Re: float with 24-bit resolution

[Mark Johnson <mark_h_johnson@raytheon.com>]

"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