Project: "Fly by Wireless"

Introduction:

WiringBaja is a multidisciplinary team focused on the effectivity of the communication in the aircraft, through the substitution of the wiring for sensors and emissor of radiofrequency. Having as result a lower weight load, cost of manufacturing and a great technological advance for aircraft and spacecraft.

The proposal presented was made for the aircraft “Cessna T303”, was selected by their simplicity on the wiring and the accessibility of the data of the model.

Methodology:

The current weight of the selected model is approximately 2.3 tons, according to the specifications of the type of aircraft the wiring should approximately be of 480 lb. of which 30% of the harnessing is candidate to be replaced by wireless communication according to the article “A Benefit Analysis of Infusing Wireless Into the Aircraft and Fleet Operations” by NASA.

Objectives:

• Reduction of wiring and weight load of the aircraft.
• Reduce the energy consumed by the systems of aircraft.
• Increase the data flow using wireless networks, making best diagnostics and eliminated redundancy on wired systems.
• Reduce maintenance and troubleshooting on wiring.

Why we choose this challenge:

We choose this challenge because with the actual technology it's something that we could already achieve soon on the near future. The wireless is a tendency of our actual technology, we could say that on the next decades this would increase exponentially and its logical that this tendency would apply to aircrafts and spacecraft were the weight is crucial and affects the performance of them.

Background:

The actual challenge is to reduce the quantity of wires used in the aircraft, for archiving this NASA proposed to use the radiofrequency devices. Our challenge consist in 3 steps, the first one is the remplacement of analog wire signals; the second step is using a gateway that receives information from the components and the third step is to have a backbone to have all the information of the aircraft.

In some cases the electromagnetic interference might be a problem, so for these cases exist diverse ways to protect and code frequencies from noise caused by wifi signals and radio frequencies

According to the article “Enabling Wireless Avionics Intra-Communications” the optimum frequency is 3 Ghz, which does not interfere others frequencies, producing less wrong lectures of data but some sensor might use different frequencies. Is good to know that all the experiments maintain a armor against external signals up to 100 dB.

We classified the diverse sensors by the amount of information that needs to transport, then use different protocols that suits those characteristics.

In the article “Gateway Integrated Wireless Sensors” explains the use of this object, and using this concept we can decode differents protocols that we already classified and making it more efficient, this device makes a virtual interface for every device, producing real time data and being useful for control systems.

The communication protocols used are:

1. 11 Mbps 802.11b (Wi-Fi)

BPSK Modulation

Frequency = 2450 MHz

Delta-F = 12.375MHz

2. 11 Mbps 802.11b (Wi-Fi)

QPSK Modulation

Frequency = 2450 MHz

Delta-F = 12.375MHz

3. 610 bps Chirp Spread Spectrum (LoRa)

Spreading Factor = 10

BW = 125kHz

Coding Rate = 4/8

Frequency = 915MHz

Delta-F = 3 MHz

4. 7812 bps Chirp Spread Spectrum (LoRa)

Spreading Factor = 8

BW = 500kHz

Coding Rate = 4/8

Frequency = 915MHz

Delta-F = 3 MHz

5. 28175 bps Chirp Spread Spectrum (LoRa)

Spreading Factor = 7

BW = 500kHz

Coding Rate = 4/5

Frequency = 915MHz

Delta-F = 3 MHz

Data transfer method:

The wanscanner method is efficient because is low power and saves energy, also you can use this technology in control systems for reliability.

Development:

According to NASA wireless technology we could eliminate at least 30% of the wiring on any aircraft so we take this to an small aircraft in order to prove that this method could be used on larger and complex aircraft, the model selected as we mentioned before is Cessna T303.

We started separating in "modules" each part of the plane according to the electrical diagram of the airplane. The model was separated on five modules:

• Instrument and control panel.
• Radar and sensors
• Engine 1
• Engine 2
• Tail

After each module was defined, and taking advantage of a common electrical ground each module would need to be energized and then each signal was evaluated to know what could be replaced by a wireless sensor in order to eliminate the wire of the signal.

These are the signals that we identified on the model with their communications protocols obtained from Nasa documents, also we segregated the signals as them:

LOW INSIDE

LOW OUTSIDE

HIGH INSIDE

HIGH OUTSIDE

Once the protocols were determined we establish that a conversion could be achieve in this model by replacing the wire signals from the engines, from the flaps and from the tail.

