The purpose of this project was to develop a new generation of a compact GPS receiver family (dual or single frequency, L1/L2C). This project was led by two main objectives:
- Development of a short and medium term, high reliability, ready for flight competitive product for present market needs for both LEO and GEO missions,
- Development of a dual frequency receiver for new carrier phase tracking applications, and for enhanced orbital position accuracy.
With regards to the previous generation of THALES ALENIA SPACE receivers, the new product offers 36% mass saving, a low power consumption in standby mode with a stand alone quick restart and the capability to process the new GPS L2CS civilian signal.
Tracking the GPS L2 Civil Signal (L2CS) has required a significant upgrade of the original signal processing chip of the T3000 receiver (PEGASE chip), to withstand the new CM (Civil Moderate) and CL (Civil Long) codes.
The key issues are twofold: first to develop a new GPS receiver generation with a smaller size, a lighter mass and less power demanding, then to have the capability to process new L2 civilian signals for enhanced position accuracy.
The main benefits of this activity are related to the development and test of the key hardware and software building blocks to process the GPS signals.
The architecture of the innovative GNSS receiver is illustrated below. The main functional features of the initial TOPSTAR 3000 GPS receiver have been preserved so as to comply with different types of missions (LEO, GEO) and classes of platforms (microsat- minisat LEO, and GEO satellites). The new product is based on a modular structure composed of the following sub-units:
- A front-end section (RF/IF) equipped with one or two RF chains,
- A Digital Processing Unit (DPU) that performs base-band signal processing and PVT computation,
- An optional DCDC converter,
- Optional reference clocks : OCXO (Oven Controlled Crystal Oscillator) or TCXO (Temperature Controlled Crystal Oscillator).
The receiver physical architecture is composed of 2 or 3 hardware modules (RF/IF, DPU and DCDC optional) that are assembled to form the receiver.
This project has been completed. A similar GPS receiver to the one developed in the frame of this contract will be embarked on the Proba2 satellite in order to demonstrate in space the capability of this new type of GPS receivers.