AvMap ekp iii c User Manual

On the bottom half of the screen (see previous Fig 7.1) there is a polar representation

of the Azimuth and Elevation of the satellites used to compute a position fix.

The Elevation is the height of the satellite above the horizon, with 5° (lowest) near the

horizon and 90° (highest) being directly overhead (the EKP-III does not normally use satellites

with Elevations lower than 10°). Azimuth is the satellite’s location in relation to true north,

measured clockwise as a bearing. A satellite with an Azimuth of 90° is to the east.

The circle contains a number indicating the number of the satellite and it is filled when

it is used for the fix solution. On the left side there are histograms indicating the S/N ratio

(SNR). The bar is filled when the satellite is used for the fix. When a valid fix is received, the

EKP-III displays the current position coordinates, Date, Time, HDOP, VDOP, GS, TRK and

ALT on the GPS page.

: L1, C/A code, DGPS/WAAS Ready

: 12

Max Solution Update Rate : 10/sec.

: < 45 sec.

: < 40 sec.

: 8 sec.

Each GPS satellite continuously broadcasts two signals: an SPS (Standard Positioning Service)

signal for worldwide civilian use and a PPS (Precise Positioning Service) signal for U.S. and

Allied military use. The SPS signal is a spread-spectrum signal broadcast at 1575.42 MHz. The

signal is virtually resistant to multipath and nighttime interference and is unaffected by weath-

er and electrical noise. All commercial and consumer GPS receivers are SPS receivers.

The SPS signal contains two types of orbit data: almanac and ephemeris. Almanac data

contains the health and approximate location of every satellite in the system. A GPS receiver

collects almanac data from any available satellite, then uses it to locate the satellites that should

be visible at the receiver’s location. Ephemeris data represents the precise orbital parameters of

a specific satellite.

Receivers listen to signals from many satellites simultaneously and triangulate a posi-

tion fix using the interval between the transmission and reception of each satellite signal (a

receiver tracks more satellites than are actually needed for a position fix, so that if one satellite

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EKP III USER MANUAL