Date: Fri, 7 Oct 94 04:30:26 PDT From: Ham-Space Mailing List and Newsgroup Errors-To: Ham-Space-Errors@UCSD.Edu Reply-To: Ham-Space@UCSD.Edu Precedence: List Subject: Ham-Space Digest V94 #282 To: Ham-Space Ham-Space Digest Fri, 7 Oct 94 Volume 94 : Issue 282 Today's Topics: AEA DSP-1232 problem Phase schedules SATTRACK V2.0 FOR UNIX/LINUX AVAILABLE NOW Tracking models ? Send Replies or notes for publication to: Send subscription requests to: Problems you can't solve otherwise to brian@ucsd.edu. Archives of past issues of the Ham-Space Digest are available (by FTP only) from UCSD.Edu in directory "mailarchives/ham-space". We trust that readers are intelligent enough to realize that all text herein consists of personal comments and does not represent the official policies or positions of any party. Your mileage may vary. So there. ---------------------------------------------------------------------- Date: 5 Oct 94 16:18:56 From: n4hy@tang.ccr-p.ida.org (Bob McGwier) Subject: AEA DSP-1232 problem It depends on what your radio is as to how it functions. What type of radio are you using? Bob -- Robert W. McGwier | n4hy@ccr-p.ida.org: ham radio, scouts, Center for Communications Research | astronomy, golf (o yea, & math!) ASM Princeton, N.J. 08520 | Troop 5700, ACM Pack 53, Sanhican #2 WWW, (609)-279-6240(v) (609)-924-3061(f)| District and Council Activities Chair. (609-443-8963 (h) | I used to be a Buffalo . . . NE III-120 ------------------------------ Date: 6 Oct 94 12:54:47 GMT From: dmgillah@mtu.EDU (David Gillahan) Subject: Phase schedules Howdy! I was womdering if any of you know where I can find updates of the phase schedule for varies satellites. Example: AO-13 Phase 1-180:mode B Phase 180-256:mode J That was the last update I have as of 20APR94, I'd like to get something more recent. Thanks! -- ***************************************************************************** * Talk to ya, Dave Attention all Skydivers: * * Until you've jumped * * Michigan Technological University into pitch blackness * * Where it's too &@#% cold! at 1250 feet with 80 * * dmgillah@mtu.edu pounds of combat gear, * * kb8por@w8yy.#upmi.mi.usa.na YOUR STILL A LEG !!! * ***************************************************************************** ------------------------------ Date: 6 Oct 1994 03:33:17 GMT From: manfred@sunspot.ssl.berkeley.edu (Manfred Bester) Subject: SATTRACK V2.0 FOR UNIX/LINUX AVAILABLE NOW SatTrack V2.0 Release Finally version 2.0 of SatTrack is ready to be released. This new version features the NOARD SGP4 propagation model, a live display for a single satellite as well as a live display for multiple satellites (as many as the computing power of the machine it runs on allows), a batch mode with arguments passed on the command line, and the orbit prediction capabilities that V1.7 had. Numerous suggestions from users of V1.7 all over the world have been incorporated in the new version, like tracking of the Sun and the Moon for system tests and EME, respectively, the calculation of off-pointing (squint) angles, and also some subroutines that allow control of ground station equipment (radios and antenna controllers). The framework for the latter is provided in a way that allows the user to easily make changes for a particular application. The program will run on Sun workstations and Linux i386 laptop computers (see documentaion file). Future releases are expected to feature the SDP4 model for satellites with a period of more than 225 minutes (V2.1) and Xwindows graphics (V3.0). Bob Kupiec was kind enough to provide an FTP site from which SatTrack can be obtained. Do the following: ftp ftp.jvnc.net (128.121.50.2) login anonymous cd /priv/kupiec/incoming (or later: cd /priv/kupiec/sattrack) get sattrack.V2.0.tar.Z Place this file into your Unix home directory, uncompress it, and then type 'tar xvpf sattrack.V2.0.tar'. This will unbundle the distribution file and will create all necessary sub-directories. Then look into the documentation file 'sattrack.doc' in SatTrack/doc for instructions how to compile sattrack (and some other auxiliary programs). It should compile perfectly on at least Sun-3's (SunOS 4.0.3), SPARCstation IPCs (SunOS 4.1.1) and i386 laptops running Linux. Make sure the compiler and linker flags in the Makefile are configured properly! Please let me know how the installation went and if you encountered any problems, bugs or imperfections. Manfred Bester Space Sciences Laboratory University of California Berkeley, CA 94720, USA (510) 642-8497 manfred@ssl.berkeley.edu ------------------------------ Date: Thu, 6 Oct 94 22:50:34 GMT From: srghsjm@grv.grace.cri.nz Subject: Tracking models ? In Article <1994Oct6.065111.1@violet.ccit.arizona.edu> dpalik@violet.ccit.arizona.edu writes: >What is the difference between the Tracking models (SGP4 propagation model, and >the others) ?? For various reasons (including computational simplicity) the complicated models that were historically developed have been simplified and refined to models such as SGP4. By doing so, some new parameters have had to be added to the basic element sets. The other most common prediction model around seems to be the TBUS predictor that uses (as expected) some TBUS elements. > >Is one more accurate ? > That's actually a more difficult question to answer than it seems. The accuracy can be required for either short term or long term periods. For all practical purposes, with the range of element sets that are available over Internet, all models are pretty good (or, equally bad, depending on your point of view). >Do they all require the same data from TLE sets ? > No. The SGP4 predictor uses NASA 2-line elements that are designed for SGP4. The NASA 2-line element format allows for SGP8, but I don't think that was used (correct me if I'm wrong). SGP8 requires some extra parameters. The TBUS predictor (used often in earth resources satellites and for many low earth orbit ground stations) uses parameters from TBUS element sets. Don't use TBUS elements in the SGP4 model, or the reverse. The W3IWI predictor model (a la "Orbit" circa 1986 or something like that) is simplified model that, while cutting a few corners, takes a fairly practical line in doing so. Source code for SGP4 and TBUS predictors is available (albeit in FORTRAN), but various people have converted these to Pascal and C. The results are variously readable code... Stephen ZL4HG +--------------------------------------------------------------------------+ | Stephen McNeill Phone : +64-4-569 0180 | | Image Processing Team Direct : +64-4-569 0183 | | Landcare Research New Zealand Ltd FAX : +64-4-569 0181 | | Box 38-491 Internet: srghsjm@gih.grace.cri.nz | | Wellington Mail Centre Omnet : s.mcneill | | New Zealand Packet : zl4hg @ zl4hg.wlg.nzl.oc | +--------------------------------------------------------------------------+ ------------------------------ End of Ham-Space Digest V94 #282 ******************************