ECE 480 Design Team 6Speed and Distance Sensor for Skiers and SnowboardersProgress Report #2November 20th, 2009Michael BekkalaMichael Blair Michael CarpenterMatthew GuibordAbhinav ParvataneniDr. Shanker BalasubramaniamSummaryECE 480 Design Team 6 has made plenty of progression since our last progress report. We ended up purchasing new microprocessors (dsPIC30F4013), which have worked fine with the ICD3 and we have been able to program these chips. We have recently purchased some flash memory for increased storage, a crystal to increase the frequency of our processor clock to 120 MHz, a lithium battery, a battery charger pack, and also a new gyroscope breakout board (we fried our original one). Project ProgressMicroprocessorAfter purchasing the dsPIC30f4013 microprocessor, all of our connection issues that we previously had were solved. The dsPIC30f4013 programs fine and we have had no issueswith it. This new microprocessor is also in a dip package, so it was easy to get right to work with it. One of the main reasons that we ordered the original PIC32 was mainly due to the fact that we wanted to interface with a computer through a USB port. This feature will no longer be used, as we will be using a serial connection to interface with the computer, which is all that the dsPIC can do. We will be making use of the “Phase Locked Loop” function of the microprocessor, along with a crystal that we recently purchased, to increase our clock to 120 MHz. This is the highest speed that the processor can handle. We also can read in our analog values and convert them to our desired measurement. Global Positioning SystemProgramming for the GPS is near completion. We have chosen which NMEA sentences we need and have successfully parsed them to obtain the required data in a useable format. The GPS code is executed by a UART1 receive interrupt. This makes programming more modular and will make combining code easier down the road. We have also received our 2MB flash memory chip and will be implementing this storage device as soon as possible.Inertial Navigation SystemThe inertial navigation system has been progressing nicely. The “navigation equations” have been deciphered and we know how to compute the position and velocity from the readings acquired from the accelerometers and gyroscopes. The navigation equations are currently being programmed to work with the microprocessor. We have purchased a Hall Effect sensor in order to see if we can use it to aid us in initializing INS. The gyro angular positions have to be initialized before the run starts, and in order to do this, you must have some reference direction, especially for the yaw rotation. We have, however, found ways to estimate the initial angular positions for pitch and roll, and may have to make some assumptions regarding yaw if the Hall Effect sensor does not work. Since our accelerometers and gyroscopes are electro micromechanical sensors, they have inherent bias drifts. Using Simulink, we set up a test to acquire the readings from the accelerometers and gyroscopes to see how much drift actually occurs. After testing, we discovered that these sensors are very accurate, with bias drifts of around only 5mV over a period of 1.5 hours. Depending on how much time we have, we may or may not try to filter out these drifts to increase accuracy. Kalman Filtering After speaking with an employee at GE Aviation-Systems, who is the resident Kalman Filtering, we have discovered that Kalman filtering may be beyond our capabilities for this project. Our PIC may not have the necessary processing power to pull off the computational complexity of a Kalman filter, and there are also many other factors that go into creating this filter that we originally did not consider. We will do our best to try to create one, but may have to just use an averaging filter. An averaging filter will be lessaccurate than a Kalman filter, but it will still be more accurate than GPS by itself.LCD InterfacingThe LCD correctly displays the values that we want to output and can correctly read fromthe dsPIC30f4013. We ordered a new LCD that requires a 3.3V supply instead of 5V, so we will not have to step up our voltage in order to power it. Battery We have just received our 3.7V 2000mAh lithium-Ion battery to power our device. It willbe stepped down to 3.3V using a buck
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