The most critical modules would be the engines that englobes also the system of the flaps, batteries, alternator, fuel systems and navigation lights and the landing gear as components. This modules have their own data flow and consist on fuel temperature,fuel consumption, RPM from the engine, temperature from the engine and also the exhaust gasses.

The module on the nose of the aircraft is where most of the sensor from the instrument panel are located, if a digital conversion is desired it will improve the power consumption, a reduction on the weight load and the penetrations in order to connect to the instrumental panel.

For the tail module, it consist on just the actuator for the rudder and the elevator located in the tail.

Second to engines modules, the instrument panel module is most important, the gateway is located in this module were all the data from the other modules are deposit there in order to measure and control the aircraft. The engines would power this module and also will share this data to let know the operator that aircraft could have a secure flight; the tail module share the information about the position of the rudder and elevator in order to control these
position and lastly all the instruments have their sensors from the nose module.

In conclusion for this model the power feed come from the engines as we mentioned before and then energize the whole plane, this wiring by logic cannot be replaced but the other signals can, by doing this a weight reduction can be achieved therefore a cost reduction would create an aircraft free of maintenance and troubleshooting for wiring.

This is the common way to connect sensors.

With RF technology we can eliminate part of the cables.

Future Plans:

A convertion to digital of the instrument panel can improve even more the weight on these model, the sensors and the measure equipment and reduce the redundancy on the systems.

The implementation of the 5G network, that is the new generation of the standar technologies of wireless communication. Having Higher speed, density and transmission of data, lower latency and will be archive reduce the energy consume in an 90%. The 5G network will allow to connect more devices and have more than 100 devices at the same time for each cell or node in a 1m2.

And lastly the implementation for bigger and complex aircraft and spacecraft.

Resources:

• “A Revolution in Aerospace Vehicle Architecture for Instrumentation and Control” https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070013704.pdf
• Gateway Integrates Wireless Sensors with Existing Aircraft Systems at "the Speed of Software" https://technology.nasa.gov/patent/DRC-TOPS-42

• Enabling Wireless Avionics Intra-Communications
  https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20170000686.pdf
• Arquitectura de puesta a tierra eléctrica para naves espaciales no tripuladas
  https://standards.nasa.gov/standard/nasa/nasa-hdbk-4001
• A Benefit Analysis of Infusing Wireless into Aircraft and Fleet Operations
  https://pdfs.semanticscholar.org/93f5/8e156437c0f4bcc0ef4771ac187c9da82edd.pdf?_ga=2.70782416.1762662848.1571601275-1251001224.1571601275
• A Revolution in Aerospace Vehicle Architecture for Instrumentation and Control https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070013704.pdf
• “Exploration of Backscatter Methods for Wireless Avionics”

https://ntrs.nasa.gov/search.jsp?R=20180004760

• BROMBACH, J., SCHRÖTER, T., LÜCKEN, A. and SCHULZ, D. (2012). Optimizing the Weight of an Aircraft Power Supply System through a +/- 270 VDC Main Voltage. [ebook] Helmut-Schmidt-University. Available at: http://pe.org.pl/articles/2012/1a/9.pdf [Accessed 19 Oct. 2019].

• Cessna T303 Specifications, Cabin Dimensions, Speed - Cessna. (s.f.). Recovered on October 20th, 2019, from https://www.globalair.com/aircraft-for-sale/Specifications?specid=471
• Anonymous (s.f.). Recovered on October 19th, 2019, from https://www.cfinotebook.net/notebook/operation-of-aircraft-systems/landing-gear+
• Landing Gear. (s.f.). Recovered on October 19th, 2019, from https://www.cfinotebook.net/notebook/operation-of-aircraft-systems/landing-gear
• Natalie Wolchover, N. W. (2011, 13 mayo). How Are Plane Electronics Grounded? Recuperado 20 octubre, 2019, de http://www.nbcnews.com/id/43024277/ns/technology_and_science-science/t/how-are-plane-electronics-grounded/
• Free CAD Designs, Files & 3D Models | The GrabCAD Community Library. (s.f.). Recuperado 20 octubre, 2019, from
  https://grabcad.com/library/cessna-crusader-1