TM 1-1510-225-10 3D-73 Table 3D-17.  GPS Status Codes DISPLAY EXPLANATION ACQ Acquisition DEGRD Navigation with position degradation FAILR Receiver failure INIT Initialization NAV Navigation NAV A Navigation with altitude aiding NAV D Navigation with data collection TRAN Transition (1)   In the initialization state, the GPS receiver   is   in   the   process   of   initializing   itself   and collecting information such as the date, time, and last position.    Next  the  receiver  collects  data  from  its  own memory    to    determine    which    satellites    should    be visible.    After  completing  the  initialization  process,  the receiver  begins  the  acquisition  process.    During  this time, the visible satellites are being acquired and data from them is being obtained. (2)   The transition state indicates an adequate number of satellites for navigation has been acquired and is being tracked but no position data can yet be produced. (3)   Normal  navigation  is  indicated  by  a  Nav, NAV A, or a NAV D GPS state.  NAV A indicates that the altitude input is being used in the position solution.   NAV D indicates that besides calculating position, the receiver    is    collecting    and    storing    in    its    memory ephemera and almanac data information. (4)   The   specific   GPS   satellites   or   Space Vehicles (SV), being received are displayed in the left column.      Each   satellite   has   its   own   identification number.      An   *   to   the   left   of   the   satellite   number indicates this particular satellite is not presently being used in the navigation solution. (5)   The  satellite's  health  is  indicated  to  the right of the satellite number.  The health information is transmitted  by  the  satellite.    Health  designators  are defined in Table 3D-18. (6)   The Signal to Noise Ratio (SNR) for each satellite   being   received   is   displayed   in   the   middle column   and   indicated   the   signal   strength   for   each satellite.    The  higher  the  SNR  value  the  stronger  the signal.  Values usable for navigation will be in the mid 30's  to  mid  50's.    Typical  values  are  in  the  middle  of this range. Table 3D-18.  Satellite Health DISPLAY EXPLANATION B Bad W Weak – Unknown Blank Good (7)   The elevation (ELE) above the horizon for each  satellite  is  provided  in  the  right  column  and  will range from 5º to 90º.  Refer to Figure 3D-111. STA+1 STATE   NAV SV SNR ELE 02  40 11^o 11  42 47^o 16  36 06^o *18B 33 65^o Figure 3D-111.  STA 1 Page b.  STA 2 Page.    The  STA  2  page  displays  the systems  estimate  of  the  position  error  expressed  in nautical  miles.    Refer  to  Figure  3D-112.    The  KLN 90B’s  position  error  depends  on  such  factors  as  the number of satellites being received, the strength of the GPS    signals,    and    the    geometry    of    the    satellites presently being used for navigation. STA 2 ESTIMATED POSN ERROR       .07NM Figure 3D-112.  STA 2 Page c.   STA 3 Page.    The  STA  3  page  displays  the software revision status of the KLN 90B host computer and  of  the  GPS  receiver.    A  field  called  OBS  CAL  is also  included  on  this  page.    The  value  indicates  the calibration of the internal resolver circuitry of the KLN 90B.