Project

# Title Team Members TA Documents Sponsor
61 Automatic Motorized Satellite Tracker/GroundStation & Down Converter Subsystem/RF frontend
 Jumana Schmidt
Rishan Patel
Wiley Tong
 Jason Jung design_document1.pdf
final_paper1.pdf
other1.jpg
photo1.jpg
presentation1.pdf
proposal1.pdf
video1.mp4
video
video
# Automatic Motorized Satellite Tracker/GroundStation & Down Converter Subsystem/RF Frontend
Team Members:
Jumana Schmidt (jumanas2)
Wiley Tong (wileyt2)
Rishan Patel (rishanp2)

# Problem:
There are over 14,000 satellites orbiting the Earth. From real-time weather images, pictures of our Sun, HAM radio, to leaked unencrypted military communications, each satellite is transmitting a variety of readily available data. Some of this data can even be life saving or critical to our infrastructure. With such intriguing information available, it is no wonder why there has been a growing interest in satellite communications for so many different communities. However, accessing satellite data directly or indirectly typically requires either internet based services, expensive tracking hardware, RF experience, and a lot of manual setup. For off-grid users, remote communities, and students learning RF/satellite communication, this creates a large barrier: even if the satellites are transmitting overhead, it’s hard to reliably aim an antenna, lock the signal, and turn that RF into usable decoded output.

Many relevant or interesting satellites, including those for weather, are low Earth orbiting (LEO), which require real-time tracking through the sky, either manually or a motorized mount. There are no commercial and affordable hands-free, motorized antenna mounts, and none of them are truly hands-off and automated. They also usually transmit in L-band and/or in S-band. So even though most of the equipment to start can be homemade or cheap, such as an antenna, some free software, and a basic software defined radio dongle (like a RTL-SDR), these microwave band signals can still be hard or impossible to properly receive and decode due to limited range. An MMDS or frequency downconverter is required for both a cheap option like an RTL-SDR and even a step up to a $300 Hack RF One. Additionally, there are not many commercial and affordable downconverters available As a result of both of these obstacles, receiving any updated critical/useful data is often impractical, inconsistent, or too costly for most people to try.

# Solution:
Our overall goal is to help make radio and satellite tracking/reception more accessible for educators, researchers, remote communities, survivalists, and radio enthusiasts alike. To accomplish part of this task, we seek to address two of the most inaccessible and unaffordable aspects: live tracking and making those microwave transmissions receivable by cheaper SDR’s. More specifically, we will create an affordable automatic, motorized satellite tracker/receiver and a custom S-band frequency downconverter.

# Solution Components:

## 1. Motorized Antenna Mount

- RTL-SDR: $30
Antenna & Dish parts: Usually negligible (could be free depending on the sources & band type)
- Azimuth Motor: $28
https://www.amazon.com/gp/product/B0FMY17QRT/ref=ewc_pr_img_3?smid=AVTJBJ76BDD27&psc=1


- Elevation Motor: $37
https://www.amazon.com/dp/B0C69W2QP7/ref=sspa_dk_detail_1?pd_rd_i=B0C69RSJNT&pd_rd_w=dJt1j&content-id=amzn1.sym.386c274b-4bfe-4421-9052-a1a56db557ab&pf_rd_p=386c274b-4bfe-4421-9052-a1a56db557ab&pf_rd_r=5H73NB21EDBPJSF5WR2Y&pd_rd_wg=dDyFo&pd_rd_r=79ee8ae1-1e2f-4b6f-bd54-edc53447b320&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM&th=

- 9 DOF IMU: BNO055 $9

- Lazy Susan Bearing: $15

- MCB & Power Management + parts: $8 + Negligible
Esp32: $8
- Mount Brackets: Machine Shop

## 2. Down Converter Subsystem/RF frontend
The RTL-SDR has a max frequency of 1.75 GHz. In order to receive and demodulate S band signals we need to build a down converter that brings 2-3.5 GHz signals into range of the RTL-SDR. The down converter is an analog heterodyne: the RF signal from the antenna will be multiplied by a 1.5 GHz local oscillator signal using an rf mixer.

This submodule would require:
- RF LNA (SKY67151-396LF)
- S band bandpass filter (BPF-AS1600-75+)
- active RF mixer (LT5560EDD#PBF)
- pll synth (LMX2531LQ1910E/NOPB)
- possibly include mcu to control pll
- oscillator reference clock (UCE4031035LK015000-10.0M)
- IF filter (built from LC components or use a detector)
- SMA connectors
- SMD rlc components
- SMD balun, tapped transformers

There will be two boards: LNA and filter board connected directly to the antenna to reduce loss, the down converter board that feeds into the RTL-SDR. Making the LNA and down converter into separate modules also makes testing easier. Even if the more complex downconverter fails the LNA module can be saved.

# Criterion For Success:
For the motorized antenna mount, we will have succeeded if the device is relatively affordable and able to smoothly automatically track a satellite, given streamed live TLE coordinates from a computer. We want the user to be able to just connect the antenna, SDR, and filters of their choice one time, and be able to send scheduled coordinates to start tracking a satellite any time. And the S-band downconverter will have been confirmed to work if we can receive S-band satellite communications on much lower, easily accessible frequencies.

## S-Band Satellite Options:
- Hinode Solar B: 2256 MHz
- Jason-3: 2215.92 MHz
- Blue Walker 3: 2245
NOAA 20: 2247.5 MHz

In the future, we’d hope to have a dashboard for data collected and logs, to make it into a more automated, full ground station. We also hope to build an adjustable down shifter so that the module can downshift signals beyond 3 GHz.

# Alternatives:

## Motorized Antenna Mount
- Ant Runner Pro: $500
## S-band Down Converter

- RTL-SDR Blog Wideband LNA + Bias Tee $28
https://a.co/d/0g0wGGSv
- Nooelec HAM It Down: $90-125
https://www.nooelec.com/store/ham-it-down.html?srsltid=AfmBOooLr50utjbiAL63G1_oEChwrt4FRbUYePs9j1fTbOP_XoPrxOto
- Sysmo S-band Cavity Filter: $80 (not always available)
https://shop.sysmocom.de/S-Band-cavity-filter-2170-2300-MHz/cf2235-kt30

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.

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- 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.

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**Criterion for Success**

- User Interface is clear and easy to use.

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

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