Qualification of a Commercial Dual-Frequency GPS Receiver for the e-POP Platform

Kurzfassung

CASSIOPE, the CAScade Demonstrator Smallsat and Ionospheric Polar Explorer, is a Canadian satellite scheduled for launch in 2007. It is a hybrid mission designed for a wide range of tasks including space-based communication, high capacity information delivery, and observations of the Earth’s atmospheric environment. A dedicated suite of eight scientific instruments, called e-PoP, will investigate space storms in the upper atmosphere and provide GPS-based navigation information. In view of budgetary restrictions, the design of e-PoP is based on the use of commercial-off-theshelf (COTS) GPS receiver technology and NovAtel’s OEM4-G2L dual-frequency receivers have been selected as the candidate hardware for this project. A total of five receivers on the satellite will be used for high precision navigation, attitude determination, and radio occultation measurements. These receivers will be cleared by the Canadian government for operation outside the common altitude and velocity limitations, but will not otherwise be significantly modified or adapted for the space application. Experience in the use of commercial components for spaceborne GPS receivers has earlier been collected on other missions, but is so far restricted to low-grade single-frequency receivers and a limited range of correlator chipsets. e-PoP in contrast, aims at the use of a fully commercial, geodetic grade dual-frequency receiver with no heritage in space applications. An extensive series of tests has therefore been conducted to assess the suitability of the envisaged approach. These include GPS signal simulator tests to validate the signal acquisition and tracking performance, as well as environmental tests to demonstrate the survivability of the receiver hardware under space conditions.