Canadian Spatial Reference System (CSRS)

Definition
The Canadian Spatial Reference System (CSRS) e survey e300 is a three-dimensional grid on which positions (latitude, longitude and height) of any object or feature can be precisely pinpointed. The infrastructure underlying a grid consists of a network of points whose coordinates are determined with the highest precision. Grids are fundamental for mapping, marine charting, navigation, boundary demarcation, crustal deformation study and other georeferencing applications.

At the heart of the CSRS leica sprinter 50 is the Canadian Active Control System (CACS); a network of continuously operating GNSS receivers. CACS data support positioning accuracy at the decimeter-level (e.g. for imagery geocoding and realtime applications), the centimeter-level (e.g. for legal surveys) and the millimeter-level (e.g. for measuring crustal motion).

Historical Background
Geodetic networks traditionally consisted of control monuments distributed across our landmass for surveyors to occupy and access the geodetic grid as well as control their surveys. In the early 1980’s, with the advent of Global Navigation Satellite System (GNSS), geodetic control became accessible from space with great accuracy. CGS established the Canadian Active Control System (CACS) to continuously track GNSS satellites and compute their precise orbits. Several networks of Active Control Points have been added across Canada for various monitoring purposes. For example, the CSRS is tied to the world gravity network with an Active Control Point (ACP) at the Canadian Absolute Gravity Station (CAGS).

The extension of the geodetic reference frame into space also brought along the requirement for monitoring the Earth’s orientation in space which is provided by observations of quasars with Very Long Baseline Interferometry (VLBI). These activities marked CGS’s entry into the space-age of precise geodetic positioning.

In the mid-1990’s a program to install and observe stable monuments, known as the Canadian Base Network (CBN), was initiated. The CBN was deployed at 200 km spacing in southern Canada and 500 km up north, for multi-epoch high-accuracy GNSS positioning. Initial observations of the CBN revealed the presence of distortions of up to 2 meters in the original realization of our national grid, the North American Datum of 1983 (NAD83). Over the past decade, re-observation of the CBN network also confirmed that crustal motion of the order of a few millimeters per year horizontally and up to a couple of centimeters vertically is occurring Canada-wide. The CBN network also provides anchor points for the integration of denser provincial high-precision networks.

Today, CGS supports users of space-based technologies with a stable, although sparse ground infrastructure, precise orbit products, gravimetric geoid models and the tools to facilitate access to the Canadian Spatial Reference System (CSRS).

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