EP0394425A1 - Systeme d'approche et d'atterrissage pour aeronefs - Google Patents

Systeme d'approche et d'atterrissage pour aeronefs

Info

Publication number
EP0394425A1
EP0394425A1 EP89912268A EP89912268A EP0394425A1 EP 0394425 A1 EP0394425 A1 EP 0394425A1 EP 89912268 A EP89912268 A EP 89912268A EP 89912268 A EP89912268 A EP 89912268A EP 0394425 A1 EP0394425 A1 EP 0394425A1
Authority
EP
European Patent Office
Prior art keywords
landing
approach
aircraft
radar
antenna
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP89912268A
Other languages
German (de)
English (en)
Inventor
Michael Arthur Jones
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BAE Systems Electronics Ltd
Original Assignee
Marconi Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Marconi Co Ltd filed Critical Marconi Co Ltd
Publication of EP0394425A1 publication Critical patent/EP0394425A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/91—Radar or analogous systems specially adapted for specific applications for traffic control
    • G01S13/913—Radar or analogous systems specially adapted for specific applications for traffic control for landing purposes
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/933—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of aircraft or spacecraft
    • G01S13/935—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of aircraft or spacecraft for terrain-avoidance
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
    • Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Definitions

  • This invention relates to an aircraft landing approach system employing radar detection of a landing strip or platform. While the invention finds application in both land based and sea based landing facilities it is particularly useful in operation with helicopter landing platforms at sea, for example on oil-rigs.
  • the approach may be a procedural approach which is agreed between an aviation authority and an operation or a group of operators, or may be an approach which is as close as possible to the current I.L.S. or Instrumented Landing System at Category 1 or better. (The category indicates the proximity of the instrument/visual transition to touchdown, the higher the category the shorter the visual control period.)
  • An object of-the invention is to provide a radar landing aid which is substantially self-contained in the aircraft but at the same tine can take advantage of any landing aids that may be present on the platform or landing strip.
  • the predominant weight of investment is therefore on behalf of the aircraft operator and may be negligible on the part of the landing facility authority.
  • an aircraft landing approach system comprises an approach radar system fitted to an aircraft, the approach radar system having azimuth angle tracking capability and ranging capability, and a landing facility recognition capability.
  • the azimuth angle tracking capability may be provided by a twin transmission beam either simultaneous or sequential and comparison of signals received in response to the two beams.
  • the azimuth angle tracking capability may be provided by a single transmission beam scanned in azimuth and comparison of signal returns received at periodic intervals within the beam width of said beam.
  • the approach radar may be a modified weather radar providing weather returns and landing facility returns selectively.
  • identification means associated with the landing facility, the identification means being adapted to transmit an identifying signal to the aircraft on interrogation by the approach radar system.
  • the identification means may comprise an active transponder adapted to transmit a pulse signal characteristic of the associated landing facility on interrogation by the approach radar system.
  • This pulse signal nay comprise a plurality of pulses having a time relationship characteristic of the associated landing facility.
  • the pulse signal ⁇ ay comprise a plurality of pulses having a presence and absence pulse code relationship characteristic of the associated landing facility.
  • the active transponder preferably comprises a wide beam antenna exhibiting a wide beam in azimuth and receiving and transmitting means adapted to receive a radar pulse signal by way of the wide beam antenna and re-transmit by way of the wide beam antenna an identifying pulse signal characteristic of the associated landing facility.
  • the active transponder may further comprise a static-split antenna providing azimuth and angle angle discrimination over angles which are small relative to those of the wide beam, the receiving and transmitting means being adapted, in response to a radar pulse signal received by the static-split antenna, to transmit a locating pulse signal indicative of the angle of the aircraft relative to the boresight of the static-split antenna and thus provide a standard glide slope for instrumented landing of fixed wing aircraft.
  • the identification means may comprise a series of reflectors having a linear distribution such as to produce a coded pulse train on reflection of a single interrogating pulse from the approach radar system, the coded pulse train being characteristic of the associated landing facility.
