SAM-M10Q - Integration manual
The internal filter gain is computed as a function of speed. Therefore, the level as defined in
the CFG-ODO-VELLPGAIN configuration item defines the nominal filtering level for speeds
below 5 m/s.
2.1.2.4.2 Course over ground low-pass filter
The CFG-ODO-OUTLPCOG configuration item activates a course over ground low-pass filter when
the speed is below 8 m/s. The output of the course over ground (also named heading of motion
2D) low-pass filter is available in the UBX-NAV-PVT message (
headMot
field), UBX-NAV-VELNED
message (
heading
field), NMEA-RMC message (
cog
field), and NMEA-VTG message (
cogt
field).
The filtering level can be set via the CFG-ODO-COGLPGAIN configuration item and must be between
0 (heavy low-pass filtering) and 255 (weak low-pass filtering).
The filtering level as defined in the CFG-ODO-COGLPGAIN configuration item defines the
filter gain for speeds below 8 m/s. If the speed is 8 m/s or higher, no course over ground low-
pass filtering is performed.
2.1.2.4.3 Low-speed course over ground filter
The CFG-ODO-USE_COG configuration item activates this feature and the CFG-ODO-
COGMAXSPEED, CFG-ODO-COGMAXPOSACC configuration items are used to configure a low-
speed course over ground filter (also named heading of motion 2D). This filter derives the course
over ground from position at very low speed. The output of the low-speed course over ground filter
is available in the UBX-NAV-PVT message (
headMot
field), UBX-NAV-VELNED message (
heading
field), NMEA-RMC message (
cog
field) and NMEA-VTG message (
cogt
field). If the low-speed
course over ground filter is not configured, then the course over ground is computed as described
in section
Freezing the course over ground
2.1.2.5 Static hold
Static hold mode allows the navigation algorithms to decrease the noise in the position output when
the velocity is below a predefined "Static Hold Threshold" level. This reduces the position wander
caused by environmental factors such as multi-path and improves position accuracy especially in
stationary applications. By default, static hold mode is disabled.
The CFG-MOT-GNSSSPEED_THRS configuration item defines the static hold speed threshold. If
the speed drops below the defined "Static Hold Threshold", static hold mode will be activated. Once
static hold mode is active, the position output is kept static and the velocity is set to zero until there
is evidence of movement again. Such evidence can be velocity, acceleration, changes of the valid flag
(for example, position accuracy estimate exceeding the position accuracy mask, see also section
), position displacement, etc.
The CFG-MOT-GNSSDIST_THRS configuration item defines the static hold distance threshold. If
the distance between the estimated position and the static hold position exceeds the defined
threshold, static hold mode is suspended or deactivated until there is evidence of no movement.
UBX-22020019 - R01
2 Receiver functionality
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