Updraft and downdraft detection in the atmosphere (Vector Vario)

Abstract

Especially in unpowered flight (gliders, hang gliders, paragliders ...) or in powered flight, aids are important that help to optimize altitude gain or reduce descent and thus improve the distance covered or the speed. During powered flights, turbulence can be detected and its impact reduced. This is useful for both manned and unmanned aircraft. For this purpose, information about the surrounding air mass is essential. The system expands the previously common measured values (pressure ~ altitude, speed (A1)) using sensors that are attached to the wings - as far out as possible - and measure meteorological data (temperature and humidity) (A2) as well as kinematic data (accelerations) (A3) and attitude data (earth's magnetic field) (A4) and combine the values in a central unit (B5). The main causes of updrafts (thermals, updrafts, convergence, waves ...) as well as areas with sinking air masses are recorded equally. By knowing the data of the surrounding air over the wingspan of the aircraft and the flight attitude, the flight can be optimized by visualizing the thermals in a display (B6) and a flight direction and / or flight speed can be suggested.

Description

[0001] In the atmosphere, rising and falling air masses are caused by meteorological effects. Especially in unpowered flight (gliders, hang gliders, paragliders, etc.), aids that help optimize altitude gain or reduce descent are important.

[0002] During powered flights, turbulence can be detected and its effects reduced.

[0003] This is useful for manned and unmanned aerial vehicles.

[0004] The primary causes of updrafts (thermals, updrafts, convergence, waves, etc.) as well as areas with descending air masses are to be recorded and supported equally. In addition to the previously used kinetic data of air mass movements (speed and acceleration), meteorological data at the wingtips and attitude data are important. Based on the basic assumption that rising air is characterized by lower density, the air density parameters and, in particular, their changes are recorded. By knowing the data of the surrounding air across the wingspan, the flight can be optimized, and the bilateral arrangement can be used to suggest a flight direction and / or flight speed (flight vector). State of the art:

[0005] The variometers commonly installed in aircraft to indicate climb / descent are primarily based on pressure measurement and its change. These are centrally positioned and available in mechanical and electrical designs. They detect a difference in altitude over time and display it. This occurs with a time delay due to the system, as a change in altitude / pressure must first occur before it can be displayed. Efforts must be made to prevent the pilot-initiated conversion of altitude energy into speed (=kinetic energy) – and vice versa – (e.g., with TEK – nozzle or electronic compensation).

[0006] Ideally, the speed-dependent sink rate of the flying object is offset to obtain a display that shows the rise of the air mass (net vario).

[0007] (Horizontal) gusts cause false readings.

[0008] Newer developments are also placed centrally and include acceleration in addition to the pressure change in order to indicate the change in movement (up / down) earlier and to minimize the time delay.

[0009] The previously common central arrangement has the disadvantage that the entire aircraft must be lifted, which requires stronger updrafts. Furthermore, the central arrangement cannot determine whether the updraft (thermal) is acting directly in the center or offset to the side.

[0010] The bilateral arrangement of the measurement sensors at the end of the wings can react much more sensitively, as the light, elastic wing tips can be lifted directly by smaller updrafts and provide differentiated signals more quickly. This is described in WO002009138213A2. However, this leads to inaccurate evaluations in turbulent air, which often prevails at the edge of thermals. The acceleration caused by the pilot cannot be reliably calculated either.

[0011] However, this method also gives a good indication of the width of the spatial position of changing air currents flown by the aircraft.

[0012] Another development approach attempts to measure thermals using only temperature sensors (DE 1291546 A, DE 2248466 A) and provide the pilot with an indication. These are based on the idea that thermal air is warmer than the surrounding air.

[0013] However, this isn't the sole driving force behind thermals. If the atmospheric stratification is in the direction of inversion, the temperature in the atmosphere doesn't decrease as much as the rising air mass cools. Therefore, this can lead to false readings in certain weather conditions.

[0014] Here, a two-sided arrangement has already been suggested in order to give a directional recommendation.