  • the series of reflectors are preferably omnidirectional and the two reflectors directional.
  • the approach radar system preferably incorporates range responsive means for initiating an offset course effective to steer the helicopter within a predetermined miss distance of the platform, the helicopter incorporating manual override means to control the landing once visual sighting is established.
  • the means for initiating an offset course may be effecti e iin response to location of the landing facility, or in response to acquisition of a predetermined range to go.
  • the means for initiating an offset course nay be effective to determine, at the predetermined range to go, a course having a predetermined angle offset from the landing facility.
  • the static-split antenna is a four-horn antenna providing angle discrimination in azimuth and elevation, the antenna being coupled to provide sum, azimuth difference, elevation difference and dum ⁇ y output channels, monitoring means must be provided for monitoring power in the dum ⁇ y ouput channel and disabling the transponder in response to an increase in power indicative of a fault condition.
  • the landing facility recognition capability is preferably adapted to locate angular limits of a landing facility by means of a static split difference characteristic, the angular extent of a boresight null, when the boresight fs aligned with said landing facility, in conjunction with the range of the landing facility, providing an indication of the angular extent of the landing facility.
  • Means are preferably included for imposing an angular jitter on the boresight to determine the limits of the null.
  • the approach radar having azimuth angle tracking capability, ranging capability and landing facility recognition capability, landing facility is identified and located, and a course is set to make a predetermined miss of the landing facility.
  • the miss distance may be predetermined and the course set to a point at this miss distance. Alternat vely, at a predetermined range to go, an offset angle is imposed on the aircraft course.
  • an angle responyie transponder on the airstrip is valuable.
  • identification of the landing facility and azimuth determination of its position are the important factors. These requirements are accommodated in certain applications of the Invention essentially by the helicopter approach radar alone or with minimal transponder equipment.
  • the approach radar carried by the aircraft may, in additon, be custom made with inherently accurate angle discrimination properties or may be adapted from an existing, e.g. weather, radar. While the former gives greater freedom of design parameters, the latter often has the advantage of existing accommodation within the aircraft, and particularly within the nose of the aircraft.
  • Figure 1 is a diagram of a helicopter approaching a landing platform at sea
  • Figure 2 is a block diagram of a helicopter mounted approach radar
  • Figures 3 and 4 are displays of rig returns in relation to limit gate determinations
  • Figure 5 is a diagram of an active transponder for use on a landing strip or platform
  • Figures 6 and 7 are plan and elevation diagrams of the Figure 5 transponder beam characteristics
  • Figure 8(a) is a block diagram of the transponder transmitting and receiving equipment
  • Fi gures 8(b) and 8(c) are diagrams illustrating the coding of aircraft positi ons in Figure 8(a) ;
  • Figure 8(d) is a diagram of the possible return pulse train resulting from an interrogating pulse shown in broken lines;
  • Figure 9 is a plan view of a hel icopter approach path to a ri g landing platform
  • Figures 10(a) and (b) are diagrams of stati c-split di fference characteristics showing the effect of a finite width 'target* ;
  • Figure 11 is a diagram of an omnidirectional antenna suitable for rig landing platform
  • Figures 12 and 13 are omnidirectional antenna arrangements switchable for di rection selection; and Figure 14 is a plan view of a series of reflectors aligned with a requi red approach path and selecti vely angled to provide off -axis position encoding.
  • Figure 1 shows a helicopter carrying an approach radar 1 mounted underneath and in a forward facing position.
  • An oi rig 3 has a landing platform 5 and, in this embodiment, a t iransponder 7 whic may be active, as illustrated by Figure 7, or passive, merely comprising reflectors.
  • FIG. 2 shows the approach radar, of the above custom made type, in more detail.
  • a magnetron 9 controlled by a clock 11 and pulse modulator 13 is coupled to azimuth displaced elements of a dish antenna 15 by way of circulators 17 to produce a static split system of simultaneous twin beams.
  • the antenna elements are so disposed as to produce individual radiation characteristics, beams, which are offset from the dish boresight 19 by approximately a quarter beam width to give an amplitude comparison system f azimuth angle determination. Sequential lobing or other accurate beam comparison system could be employed alternatively. Elevation angle tracking may well not be necessary since the operational circumstances are fairly limiting and the aircraft pitch angle is likely to be small. Provision may be made for measuring pitch angle in the aircraft and controlling elevation of the transmit beams accordingly.
