Project

# Title Team Members TA Documents Sponsor
18 S-band Radar Altimeter
 Bobby Sommers
Elliot Rubin
Rayan Nehme
 Koushik Udayachandran design_document1.pdf
final_paper1.pdf
photo1.png
presentation1.pdf
proposal1.pdf
proposal2.pdf
video
Problem:
Currently, hobbyist RC aircraft and civil drones rely on GPS and barometers for altitude measurements. While these methods are reliable and accurate, they may not tell the operator the full story. GPS is a line of sight system and does not work when the receiver is obscured by terrain or buildings. Barometers read air pressure, but will not measure the distance between an aircraft and terrain. A radar altimeter would provide low-flying drones and RC aircraft with accurate altitude measurements relative to terrain.

Solution Overview:
Our solution relies on a FMCW (frequency modulated continuous wave) S-band radar altimeter powered off of an internal battery. The radar altimeter will be mounted to the bottom of the drone and will use the 2.4GHz ISM band in its operation.

Solution Components:

Processing Unit:
The processing unit will consist of a microcontroller, barometric altimeter, and an SD card slot. The microcontroller will calculate the range to terrain based on the doppler shift from the radar and will log this information to the SD card. It will also record the altitude measured via the barometric altimeter to compare with the radar measurement. Finally, the microcontroller will generate the control signal for the FMCW waveform.

Radar Unit:
The radar unit will consist of two submodules: the transmitter and the receiver.

The transmitter performs frequency modulation using a VCO (voltage controlled oscillator) with a tune voltage generated by the microcontroller. This tune voltage is used to sweep the VCO frequency and creates an FM waveform. A PA (power amplifier) is used to increase the transmit power and is connected to the Tx patch antenna. The Rx patch array receives the reflected signal, amplifies it through a LNA (low noise amplifier), down converts it with a mixer, and provides the demodulated signal to the processing unit.

Power Unit:
The power unit consists of a shielded switching converter to provide DC supply voltage to the other units. This DC power will be regulated by a LDO (low dropout regulator) to provide low-noise power to sensitive components such as the LNA and the VCO.

Criterion for Success:
Our radar altimeter should accurately and precisely measure distance within 1m and record measurement data to a SD card for post processing. It should have a minimum range of 20 m.

Alternatives:
There are several 24GHz radar altimeters designed for use on UAVs, but they are more expensive and are not targeted to consumers. Development boards from semiconductor companies and vendors such as Adafruit and Seed also operate in the 24GHz band, but have very limited range (<10 m).

GYMplement

Srinija Kakumanu, Justin Naal, Danny Rymut

Featured Project

**Problem:** When working out at home, without a trainer, it’s hard to maintain good form. Working out without good form over time can lead to injury and strain.

**Solution:** A mat to use during at-home workouts that will give feedback on your form while you're performing a variety of bodyweight exercises (multiple pushup variations, squats, lunges,) by analyzing pressure distributions and placement.

**Solution Components:**

**Subsystem 1: Mat**

- This will be built using Velostat.

- The mat will receive pressure inputs from the user.

- Velostat is able to measure pressure because it is a piezoresistive material and the more it is compressed the lower the resistance becomes. By tracking pressure distribution it will be able to analyze certain aspects of the form and provide feedback.

- Additionally, it can assist in tracking reps for certain exercises.

- The mat would also use an ultrasonic range sensor. This would be used to track reps for exercises, such as pushups and squats, where the pressure placement on the mat may not change making it difficult for the pressure sensors to track.

- The mat will not be big enough to put both feet and hands on it. Instead when you are doing pushups you would just be putting your hands on it

**Subsystem 2: Power**

- Use a portable battery back to power the mat and data transmitter subsystems.

**Subsystem 3: Data transmitter**

- Information collected from the pressure sensors in the mat will be sent to the mobile app via Bluetooth. The data will be sent to the user’s phone so that we can help the user see if the exercise is being performed safely and correctly.

**Subsystem 4: Mobile App**

- When the user first gets the mat they will be asked to perform all the supported exercises and put it their height and weight in order to calibrate the mat.

- This is where the user would build their circuit of exercises and see feedback on their performance.

- How pressure will indicate good/bad form: in the case of squats, there would be two nonzero pressure readings and if the readings are not identical then we know the user is putting too much weight on one side. This indicates bad form. We will use similar comparisons for other moves

- The most important functions of this subsystem are to store the calibration data, give the user the ability to look at their performances, build out exercise circuits and set/get reminders to work out

**Criterion for Success**

- User Interface is clear and easy to use.

- Be able to accurately and consistently track the repetitions of each exercise.

- Sensors provide data that is detailed/accurate enough to create beneficial feedback for the user

**Challenges**

- Designing a circuit using velostat will be challenging because there are limited resources available that provide instruction on how to use it.

- We must also design a custom PCB that is able to store the sensor readings and transmit the data to the phone.