As can be seen by the examples given below, design and planning problems related to ship-handling techniques increasingly rely on the use of ship-handling simulators.(i) Design and planning of port and harbour facilities with respect to the layout and dimensions of channels, turning basins, breakwaters, jetties, etc.(ii) Assessment of the ship manoeuvrability required to ensure safety in given port and harbour conditions.(iii) Establishment of proper ship-handling procedures required to ensure safety under given conditions.

The Global Positioning System (GPS) will be an extremely high-performance satellite-based navigation system which is expected to provide a sole means air navigation service for most aeronautical flight phases. It will be particularly suitable for ‘en route’, ‘terminal’ and ‘non-precision approach’ phases, thus providing substantial savings on aircraft operating costs.

However, GPS has three major disadvantages for civil aviation: (1) Insufficient system integrity, since satellites can transmit erroneous information for two hours before being repaired or neutralized. In such an event, the many simultaneous users of the satellite that has lost its integrity can derive false positions and remain unaware of the problem. (2) Availability constrained by the limited number of satellites. Users are then unable to obtain a position fix or else obtain a result with significantly degraded performance. (3) Deliberate spatio-temporal degradation (selective availability) of system performance, the characteristics of which are not fully known or defined.

Many solutions to these problems have been put forward. One concept uses the redundancy of the GPS system itself (receiver autonomous integrity monitoring). Another set of solutions is based on complementary information from autonomous navigation equipment (altimeter, clock, inertial system) or external navigation systems already available or being developed (Omega, Loran-C, GLONASS). A third type of solution is to implement a system by which to monitor the status of the GPS satellites and broadcast the information to users.

This paper reports on the different techniques put forward and uses different qualitative criteria (technical feasibility, cost, political independence, etc.) to assess their suitability for civil aviation applications. The comparison leads to the recommendation of a system to monitor the status of the GPS satellites and broadcast the information to users. The characteristics of such messages would be as similar as possible to those of GPS messages.

Although INMARSAT's founding charter includes provision for a space segment for radiodetermination, the organization has, to date, concentrated on the telecommunications aspects of its mission. However, a satellite radiodetermination (including radionavigation) services development programme has been under way for about two years, and includes both study and experimental activities. Early studies performed for INMARSAT on both passive and active radiodetermination provided a number of significant conclusions, including the rather obvious but important fact that all satellite radiodetermination concepts possess two common elements: the forward transmission (broadcast) of a relatively wideband timing/ranging signal, and the precise tracking in orbit of the satellites.

The Federal Aviation Administration (FAA) is conducting experimental programmes to support introduction of satellite navigation and communications services into the air traffic control system during the 1990 time period. This work programme is closely related to the activities that have been conducted by the ICAO Future Air Navigation Systems (FANS) Committee and will result in development of standards for avionics systems and services for the Global Positioning System (GPS), as well as digital voice and digital data link services. This paper summarizes the FAA programmes supporting the introduction of the new satellite services.

The concept of differential GPS has been under study, test and refinement for about 10 years. Operational use of differential GPS is now practical, effective and highly reliable. Refinements to the concept of differential GPS have evolved over this period, several of which have been reported by Trimble Navigation personnel. It is now reasonable to conclude that the ‘second generation’ of differential GPS has arrived, with a collection of technical improvements and features that make its use even more accurate, robust and reliable.

In 1983, the Netherlands proposed to the International Maritime Organization (IMO) at the 48th Session of the Maritime Safety Committee (MSC) that the Organization should place on the work programme a study of a worldwide satellite navigation system for marine use.

The Global Positioning System (GPS) offers an absolute positioning accuracy of 15 to 100 metres. Inertial navigation complements GPS in that it provides relative positioning and is totally self-contained. These two positioning sensors are ideally suited for system integration for although there is not necessarily an improvement in accuracy, the integration of GPS with inertial navigation systems (INS) does enable an increase in system performance.

This paper is the second chapter of a series on Air Navigation Systems during the fifty years from the early oceanic flights and the inception of commercial aviation to the introduction of INS in civil aircraft. These papers are intended as critical commentaries. A definitive history has yet to be written. The writer would be grateful to receive criticisms of the paper or comments on the subject.

Navigation aids in use today have their origin in mainly military operational requirements for navigation accuracy, coverage and integrity. They have also been directed at the needs of air and sea operations.

The purpose of this paper is to show the effect of incorporating various discrete grid systems in a micro-based, ship weather-routeing system, which employs Bellman's dynamic programming algorithm, and either a cost-objective or time-objective performance measure. A simple ship speed and power function is utilized, in the cost computation. The calculation of the least-cost/least-time route is briefly described, but it is the derivation of the discrete grids and their influence on the route decisions that forms the paper's emphasis. The measure of cost within this paper is necessarily notional.

This contribution is an updated version of a paper presented at the thirteenth annual meeting of the International Omega Association. It discusses the extraction of directional as well as positional information from the Omega signal pattern. The two outputs might be combined to form a self-contained, Omega-based, ship or aircraft navigation system, or the directional information could be fed to a conventional gyro-magnetic compass as an alternative to the magnetic input. Directional information from other VLF transmissions could also be used.