHz • Criticality • Used to check internal levels of oxygen of crew system vehicle to make sure the crew can breath
DYNAMENT CARBON DIOXIDE INFRARED SENSOR • Measures CO2 in a range of 0 to 1000ppm up to 0 to 5% volume CO2 • Accuracy of ± 1% measuring range • Operating temperature range • -20°C to 50°C • Power Supply • 3V to 5V DC • Current Consumption • 60 mA • Response time of <30 sec in 20°C
DYNAMENT CARBON DIOXIDE INFRARED SENSOR • Sampling Rate • Response time <30 sec in 20°C temperature • Signal Band • Source drive frequency: • 2Hz minimum • 3Hz typical • 4Hz maximum • Output signal is around 15 MHz • Criticality • Used to check internal levels of carbon dioxide of crew system vehicle to make sure the crew does not suffer carbon dioxide poisoning
MLX90316 Rotary Position Sensor IC • Absolute rotary position IC with Magnetic design • Measures from 0 to 360 degrees • Voltage Requirement • 4.5-5.5 V • Has a 10V voltage protection • Current Consumption • Slow mode = 8.5-11 mA • Fast mode = 13.5-16 mA • Temperature Range • -40°C to 150°C
MLX90316 Rotary Position Sensor IC • Sampling Rate • Slow mode = 600 μs • Fast mode = 200 μs • Signal Band • Slow mode = 7 MHz • Fast mode = 20 MHZ • Criticality • Used to measure the rotational position of the spacecraft during attitude dynamics
Bosch Sensortec BMA180 Digital triaxial acceleration sensor • Three axis accelerometer with integrated temperature sensor • ultra-low noise and ultra high accuracy • Programmable g-ranges (1g, 1.5g, 2g, 3g, 4g, 8g, 16g) • Zero-g Offset • ±5 to 60 mg • Voltage Requirement • 4.25 V Current Consumption • For sleep mode to low noise mode 0.5-975 μA • Temperature Range • -50°C to 150°C
Bosch Sensortec BMA180 Digital triaxial acceleration sensor • Bandwidth • High pass = 1Hz • Band pass = 0.2 – 300 Hz • Sampling Rate • 1200 samples/sec • Signal Band • Noise density @1200Hz, 2g, 150-200 μg/√Hz • Input runs on 7.5-10 MHZ • Outputs data at 2400-1200 Hz • Criticality • Used to measure the acceleration and the spacecraft’s respective position
Bosch LRR3: 3rd generation Long-Range Radar Sensor • Detect objects and measure velocity and position relative to movement of host radar-equipped vehicle • Distance accuracy 0.5…250m (±0.1m) • Relative speed accuracy -75…+60m/s (±0.12m/s) • Vision Range • Horizontal opening angle 30° (-6 dB) • Vertical opening angle 5° (-6dB) • Power Consumption • Typically 4 W • Temperature Range • -40°C to 85°C (periphery) • Max Number of detected Objects = 32
Bosch LRR3: 3rd generation Long-Range Radar Sensor • Sampling Rate • Cycle time is typically 80ms • Signal Band • Transmits radar waves in 76-77 GHz • Criticality • This is useful for landing on the moon as to detect the distance from the surface of the moon to the spacecraft
SENSOPART Visor Vision Sensor • Allows sight via flashing light at fast times • Uses 8 LEDS for fast measurement • Takes 13s to power up when turned on • Voltage Requirement • 24V DC Current Consumption • About 200 mA • Temperature Range • -20°C to 60°C
SENSOPART Visor Vision Sensor • Sampling Rate • Cycle time is typically 20ms pattern matching • Cycle time is typically 30ms contour • 2ms brightness, contrast, grey level • Signal Band • Transmits in 62-73 GHz • Criticality • This is useful for landing on the moon as to detect craters and dangerous landmasses so the spacecraft can land in the designated location
CT-602 Star Tracker • Sampling Rate • Cycle time is typically .3 deg/sec • Signal Band • Transmits radar waves in 10 Hz • Criticality • The CT-602 features a radiation-hardened processor and additional memory that combine for increased environmental tolerance and greater mission programmability
E2EM • Sampling Range • Measures 4 mm distances • Signal Band • Transmits radar waves in 1 kHz • Criticality • Long-distance at up to 30 mm enables secure mounting with reduced problems due to work piece collisions
K7L-AT50 / -AT50DUltra-miniature Sensor Amplifier • Rated power supply voltage of 10 to 30 DC • Detection time is 10s max • Current is 100 mA at 30VDC max • Power needed is 1W • Temperature range is -10 to 55°C • Resistance • Range 0 = 0 to 250 kΩ • Range 1 = 0 to 600 kΩ • Range 2 = 0 to 5 MΩ • Range 3 = 0 to 50 MΩ
K7L-AT50 / -AT50DUltra-miniature Sensor Amplifier • Sampling Range • 800ms max • Signal Band • 50/60 Hz for 1 min • Criticality • Prevents leakage of fuel tanks which would help prevent potential disasters from happening
KM50-EPower Monitor • Rated power supply voltage of 100 to 240 VAC • Detection time is 10s max • Current is 5,50,100,200,400, or 600 A • Power needed is 4kW to 480 kW • Temperature range is -10 to 55°C • Accuracy for the time is about ±1.5 min/month at 23°C
KM50-EPower Monitor • Sampling Range • 800ms max • Signal Band • 50/60 Hz • Criticality • Tells if any electronics systems are damaged or broken.