Chapter 4

SPAN-IGM Dual Antenna

2.Enter the lever arm from the SPAN-IGM to the secondary antenna (secondary antenna is connected to the second receiver) using the SETIMUTOANTOFFSET2 command.

Abbreviated ASCII example:

SETIMUTOANTOFFSET2 0.54 2.32 1.20 0.03 0.03 0.05

Alternately, the angular offset between the dual-antenna baseline (from Primary GNSS antenna to Secondary GNSS antenna) and the IMU frame forward axis can be entered directly via the EXTHDGOFFSET command.

We recommend entering the lever arms rather than entering the angular offset as this is easier to measure and will lead to better overall accuracy.

Refer to the SPAN on OEM6 Firmware Reference Manual (OM-20000144) for the syntax of the above commands.

As with all ALIGN-capable products, the GNSS baseline solution is available from the GPHDT and HEADING logs. For INS heading, use the INSATT or INSPVA logs.

The SPAN-IGM can be configured for different alignment routines depending on the motion conditions experienced during the alignment period. For example, in marine applications, the dynamics required for either a coarse or kinematic alignment cannot be guaranteed, so a different alignment routine will be required.

The different alignment routines are described in the following sections:

4.2.1Alignment on a Moving Vessel - Aided Transfer Alignment

This alignment routine is the preferred dual antenna alignment method. It is used if the alignment mode is set to AIDED_TRANSFER using the ALIGNMENTMODE command, and can be used if the alignment mode is set to AUTOMATIC.

If your vehicle is not stationary during the alignment, such as may be the case on a ship, use the Aided Transfer Alignment routine. This alignment method uses the ALIGN baseline solution to perform an instantaneous alignment of the vehicle attitude.

The alignment happens instantaneously after the SPAN-IGM computes a verified, fixed integer, ALIGN solution. The INS status changes to INS_ALIGNMENT_COMPLETE or INS_SOLUTION_GOOD, depending on the variances of the ALIGN solution, and the measured lever arm/external heading offset.

To guarantee the use of this alignment mode, the configuration command ALIGNMENTMODE must be sent to the receiver:

ALIGNMENTMODE AIDED_TRANSFER

4.2.2Alignment on a Stationary Vehicle - Aided Static Alignment

An alternative to the aided transfer alignment, the ALIGN heading can be used as a seed for a coarse static alignment. In this mode, the standard coarse alignment routine runs given the initial azimuth value. As with the transfer alignment, the first verified fixed RTK solution is used to provide the alignment seed after which the coarse alignment (INS_ALIGNING) begins. After the coarse alignment is complete, the INS status changes to INS_ALIGNMENT_COMPLETE. After the attitude accuracy has converged, the INS status changes to INS_SOLUTION_GOOD. This alignment mode is useful if the initial vehicle roll is more than 20 degrees.

To use this alignment mode, the configuration command ALIGNMENTMODE must be sent to the receiver.

ALIGNMENTMODE AIDED_STATIC

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SPAN-IGM User Manual Rev 2

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Novatel OM-20000141 user manual Alignment on a Moving Vessel Aided Transfer Alignment
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OM-20000141 specifications

The Novatel OM-20000141 is a high-performance multi-GNSS (Global Navigation Satellite System) receiver designed for various applications including precision agriculture, autonomous vehicles, and surveying. This state-of-the-art device combines cutting-edge technologies to provide accurate and reliable positioning data, making it an indispensable tool for professionals in fields that rely on geolocation.

One of the standout features of the Novatel OM-20000141 is its multi-frequency support, allowing it to receive signals from GPS, GLONASS, Galileo, and BeiDou systems. This capability significantly enhances the accuracy and reliability of positioning information, particularly in challenging environments where signal interference can occur. By utilizing multiple frequencies, the OM-20000141 can mitigate errors caused by atmospheric disturbances and multi-path signals, resulting in improved precision.

In addition to its multi-GNSS capabilities, the receiver incorporates advanced RTK (Real-Time Kinematic) technology, enabling centimeter-level accuracy. This is particularly beneficial for applications that require pinpoint geolocation, such as precision agriculture, where farmers need to optimize crop yields and resource usage. The RTK technology allows users to achieve real-time positioning corrections, making it a vital tool for surveying and construction projects that demand high precision.

The Novatel OM-20000141 also features built-in connectivity options, including Bluetooth and USB interfaces, facilitating seamless integration with other devices and systems. This connectivity is crucial for enabling real-time data sharing and remote monitoring, enhancing the usability of the device in various operational environments.

Robustness is another significant characteristic of the OM-20000141. Designed to withstand harsh conditions, the receiver features a durable housing that protects it from dust, moisture, and extreme temperatures. This resilience ensures that the device operates effectively in all weather conditions, making it suitable for outdoor applications.

Furthermore, the receiver is equipped with intelligent positioning algorithms that optimize performance in urban canyons and dense foliage areas, where traditional GNSS receivers may struggle. By leveraging these algorithms, the OM-20000141 can maintain reliable positioning even in challenging environments.

Overall, the Novatel OM-20000141 stands out as a versatile and reliable GNSS receiver, merging advanced technologies to deliver high accuracy and reliability. Its exceptional features make it an invaluable asset for professionals in various industries, enhancing their ability to achieve precise geolocation and optimize their operations.
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