• 12-channel SBAS-enabled GPS receiver complying with TSO C145a
• Supports primary means GPS navigation in areas of SBAS coverage and in oceanic/remote areas
• Supports GPS-based vertical path approach capability (e.g., LPV) available with future FMS upgrade
• Performs Fault Detection and Exlusion (FDE) and Predictive RAIM functions for operations outside of SBAS coverage
• ARINC 743A compliant
• Supports field loading of application software
• Fully integrated with Rockwell Collins Pro Line 4 and Pro Line 21 FMS systems to provide oceanic/remote, enroute, terminal and approach operations

The Rockwell Collins GPS-4000S Global Positioning System sensor provides aircraft equipped with flight management systems (FMS) the capability for GPS-based en route and terminal navigation as well as GPS-based approach capability. The sensor's Space Based Augmentation System (SBAS) capabilities enable use of GPS for primary means navigation in areas of SBAS coverage including the currently operating Wide Area Augmentation System (WAAS) in the United States. The GPS-4000S is compatible with other SBAS systems being developed in accordance with RTCA DO-229( ). For example, Japan is developing the MTSAT Satellite-based Augmentation System (MSAS). Europe is EGNOS European Geostationary Navigation Overlay System.

The GPS-4000S processes the transmissions of up to 10 GPS satellites and two SBAS Geo stationary satellites simultaneously, calculating navigation solutions based on information from all satellites in view. The position, velocity and time information are provided to the Flight Management System for incorporation into the FMS navigation function.

When operated in an area within coverage of an SBAS system, the GPS-4000S utilizes correction and integrity information from the SBAS satellites to provide increased accuracy, integrity and availability.

When operated outside of SBAS coverage, a minimum of four satellites with acceptable geometry or three satellites plus calibrated barometric altitude are required in order to calculate a navigation solution. With additional satellites, the system can improve the fault tolerance and accuracy of the navigation solution and provide Fault Detection and Exclusion (FDE) to detect and isolate faulted satellites. The unit also provides predictive RAIM, which is used to determine whether the satellite geometry at the destination airport will be sufficient to support approach at the planned time of arrival.

The Rockwell Collins GPS-4000S is a 2MCU unit that houses the GPS processor, GPS receivers, processing circuitry and necessary inputs and outputs. The unit is fully digital, uses 28  V  DC power and requires a minimum of interconnect. The unit uses standard ARINC 429 interfaces and complies with ARINC 743A communication requirements. When connected with a compliant antenna, the GPS-4000S provides GPS position solution for use by the FMS and other equipment. The GPS-4000S integrates with all Rockwell Collins Pro Line 4 and Pro Line 21 applications that include an FMS.

The FMS utilizes the GPS-4000S PVT data to navigate oceanic/remote, en route and terminal areas and to fly GPS based approaches. The GPS-4000S can be used for primary means navigation in areas of SBAS coverage and in oceanic/remote areas. When an optional future FMS upgrade is accomplished, the GPS-4000S will support Localizer performance with Vertical Guidance (LPV) approaches.

The GPS processor is an evolution of the precision lightweight GPS receiver, the U.S. military standard receiver produced by Rockwell Collins. The processor accepts 24 GPS channels and outputs position, velocity and time mark discrete coincident with GPS seconds. The engine also provides Fault Detection and Exclusion (FDE), using all satellites in view for both the navigation solution and RAIM. Altitude aiding enhances the availability of the navigation solution and FDE, and it accepts external aircraft velocity to aid its tracking loops. Reacquisition after power off is aided by self-contained nonvolatile memory of the satellite almanac, last calculated position, velocity, time and by input of external aircraft position, velocity and time.

The RF front end feeds dual signal processing Application Specific Integrated Circuits (ASICs) to form a GPS receiver with 12 coarse acquisition code channels. The ASICs share addresses and data with the microprocessor, RAM and ROM to form the digital subsystem.

The 2MCU mechanical package of the GPS-4000S has been designed to provide improved heat dissipation and greater strength. Increased reliability is provided through improved shock and vibration resistance and reduced interconnect. Extensive use of surface-mount components and large-scale integration circuits reduces size and weight and improves performance.