Frequently Asked Questions
What is GPS?
The Global Positioning System (GPS) has become a widely used solution for surveying and
other activities that require accurate geographic locations. GPS is a satellite-based
positioning system operated by the United States Department of Defense and is used by
both military and civilian users. Data collected through GPS is used for forestry
applications, environmental studies, GIS database creation and maintenance, vehicle
dispatching and many other applications. It allows users world-wide to obtain
coordinates which are accurate to approximately 20m, or better. More accurate
results require differential GPS (DGPS) positioning techniques to be used.
This means the user requires two GPS receivers; one of the receivers must be
capable of operating as a base station.
What is BCACS?
The Government of British Columbia, in cooperation with Federal agencies, local
governments, Crown corporations and industry, is making it easier for users to collect,
merge, and overlay geographic data by providing standardized, low cost and instantaneous
positioning through the British Columbia Active Control System (BCACS).
The BCACS network comprises permanent, continuously operating GPS base stations which
are linked via computer and telecommunication networks. These base stations provide data
which allow users to correct the coordinates obtained with their single receivers to
achieve positions accurate to less than 5 metres, or even less than 1 metre.
What BCACS real-time differential services are available?
The services available to provide real-time DGPS (digital global positioning system) corrections supporting
all user needs, include:
- Regional (coverage
for British Columbia and surrounding areas, including all of
Alberta) providing 1-10 metre accuracy
DGPS, providing centimetre to metre level positioning within
- Canada-wide digital
(CDGPS) service providing 1-5 metre coverage for all of Canada
- An enabling
environment for other value-added and integrated business solutions
What are the Benefits of a Municipal ACS?
- Decreases maintenance (human and fiscal resources) over a physically monumented system -
this applies for both Municipal and Provincial partners. The cost avoidance of maintaining
and extending the present survey control monument base.
- Supports other municipal programs (e.g., Intelligent Vehicle Location (IVL), E911
applications, Transit Authorities, etc.).
- Provides a common GSR for all agencies with spatially positioned data (i.e. federal/
provincial/municipal and regional government; utility companies; private sector; etc.),
supporting data sharing between agencies.
- Avoids fragmented and single-purpose differential GPS service provisioning.
- Improved accuracy, consistency, currency and completeness of positional information.
- Ability to provide users with information regarding the integrity of the data.
- Will enable the municipalities and the Base Mapping & Cadastre Section of GeoBC to fully meet the future requirements of GPS
users with respect to timely and cost effective access to the GSR.
- Will enable the realization of a precise and uniform provincial GSR consistent with
modern spaced-based positioning technology. Will extend the relevance of the GSR more
effectively to applications in geo-referencing, positioning and navigation requiring
real-time or near real-time access.
- Can help remove some of the cost barriers that limit the present utilization of provincial
mapping standards by other organizations.
- Will promote greater synergy between municipal departments through the provision
of direct access to the positional framework of corporate databases.
What are the Phases in Implementing BCACSm?
BCACSm is undertaken as a partnership between municipalities and the Provincial government.
As such, a Memorandum of Agreement is first signed between interested local governments and
the Province. Components and phases of the implementation are:
- On line BCACSm Data Access
- Establish Municipal Active Control Points (ACPs).
- Establish BCACSm Post-Mission Service.
- Implementation of a Robust, Highly Accurate, NAD83 Control Network.
- Adopt NAD83 as Geo-referencing Standard.
- Re-adjustment and Adoption of New Provincial Vertical Datum.
- Implementation of a High Accuracy Geoid Model.
- Implementation of the BCACSm Real-time Service.
- Development and publication of BCACS and BCACSm Geo-positioning Standards and Municipal Application Standards.
- Testing demonstration and applications pilots
- BCACS augmentation
For further details contact the Base Mapping & Cadastre Section of GeoBC .
Who can use the BCACSm?
Anyone who needs precise positions can use the BCACSm.
Positions accurate to 1 metre, or even to the centimetre level, are available
instantaneously via a UHF radio link. Surveyors, engineers, mappers and others
can effectively use the BCACSm for:
- Land surveying - Cadastral surveys
- Engineering surveys - as-built surveys, utility and infrastructure layout, inspections,
- GIS data collection - GIS pickup, thematic mapping, utility data capture
- Police and Enforcement - incident analysis, tracking, spills, etc.
- Fleet Management - vehicle routing, emergency response, fuels savings, time savings, etc.
How do I obtain GPS corrections for the BCACSm - CRD?
Differential GPS corrections are available for both real-time and post-mission applications
from the BC ACSm - CRD.
Post-mission corrections can be accessed via Crown Registry and Geographic Base. Click here to complete an account.
To access the BCACSm - CRD real-time corrections; please contact the Capital Regional District at:
Tel: (250) 883-1326
How do I configure Trimble Pathfinder?
Instructions for Configuring Trimble Pathfinder
Instructions for setting up Trimble Pathfinder Office to access BCACS RINEX files are provided in the document: BCACS - Pathfinder Office RINEX [PDF]
The FTP address format is included to eliminate the need to type this confusing address and to minimize typos. The codes for the Product and Station are included also.