home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
The PC-SIG Library 10
/
The PC-Sig Library - Shareware for the IBM PC and Compatibles (PC-SIG)(Tenth Edition Disks 1-2804)(1991).iso
/
PC_SIGCD
/
04
/
4
/
DISK0447.ZIP
/
AIRNAV.DOC
< prev
next >
Wrap
Text File
|
1980-01-01
|
6KB
|
145 lines
FILE: AIRNAV.DOC
AIR NAVIAGTION - FLIGHT PLANNING PROGRAM
1. INTRODUCTION
The AIRNAV program is written to prepare a flight log for
flight over a predetermined route of up to twenty points (for
most light aircraft this provides waypoints close enough
together, and enough waypoints for one leg without refueling.
The log gives the geographic coordinates of the point, the
distance between points, the true course, and the estimated time
between points. It prints space on the log for entering actual
time between points. All flight planning is done on the basis of
one estimated speed for the entire series of legs. The effects of
wind and changes of speed with changes of altitute are not taken
into consideration in this program.
The effect of wind and altitude need to be considered in the
intial selection of an estimated groundspeed but since they
change substantially over any single 300 to 400 mile trip segment
the pilot will have to make these revisions manually. An
additional program module could be added to compute effect over
the planned flight segement.
Waypoint data is contained in a separate sequential file which is
loaded into memory at the start of the program. For flight
planning in various regions, such as the Pacfic Northwest and
Alaska, the complete file of data for the United States can be
broken down into regions, enabling the program to run faster.
2. PROGRAM STRUCTURE
The program is arranged in four modules. These are:
Calculate flight
Calculate intermediate points
Edit waypoint lists
Load new file
a. The flight cacluation prompts for load of a waypoint data
file and for input of the starting waypoint and up to 19
additional waypoints. Each waypoint is in the file in a string
39 characters long which inlcude eight letters for the name
(additional letters are chopped off on input), four letters as
the aviation "identifier", the lattitude and longitude (which can
be plus or minus for north and south lattitude, and east and west
longitude to make the program work world wide. The program
calcualtes the course and distance between each set of waypoints
by spherical trigonometry and computes the estimated time between
points based on the estimated groundspeed. Output is in the form
of a flight log. Courses are given as true but the deviation for
each waypoint is printed out so the pilot can make the mental
calculation.
b. Calculate Points - This module will calculate the great
circle course and distance between any two given points. It will
calculates the geographic coordinate of points at equal distances
along a great circle route, and will also calculate the longitude
and distance from the start at which the great circle course
intercepts any given lattitude, or the lattitude and distance
from the start at which it intercepts any given longitude.
c. The edit module will add to, change, or list the points
in the waypoint file
d. The new file module will load a new waypoint file into memory.
3. DATA FILES
Data files consist of 39 characters. The program was
originally wiritten for the Actrix computer which would hold only
500 waypoints in string space, so files of waypoints were set up
on a regional geographic basis.
Data files can be written modified and rearranged using any
text editor, or can be compiled and sorted from a data base.
Alternatively there is a uility program "SORTED.BAS" for use in
building and sorting waypoint files. It uses the Shell-Metz sort
procedure but still runs slowly. This is the format for the
waypoint string.
"SAMPLE FORMAT FOR WAYPOINT ENTRY"
"LOPEZISL S31- 048-29.2 0122-56.3 -21 WA"
"________ ____ ________ _________ ___ __"
The first item is eight characters containing the name of the
waypoint. For simplicity spaces and periods in the waypoints are
eliminated and names run together. Also, prefaces such as "Fort"
and "Saint" are abbreviated FT and ST without the period. When
entering the names of waypoints you can enter the full name (more
than eight characters. The input routine will chop off all but
the first eight.
The second item is the aviation "identifier" - four characters.
As a convention of this program intersections are writen with the
first three letters of the intersection name followed by an "I"
as the fourth letter.
The magnetic variation is given so it can be printed out on the
flight plan and the two letter abbreviation for the state,
province, our country is the last item.
4. CALCULATE FLIGHT
a. Load basic, load "AIRNAV-B.BAS" and run
b. You can select the "Load file" option first, then read
through the list of waypoints with the "Edit" option for
familiarization, or go directly to the "Calculate Flight" module.
c. Enter up to twenty waypoints in succession. As the
waypoints are entered they are listed in sequence so you you
where you are. You can start over by typing "START". If you
don't remember what waypoints are on the list you can type
"LIST". The program will switch to the "Edit List" module so you
can see if your selected waypoint is on the list, or enter it if
it isn't. When you have entered all the waypoints enter "Done".
You will then be prompted for the estimated groundspeed. When
this is entered the program will commence retrieving the
waypoints from memory and calculating the program.
d. If the waypoint you have entered does not exist you will
be promted to re-enter another waypoint, or a different spelling.
At this point you can again go back and look at the list to
check to spelling, or to add another waypoint.
e. When calculations are complete for each leg the computer
will print out the flight log. At the conclusion of the printing
it will as if you want to add another leg. You can input
additional legs, one at a time.
5. CALCULATE INTERMEDIATE POINTS
In this portion of the program you select the starting and
ending points, and a leg distance. The program will calculate
the geographic coordinates of the points at the end of each leg
segement. You can also compute the lattitude at which the course
intercepts any given longitude, or the longitude at which it
intercepts any given degree of latittude.
estimated groundspeed. When
this i