Engineering lesson 8: Payload and groundstations
This lesson includes detailed instructions for the ground stations and tracking stations.
NOTE: For official NEBP teams, the Polulu and Arduino you receive are already programmed. The tracking software .exe was sent in Spring 2023. If you need anything else or have questions, please contact your pod lead. Thanks!
NOTE: A New folder of resources posted on 5/9/23 includes:
3D print files
Ground station code (the folder contains a zipped file and the main .exe)
Raspberry Pi video system
- Instruction manuals
- Ubiquiti Radio Config files
See Lesson 11 for an Overview of the RFD900 ground station
- New (posted 4/2/23) Mechanical design of flight boxes
- Tracking station assembly and wiring video
- Ground station schematic
- Pololu driver settings
- Ubiquiti radio
Mechanical design of flight boxes
Payload box building is more on the art side rather than engineering. They do need to be sturdy, recoverable, and take a 40 mph ground impact. Many designs will work. This document will share one version. A good place to start is with constraints for boxing and landing the payloads.
The University of Maine High Altitude Ballooning Team generally tries to reduce payload weight whenever possible and practical. As a result our boxes tend to be light. Because Maine has many water bodies, boxes need to float. As much as making the boxes waterproof would be nice, no box as of yet has kept all water out. Box design can help keep some water out but probably not all. Avoiding salt water landings is very important as it is very destructive to powered electronics.
Tracking station assembly
Tracking station assembly video - [YouTube video by Chad Dunbar, Montana Space Grant Consortium. 1:31:31. Closed captioned]
Tracking station wiring
Tracking Station Wiring Video - by Randy Larimer, Montana Space Grant Consortium [YouTube video, 24:40]
Ground station wiring schematic
See the diagram below and also this downloadable version
Pololu driver settings
You can also download the Pololu driver settings in PDF [same as HTML text below]
This requires the Pololu Tic Control Center and Tilt and Pan stepper motor configuration files. Plug in USB to Micro USB into the computer and open Pololu Tic Control Center.
There are two stepper motors in the ground station. One pointed down that controls the pan and the other on the side that controls the tilt. See Figure 1 Ground Station Stepper Motors.
- Follow the wire from the stepper motor that controls the tilt to the motor controller (Figure 2). Connect the micro-USB to the motor controller.
- On the Tic Control Center, click on the dropdown on the top left of the window and select something like #01234567 T825. See Figure 2 Pololu Tic Center.
- Click on File on the top right of the window and then select Open settings file… and select the Tilt configuration. Click Apply settings at the bottom of the window.
Figure 3 “Open settings file...” option and Apply settings button
- Repeat for the pan motor.
Ground Station (BRAD) Tracking Software Instructions
Written by: Mathew Clutter
You can also download these instructions as an alternate PDF [same content as below]
If you are reading this, you likely want to track a balloon using the Montana Space Grant’s BOREALIS program’s ground station. This document will lay out the steps to use the software associated with the ground station to track a balloon.
To launch the GUI, double click on the file called main.exe. This will launch the tracking software.
- Select or enter your Balloon IMEI in the top left corner
- After selecting your balloon’s IMEI, hit the confirm IMEI button.
- Ensure that the date in the status box in the bottom right corner is the correct date. If not, the balloon will not be tracked properly.
- Select and connect the Arduino in the box below the IMEI selection
- Ensure that the Arduino connected to the ground station is selected and press the
“Connect to Arduino” button.
- If you have not yet connected the Arduino on the ground station, plug in the Arduino and then git the Refresh button. This will find the Arduino.
3.Obtain the GPS location of the Ground Station setup
- Enter in the ground station coordinates into the ground station location boxes.
- After obtaining/entering the location of the ground station, hit the “Set Ground Station Location” button.
4. Use the adjustment buttons to point the solar sight at the sun
- Adjust the size of the motor movement using the “Degrees Per Click” box.
- Ensure that the sun is centered in the solar sight.
5. Set the starting position that the antenna is pointing at.
- Ensure that the ground station location is set and the solar sight is pointing at
- In the event that the sun is not visible, do your best to estimate the azimuth and elevation that the ground station is pointed. It is recommended to use a compass to obtain the azimuth, and a level to set the elevation to 0. If using a compass, ensure that you are using true north, and not magnetic north. Many phone compasses will automatically calculate the declination for you, and give the reported position in terms of true north.
