AutoSatTracker is an ESP8266 sketch that performs completely autonomous Earth satellite tracking. All control and monioring is done over a wifi with phone, tablet or host computer via a web browser so a separate App is not required.
The system requires the following equipment:
[] ESP8266: Adafruit Huzzah https://www.adafruit.com/product/2821
[] GPS module for time and location: Adafruit https://www.adafruit.com/product/746
[] I2C 9 DOF spatial sensor attached to the antenna to measure where it is pointed:
Adafruit https://www.adafruit.com/product/2472
[] PWM servo I2C controller: Adafruit https://www.adafruit.com/product/815
[] 2D gimbal to point the antenna moved by two hobby servo motors:
I used parts from https://www.servocity.com/
The main program is AutoSatTracker-ESP.ino which uses the following classes:
Gimbal control the two servos
Circum manage time and location including GPS
Sensor read the spatial sensor
Target compute the satellite location
Webpage display and update the web page
Also required are the following Arduino IDE libraries:
https://github.com/mikalhart/TinyGPS
https://github.com/adafruit/Adafruit_BNO055/archive/master.zip
https://github.com/adafruit/Adafruit_Sensor/archive/master.zip
https://github.com/adafruit/Adafruit-PWM-Servo-Driver-Library
https://github.com/esp8266/Arduino
Helpful: https://learn.adafruit.com/adafruit-all-about-arduino-libraries-install-use
- Huzzah 3V .. 3.3 V DC
- Huzzah EN .. system ground
- Huzzah 2 .. GPS RX
- Huzzah 3 .. GPS RX
- Huzzah 4 .. PWM and DOF SDA
- Huzzah 5 .. PWM and DOF SCL
- Huzzah GND .. system ground
The ephemeris calculations are extracted and slightly modified from P13, see below. All development was performed on an Apple iMac using Arduino IDE 1.8.5.
During development, the web pages changed often and it was a pain to keep editing them while wrapped in C strings in Webpage.cpp. So instead, they were moved to ast.html and ask.html as plain text then reformatted with the perl script preppage.pl which automatically inserts them into Webpage.cpp. The script preprun performs both insertions. This approach also allows these html fies to be viewed directly in a browser to check html errors, proper layout and local functionality without another burn cycle of the ESP. The web pages were tested in Chrome, Safari and Firefox on MacOS and iOS 12 and Edge on Windows 10.
The main loop() in AutoSetTracker.ino just polls for ethernet and GPS activity then updates the tracking. Webpage::checkEthernet() checks for a new client connection and replies depending on the URL they request. The default "/" returns the main web page. After rendering the page, the browser starts an infinite loop issuing XMLHttpRequests for "/getvalues.txt" which returns many NAME=VALUE pairs. In most of these, the NAME is the DOM id of the page element to display the VALUE. A few NAMEs, such as T_TLE, require special handling. Page controls also issue an XMLHttpRequest POST method with a new NAME=VALUE pair. These pairs are passed to each subsystem for action.
When first booted the ESP tries to connect to the last known WiFi station using the last IP it used. If this fails, the ESP changes to Access Point mode as SSID SatTracker. Connecting to this and browsing to 192.168.10.10 brings up a web page allowing entry of info needed for connecting to your WiFi station. After Submitting this page, ESP again tries to connect to a WiFi station. This process repeats until a station connection is successful.
Let me know what you think.
73, Elwood, WB0OEW ecdowney@clearskyinstitute.com
The P13 code as used here was written by Mark VandeWettering, K6HX, as part of his angst project. See his blog postings at http://brainwagon.org/the-arduino-n-gameduino-satellite-tracker:
_ The Arduino n' Gameduino
__ _ _ _ __ _ | | Satellite Tracker
/ | ' \/ _ (-< |
_,|||_, //_| Written by Mark VandeWettering, K6HX, 2011
|_/ brainwagon@gmail.com
Angst is an application that I wrote for the Arduino and Gameduino. It is being distributed under the so-called "2-class BSD License", which I think grants potential users the greatest possible freedom to integrate this code into their own projects. I would, however, consider it a great courtesy if you could email me and tell me about your project and how this code was used, just for my own continued personal gratification.
Angst includes P13, a port of the Plan 13 algorithm, originally written by James Miller, G3RUH and documented here:
http://www.amsat.org/amsat/articles/g3ruh/111.html
Other implementations exist, even for embedded platforms, such as the qrpTracker library of Bruce Robertson, VE9QRP and G6LVB's PIC implementation that is part of his embedded satellite tracker. My own code was ported from a quick and dirty Python implementation of my own, and retains a bit of the object orientation that I imposed in that code.
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Make sure to update both sun.h and wmm.h regulary
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To update wmm.h, download WMM.COF from https://www.ngdc.noaa.gov/geomag/WMM/soft.shtml and use tools/wmmconverter.py to convert to wmm.h. Next update needs to be done End of December 2020
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The sun coefficients need to be updated in approx. 2030
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If the servo moves back and forth on tracking due to measurement errors of the BNO055 sensor, make sure to mod GOOD_ERROR to the error degree (currently 0.8 degree) in Gimbal.h
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Before tracking, set the min and max ranges of the servo. For my servos (D645MW as Tilt and HS-785HB as Pan) the values 900 as min and 1900 as max were just fine.
- Satellite-Tripod with 32mm Adaption (https://www.amazon.de/gp/product/B01B5LXBLW)
- 1x Servo D645MW (https://www.amazon.de/gp/product/B01D37MH8Y) - Get a second one as these need to be modded and these can break easily :D
- 2x LM2596 DC Converter for 3.3v and 6v (https://www.amazon.de/gp/product/B077VW4BTY). Only 1 needed if you use 5v instead of 6v
- 1x PCA9685 12Bit PWM Servo-Driver (https://www.amazon.de/gp/product/B072N8G7Y9)
- 1x Adafruit Feather HUZZAH mit ESP8266 WiFi/WLAN Development Board (https://www.amazon.de/Adafruit-Feather-Development-integriertem-Akku-Ladeger%C3%A4t/dp/B01BMRTULO)
- 2x 1" Bore, Face Thru-hole Clamping Hub, 1.50" Pattern 545354
- 2x 1" Bore, Face Tapped Clamping Hub, 1.50" Pattern 545352
- 1x 0.375" Hub Spacer 545380
- 1x 0.250" Hub Spacer 545376
- 5x 90° Dual Side Mount E (2 pack) 585596
- 1x 9.00” Aluminum Channel 585450
- 1x Actobotics® Hardware Pack A 632146
- 1x CM-785HB-5-U Servo Gearbox CM-785HB-5-U
- 1x SPT-400-5-25 Tilt System SPT-400-5-25
- 1x 6.00” Aluminum Channel 585446
- AWG 22 Cable
- DC Adapter (https://www.amazon.de/gp/product/B00VG7FH0O/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1)
- Power-Adapter 5v 4A for testing (https://www.amazon.de/gp/product/B07NSSD9RJ/ref=ppx_yo_dt_b_asin_title_o04_s01?ie=UTF8&psc=1)
- Dupont Adapter Set for Servo and Tool Connection (https://www.amazon.de/gp/product/B07QX51F3B/ref=ppx_yo_dt_b_asin_title_o05_s01?ie=UTF8&psc=1)
- Cable connectors (https://www.amazon.de/gp/product/B0758TKCRD/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1)
- 5v Battery Pack 10000mAH or 3S 50C 11.1v LiPo
- Micro-USB cable