Abstract: Tasks envisioned for future generation Mars rovers—sample collection, area survey, resource mining, habitat construction, etc.—will require greatly enhanced navigational capabilities over those possessed by the Mars Sojourner rover. Many of these tasks will involve cooperative efforts by multiple rovers and other agents, adding further requirements both for accuracy and commonality between users. This paper presents a new navigation system called a Self-Calibrating Pseudolite Array (SCPA) that can provide centimeter-level, drift-free localization to multiple rovers within a local area by utilizing GPS-based transceivers deployed in a ground-based array. Such a system of localized beacons can replace or augment a system based on orbiting satellite transmitters, and is capable of fully autonomous operations and calibration. This paper describes the basic principles of navigation using an SCPA, focusing on the critical issue of array self-calibration. The new algorithm presented herein—called Quadratic Iterative Least Squares—achieves successful self-calibration 99.80% of the time even under extremely adverse conditions. The paper concludes with a description of the experimental prototype developed to demonstrate these capabilities and presents successful results from field trials which validate both the navigation and self-calibration functions of the SCPA.

Abstract: Military aircrews are beginning to experience the benefits of having quality global positioning system (GPS) navigation information available in the cockpit to support their tactical missions. However, another big improvement in situational awareness is the new capabilities known as communications, navigation, surveillance/ air traffic management (CNS/ATM). If tactical military are to operate within this new performance based airspace, they require operational RNP RNAV, Mode S, and 1090ES ADS-B functionality. To achieve these functionalities, dual use avionics and integrations must be found to capture civil functionality with military equipment. The bottom line is that tactical military achieves the required functionality or they can expect delays, rerouting, and some airspace exclusions. This paper describes one way to get RNP RNAV, Mode S, and 1090ES ADS-B capability in tactical military aircraft.

Abstract: Owing to the maturity of satellite technology and Global Positioning System (GPS), the new generation of Air Traffic Management (ATM) technique is designated to utilize the navigation information provided by the Global Navigation Satellite System (GNSS). For precision landing and take-off of an aircraft, the Local Area Augmentation System (LAAS) is needed to enhance the navigation accuracy, integrity, reliability and availability. Present study simulates the concept of LAAS and has established a ground-based Real-Time DGPS (RT-DGPS) reference station. This base station provides 0.5-meter RMS error and 0.2-meter correction for static horizontal navigation and 1.1-meter RMS error and 2-meter correction for dynamic horizontal navigation. The verification of pseudo-attitude in flight is also accomplished in an ultralight vehicle. The flight test combined with the RT-DGPS technique has qualitatively demonstrated that the GPS-determined attitude is feasible and quantitatively proved the pseudo-roll and pseudo-heading angles are especially reliable.

Abstract: The international civil aviation organization (ICAO) has defined the international standard for the global navigation satellite system (GNSS) based on GPS for aviation use. Navigation systems for aviation must ensure not only the specific positioning accuracy but also the required reliability performance. Continuity is one of the measures of system reliability, and is defined as the probability that the system operates without nonscheduled interruptions over a certain period of time. We have already proposed a method of computing the continuity of GPS for the approach and landing flight phase. However, the method cannot be applied to flight phases such as enroute or terminal airspace because of the longer periods for such phases, for example 1 hour, over which the continuity requirements are defined. This paper describes a method of computing continuity with consideration of the progress of time, taking into account the movement of the aircraft relative to navigation satellites. Some computation examples are also presented. © 2002 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 86(3): 26–34, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.10044

Abstract: Shipboard-relative GPS (SRGPS) is a variant of the Joint Precision Approach and Landing System (JPALS) that is being developed to support automatic shipboard landings in zero-visibility conditions. At present, the navigation system requirements specify a vertical protection level of 1.1 m, an integrity risk of approximately 10−7, and a system availability of at least 99.7 percent. Because of the stringent nature of these specifications, differential carrier-phase solutions are being pursued. In this context, this paper gives a detailed analysis of the fault-free integrity and availability of SRGPS. The performance of single- and dual-frequency architectures is evaluated for both floating-ambiguity and fixed-integer carrier-phase differential GPS (DGPS) navigation. The sensitivity of SRGPS availability is quantified with respect to raw code and carrier measurement quality, spatial decorrelation of ionospheric and tropospheric errors, and broadcast service radius. Necessary conditions to achieve the desired navigation performance are defined.

Abstract: This paper assesses the capability of GPS to provide the level of safety required for different aircraft flight navigation operations. It presents an analysis of the protection offered against potential catastrophic GPS failures at system and user levels. This is followed by an assessment of the different approaches to augmenting GPS for civil air navigation. Results show the inadequacy of GPS as a system for real-time safety critical use.