[0015] Others limit themselves to humidity (US 6012675) and consider temperature measurement as unsuitable for thermal detection. (from column 1 line 67 “thermal detection devices based on temperature measurements would then steer the pilot away from rising air” translated: “Thermal detection devices based on temperature measurement would steer the pilot away from the rising air”)

[0016] This is repeated again in column 3 starting at line 21.

[0017] Although temperature is also measured in this patent, it is only used to eliminate temperature effects from the humidity measurement and it is mentioned that the measured relative humidity can be converted into absolute humidity / partial pressure (column 3, line 32).

[0018] Overall, this invention aims to detect whether thermals are present and to identify the boundaries at entry and exit.

[0019] The goal—through the two-sided arrangement—was primarily to identify a direction in which the pilot should steer. Quantification is limited.

[0020] Reasons for the limitation - only to humidity - are: "The advantage of moist thermal detection is enhanced by the fact that the humidity changes at the boundaries of an updraft are often more abrupt, thus easier to detect than variations of temperature of same significance." translated: “The advantage of wet thermal detection is enhanced by the fact that humidity changes at the boundaries of an updraft are often more abrupt and therefore easier to detect than temperature fluctuations of equal significance.”

[0021] More recent ideas combine temperature, humidity, and pressure (DE 20 2021 002 372) to calculate a density. When the density changes to lower values, thermals can then be detected. The idea behind this is that air with low density rises.

[0022] The measurement is only carried out in the middle of the aircraft, so no direction can be detected.

[0023] Density decreases with altitude. As the aircraft climbs, it becomes difficult to determine whether the aircraft is still in the thermal or has already partially left it.

[0024] Pressure measurement is also required to determine density. This requires calculating three values (pressure, humidity, temperature) with their absolute values, all of which are subject to tolerances. This makes it difficult to detect even the smallest changes. The inclusion of pressure, which changes with altitude, makes it difficult to compare the thermal quality of the air at different altitudes, as pressure (= altitude) has a strong influence on density but does not allow for any statement as to whether "thermal" properties are changing. Quantification is generally possible, but the centralized arrangement makes it impossible to detect direction.

[0025] With this system, the pilot only notices the loss of thermals when the fuselage and the wing are outside the thermals. Summary of the state of the art:

[0026] Previous proposals for detecting thermals are based on measuring individual physical quantities. The physics of thermals is very complex and strongly dependent on the current weather conditions and, in particular, the altitude stratification of the atmosphere.

[0027] Commercially available variometers measure the change in altitude per time (1st derivative of altitude with respect to time) or the acceleration (2nd derivative of altitude with respect to time).

[0028] This means that you see the result of the thermals, but not their meteorological causes.

[0029] This is measured centrally in the middle.

[0030] Whether the aircraft is inside or outside the thermal is only indicated by the display of good or poor climb or descent.

[0031] A decrease in climb either means that the thermal is being abandoned or that the thermal itself is weakening. The cause is unclear.

[0032] The measurement of basic meteorological data of the environment is not yet common practice.

[0033] However, the suggestions made so far with temperature, humidity or density are not comprehensive enough to evaluate and display the complex processes of thermals.

[0034] Additional environmental cues would be very helpful for making better decisions about the flight path. Collecting and displaying these cues separately for the right and left sides would improve the decision-making process.

[0035] This unsatisfactory situation can be improved with the following system: The system consists of the main components: (shown in Figure 1)A: System of sensors for determining: A1. the static pressure or pressure change to detect the rise or fall and the total pressure to detect the speed. A2. of accelerations (translational, rotational) to measure the change in speed / rotational movements. A3. the temperature and humidity to detect a different composition of the atmosphere along the flight path and in comparison between left / right. A4. the position using a geomagnetic field sensor Arrangement:

[0036] Components A1 and optionally A2 are located in the middle of the aircraft.

[0037] The components A2 and A3 are placed at least at both wing tips in order to measure an areal distribution / change over the flown area.

[0038] For position measurement, it is advantageous if the A4 sensor can measure as undisturbed as possible by other magnetic fields. This is ideally possible at the wing tips, but not mandatory. B: Data processing and display: B5. The sensors from A transmit the central data and those from the right and left sides (preferably wirelessly) to a processing unit, which then calculates the climb / descent rate. In addition to displaying the current values and the changes, a forecast for the further flight path is derived and a suggested flight vector is created.

