A New Team! A New Beginning!

After an excellent performance from our seniors in the SUAS 2012, its time for us to take the project forward. On behalf of the entire team, i thank all my seniors for giving us the opportunity to be a part of team jatayu , and i will keep everyone updated with the progress of our team in my future posts . cheers :-)

The SUAS

It’s been a long time since a post and there are reasons for that. After my last post, we as a team were completely focussed on the Student Unmanned Aerial Systems (SUAS) 2012 Competition held by the Autonomous Unmanned Vehicle Systems International (AUVSI).  A prestigious event and a very challenging one too. Let me amaze you by giving a brief overview of the Competition.  The statement of the competition is:

 A team of Navy Seals have been tasked to rescue family members of international diplomats who have been taken hostage. Your unmanned aerial system (UAS) is supporting their sweep with intelligence, surveillance and reconnaissance (ISR). In order to support them, your UAS must comply with Special Instructions (SPINS) for departure and arrival procedures, and then remain within assigned airspace. It will be tasked to search an area for typical targets, and may be tasked to conduct point reconnaissance if requested. Additionally, the UAS may be tasked to relay data from a third party Simulated Remote Intelligence Center (SRIC).  Immediate ISR tasking may be requested outside currently assigned airspace, causing the UAS operators to request deviations. Let me amaze you by giving a brief overview of the Competition.

The event consisted of three major Parts:

1.       Paper:  A technical paper has to be submitted first, before the event. The paper enlists all the design and implementation of the system which will participate in the competition. By system I mean the plane, the electronics, wireless networks and all the theory which has been implemented.  

2.       Oral Presentation/Flight readiness review: Now after landing at the US navy base (Yes, that’s where it is held) , teams have to give a presentation in front of the judges explaining the design and implementation thereby bringing out if the system is ready to fly safely. Safety is an important consideration and before the actual flight teams have to show if all the failsafe mechanisms are working.

3.       Flight Demonstration: This is the final part and also a major one. Here teams have to show their system’s working. The system(plane and all its electronics) is expected to perform

a.       Auto-Takeoff (Once powered the system should automatically takeoff- No Remote Controlled support)

b.      Waypoint Navigation: The plane should fly over specific locations (Latitude and Longitude given prior)

c.       Enroute Search and Area Search: The plane has a camera which sends back a live feed back to the ground station. Along the route and in a given specific area some targets will be placed on the ground (size between 2x2 and 8x8 sq. ft, targets are alphanumeric and multi-coloured). The plane has to follow the route precisely and search the area capturing anything under it in the video. The live feed is then passed to ground station and the video has to be processed to detect targets. The various specs of the targets have to be then reported to the judges. Eg. Colour, Background colour, its identity and much more.

d.      Autonomous Landing: Easily one of the most difficult tasks.

e.      Simulated Remote Intelligence Centre (SRIC): The plane has to hover around a region where a strong Wi-Fi beam is projected. The system has to login to the the network and relay a file back to the ground station. 

Well, you may feel that’s a lot but there are many more small things which I haven’t mentioned here.

Our Conduct

We chose a stable plane model called the Telemaster. It is a High-Winger and has a rigid frame, well suited for windy conditions. Ardupilot was thoroughly configured and tested and additional electronics and programming was added to meet the requirements of the competition. An analog camera and a transmitter-receiver system working at a frequency of 1.2 GHz was used to capture the video and send it back to the Ground Control. Communication between the Ardupilot and the Ground Station was established using xbee’s working at a frequency of 2.4 GHz. Image processing algorithms were developed to detect alphanumeric shapes. An open-source library called OpenCV  was very helpful in implementation of these algorithm. A lot of hard work went into setting up each part of the system. More work went into combining all these parts into one system. The time at hand was short and under the tight schedule we could barely make the system work in total. Testing the system was out of the question and we just went ahead to the competition without any testing.

In the competition, things didn’t go as well as we had planned but that was expected; “It was the first time”. We couldn’t do well in the Paper and Oral Presentation but our plane flew very well autonomously. Thanks to this we secured the 14^th place among 30 teams in Mission Performance. We were acknowledged as the best debutant team and also given the Never Say Die Title for recovering well after a not-so-good start. We also won a cash prize of $2000.

The SUAS was a challenging event and the experience was amazing making it ensconced in every member of Project Jatayu.

The Xbee protocol

The previous post introduced you to the Ardupilot, an autopiloting system. The Ardupilot after the initial setup is ready to send the raw as well as processed sensor data.This data is crucial as it affirms the fine movement of plane. Data such as the gps locations over which the plane has to fly (it's called waypoints) also has to be sent to the Ardupilot.  One may ask how is data transmitted to and from the plane in air, back to the ground. The answer is the telemetry unit, it is a communication link between the computer and the Ardupilot unit. The telemetry unit consist of a pair of xbee's.

Basically xbee is a transreciever with a powerful microcontroller. The microcontroller holds a unique network ID of the network therby enabling only other xbee's having same network ID to communicate to each other. The protocol used for the communication is called the zigbee protocol. Digi is the creator of this tiny master-piece. The above picture shows a xbee with pig-tail antenna. These are efficient for small range but as the projects demand is a larger range we chose an xbee whose antenna can be attached externally, that is xbee with an SMA connector. Currently we are using antenna of gain 5db and frequency 2.4 GHz(This frequency is legally free in India).

Xbee with SMA Connector

  

5db Antenna with SMA Connector