A Canadian constellation of C-band SAR satellite
- Paper ID
2075
- author
- company
Canadian Space Agency
- country
Canada
- year
2005
- abstract
The Canadian federal budget 2005 provided the Canadian Space Agency with funding over the next five years to start the initial phases of the development of the next generation of C-band SAR satellites in order to ensure implementation toward the end of the RADARSAT-2 program. This project is based on a small satellite SAR concept that was described previously in a number of papers such as [1,2]. Between three and six small-satellites SAR will be flown in the configuration of a constellation for environment monitoring, maritime surveillance and disaster management. The constellation is expected to improve Canada’s ability to manage its resources and environment and improve security by providing daily coverage of Canadian territory and water. It will also have the ability tom make observation anywhere else in the world on a daily basis on demand. The mission is a C-band SAR satellite constellation, including space segment, ground segment and operations. The mission baseline proposes a phased approach to implementation to reduce cost. Three satellites would be developed to meet environmental requirements, with an option to add three additional satellites to meet defence requirements. The ability to develop a constellation of SARs is contingent on significant cost reduction for each satellite. It is estimated that the total mission cost of a three-satellite system will be less than the development cost of RADARSAT-1. The constellation will operate in two modes: wide area coverage and high-resolution. In wide-area mode, it will monitor and acquire data over large areas of interest at medium resolution (50m), mostly for environmental and maritime applications. In high-resolution mode, the constellation will acquire specific on-demand images at a spatial resolution of 5m. Each satellite follows the previous satellite in the same orbital plane, at an approximate distance of 600km from the ground. Each satellite has a slight ground path shift from the previous satellite to increase the coverage area. The basic mode of operation is ScanSAR, with 50m ground resolution and a 350km swath. The satellites work together to scan broad areas in ScanSAR mode, and detect changes or areas of greater interest. If required, satellites can communicate with the ground in order to task the following satellite in the constellation to acquire a high resolution 5m image of a selected area or target. As the satellites each have a ground swath of about 350km, the combined swath of a given pass of the entire constellation may exceed 2000km. The satellites are separated by 10 minutes. They are in a sun-synchronous orbit, and fly by at 6 a.m. and 6 p.m. The standard satellite offers a single polarization capability. However, several options are being considered to ensure that the system as a whole can offer multi-polarization information, either by flying a dual polarization satellite or by varying the polarization across the satellites in the constellation. The constellation will operate as a single system, with one satellite collecting information that is used to task the next satellite. In order to do this, communication with ground facilities capable of telemetry, tracking and control and processing is required. Initially, this will be possible over North America. To support the Canadian operations concept, three new ground stations are planned, on the east and west coasts of Canada and in the north. The east and west stations will be co-located with existing facilities for maritime surveillance. The northern facility would likely be situated in Resolute or in Inuvik, though further study is required to determine the best coverage and the most efficient operations scenario. A Phase 0, feasibility study, is being completed in April 2005 and phase A of the program is starting in May 2005. This paper will describe the proposed mission and provides a status of the evolution of the project through phase A. [1] G. Séguin, Toward the development of a constellation of RADARSAT satellites, ISTS 2004, Miyazaki, Japan [2] G. Seguin, ‘Small Satellite SAR’, joint ASAR workshop/CEOS WGCV-SAR workshop 2003 proceeding, St-Hubert, Canada, June 2003.