Flight level

Abstract: Methods and apparatus for determining altitude, specifically altitude in an aircraft, and an estimated error of the altitude The altitude determination preferably uses a first altitude based on hydrostatic calculations, including local pressure and temperature, as well as a second altitude which is preferably a GPS altitude A radio altimetry can also be used instead of or to complement the GPS altitude Other sources of altitude determination can be used in the equation for the calculation of the final altitude Each of the sources of altitude determination is provided with a complementary estimated error In the final determination of the probable altitude, each source of altitude information is preferably accorded a weighting according to the estimated error of the altitude source For global positioning altitude, the final combination of the altitude sources uses a complementary filter which takes into account the selective availability of the GPS altitude

Abstract: [1] Wind, temperature, and humidity observations from radiosonde and aircraft are the main sources of upper air information for meteorology. For mesoscale meteorology, the horizontal coverage of radiosondes is too sparse. Aircraft observations through Aircraft Meteorological Data Relay (AMDAR) sample an atmospheric profile in the vicinity of airports. However, not all aircraft are equipped with AMDAR or have the system activated. Observations inferred from an enhanced tracking and ranging (TAR) air traffic control radar can fill this gap. These radars follows all aircraft in the airspace visible to the radar for air traffic management. The TAR radar at Schiphol airport in Netherlands has a range of 270 km. This Mode-S radar contacts each aircraft every 4 s on which the transponder in the aircraft responds with a message that contains information on flight level, direction, and speed. Combined with the ground track of an aircraft, meteorological information on temperature and wind can be inferred from this information. Because all aircraft are required to respond to the TAR radar, the data volume is extremely large, being around 1.5 million observations per day. Note that there are no extra costs for this data link. The quality of these observations is assessed by comparison to numerical weather prediction (NWP) model information, AMDAR observations, and radiosonde observations. A preprocessing step is applied to enhance the quality of wind and temperature observations, albeit with a reduced time frequency of one observation of horizontal wind vector and temperature per aircraft per minute. Nevertheless, the number of observations per day is still very large. In this paper it is shown that temperature observations from Mode-S, even after corrections, are not very good; an RMS which is twice as large as AMDAR is observed when compared to NWP. In contrast to the temperature observations, the quality found for wind after correction and calibration is good; it is comparable to AMDAR, slightly worse than radiosonde but certainly very valuable for mesoscale NWP.

Abstract: We estimate the capacity of a generic airspace region given convective weather constraints and various operational conditions. We model en route airspace for future operations where jetway routing is removed and aircraft paths may conform with the geometry of hazardous weather constraints. Within a constant flight level, decentralized and centralized control of traffic are considered. Decentralized, Free Flight operational conditions consider aircraft flying in any direction vs alternating altitude rules. Centralized operational conditions consider traffic that monotonically progresses in one primary direction and a unidirectional flow where all traffic must remain within pre-defined flows (e.g., from West to East). Under these conditions, we compute the theoretical maximum capacity and compare it to algorithmic solutions. Additionally, we compute the capacity when aircraft fly in platoons – two or more aircraft flying in the same direction in close proximity – in order to understand the effect of platooning on airspace capacity. Finally, we define a complexity metric, and compare the complexity of the resulting traffic flows under each experimental condition.

Abstract: Among the operations in the general-aviation community, one of the most important objectives is to improve safety across all flight regimes. Flight-data-monitoring or flight-operations-quality-assu...