Pass prediction algorithm
I'm trying to write my own pass prediction program for tracking FM satellites. This program will this notify the users of upcoming passes via APRS messaging. I would like to find an algorithm that will predict AOS/LOS time and azimuth and the maximum elevation. I'm also hoping this algorithm will not be too computationally intensive as it may possibly be used for hundreds of different station locations.
Can anyone help?
73, Reid N0RC
--- On Mon, 6/28/10, Reid Crowe reid.crowe@gmail.com wrote:
From: Reid Crowe reid.crowe@gmail.com Subject: [amsat-bb] Pass prediction algorithm To: amsat-bb@amsat.org Received: Monday, June 28, 2010, 8:59 AM I'm trying to write my own pass prediction program for tracking FM satellites. This program will this notify the users of upcoming passes via APRS messaging. I would like to find an algorithm that will predict AOS/LOS time and azimuth and the maximum elevation. I'm also hoping this algorithm will not be too computationally intensive as it may possibly be used for hundreds of different station locations.
Can anyone help?
I'd suggest looking at books on spacecraft mechanics.
One which may help is "Fundamentals of Astrodynamics" by Roger R. Bate, Donald D. Meuller, and Jerry E. White (published by Dover). It's one of the better books on the subject, in my opinion, as I found it easier to read than many of the others I've seen. One does need some familiarity with calculus and linear algebra in order to understand the theory, however, but it's not overwhelming.
Another one is "Modern Spacecraft Dynamics & Control" by Marshall H. Kaplan (published by John Wiley & Sons). It's good, too, but I didn't find it as easy to go through as the other one.
73s
Bernhard VA6BMJ @ DO33FL
Reid,
My suggestion is that you start from "Predict", an open source satellite tracking and orbital prediction program:
http://www.qsl.net/kd2bd/predict.html
73, Steve N9IP
On Mon, 2010-06-28 at 10:26 -0700, B J wrote:
--- On Mon, 6/28/10, Reid Crowe reid.crowe@gmail.com wrote:
From: Reid Crowe reid.crowe@gmail.com Subject: [amsat-bb] Pass prediction algorithm To: amsat-bb@amsat.org Received: Monday, June 28, 2010, 8:59 AM I'm trying to write my own pass prediction program for tracking FM satellites. This program will this notify the users of upcoming passes via APRS messaging. I would like to find an algorithm that will predict AOS/LOS time and azimuth and the maximum elevation. I'm also hoping this algorithm will not be too computationally intensive as it may possibly be used for hundreds of different station locations.
Can anyone help?
I would suggest you look at the digi_ned source code. It works great and does everything you want. There was a change on the last update where he replace the display of azimuth/elevation to HIGH(over 30 degrees) and LOW (Below 30 degrees). That change actually works very well when driving down the road. But it was nice to see the actually numbers when sitting still. The code before this last update did that.
73 kim - ac7yy
... This program will this notify the users of upcoming passes via APRS messaging.
Better to use OBJECTS so that all of the following shows up on the front panel of the radio:
Satellite Name Direction, and Range Uplink Freq (and doppler) Downlink Freq and Doppler Elevation (HIGH or LOW). Direction of movement
I would suggest you look at the digi_ned source code. It works great and does everything you want. [that is, sending out all the Satellite Objects info on APRS shown above]
There was a change on the last update where he replace the display of azimuth/elevation to HIGH(over 30 degrees) and LOW (Below 30 degrees). That change actually works very well when driving down the road.
And if it is like the original APRSdata.EXE, those are encoded with a leading % sign so that the D700 radio with a voice chip will actually SPEAK "HIGH" and "LOW" so you never even have to look at the radio.
For example, you are just driving down the road, and your D700 (with voice chip)announces: "AO-51 435.300 -5 KHz 145.85 +1 KHz HIGH"
And if you look at the radio, it displays all the other info above.
This is just part of the local INFO that can be pushed to the front panel of the APRS radios as a service to the mobile operator. I'm glad you are taking on this challenge, because, no one uses the original APRSdata.EXE that did this, there are very few DIGI-NED's on the air doing it, and so we need a Windows version that each local area can run to serve their users.
Bob, WB4APR
On 06/28/2010 10:27 PM, Robert Bruninga wrote:
And if it is like the original APRSdata.EXE, those are encoded with a leading % sign so that the D700 radio with a voice chip will actually SPEAK "HIGH" and "LOW" so you never even have to look at the radio.
Is there a list of those words for the TM-D700 ?
sending %HIGH to the TM-D710 is just spelling each letter :o/
Kai Gunter LA3QMA
sending %HIGH to the TM-D710 is just spelling each letter :o/
There is a list of codes somewhere. To speak one of the pre-set words, you just include the text %XX where XX is a two byte HEX value of the word you want spoken. I guess you could just try all 256 codes and write down the words spoken? Should be the same voice chip as in the D700.
Bob WB4APR
And if it is like the original APRSdata.EXE, [the elevation of the satellite object is]... encoded with a leading % sign so that the D700 radio with a voice chip will actually SPEAK [the elevation] "HIGH" and "LOW" so you never even have to look at the radio.
On 06/29/2010 08:25 PM, Robert Bruninga wrote:
sending %HIGH to the TM-D710 is just spelling each letter :o/
There is a list of codes somewhere. To speak one of the pre-set words, you just include the text %XX where XX is a two byte HEX value of the word you want spoken. I guess you could just try all 256 codes and write down the words spoken? Should be the same voice chip as in the D700.
Bob WB4APR
hmm ok then it doesn't work as i have tested this. i don't remember the URL. Not sure if it's a TM-D710 bug or if it's not implemented.
Kai Gunter LA3QMA
Reid Crowe wrote:
I'm trying to write my own pass prediction program for tracking FM satellites. 73, Reid N0RC
Hi Reid,
If you want something in C, try predict. If BASIC is more to your liking, then try G3RUH's plan13 program. Both come with source code. Predict is GPL. Plan13 comes with G3RUH's writeup, which includes an excellent explanation of what the program does and how it does it.
predict is at http://www.qsl.net/kd2bd/predict.html
plan13 is at http://www.amsat.org/amsat/articles/g3ruh/111.html
Both will run on computers with minimal CPU resources.
Douglas KA2UPW/5
participants (7)
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B J -
Douglas Quagliana -
Kai Gunter Brandt -
kim -
Reid Crowe -
Robert Bruninga -
Stephen E. Belter