About GPS fix status

When GPS data are processed each GPS fix is assigned a status based on its compliance with criteria such as platform speed, time gaps, and data validity. The GPS fix status indicates the quality of the fix and is used to determine cruise track quality and the quality of ping positions.

GPS fix status values

1. Good:
1. Fixes that meet all criteria for validity, including acceptable speed and time gaps.
2. Good (Uncertain):
   1. Assigned when fixes partially meet gap criteria but the fix is not definitively good or bad.
   2. GPS fix status Method 1 assigns Good (uncertain) to fixes before Fix G.
3. Bad:
1. Fixes that fail one or more criteria, such as exceeding maximum apparent speed or having invalid coordinates.
2. GPS fix status Method 2 assigns bad to fixes before Fix G.

Display of fix and track quality

Good and Good(uncertain) fixes are displayed as a default green cross on cruise tracks, with track segments between good fixes. The Track quality between fixes is determined by the Ping position status.

Bad fixes are displayed as a default red cross. Bad fixes are not connected to track segments.

Notes:

• Exported GPS fix data may include additional status values, such as "good (uncertain)", which reflect partial compliance with criteria. These values are not displayed in Echoview.

Where to view GPS fix status:

1. Echograms
2. Cruise tracks
3. Tables

How GPS fix status is determined

Echoview uses a multi-stage algorithm to assign GPS fix status. This involves filtering out invalid fixes, identifying the first good fix (Fix G), and evaluating the status of each subsequent fix. For more details, see Determining GPS Fix Status.

See also

Determining GPS fix status
Determining Ping position status
About Ping Position Status
About Cruise Tracks
Position status area on Echograms
About Tables