Hardware-in-loop CubeStar emulator
Date
2021-03
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : Stellenbosch University
Abstract
AFRIKAANSE OPSOMMING: Aangesien ster volgers huidiglik die mees akkurate oriëntasie afskatting voorsien
aan satelliete word beter elektronika en algoritmes konstant ontwikkel om ster
volgers te vervaardig met laer koste, groottes en kragvereistes maar beter akku-
raatheid. Om hardeware-in-lus emulasies met die CubeStar in 'n kantoor of labo-
ratorium omgewing te kan uitvoer was 'n emulasie omgewing ontwikkel en getoets
vir hierdie projek. Die emulasie omgewing voorsien 'n meer gerie ike alternatief
as om die naghemel te moet afneem om die doeltre endheid van sekere sagteware
algoritmes op ster volgers te evalueer wat die akkuraatheid en uitvoeringstyd ver-
beterings sal aandui wat deur opgradeerde elektroniese komponente en algoritmes
voorsien word.
Die emulasie omgewing wat in hierdie projek ontwikkel was kan hardeware-in-
lus emulasies uitvoer vir 'n CubeStar wat gekalibreer is of wat nog nie gekalibreer
is nie deur ster projeksie sagteware te gebruik om sterre op 'n rekenaarskerm te
projekteer wat die naghemel simuleer. Ster fotos kan projekteer word met gemid-
delde siglyn hoekfoute van slegs 2.47 boogsekondes en gemiddelde siglyn rotasie
foute van slegs 1.45 boogsekondes.
Die emulasie omgewing was demonstreer deur sterre te projekteer wat beide nie
beweeg nie of beweeg teen konstante hoeksnelhede vir die CubeStar om die sterre
af te neem. Vir sterre wat nie beweeg nie het die CubeStar oriëntasie afskatting
akkurathede gewys van siglyn hoekfoute onder 0.107° en siglyn rotasie foute onder
0.0667°. Met sterre wat teen konstante hoeksnelhede beweeg van tot 0.25°/s op
elke as het die CubeStar gewys dat dit die oriëntasie kan volg met gemiddelde
siglyn hoekfoute onder 0.145° en gemiddelde siglyn rotasie foute onder 0.1°.
ENGLISH ABSTRACT: As star trackers currently provide the most accurate attitude estimation to satel- lites, the electronics and algorithms are constantly evolving to produce star track- ers with decreased cost, size and power requirements while providing better ac- curacies. To perform hardware-in-loop emulations with the CubeStar in an o ce or laboratory environment, an emulation environment is developed and tested in this project. The emulation environment provides a more convenient alternative than the need to capture the night sky to test the e ciency of certain software algorithms on star trackers to evaluate accuracy and execution time improvements provided by upgraded electronic components and software algorithms. The emulation environment developed in this project enables hardware-in-loop emulations to be performed with a calibrated or uncalibrated CubeStar with the use of star projection software that projects stars onto a computer monitor that simulate the real night sky. Star images are projected with average boresight angle errors of only 2.47 arcseconds and average boresight rotation errors of only 1.45 arcseconds. The emulation environment was demonstrated by projecting stars that were both not moving or moving with constant angular rates for the CubeStar to cap- ture. For stars that were not moving the CubeStar showed attitude estimation accuracies of boresight angular errors below 0.107° and boresight rotation errors below 0.0667°. For stars projected with angular rates of up to 0.25°/s on each axis the CubeStar showed that it could track the attitude with estimation errors of average boresight angular errors below 0.145° and average boresight rotation errors below 0.1°.
ENGLISH ABSTRACT: As star trackers currently provide the most accurate attitude estimation to satel- lites, the electronics and algorithms are constantly evolving to produce star track- ers with decreased cost, size and power requirements while providing better ac- curacies. To perform hardware-in-loop emulations with the CubeStar in an o ce or laboratory environment, an emulation environment is developed and tested in this project. The emulation environment provides a more convenient alternative than the need to capture the night sky to test the e ciency of certain software algorithms on star trackers to evaluate accuracy and execution time improvements provided by upgraded electronic components and software algorithms. The emulation environment developed in this project enables hardware-in-loop emulations to be performed with a calibrated or uncalibrated CubeStar with the use of star projection software that projects stars onto a computer monitor that simulate the real night sky. Star images are projected with average boresight angle errors of only 2.47 arcseconds and average boresight rotation errors of only 1.45 arcseconds. The emulation environment was demonstrated by projecting stars that were both not moving or moving with constant angular rates for the CubeStar to cap- ture. For stars that were not moving the CubeStar showed attitude estimation accuracies of boresight angular errors below 0.107° and boresight rotation errors below 0.0667°. For stars projected with angular rates of up to 0.25°/s on each axis the CubeStar showed that it could track the attitude with estimation errors of average boresight angular errors below 0.145° and average boresight rotation errors below 0.1°.
Description
Thesis (MEng)--Stellenbosch University, 2021.
Keywords
Artificial satellites, UCTD, Emulators (Computer programs), CubeStar, Hardware-in-the-loop simulation