Chirag "CJ" Sirigere
In this detailed CAD model, the payload (named "The RHIT Stuff") can be seen in the nose cone of the rocket. In the top half of the body tube, the main and drogue chute deployment system can also be seen along with the Rose Petal altitude assurance controller in the center. Near the aft section, the mechanical Rose Petal air-brakes and the motor housing are stored.
Rose Petal Air-Braking
By extracting the altitude information from the Rose Petal altimeter, the overall air-brake system is linearly-actuated using a paintball air tank. Once the rocket reaches a certain altitude, the controller sends a predetermined sequence of signals to solenoid valves to deploy the air-brakes vertically, effectively slowing down the rocket to the desired height of approximately 5000 ft.
Time-Integration Position Estimation
The main challenge of the competition was to determine the position of the competition rocket without GPS! The payload team decided to use time integration as our main position determination method with a high- and low-range accelerometer. Other methods were considered such as triangulation, but the ground station area was limited so triangulation was not an effective solution. The major problem with time integration was that there was an indescribable amount of noise that carried over through the integrations that made the rocket's position estimation drift between hundreds to thousands of feet away from its actual position!
Yagi RF Telemetry System
Throughout the launch vehicle's flight, data such as its altitude, acceleration, velocity, position, and rotational motion, are being measured by the onboard payload. The telemetry data are also sent from the rocket to the ground station Yagi antenna using RF XBee, GNU Radio, and Hack RF modules. In addition, the RF Yagi System uses directional transmissions from the ground station to determine the position of the launch vehicle. As shown on the left, the antenna rotates to locate the highest signal strength that is transmitted by the rocket.