GPS#

The GPS sensor can be configured to use prerecorded data to simulate different scenarios:

  • xxx_quality: scenario where GPS data are of xxx quality where xxx can be good, medium, or bad

  • xxx_quality_with_fix: same as xxx quality but preceded by xxx quality fix search

  • smartphone: scenario where GPS data contain errors typical from a smartphone

To deactivate the use of prerecorded data, set empirical_error_mode to an empty string. By default, empirical_error_mode is set to an empty string, except for ANAFI Ai for which it is set to good_quality.

Note

Some GPS parameters are expressions that are expected to modify the corresponding perfect output accessible via the val variable. These are:

  • position_east_m_expr

  • position_north_m_expr

  • position_up_m_expr

  • velocity_east_expr

  • velocity_north_expr

  • velocity_up_expr

Others are expressions that directly set arbitrary values:

  • pos_accuracy_m_expr

  • speed_accuracy_mps_expr

  • pdop_expr

  • hdop_expr

  • vdop_expr

  • range_rms_expr

  • std_lat_expr

  • std_long_expr

  • std_alt_expr

  • num_sv_expr

All parameters#

Name

Description

Expected type

delay_ms

Delay of the GPS in milliseconds.

integer

delta_position

Relative position of the GPS sensor in body frame in meters.

3-component vector

empirical_error_mode

Empirical Error Mode. If set to a mode name supported by the simulated drone, replays predefined errors over several GPS variables.

string

faa_mode_indicator

(FAA) Mode indicator. Possible values are: N (No Fix), A (Autonomous GNSS Fix), D (Differential GNSS Fix), E (Estimated/Dead Reckoning Fix).

string

fix_mode

Current fix mode. Possible values are: 1 (Fix not available) 2 (2D mode selected) 3 (3D mode selected).

integer

hdop_expr

Arbitrary value of the horizontal dilution of precision (HDOP). Expression supported.

string

num_sv_expr

Arbitrary value of the number of satellites. Expression supported.

string

number_delay_samples

DEPRECATED. Delay of the GPS as a number of samples.

integer

out_of_order

If true, put the sensor out of service.

boolean

pdop_expr

Arbitrary value of the position dilution of precision. Expression supported.

string

pos_accuracy_m_expr

Arbitrary value of the position accuracy estimate [meters]. Expression supported.

string

pos_mode

Positioning mode. Composed of two character, the first character is for GPS and second character is for GLONASS. The signification of each character is as follows: N (Constellation not in use, or no valid fix), A (Autonomous (non-differential)), D (Differential mode), P (Precise (no degradation, like Selective Availability)), R (Real Time Kinematic), F (Float RTK), E (Estimated (dead reckoning) Mode), M (Manual Input Mode), S (Simulator Mode).

string

position_east_m_expr

Expression of drone position in Gazebo system coordinates - East direction [meters].

string

position_north_m_expr

Expression of drone position in Gazebo system coordinates - North direction [meters].

string

position_up_m_expr

Expression of drone AMSL altitude [meters].

string

quality

Quality indicator for position fix. Possible values are: 0 (No Fix), 1 (Autonomous GNSS Fix), 2 (Differential GNSS Fix), 6 (Estimated/Dead Reckoning Fix).

integer

range_rms_expr

Arbitrary value of the RMS value of the standard deviation of ranges. Expression supported.

string

rtk_fix_status

RTK fix status. Possible values are: none (No fix), float (Floating ambiguities), fix (Fixed)

string

selection_mode

Selection mode for the fix. Possible values are: M (Manual (forced to operate in 2D or 3D)) A (Automatic (2D or 3D)).

string

speed_accuracy_mps_expr

Arbitrary value of the speed accuracy estimate [m/s]. Expression supported.

string

status

Navigation receiver status. Possible values are: A (Valid) or V (Navigation receiver warning).

string

std_alt_expr

Arbitrary value of the standard deviation for the altitude error. Expression supported.

string

std_lat_expr

Arbitrary value of the standard deviation for the latitude error. Expression supported.

string

std_long_expr

Arbitrary value of the standard deviation for the longitude error. Expression supported.

string

update_rate

Sensor frequency [Hz].

floating-point number

vdop_expr

Arbitrary value of the vertical dilution of precision (VDOP). Expression supported.

string

velocity_east_expr

Expression defining drone velocity along East direction [m/s].

string

velocity_north_expr

Expression defining drone velocity along North direction [m/s].

string

velocity_up_expr

Expression defining drone vertical velocity [m/s].

string