From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,7a2d45f282a1da1c X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-08-15 11:08:34 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!bloom-beacon.mit.edu!cambridge1-snf1.gtei.net!news.gtei.net!bos-service1.ext.raytheon.com!dfw-service2.ext.raytheon.com.POSTED!not-for-mail Message-ID: <3F3D2195.D984062E@raytheon.com> From: Mark Johnson X-Mailer: Mozilla 4.76 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: float with 24-bit resolution References: <3F3CCB0F.543478AF@adrianhoe.nospam.com.my> <3f3cd7f4$1_2@news.tm.net.my> <3F3CE28D.B841A191@raytheon.com> <3F3D10B7.9080707@attbi.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Fri, 15 Aug 2003 13:08:21 -0500 NNTP-Posting-Host: 192.27.48.39 X-Complaints-To: news@ext.ray.com X-Trace: dfw-service2.ext.raytheon.com 1060970913 192.27.48.39 (Fri, 15 Aug 2003 13:08:33 CDT) NNTP-Posting-Date: Fri, 15 Aug 2003 13:08:33 CDT Organization: Raytheon Company Xref: archiver1.google.com comp.lang.ada:41527 Date: 2003-08-15T13:08:21-05:00 List-Id: "Robert I. Eachus" wrote: > > Mark Johnson wrote: > > > For example, on one system I simulated, a ship did not move until > > reaching 5 knots because the result of (speed * delta_time) was less > > than the LSB of the distance value. We had to use double precision for > > location (X, Y) for most calculations and then use the MSB portion for > > display on the screen. > > Hmmm. I've solved the same problem by recalculating the predicted > position whenever needed from the last known position and velocity. But > that was in a radar application, where I was doing data fusion, so > running each location, velocity pair forward made more sense. > I believe we are describing the same situation with a slightly different emphasis. For example, in a a simulator, the user interface for the instructor may be in terms of Ship A Speed 5 knots Bearing 220 degrees followed by a command like Turn right 10 degrees and we have to take that information plus the current location to generate a new location at the iteration rate of the model (say 30 Hz). The instructor is dealing with terms such as speed, bearing, and changes in those values while the software inside must generate X / Y position and do the appropriate conversions. --Mark