[0039] This data will be passed on and B6. a display (visual and / or acoustic and / or haptic) is shown.

[0040] With this improved spatial perception of the updraft, the pilot can optimize his flight. GPS signals and the position of the magnetic field are used to determine the spatial position. Physical background: ρ=pRs*T[kg / m3] p=pressure in Pascal, Rs = specific gas constant of dry air with 287.058 J / (kg*K) T = temperature in Kelvin

[0041] If humidity is included, Rs in formula 1 is replaced by Rf: Rf=Rs1−φ*pdp*(1−RsRd) Rd = gas constant water vapor with 461.523 J / (kg*K) φ = relative humidity in % pd = saturation vapor pressure of water in air

[0042] Using the Magnus formula, the saturation vapor pressure can be approximately determined, which in turn depends on the temperature t. Note that t must be specified in °C. Eω(t)=6.112 hPa⋅exp(17.62⋅t243.12°C+t) for −45°C≤t≤60°C

[0043] Formula 4: ρ (p, T, φ) : the function for determining the air density with the given measurement data using formulas 1, 2 and 3.

[0044] For a constant pressure this is visualized in Figure 2.

[0045] Here you can clearly see the influence of temperature and humidity.

[0046] A different pressure shifts the area predominantly in the Z-axis, whereby a different weighting of the humidity is set via formula 2 (which also includes the pressure).

[0047] Assuming that the air pressure in small horizontal spaces is constant, For simplicity, we can restrict ourselves to the temperature T and relative humidity φ.

[0048] This “pressureless” part of formula 4 is referred to as the “relative density coefficient” because it summarizes the meteorological factors influencing the density - independent of the pressure, which constantly changes as the aircraft ascends.

[0049] This makes it easier to detect thermals (inside / outside).

[0050] Figure 2 shows the great influence of humidity on air density and thus humidity - in addition to temperature - makes a decisive contribution to thermals.

[0051] The name thermal is therefore somewhat misleading.

[0052] Therefore, one parameter alone can never lead to a useful result.

[0053] The first approaches, which only considered temperature, neglected humidity.

[0054] Later approaches limit themselves to humidity and ignore temperature.

[0055] Both approaches cover the width of the area flown over, so that direction detection is possible.

[0056] More recent approaches are based on density measurement, but are arranged centrally.

[0057] However, a measured difference in air density is not a reliable indication of a thermal / updraft, since dynamic effects often overlap and a thermal tube must first develop over time.

[0058] Furthermore, a mere observation of density is not a reliable indicator. The locally measured lower density may, for example, be covered by an even warmer layer of air with an even lower density, so that an upward tendency may not yet be present.

[0059] Therefore, this approach has not been very useful so far.

[0060] Without a double arrangement, direction detection is not possible.

[0061] Only the combination of the measured values according to A3, including the measured values with A2 and A1, provides information as to whether it is a suitable air mass that also rises. Thermals:

[0062] Rising warm air, warmed near the ground and laden with moisture through evaporation, rises and cools with altitude, but usually remains warmer and more humid than the surrounding air. Temperature differences (thermal / ambient) decrease on the upward path through expansion (cooling) and via Brownian motion (without material transport) and mixing at the edge. Whether the surrounding atmosphere remains warmer or cools more than the surroundings depends on the altitude stratification of the atmosphere.

[0063] The thermals are often surrounded by descending air masses, which leads to vortices and mixing.

[0064] Humidity compensation requires material transport because water molecules have to diffuse, which takes place much more slowly.

[0065] Therefore, the absolute humidity content remains virtually unchanged within the thermal zone. Outside the thermal zone, the humidity changes with the stratification of the ambient air.

[0066] As the temperature decreases with altitude, the relative humidity in the thermals increases. When this occurs to saturation, the moisture condenses, signaling the end of dry adiabatic ascent and usually forming the base of a cumulus cloud.