  • altitude measurements are taken, either by independent altimeter or by employing the ranging facility of the radar and a small portion of radar power directed downwards. In either event elevation of the main beams is controlled simply to ensure illumination of the landing facility : no elevation angle measurements are made by the receiver.
  • a local oscillator 21 is locked to the transmitter frequency to produce a constant I.F. output from mixer 23.
  • a frequency locking loop comprises offset filters 25 and 27, comparator 29 control voltage amplifier 31 and local oscillator 21.
  • the resulting L.O. frequency is mixed (33) with the outputs of circulators 17 to produce respective I.F. received pulse signals.
  • the mixers 33 are associated with T.R. cells to protect the receiver.
  • a switch 35 combines the received signal in one of two modes. For detection purposes it combines the two signals coherently hence giving a higher gain, single beam antenna, and in a tracking mode it time multiplexes the two signals into a common receiver channel.
  • the I.F. signal is detected (37) and applied to a range gate assembly 39.
  • the range so determined is then displayed (42).
  • An integrator 43 and AGC amplifier 45 maintain a normalised signal level.
  • the resulting range tracked pulse is applied to a de-multiplex and comparator circuit 47 where the separate target pulses are re-produced and compared to provide an error signal which is integrated (49) to produce, in the angle tracking mode, the target angle off helicopter axis as an output.
  • the dish 15 is controlled by this signal, by way of a servo circuit 51, to track the target (rig or other landing platform) ie, to align the antenna boresight with the rig.
  • the servo ichanism 51 is controllable by alternative inputs, ie an angle scan circuit 57 which is responsive to range, and an overriding manual input.
  • the angle of the source equipment, ie the rig, with respect to the mechanical axis of the radar, which is usually that of the aircraft, is taken from the antenna pick-off's in the dish dr ve servo 51.
  • Aircraft angle motion can be fed in at 53 via the switch waveform generator 55 causing a servo demand to cancel out that aircraft motion on the antenna 15.
  • the input signal to the dish servo gives an angle output essentially independent of aircraft angular movement away from the originally (or subsequently set) line of sight, and can be used as an angle demand to the aircraft crew (or to its autopilot) to achieve the desired course.
  • the antenna pick-off output can be monitored and aircraft motion combined with it to obtain the correct angle demands outside the radar.
  • Range tracking effected by the range gate assembly 39 and tracking loop 41, can be of a simple nature, e.g. an earl /late gate operating on the nearest point of the rig with a further jittered gate to operate on the furthest point of the rig, and hence allow an estimate of the rig length along the radar boresight.
  • Figure 3 shows the rig return 59 (amplitude against range), and the range gates determining the range limits.
  • early/late gates 61/63 which overlap in time are supplied with the return signal either by provision of separate gates or alternate time designations of the same gate.
  • the 'early' gate output has an amplification x2 and the 'late' gate an amplification of xl (relatively).
  • the two gates each cover a range of 30 metres, the two overlapping by half. It may be seen that when the rig return just falls within the whole of the late gate (as shown) there will be equal outputs from the two amplifiers. One or other output will, predominate as the rig limit falls earlier or later than as shown.
  • the outputs are compared and the error integrated to control the timing of the early/late gates to lock on to the condition shown.
  • the range so determined is presented on the display.
  • the far limit of the rig is obtained by a 'jittered' gate 65 which is 'jittered' between two positions the width of the gate apart.
  • the outputs of the two gate positions are amplified differentially and when a difference of a specified threshold value e.g. 20dB exists between them the junction of the two positions lies on the far limit of the rig return signal.
  • the near and far points of the rig return signal 67 are arranged symmetrically about the centre gate of the block by means of an a.g.c. controlled threshold comparison and the range tracking loop operates to maintain this situation. Range to the nearest point of the rig and the length of the rig are then simultaneously and continuously available, whilst the antenna is looking at the rig, within the range gate block.
  • Figure 15 illustrates an alternative form of approach radar mentioned earlier. This is based on a weather radar which would normally be housed in the nose of the aircraft.
  • An antenna 143 is scanned continuously under the control of a scanner circuit 145. Interrogating pulses are transmitted in the usual manner by magnetron 147, modulator 149, circulator 151 and antenna 143.