- Click the “Calculate Starting Position” button on the right side of the screen. (unless calibrating using compass and level)
- Once the starting position is calculated, hit the “Set Starting Position” button.
6. Hit the “Start Tracking” button in the bottom left to begin tracking the balloon!
- Basic tracking will simply point the antenna at the last position reported by the Iridium. Tracking with prediction will attempt a more precise tracking by extrapolating the change in position between previous Iridium pings, to continue adjusting the pointing of the antenna between pings of the Iridium.
- The “Stop Tracking” button will end the tracking
- The E-stop button will immediately stop the tracking, not allowing the ground station to finish its last commanded location.
Other items to note:
- Internet connection is required to run the ground station tracker.
- This is due to the balloon position coming from the web server.
- Ensure that your Iridium is on and actively pinging the server before starting tracking.
- Additional information and error messages will appear in the bottom right corner in the status box. If something is not working, this may help you to debug what the issue is.
- The tracker is designed to work with Windows. If you have the desire to play with serial ports, and potentially other issues, it shouldn’t be too hard to port to OSX or Linux if you so desire.
- The python source code is provided, and will function (on Windows), assuming you install all of the dependencies needed.
- If you have two monitors connected when running the tracker, you may need to resize the window to get it to scale correctly.
- This software is still being developed, so it is very likely that there are bugs that have not yet been found. Please inform me if you have any problems using this software!
- If you have any other questions or concerns, contact me at: email@example.com
View the entire Ubiquiti Radio setup manual as a PDF document [alternate download; same as below]
A pair of Ubiquiti radios will be configured to become a transparent bridge to connect the ground station and the payload. The Ubiquiti radios acts as a long wireless ethernet cable between two points. This document will describe the configuration process and required equipment to create a working transparent bridge.
- A pair of Rocket M5 Ubiquiti radio (Or similar model but this document is best for Rocket M5 Ubiquiti radio)
- 4 ethernet cables (Straight-Through)
- 2 Ubiquiti power boxes with its power cable
- Antennas for both radios
The following steps will prepare the Ubiquiti radios for long distance connection. Skip to Advance Setup section to allow the Ubiquiti radio to be connected to a router.
The radio connected to the computer will be called the Ground Station Radio and the other radio connected to the Raspberry Pi will be called the Payload Radio.
In order to setup the Ubiquiti Radio for the first time, the user must configure their computer to have a static IPv4 address set to 192.168.1.x in their ethernet port. This configured computer will be used to change the settings of the Ubiquiti radio.
Ubiquiti Radio connection for Ground Station and Payload
The computer is now prepared to configure the Ubiquiti Radio, the Ubiquiti Radio needs to be powered and connected to the computer. First, connect an ethernet cable from the Ubiquiti Radio to the power box’s port labeled POE. Then, another ethernet cable is connected from the configured computer to the power box’s port labeled LAN. The power box can then be plugged into a wall. Two yellow LED should light up on the Ubiquiti Radio.
Accessing Radio’s Configurations
Ubiquiti Radio’s settings can now be accessed. Open a web browser like Google Chrome or Firefox and then go to http://192.168.1.20 (make sure its http, not https). The first time will show a screen of unsecure network, allow the site and should show a first-time setup screen.
Enter the login information (By default, username: ubnt password: ubnt). Enter United States and English for the other two. Tick the agreement to continue to login.
After login, the screen should look like the following:
Changing Ubiquiti password
Go to the System tab and click on the key next to the user name. Enter the current password, new password and the new password again. Click Change and click Apply when the blue bar appears.
Changing Time Zone
Go to the System tab and change the Time Zone to your time zone. This could help with logs.
Picking and Assigning the Ground Station SSID
One of the Ubiquiti radios is assigned to the Ground Station Radio. It is highly recommended to label the radio accordingly to avoid confusion.
