User's Manual Part 1

88 OEMV Family Installation and Operation User Manual Rev 5B
Chapter 5 Positioning Modes of Operation
5.4.2 L-Band Service Levels
Two levels of service are available:
Standard - Sub-meter accuracy from OmniSTAR VBS (subscription required)
and CDGPS
Extra Performance - Decimeter accuracy from OmniSTAR XP (subscription required)
High Performance - Sub-decimeter accuracy from OmniSTAR HP (subscription required)
Standard Service
The OmniSTAR VBS service uses multiple GPS base stations in a solution and reduces errors due to
the GPS signals travelling through the atmosphere. It uses a wide area DGPS solution (WADGPS) and
data from a relatively small number of base stations to provide consistent accuracy over large areas. A
unique method of solving for atmospheric delays and weighting of distant base stations achieves sub-
meter capability over the entire coverage area - regardless of your location relative to any base station.
CDGPS is able to simultaneously track two satellites, and incorporate the corrections into the
position. The output is SBAS-like (see WAAS32-WAAS45 in the OEMV Firmware Reference
Manual), and can incorporate these corrections to generate differential-quality position solutions.
CDGPS allows anyone within the area of coverage to take advantage of its benefits.
CDGPS\OmniSTAR VBS services are available on
OEMV-1, OEMV-1G and OEMV-3-based products.
NovAtel’s DL-V3 and ProPak-V3 provide GNSS positions with L-Band corrections in one unit, using
a common antenna. This means that, with CDGPS or a subscription to the OmniSTAR VBS service,
the DL-V3 or ProPak-V3 are high quality receivers with sub-meter positioning capabilities. To obtain
OmniSTAR VBS corrections, your receiver must have a VBS subscription from OmniSTAR.
The position from the OEMV receiver is used as the L-Band system’s first approximation.
After the L-Band processor has taken care of the atmospheric corrections, it then uses its location
versus the base station locations, in an inverse distance-weighted least-squares solution. L-Band
technology generates corrections optimized for the location. It is this technique that enables the L-
Band receiver to operate independently and consistently over the entire coverage area without regard
to where it is in relation to the base stations.
High Performance Service
The OEMV-3, DL-V3 or ProPak-V3 with the software model for OmniSTAR High Performance (HP)
service gives you more accuracy than with the OmniSTAR VBS or CDGPS services. OmniSTAR HP
computes corrections in dual-frequency RTK float mode (within about 10 cm accuracy). The XP
service is similar to HP but less accurate (15 cm) and more accurate than VBS (1 m). HP uses
reference stations while XP uses clock model data from Nasa’s Jet Propulsion Laboratory (JPL). To
obtain HP or XP corrections, your receiver must have an HP or XP subscription from OmniSTAR.
 1. For optimal performance, allow the OmniSTAR HP or XP solution to converge prior to
starting any dynamic operation.
2. OmniSTAR XP is now available over a wider coverage area than previously.