  • the return signal including radar returns at the transmitter frequency and beacon (ie transponder) returns at a shifted frequency, are passed to a mixer 153 producing separation of the beacon signal in the upper path and the radar return in the lower path. Both signals are subjected to sensitivity-time-controls 155 followed by matched filters 157 and detectors 159.
  • the beacon signal consisting of a coded pulse series, is then converted to parallel format 161 and applied to a processor 163 for decoding.
  • a processor 165 provides accurate azimuth angle determination by sampling the radar returns at brief intervals, to obtain values from a single 'target' at different points on the single beam as 1t scans.
  • Range, resolution is provided by selection, according to range, of the number of basic range gate units, each of say 20 metres, that are grouped together for processing. The greater the range the greater the grouping and the coarser the resolution.
  • the grouping, or range collapsing, is performed by circuit 167, the resluting signals being integrated (169) and applied to the processor 165.
  • the resulting information is then displayed in various forms under manual control.
  • FIGs 5, 6, 7 and 8 illustrate an identifying transponder for use in conjunction with the approach radar of Figure 2, and particularly for use in the case of land based airstrips for fixed wing aircraft where elevationon approach is critical. Variants of this transponder may also be used for land based helicopter platforms.
  • the transponder shown in Figure 5, comprises a wide beam localiser antenna 70 for receiving an interrogating radar pulse and returning an identifying pulse, and a narrow beam, 4-horn feed, static split antenna 71 to define an approach path and locate an approaching aircraft relative to this path.
  • the dual antenna assembly having a common boresight 72, is mounted on a pedestal at a height of approximately 1 metre and is energised by a remote power source.
  • Figures 6 and 7 show the transponder in plan and elevation, fitted to an airstrip.
  • the localiser beam 73 has a beam width of 100° in azimuth and 6° in elevation, the beam being upwardly directed at 3°.
  • Central in the localiser beam are the 4 beams of the static split antenna having an overall beam width of 10° in azimuth and 2i° in elevation and again has a (glide) slope of 3°.
  • the static split antenna 71 is purely a receiving antenna, the resulting location information being transmitted by the localiser antenna 70.
  • FIG. 8(a) shows, diagrammatlcally, the circuitry and function of the transponder of Figure 5.
  • An aircraft carrying the approach radar of Figure 2 and lying just (say) within the localiser beam 73 will transmit an interrogating pulse which will be received by the localiser.
  • the radar frequency is in the X band, typically 9-10 GHz.
  • the pulse is received by antenna 70, filter 75, circulator 77 and mixer 79 where it is mixed with a local oscillator (81) signal of frequency f o -150 M4z, f 0 being the radar frequency.
  • the mixer 79 thus produces an IF at 150 MHz which, after transmission by a blanking gate 83 is passed to an array of. delay lines.
  • a first of these delay lines, 85 has a delay of d j /2, ie half of a basic unit delay.
  • the pulse thus delayed is applied to a detector 87 and a monostable 89 which disables the gate 83 and effectively disables the receiver for a period of 7 delay units. Reception via the static split antenna is also disabled by way of gates 91.
  • the first received pulse is further delayed a half unit by delay line 93 to give a total delay of one unit, and re transmitted by way of mixer 95, amplifier 97, circulator 77 and antenna 70.
  • This pulse 'echo' is used by the approach radar for range assessment as explained above, the total echo time being the transmission time plus the standard unit delay.
  • the original pulse output of gate 83 is also passed to a delay line dg providing 6 units of delay prior to transmission via antenna 70.
  • the two pulses thus transmitted provide the transponder identification, the delay between them being unique. More complex ID codes can of course be provided by further dela stages.
  • the ID pulse code is returned to the approaching aircraft once the aircraft is within the localiser beam.
  • the antenna 71 When the aircraft comes closer to the approach path, and in particular within the static aplit beam, its interrogating pulse will be received by the antenna 71. Confirmation of the location within the main static split beam is given when the relative received power levels between localiser and static split beam are recognised within a suitable tolerance. This prevents acceptance on a sidelobe of the radar transmission.
  • the pulse signal received by the antenna 71 is summed and differenced in azimuth and elevation in known manner to produce the three channels S, Da and De. These are detected (101) and applied to the gates 91 which are not yet closed.
  • AGC amplifiers normalise the signals to the sum reference level and the resulting signals are applied to hardware logic 103 and threshold circuits 105. Limits of angle error are set by these threshold circuits to determine the locations shown in Figures 8(b) and (c) which are, diagrammatically, end views of the static split bea 71, centred on the boresight 72.
