Brian W. Schipper

Differential GPS/inertial navigation approach/landing flight test results

In November of 1990 a joint Honeywell/NASA-Langley differential GPS/inertial flight test was conducted at Wallops Island, Virginia. The test objective was to acquire a system performance database and demonstrate automatic landing using an integrated differential GPS/INS (Global Positioning System/inertial navigation system) with barometric and radar altimeters. The flight test effort exceeded program objectives with over 120 landings, 36 of which were fully automatic differential GPS/inertial landings. Flight test results obtained from post-flight data analysis are discussed. These results include characteristics of differential GPS/inertial error, using the Wallops Island Laser Tracker as a reference. Data on the magnitude of the differential corrections and vertical channel performance with and without radar altimeter augmentation are provided.<<ETX>>In November 1990, a differential GPS/inertial flight test was conducted to acquire a system performance database and demonstrate automatic landing using an integrated differential GPS/INS with barometric and radar altimeters. Flight test results obtained from postflight data analysis are presented. These results include characteristics of DGPS/inertial error, using a laser tracker as a reference. In addition, data are provided on the magnitude of the differential correlations and vertical channel performance with and without radar altimeter augmentation. Flight test results show one sigma DGPS/inertial horizontal errors of 9 ft and one sigma DGPS inertial vertical errors of 15 ft. Without selective availability effects, the differential corrections are less than 10 ft and are dominated by receiver unique errors over the time period of an approach. Therefore, the one sigma performance of the autonomous GPS (8-ft horizontal and 20-ft vertical) is very similar to the DGPS/inertial performance. Postprocessed results also demonstrate significant improvements in vertical channel performance when GPS/inertial is aided with radar altimeter along with a low-resolution terrain map.<<ETX>>

Multipath detection and mitigation leveraging the growing GNSS constellation

This paper describes a method to observe the likely presence of multipath errors and mitigate them from the computation of the GNSS position solution.

A MEMS-based guidance, navigation, and control unit

Honeywell Laboratories, in conjunction with Honeywell Sensor and Guidance Products (SGP) operation, has developed a next generation guidance, navigation, and control unit based on MEMS sensor technology occupying less than 25 in./sup 3/. This product, known as the micro Flight Management Unit (/spl mu/FMU), has applicability across a wide variety of military and commercial applications, including low cost military gun hardened projectiles, personal navigation systems, and commercial AHRS. When coupled with Honeywells second generation C++-based Embedded Computer Toolbox and Operating System (ECTOS/sup TM/ IIc), the /spl mu/FMU can be utilized easily and effectively for rapid prototyping demonstrations (including customer generated guidance and control software), as well as full production systems. Utilizing a Motorola PPC745 (G3) processor, the /spl mu/FMU has been designed to accommodate next generation GPS/INS ultra-tightly coupled integration algorithms. The /spl mu/FMU electronics have been high G tested to 6,300 Gs (non-operating), successfully demonstrating that the hardware survives and operates after exposure to high G shock. This paper presents an overview of the /spl mu/FMU and ECTOS/sup TM/ IIc software. The hardware architecture and technical specifications of the /spl mu/FMU will be presented, along with the process used to validate the /spl mu/FMUs high G survivability. The software architecture, capabilities, and customer usability /programmability features of ECTOSTM IIc will also be described.

A testbed for frequency domain GPS acquisition and receiver simulation

Honeywell has assembled a PC-based data acquisition system to collect digitized RF data from a GPS receiver front end, along with a test bed software set that uses the collected RF data to execute frequency domain acquisition, time domain tracking, pseudorange computation, and computation of GPS position solution. The test bed software is written almost entirely in Matlab with a few C-code files included to build Matlab executable (MEX) modules. This paper will describe the frequency domain processing techniques and also the rest of the post-processing that is executed.

Differential GPS/inertial navigation terminal area guidance flight test results

Terminal area flight test results of a differential GPS (Global Positioning System) inertial navigational system are presented. The flight test was a joint Honeywell/NASA-Langley project completed in November 1990. Over 120 landings were made with the NASA Transport Systems Research Vehicle (TSRV), a specially modified Boeing 737-100, including 36 fully automatic differential GPS/inertial landings. A description of the system implementation and preliminary flight test results are provided.<<ETX>>