GPS Status Screens
POS PROP means that navigation has been temporarily lost and the
KMD 150 is dead-reckoning (or propagating) its position based on the
last known position, track and ground speed. It will not dead-reckon for
more than a few seconds at a time.
Other information that is displayed, on this Screen includes:
ANTENNA CURRENT Against this heading there will be an indication if
the antenna is drawing too much, too little or the correct amount of cur-
rent. If the indication is <5mA then the antenna is probably open circuit
and must be investigated. If the indication is >40mA then the antenna is
probably short circuited and must be investigated. If the indication is OK
then the antenna is drawing the correct amount of current.
DOP (Dilution of Precision), this is a number between 00.0 and 99.0 that
represents the dilution of quality of the calculated fix due to satellite
geometry. 00.0 is best, 99.9 is worst. If this figure is greater than 5.0,
performance of the system is likely to be degraded because some of the
visible satellites appear too close to each other. DOP is calculated from
the angular separation between the various visible satellites. Greater
separation results in better fix geometry and a lower DOP. (This DOP
figure is not measured in any specific units.)
UTC/DATE, which is Universal or Greenwich Mean Time and Date.
LOCAL OFFSET, which is the difference between UTC and local time.
LOCAL TIME, which is calculated by adding Local Offset to UTC.
LAST FIX. If the unit does not have a current valid fix, this is the position
at which it last had a fix. If the unit has a fix, this is the present position.
SATS (eight satellite numbers), SIGS (signal strength for each satellite)
and STAT (status of each satellite).
Each satellite has a PRN (Pseudo Random Noise) or identification
number. The satellite PRN numbers are displayed in a line beside the
word SATS. The two digit number under each PRN number is an indica-
tion of the signal strength being received from that satellite expressed in
terms of a percentage. Best is 99, worst is 00. These numbers can be
used for finding and eliminating electrical interference. Readings of 60
and above indicate a good installation.
Under each signal strength number is a two character code. These indi-
cate the status of each satellite. These codes are: CS, CA, AS, FA, BD,
MD, TA, EA, and AP. These relate to the eight possible receiver modes
and are detailed in the next paragraphs.
CS: Code Search. This is the receiver's initial stage in acquiring a satel-
lite. It means that the receiver is trying to match its internal code to the
Rev 1 Mar/2000
KMD 150 Pilot's Guide