User Guide

u-center-User Guide
UBX-13005250 - R18
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Production Information 5 u-center Menus and Windows
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5.2.4 Icons and text field of console views
Element Name Description
/
Lock / Locked Prevents the console from being updated with new data when locked. Pause key can be used to
Lock/Unlock the current console window.
Clear All Erases all data in the console.
Show/Hide PC time Shows/Hides the PC time in the console.
Filter On/Off Filters unwanted data from the data stream. This allows searching for certain expression, e.g. all
RMC messages.
Pause player Pauses the player when the search expression is found. Only works in playback mode.
Table 12: Description of the buttons and text field of the console views
5.2.5 Regular expression evaluation
Normally, when you search for a sub-string in a string, the match should be exact. So if we search for a sub-
string "abc" then the string being searched should contain these exact letters in the same sequence for a match
to be found. We can extend this kind of search to a case insensitive search where the sub-string "abc" will find
strings like "Abc", "ABC" etc. That is, the case is ignored but the sequence of the letters should be exactly the
same. Sometimes, a case insensitive search is also not enough. For example, if we want to search for numeric
digit, then we basically end up searching for each digit independently. This is where regular expressions come
in to our help. Regular expressions are text patterns that are used for string matching. Regular expressions are
strings that contain a mix of plain text and special characters to indicate what kind of matching to do. Here's a
very brief tutorial on using regular expressions.
Suppose, we are looking for a numeric digit then the regular expression we would search for is "[0-9]". The
brackets indicate that the character being compared should match any one of the characters enclosed within the
bracket. The dash (-) between 0 and 9 indicates that it is a range from 0 to 9. Therefore, this regular expression
will match any character between 0 and 9, that is, any digit. If we want to search for a special character literally
we must use a backslash before the special character. For example, the single character regular expression "\*"
matches a single asterisk. In the table below the special characters are briefly described. A regular expression
search is case sensitive.
Character Description
^ Beginning of the string. The expression "^A" will match an "A" only at the beginning of the string.
[^ The caret (^) immediately following the left-bracket ([) has a different meaning. It is used to exclude the remaining
characters within brackets from matching the target string. The expression "[^0-9]" indicates that the target character
should not be a digit.
$ The dollar sign ($) will match the end of the string. The expression "abc$" will match the sub-string "abc" only if it is at
the end of the string.
| The alternation or logic OR character (|) allows either expression on its side to match the target string. The expression "a|
b" will match "a" as well as "b".
. The dot (.) will match any character.
* The asterisk (*) indicates that the character to the left of the asterisk in the expression should match 0 or more times.
+ The plus (+) is similar to asterisk but there should be at least one match of the character to the left of the + sign in the
expression.
? The question mark (?) matches the character to its left 0 or 1 times.
() The parenthesis affects the order of pattern evaluation.
[] Brackets ([ and ]) enclosing a set of characters indicates that any of the enclosed characters may match the target
character.
Table 13: Regular expression syntax
5.2.5.1 Examples
Let's assume that the lines in Figure 22 would appear in the NMEA console without filtering.