[0067] If an aircraft flies towards a thermal, it is not known whether and how the thermal will be hit (picture 3 right below the aircraft touches the thermal with the outer edge of the wing).

[0068] With the dual-sided arrangement of the measuring technology, thermals can be located more easily, as it is sufficient for a wing to touch the thermal, which will measure better conditions there (higher temperature, higher humidity, slight upward movement of the wing). The aircraft does not need to move vertically, as is the case with conventional systems.

[0069] If better conditions are indicated, the flight direction can be changed and the circling into the thermal tube can take place.

[0070] The flight path then takes place on a circular path (picture 3 upper left aircraft) and the aircraft climbs with the rising air.

[0071] Even within thermals, conditions are not constant. Due to mixing at the edges, wind offset, and deformation, the upward-moving airflow can travel at different speeds. Position calculation

[0072] The circular path is used to fly the thermal tube inside the area of greatest climb and the system records the measurements described above and provides information about where better lift conditions prevail.

[0073] An exact localization of the measured values is necessary.

[0074] Due to the aircraft's speed (typically 15-50 m / s), fast measurement cycles are advantageous. This is technically feasible with sensors A1, A2, A3, and A4.

[0075] Common methods for absolute location determination are satellite-based systems (GPS), which calculate the current absolute position.

[0076] In principle, directions are calculated using two positions.

[0077] The direction of flight can only be determined retrospectively from the two positions.

[0078] A current direction with a high measurement frequency is therefore not easily possible.

[0079] Furthermore, the thermal tube is usually displaced by wind. A circular thermal path, therefore, becomes a displaced spiral (seen from above) with the satellite system measuring absolute values.

[0080] With the A4 relative magnetic measurement system, a circle remains a circle, and the measured values can be clearly visualized in an image. The aircraft's speed is included in this calculation.

[0081] Typically, a thermal tube has a strong core that slopes downwards. Detection of the spatial distribution is easier with designs that have multiple sensors installed across the width of the aircraft.

[0082] The usual central recording in the fuselage averages over the width and thus a spatial distribution can be poorly recorded.

[0083] The A4 magnetic field sensor can determine the precise position of the flying object in space. It can be installed in the center of the wing or, better yet, at both ends of the wing. Interference is significantly lower there than with a central "compass," which can be disrupted by various metallic components and electrical currents.

[0084] To maintain efficient circling flight, the aircraft is banked (angle α in Figure 3). This causes the inner wing to be lower and the outer wing to be higher in circling flight. With typical wingspans, differences in altitude of several meters are present.

[0085] With a standard temperature decrease with altitude of 1K / 100m in the lower atmosphere, the altitude difference will be 0.01K per meter of altitude difference between the two wing tips.

[0086] This temperature difference also affects the measured relative humidity.

[0087] There is also a different air pressure, which must also be taken into account.

[0088] To account for and calculate this difference, the inclination must be measured. The data from magnetic field sensor A4 is used here, as it provides this data without delay. Due to its accuracy and speed, magnetic field sensor A4 is used. Alternatively, the sensor data from sensor A3 could also be used.

[0089] Using the measured angle α and the wingspan, a height difference Δh can be calculated. This height difference can be used to correct the measured humidity and temperature values.

[0090] What is new is the arrangement of the combined measurement of temperature and relative humidity together with acceleration and magnetic field at the end of the wings.

[0091] Temperature and humidity are calculated to produce a “relative density coefficient”.

[0092] This indicates whether the flying object is inside or outside the thermal.

[0093] Pressure measurement on the wings can be omitted due to the double arrangement (see explanation in formula 4), as this would only provide inaccurate values due to the flow.

[0094] The absolute value of the density can be calculated using the pressure measurement at the center. This pressure measurement also serves as an integrating value for the altitude change.

[0095] The pressure value determined in the middle is converted to the inner / lower and the outer / higher with the height correction Δh / 2.

[0096] Combined with the acceleration sensor, which detects the change in vertical flow via wing lift or depression, and the position detection via the magnetic field sensor, a more comprehensive assessment of the updraft and downdraft areas is dynamically and meteorologically possible, in contrast to the consideration of individual or a few measured values.

