Network-Based Rtk Techniques; Enhanced Positioning Engine (Dion) - Topcon B111 Hardware Integration Manual

Network-based RTK Techniques

The RTK engine in the B111 board supports three widely used network RTK implementation techniques,
specifically, VRS, FKP, and MAC.
Virtual reference station (VRS). The network software collects raw data measurements from several
reference stations that belong to a network. These data are then estimated and processed to produce
ionospheric and tropospheric corrections for each station and each satellite. After the rover receiver transmits
its approximate position to the network software using an NMEA GGA message, the corrections are interpolated
to the position of the rover. Interpolated corrections are used to reconstruct the measurements of pseudo range
and carrier phase of a virtual reference station located close to the rover. The reconstructed measurements are
transmitted to the rover as RTCM or CMR messages.
Further Reading:
How to configure the B111 for VRS rover mode using GRIL commands in the
Area correction parameters (FKP). Unlike the VRS approach, the network software calculates coefficients for
modeling ionospheric, tropospheric, and orbital effects for each satellite over a specific network area. The
coefficients are then transmitted to the rover as RTCM message type 59, so that the rover can generate the
corrections and apply them to its own observations to compute the position with high accuracy.
Further Reading:
How to configure the B111 for FKP rover mode using GRIL commands in the
Master-auxiliary concept (MAC). This approach assumes the usage of one master reference station and a
number of auxiliary reference stations to generate network correction messages. The master station transmits
full raw observations and coordinate information while auxiliary stations transmit ionospheric and geometric
correction differences and coordinate differences calculated between the master and each auxiliary station. The
rover accepts all these data as RTCM 3 messages and applies them to get its own accurate position.
Further Reading:
How to configure the B111 for MAC rover mode using GRIL commands in the

Enhanced Positioning Engine (DION)

DION is an enhanced absolute positioning engine that allows you to use a single B111 to compute smoothed
and consistent position solutions. Instead of using instantaneous yet rather noisy pseudorange measurements
of an ordinary single point positioning, you can activate the DION engine to get more accurate and reliable
results without the requirement of any additional hardware or software. What sets DION apart from other
positioning engines is an innovative approach to combining the simplicity and availability inherent in the absolute
positioning with the reliability and accuracy of the relative positioning.
Currently DION can be used in standalone and DGPS positioning modes. You can also enable it on a TPS receiver
acting as a moving RTK base.
DION has two modes of operation:
•
Smooth mode, used when you need to get a smooth variation of absolute or DGPS positions. In this mode,
the absolute and DGPS positions obtained from pseudorage measurements will be smoothed by the refined
delta positions obtained from the corresponding carrier phase measurements thus reducing the noise level of
pseudorange measurements and removing position jumps.
•
Local mode, used when you need to get a stable pass-to-pass accuracy at the decimeter level. This mode is
ideal for applications where a vehicle (e.g., tractor) must follow and replicate the designated route. Local mode
requires coordinates of the starting point entered in the B111.
Further Reading:
How to configure the B111 for DION mode using GRIL commands in the
Firmware Features
P/N: 1018409-01
GRIL Reference Manual.
GRIL Reference Manual.
GRIL Reference Manual.
GRIL Reference Manual.
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