Subject: CDGPS: Canada-wide DGPS now available
Newsgroups: sci.geo.satellite-nav,alt.satellite.gps
Date: Thu, 06 Nov 2003 09:14:17 -0800

From the CDGPS website:
http://www.cdgps.com/

CDGPS is a new nation-wide DGPS service developed for the Canadian market
that provides unmatched accuracy and coverage for positioning applications
across the country. As a wide-area, or satellite-based service, the
broadcast CDGPS corrections can be accessed anywhere in Canada using a
custom-built CDGPS receiver. The correction data - based on world-class 
algorithms developed by Natural Resources Canada and positioning data from 
Canadian reference stations - is optimized for Canada, resulting in 
superior meter-level accuracy with most GPS receivers and sub-meter with 
dual frequency technology.

The service is being offered as a free utility with no recurring 
subscription charges to support and stimulate Canadian industry.
It includes:
* nation-wide Canadian coverage
* superior performance in foliated conditions
* meter-level positioning accuracy(~ 1m) with mapping-grade GPS receivers
* sub-meter accuracy(~ 0.3m) with dual frequency GPS receivers
* spatial integrity with all Government maps and surveys
* 24 x 7 operations with built-in network redundancy
* open published broadcast protocol
* no service costs

The CDGPS DGPS service uses "wide-area" technology deriving corrections 
from real-time positioning information collected across the country. This 
data is transmitted to Ottawa where mathematical algorithms produce a 
single GPS*C correction data stream which is uplinked to the MSAT 
satellites for broadcast across Canada.

This real-time signal is accessed by end-users with a small custom-built
CDGPS receiver which translates the data stream into localized RTCM SC-104 
messages which correct the positions of single-frequency GPS receivers. The 
CDGPS receiver also works directly with dual frequency GPS receivers (using 
the core GPS*C feed for superior accuracy) or data recorders (providing 
NMEA position data without the need for an external GPS receiver). 

End-users must purchase a CDGPS receiver to access the CDGPS signal. This 
unit has been custom developed by Ottawa-based Mobile Knowledge Inc. to 
complement the CDGPS service and support real-time, in-field requirements. 
It is designed for portable applications, has several built-in 
capabilities, and is low-cost:
* small: 7.6 x 12.7 x 2.5cm & 500 grams (3" x 5" x 1" & 1.1 lbs)
* low power: will operate for up to 8 hours on 4 AA batteries
* rugged, weatherized form-factor suitable for outdoor use
* patch antenna or quadrifiler antenna (better for higher latitudes)
* onboard GPS chip
* standard serial port to connect to GPS receivers
* outputs GPS*C, RTCM SC-104 or NMEA data formats
* retail price ~$1,500 Canadian 

The small size, rugged form-factor and low power draw make this unit ideal 
for portable applications. In addition, the onboard GPS chip enables the 
receiver to output actual positions in standard NMEA format for use with 
data recorder/PDA applications, eliminating the need for an external GPS 
receiver. The CDGPS receiver outputs corrections in localized RTCM SC-104, 
an industry standard format compatible with the vast majority of GPS 
receivers. The unit also outputs GPS*C, an RTCA-like format suitable for 
dual frequency GPS receivers.