Go to the Wireless tab, Change the Wireless Mode from Station to Access Point. Tick the checkbox next to WDS (Transparent Bridge Mode). In the textbox next to SSID, enter an appropriate name that the pair of radios will use to connect to each other. Change the Channel Width to 5Mhz. Tick the checkbox next to Frequency List, Mhz and then enter the following: 5160,5200,5240,5740,5780,5820. The following is a list of frequency allowed to be used in US. Please check with the local area for allowed frequencies. Make sure the check box next to Max TX Rate, Mbps dropdown is checked. After the changes, the screen should like the following:
Click Change and then click Apply once the blue bar appears
Assigning the Ground Station Radio with an IP address
Go to the Network tab, change the IP address from 192.168.1.20 to 192.168.2.31. Change the Gateway IP from 192.168.1.1 to 192.168.2.1. Click Change and then click Apply once the blue bar appears. You will NOT be able to access the configuration through 192.168.1.20 anymore instead it will be the newly assigned IP (192.168.2.31). Accessing the site will require changing the configured computer’s IP, which will be done later.
Assigning the Payload Radio
Before proceeding to this step, make sure to do the same steps from Accessing Radio’s Configurations to Changing Time Zone for the Payload Radio.
Go to the Network tab, change the IP address from 192.168.1.20 to 192.168.2.35. Change the Gateway IP from 192.168.1.1 to 192.168.2.1. Click Change and then click Apply once the blue bar appears. You will NOT be able to access the configuration through 192.168.1.20 anymore instead it will be the newly assigned IP (192.168.2.35). Accessing the site will require changing the configured computer’s IP.
Changing the Configured Computer’s IP
Changing the configured computer’s IP is changed again to be able to access the Radio’s configuration. Same steps in Computer Setup section, the IP is changed from 192.168.1.2 to 192.168.2.2.
Connecting the Payload Radio to the Ground Station Radio
Go to the Wireless tab, Change the Wireless Mode from Station to Station. Tick the checkbox next to WDS (Transparent Bridge Mode). In the textbox next to SSID, enter the SSID assigned to the Ground Station Radio. Change the Channel Width to 5Mhz. Tick the checkbox next to Frequency List, Mhz and then enter the following: 5160,5200,5240,5740,5780,5820. The following is a list of frequency allowed to be used in US. Please check with the local area for allowed frequencies. Make sure the check box next to Max TX Rate, Mbps dropdown is checked. After the changes, the screen should like the following:
Click Change and then click Apply once the blue bar appears.
If all the steps were followed correctly and both radios are powered, the other 4 LEDs on both the radios should light up. Both radios can now be accessed from either side by entering their assigned IP address.
The following steps will help the Ubiquiti radios work to its full potential which could result to better bandwidth and further distance communication.
By updating the firmware, the radios could receive additional settings and receive optimization from the company.
Make sure that the computer has internet access by connecting to Wi-Fi. If this cannot be done, then skip this section and go to Uploading Firmware section.
Go to System tab, Click Check Now button next to Check for Updates. If it fails, skip this section and go to Uploading Firmware section. This maybe due to Firmware being too old.
Due to Firmware Update, the Time Zone may have change. Make sure to change it to the appropriate timezone.
If the option of connecting to Wi-Fi while tethered to the Ubiquiti is not available, uploading the updated firmware is possible.
Before disconnected from the Radio, take note of the Firmware Version:
While connected to the Internet, go to https://www.ui.com/download/.
Since this manual is optimized for Rocket M5 radios, the firmware download can be found from clicking dropdown airMax® M Series, then Rocket® M, then M5
Download the latest firmware version with the same board type
Click I Accept when the popup appears then click Download File button.
Connect to the Ubiquiti Radio. Upload the firmware by going to System tab and clicking Choose File button next to Upload Firmware
Choose the recently downloaded firmware file and click Open.
Click Upload when it shows
When the blue bar appears, click Update
The update will take time. DO NOT POWEROFF.
Check if the firmware has been successfully updated by going to System tab again
Additional settings changes
Both the payload and ground station radios were configured to use the default antenna. Depending the on the antenna chosen, the output power of the communication changes.
By checking the datasheet of the antenna used, an exact “dBi” can be found. For example, the RD-5G-30 was found to have 30 dBi which results to a maximum 23 dBm output power with
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