Introduction - What is HPredict?
HPredict is a low-orbiting satellite position prediction program
for HP calcs (HP48/49/50). It will enable you to track one or multiple
satellites, given the TLE (Two Lines Element, see ) of the satellites
HPredict is a free software under the GNU's Public Licence. It is the
work of Khanh-Dang NGUYEN THU-LAM (kdntl ![at]()
yahoo . fr.)
HPredict is not yet available for download. I hope I could
publish it as soon as possible (today is 2007-10-30).
FAQ
- What algorithms does HPredict use? How accurate is it?
- HPredict use the SGP algorithm described in the
Spacetrack Report Number 3, available
here.
The SGP algorithm is the fastest (SGP4 requires much more calculus)
but it is accurate enough for most purposes, including visual observation
of the ISS, or antenna positionning for radio amateurs.
A TLE file older than two or three weeks should't be used.
- I don't like HPredict. What other satellite's prediction programs are
there for HP calcs?
- Actually, I wrote HPredict because no other programs fitted my needs.
You can try Above by Albert P. Gerheim, available
here (hpcalc.org) and
here (author's page).
Above is great but it is very very slow (it is written in pure User
RPL).
TODO/Bugs
Download
Please go to the download page.
References