Heading
This page is used when you want the receiver to deliver heading, roll or pitch measurements.
In the so-called external heading mode, the receiver uses its own antenna connected to the “Antenna 1” input. One of its ports is declared as the one providing the receiver with corrections in ATOM or RTCM-3 format from an external GNSS receiver to which the second GNSS antenna (defined as “Antenna 2” on your receiver) is connected. The local “Antenna 2” input is not used here.
Combining these incoming data with the data from its own antenna, the receiver will be able to determine the heading of the baseline connecting the two antennas.
The two antennas should be installed to guarantee an ever-fixed baseline length.
The heading determined by the receiver always depicts the direction from “Antenna 2” to “Antenna 1”.
Depending on the orientation of the baseline with respect to the vehicle centerline (ship, plane, land vehicle, etc.), the receiver will either compute the heading + pitch or heading + roll angles. The value you assign to the azimuth offset parameter will determine whether the receiver will compute the roll or pitch angle:
• Computing Heading + Pitch: The baseline should be strictly parallel (azimuth offset= 0°), or roughly parallel (azimuth offset close to 0°), to the vehicle centerline. “Antenna 1” should be placed ahead of “Antenna 2” with respect to direction of travel.
NOTE: You can reverse the locations of Antenna 1 and Antenna 2, but in this case you should enter a azimuth offset equal, or close to 180°.
• Computing Heading + Roll: The baseline should be strictly perpendicular (azimuth offset= 90°), or roughly perpendicular (azimuth offset close to 90°), to the vehicle centerline. For an observer taking a look at the antennas from the back of the vehicle while looking towards the front of the vehicle, “Antenna 1” should be seen on the right and “Antenna 2” on the left.
NOTE: You can reverse the locations of Antenna 1 and Antenna 2, but in this case you should enter an azimuth offset equal, or close to 270°.
If the azimuth offset is set to a value exceeding 15° from either North, South, West or East, then the receiver will deliver the heading component of attitude, but not the pitch or roll angle.
From the operational point of view, the receiver that uses “Antenna 1” operates as a rover while the receiver using “Antenna 2”(external receiver) operates as a moving base.
Activating the external heading mode in your receiver will necessarily re-configure the receiver using “Antenna 1” as a rover. If it was previously set up as a base, then it will instantaneously become a rover as soon as you activate the heading mode. If it’s already a rover computing RTK positions, switching to heading mode will not impact the processing and availability of RTK positions.
The following groups of parameters need to be defined:
• Receiver
• Satellites
• Heading
Receiver
Parameter |
Designation |
$PASHS |
---|---|---|
Antenna |
Select the model of antenna used as “Antenna 1”. Antenna 1 is the antenna connected to the coaxial plug marked with a satellite icon. |
ANP,OWN |
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Fast Output |
Set this option as follows: • Check it to enable fast output of heading measurements. • Clear it to disable fast output of heading measurements. |
CPD,FST |
Satellites
Use this area to define the constellations received by the receiver as well as the elevation mask applied for all constellations.
Parameter |
Designation |
$PASHS |
---|---|---|
Position Elevation Mask |
Enter the elevation mask, in degrees, used by the receiver to compute the heading. No data from any visible satellite located below this elevation angle will be used in the heading measurement. |
ELM |
GPS |
Check this button to enable GPS tracking. Clear it otherwise. |
GPS |
GLONASS |
Check this button to enable GLONASS tracking (requires installed S option). Clear it otherwise. |
GLO |
SBAS |
Check this button to enable SBAS tracking. Clear it otherwise. |
SBA |
QZSS |
Check this button to enable QZSS tracking. Clear it otherwise. |
QZS |
GALILEO |
Check this button to enable GALILEO tracking. Clear it otherwise. |
GAL |
Heading
Parameter |
Designation |
$PASHS |
---|---|---|
Mode |
Make the appropriate selection: • Off: No heading measurement requested • External: Heading measurement requested, external GNSS receiver and its antenna used to provide the receiver with the appropriate data. |
CPD,ARR,MOD |
Input Port |
(Visible only if Mode= “External”) Choose the serial port through which data from the external GNSS receiver (and the second GNSS antenna) are applied to the receiver (A, B, F, C, D, E, I or P). |
CPD,ARR,MOD |
Baseline Length |
Enter the distance between the two antennas used (baseline length). Setting this parameter to “0” forces the receiver to start an-auto calibration sequence. Auto Calibration: Checking this button amounts to entering “0” in the Baseline Length field, which, as explained above, will result in starting an auto-calibration sequence. |
CPD,ARR,LEN |
Azimuth Offset |
Designates the angle deviation (0-359.99°) between the horizontal component of the baseline and the horizontal direction of the object for which you want to determine the heading. This parameter makes sense in a vehicle for example where the baseline resulting from the installation of the two antennas is not parallel to the direction in which the vehicle is moving (default: 0). Specifying the azimuth offset also allows the receiver to deliver an accurate measurement of the roll or pitch angle (depending on whether the baseline is oriented in a direction respectively perpendicular or parallel to that of the vehicle). Keep this parameter equal to zero if it does not make sense to define an azimuth offset in your application. |
CPD,ARR,OFS |
Maximum Baseline Elevation |
Set the maximum value of expected baseline elevation (0-90°; Default: 15°). |
CPD,ARR,PAR |
Elevation Offset |
Designates the angle deviation (±90°) between the orientation of the baseline and the orientation of the object for which you want to determine the roll or pitch angle. This parameter makes sense in a ship for example where the baseline resulting from the installation of the two antennas is not parallel to the orientation of the deck (default: 0). Keep this parameter equal to zero if it does not make sense to define an elevation offset in your application. |
CPD,ARR,OFS |
Maximum Baseline Length Error |
Set the maximum error that is tolerated in the determination of the baseline length (0.001-10.000 meters) |
CPD,ARR,PAR |