[0097] The doubling of the measured values by positioning them at the wing tips results in greater accuracy and a more comprehensive coverage. Differences and rates of change are particularly important for the calculation.

[0098] Due to various weather phenomena, air pressure changes throughout the day.

[0099] Likewise, air pressure generally varies in different (regional) areas. Temperature is also subject to regional variation and has a daily pattern.

[0100] All of this affects the absolute values.

[0101] The focus is on recording the change in values, as these can be recorded more accurately than absolute values. Change over the flight path / time (along the flight path):

[0102] Assuming that the air pressure in small spaces of a plane does not differ significantly (p1 = p2), it makes it possible to derive the temporally different measured values (T1, T2 and φ1, φ2 ) according to time / distance and to obtain a temperature gradient and a humidity gradient.

[0103] For dry air, the density change can be calculated as a derivative over time or distance: Δρ=ρ1ρ2=p1*Rs*T2p2*Rs*T1∼T2T1

[0104] The ratio of densities over time (at the same pressure) is inversely proportional to the temperature (p=constant, Rs=constant).

[0105] Formula 5, extended to include humidity, results in a more complex derivation. The slope can be estimated as a function of temperature change (T1, T2) and humidity change (φ1, φ2) using the slope of the area in Figure 2: Δρ=ρ1ρ2=p1*Rf1*T2p2*Rf2*T1⇒ρ'(φ,T)

[0106] Analogously, this is done across the width of the flight path, i.e. across the area flown over.

[0107] The temporal values (1 and 2) and the spatial values (left / right) provide measurement points.

[0108] The task is to influence the flight path so that the values ​​lead to a lower air density. From this, a flight vector can be suggested. Difference between Left / Right Δ(L / R) and also the change in the difference L / R Δ'(L / R)

[0109] The measured values left(ρl) / right(ρr) also receive a (changing) gradient.

[0110] The speed of change is a strong indication of different air masses.

[0111] With the two results, a direction vector can be calculated that indicates the flight path to the lowest density.

[0112] Concentrating only on the change in values and their rate of change due to the distance / time travelled and on the differences between left and right results in a spatial distribution of different temperature and humidity across the area flown over.

[0113] With these two significant parameters, a “relative” density distribution can be estimated that describes a beard (thermal tube) well.

[0114] A display of the measured values provides a good overview of the thermals and makes it possible to find a flight path that optimizes climbing or, in sink areas, helps to avoid them or minimize sinking. Summary of sensor data:

[0115] The combination of these three approaches described (A.1, A.2, A.3) enables a better indication of climb / fall, as a plausibility check can be performed.

[0116] With the A4 sensor, the position of the measuring points can be better determined and corrections can be made due to the different heights (due to transverse inclination) of the two outer measuring points.

[0117] The interpretation of an isolated change in values involves the problem of misinterpretation.

[0118] The overall view delivers significantly better results. Advertisement:

[0119] The display can be done in different ways.

[0120] The flight path can be displayed on screens. The lift strength can be highlighted in color so that the pilot can identify his flight path (e.g., a circular path in a thermal) and the air quality. This allows him to adjust his circular paths to achieve better climb.

[0121] This can also be communicated to the pilot through sounds or voice signals, so he does not have to look at the display as often and can concentrate on his surroundings.

[0122] Alternatively, this can be communicated to the pilot by means of a vibration sensor. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 002009138213A2

[0010] DE 1291546 A

[0012] DE 2248466 A

[0012] US 6012675

[0015] DE 20 2021 002 372

[0021]

Claims

[1] System for the more effective detection of updraft and downdraft areas with a central processing unit with sensors (pressure / altitude, speed, magnetic field sensor, GPS (Global Positioning System) and a display (optical and / or acoustic and / or haptic) and: - sensors mounted on the outside of the wings for at least temperature and humidity - acceleration sensors (axial and rotational) mounted on the outside of the wings - magnetic field sensor mounted on the outside of the wings for position determination to record the changes and differences in these parameters over the flight path and the area / wingspan flown with display of the thermals and a flight direction and speed suggestion based on this (flight vector).

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