  • Angular region 2 extends from the extreme right of the beam to the threshold 107; region 3 extends from the extreme left to the threshold 109; region 4 extends up to threshold 111; and region 5 extends down to threshold 113.
  • region around the boresight, ie on the correct guide slope lies in all four regions 2, 3, 4 and 5.
  • These angular regions, distinguished by the sum and difference signals and the threshold circuits are encoded by return pulses delayed by a corresponding number of unit delays, ie 2, 3, 4 and 5, the pulses occurring between the ranging return pulse 1 and the ID pulse 6, as shown in Figure 8(d). If the aircraft lies t the top left 1t will produce pulses 3 and 5, top right 2 and 5, bottom right 2 and 4, and bottom left 3 and 4.
  • the pulses are produced by gates 122, 123, 124 and 125 and delay . lines d 2 , 3» d ⁇ and dg according to the above coding, thus a 'reflected' pulse train consisting of pulses 1, 3, 5 and 6 indicates a requirement to dive and turn right, and so on. An absence of all pulses 2, 3, 4 and 5 indicates the aircraft is not in the glide beam at all and the presence of all pulses 2, 3, 4 and 5 indicates the aircraft is on the correct glide slope, the objective of the landing system.
  • pulse codes are possible and the number of delay lines can be adjusted accordingly.
  • the pulse code would preferaly be long enough to give a normal looking analog signal to the operator or the aircraft autopilot via standard binary coding and an ADC, ie the retransmitted pulses would be coded to represent a number of degrees off boresight in standard binary forms. This is an example using time delay ID of the landing platform.
  • the return angle indication pulses would be interposed in a similar way if pule code ID of the landing platform was used.
  • FIG. 9 Helicopters operating in the North Sea are fitted with area navigation and weather radars and altimeters. Hence the helicopter 61 in Figure 9 can steer by its area navigation system and its weather radar at a controlled altitude until the point A, typically 12 nautical miles 'to go' at which the approach radar can usefully be switched on.
  • the angle and range controls disable the angle and range tracking loops.
  • An appropriate angle scan to cover uncertainty in the expected 'angle-off of the rig is implemented by the angle control.
  • a minimum of three range gates are placed contiguously to cover 90m or can be spaced with intervals such that the smallest rig to be approached is bound to be detected by one of them (e.g.3 gates spread over 180m should ensure that all rigs with a 45m minimum dimension are detected).
  • the range uncertainty between aircraft and rig is covered by stepping (or equivalently continously scanning) these gates over the uncertainty before the antenna beam angle changes and slowly enough to allow an adequate number of Tx pulse echoes to be received e.g. approx. 20.
  • the gates must remain at each step of 4ms and 20 range steps, each of 180m are needed i.e. 80ms.
  • the maximum usable scan rate would be 100 deg/sec. If 100 Tx pulse echoes are desired for each assessment, ie at each range step, and only the middle half of the beam is utilised to maximise antenna gain, this scan rate would be reduced to 10 deg/sec, ie. 6 sec for a 60-deg scan.
  • this scan rate would be reduced to 10 deg/sec, ie. 6 sec for a 60-deg scan.
  • the aircraft flies at safe height,in 12 sec at 75 m/s helicopter speed, the helicopter will have travelled less than 1 Km towards the rig before the rig must again be encountered, ie. only £ of the range uncertainty set in this example's worst case.
  • the exact estimation of the extent of the range uncertainty is not critical, only that the minimum range set should not be such that the rig is inside this range at the start.
  • the number of steps needed by the block is reduced (perhaps to one) and speed of detection is increased and/or scan rate can be appropriately increased.
  • the number of pulse echoes desired for each aircraft is reduced from 100 to, say, 50 then the scan rate can be doubled etc.
  • the radar identifies a rig autonomously by its length being greater than a certain value programmed in, either permanently, for each flight, or by the crew knowing roughly the direction of approach, and the length of the rig in this direction.
  • the approach radar will show a size related null on boresight due to finite across-boresight "width" of the rig, e.g. a 450m "wide" rig would show approximately a 1J° null at 18 Km range and approximately 3° at 9 Km range. This is indicated in- Figures 10(a), showing the difference characteristic for a point source, and 10(b) for an extended source.
  • the antenna 1s jittered after detection about the target by a small angle the angular extent of the null can be measured and used as an extra identification means.
  • the approach radar will identify it and lock on to it as described above. Having identified the required rig by one method or another, and determined its bearing, the radar angle measurement of the required rig is then used to steer the helicopter directly towards the rig, ie. a steering angle of the error angle between the rig as measured by the radar and an estimate of the helicopter velocity vector.
  • This section of the course is shown in Figure 9 from B at typically lOn to C at l ⁇ nm. As the helicopter closes on the rig, the radar S/N will rise and its angle error decrease, allowing more accurate angle (and range) estimation.
  • the approach radar instructs a 10° turn away from the rig to prevent collision with it.
  • This course can be maintained or the course can be controlled from the radar information until 0.5nm to go, at D.
  • the approach radar indicates to the operator that he must transfer to visual for landing.
  • S ⁇ Assuming the helicopter has an incidence S ⁇ .
  • the approach radar will have tolerances which give a total azimuth angle result of ⁇ +S ⁇ + radar errors.
  • the radar is ⁇ x° accurate and to ensure that the above 10° turnaway, in general X° turnaway, is achieved, X+2x° turnaway is used, approximately, resulting 1n an extra 2xC/ D at Dn .
  • the course can be controlled to ensure no collision with the rig before visual sighting by other courses, for example, indicating angle to the helicopter, such that the point of minimum radar approach distance Dnm is steered towards, as measured normal to the line between rig and helicopter, or as measured normal to the approach path as remembered by a gyro or other reference prior to turnaway.
  • the object is to control the helicopter to an estimated point either left or right of the rig (see Figure 9) this point being on the normal (YY) to that of the initial approach (XX) and a distance D from the rig.
  • This f «orm of control can use angle and range measurements from the radar continually, to determine the approach point D from the rig and compute an angle such that the helicopter approaches this point whi lst stil l maintaining its velocity vector pointing away from the ri g when close to the rig.
  • a suitable steering angle then becomes
  • M is distance on XX axis
  • N is di stance on YY axis
  • Figures 11, 12 and 13 show alternative embodiments of transponder localiser antenna from that employed in Figure 8, particularly for use with rigs.
  • Figure 11 shows a fixed 4-horn antenna providing omnidirectional coverage. If these antennas 115 are combined statically, continuous omnidirectional coverage is obtained but at a relatively low gain and requiring careful design at the four beam overlaps to avoid interference nulls. It needs switching to achieve a relatively high gain and an easy design.
  • Figure 12 shows a similar arrangement but in which the elements are switchable in pairs (117, 119) according to the direction of the source.
  • a comparator 121 compares the signal level of the two pairs and operates a switch 127 to select the dominant pair.
  • Figure 13 shows a further omnidirectional antenna but having four elements 129 selectable (131) one at a time according to signal source direction.
  • the aircraft is in radio contact with the landing controller and the latter can switch to the antenna covering the approach.
  • Figure 14 illustrates a form of passive transponder for use on rigs.
  • a series of reflectors (133-139) are arranged spaced apart in a line 140 indicating the required approach path.
  • Four reflectors are shown, the first and last (133 and 135) being omnidirectional in azimuth and spaced so as to produce a relative delay of an interrogating pulse such as to identify the rig.
  • the other two reflectors 137, 139 are directional and are directed so as to diverge from the approach path 140 one to left and the other to the right. They are also spaced apart so as to enable their reflected pulses to be distinguished.
  • the divergence is such that an aircraft on the correct path will miss both 'beams' but will detect a reflection from one or the other if 1t is off track to left or right.
  • the resulting pulse trains are shown: P is the interrogating pulse, Pi the ID pulses, PI the pulse indicating 'left of centre' and Pr indicating 'tight of centre'.
  • the active transponder of Figure 8 has provision for a safety feature in the event that its beam patterns are distorted by external reflecting obstacles or internal failure of one or more components.
  • the static split antenna provides outputs which are summed and differenced in known manner to provide a sum or reference channel, an azimuth difference channel and an elevation difference channel.
  • a fourth channel normally results from this process which is a dumr ⁇ y channel providing no useful information.
  • the power in this channel is normally ery small compared to that in the sum channel and is applied to a dummy load. If the boresight of the beam distorts in any fashion then the power in this dummy channel increases significantly. Hence the power in this channel is monitored and a rise is used to disable the transponder.
  • the tolerance on the rise can be appropriately increased on command from the aircraft as the range to go decreases.
  • the ability of the monitor to self test for external or internal beam distortion still remain and expensive routine calibration Is then avoided.
  • the approach radar will thus receive no echo and the system is fail-safe since the approach radar will be prepared to fall back on its own autonomous techniques described above for detecting and identifying the rig.

Landscapes

  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

L'invention concerne un système d'approche et d'atterrissage pour aéronefs dans lequel le radar d'approche (1) comporte des dispositifs précis de visualisation des cibles mobiles et de poursuite continue, ainsi qu'un dispositif de reconnaissance de plateforme pouvant identifier un répondeur actif (7) et identifier une structure d'atterrissage par exemple une plateforme (5) de forage pétrolier, en l'absence ou en cas de défaillance d'un répondeur. Dans le cas d'un aéronef à ailes fixes un répondeur actif renvoie des informations de localisation d'aéronef et dans le cas d'une plateforme d'hélicoptère un système réflecteur passif peut aussi renvoyer des informations relatives à la position d'un hélicoptère. Le fonctionnement du système consiste à determiner une route, de préférence à partir du point de reconnaissance et de localisation de la plateforme, passant à côté de la plateforme et à partir de laquelle on effectue une approche visuelle.
EP89912268A 1988-10-26 1989-10-26 Systeme d'approche et d'atterrissage pour aeronefs Withdrawn EP0394425A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB888825106A GB8825106D0 (en) 1988-10-26 1988-10-26 Radar navigation system
GB8825106 1988-10-26

Publications (1)

Publication Number Publication Date
EP0394425A1 true EP0394425A1 (fr) 1990-10-31

Family

ID=10645852

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89912268A Withdrawn EP0394425A1 (fr) 1988-10-26 1989-10-26 Systeme d'approche et d'atterrissage pour aeronefs

Country Status (5)

Country Link
EP (1) EP0394425A1 (fr)
CA (1) CA2001488A1 (fr)
DK (1) DK276090A (fr)
GB (2) GB8825106D0 (fr)
WO (1) WO1990004795A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5364716A (en) * 1991-09-27 1994-11-15 Fujitsu Limited Pattern exposing method using phase shift and mask used therefor

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7136012B2 (en) 2003-04-01 2006-11-14 Lockheed Martin Corporation Approach radar with array antenna having rows and columns skewed relative to the horizontal
RU2496131C1 (ru) * 2012-07-10 2013-10-20 Открытое акционерное общество "Раменское приборостроительное конструкторское бюро" (ОАО "РПКБ") Способ управления летательным аппаратом при заходе на посадку
RU2520872C2 (ru) * 2012-07-10 2014-06-27 Открытое акционерное общество "Раменское приборостроительное конструкторское бюро" (ОАО "РПКБ") Комплексная система управления траекторией летательного аппарата при заходе на посадку
US9646506B2 (en) * 2015-09-30 2017-05-09 Honeywell International Inc. Methods and apparatus for managing a premature descent envelope during descent of an aircraft
US9745078B2 (en) 2016-02-01 2017-08-29 Honeywell International Inc. Systems and methods of precision landing for offshore helicopter operations using spatial analysis
US10578733B2 (en) 2016-02-05 2020-03-03 Honeywell International Inc. Low-power X band beacon transponder
US9836064B2 (en) 2016-03-02 2017-12-05 The Boeing Company Aircraft landing systems and methods
RU2620587C1 (ru) * 2016-04-27 2017-05-29 Акционерное общество "Лётно-исследовательский институт имени М.М. Громова" Способ определения координат летательного аппарата относительно взлётно-посадочной полосы
US10684365B2 (en) 2017-08-22 2020-06-16 Honeywell International Inc. Determining a location of a runway based on radar signals
RU2668597C1 (ru) * 2017-11-30 2018-10-02 Андрей Викторович Тельный Способ выявления неисправностей и отказов бортовых измерителей параметров движения и спутниковых навигационных систем движущихся объектов
GB201814241D0 (en) * 2018-08-31 2018-10-17 Airbus Operations Gmbh Deformation sensing system
WO2020089629A1 (fr) * 2018-11-01 2020-05-07 Bae Systems Plc Dispositif de transmission de signal
CN112046770B (zh) * 2020-08-20 2022-07-08 中国南方电网有限责任公司超高压输电公司检修试验中心 一种直升机外挂装置及其安装方法

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
BE481269A (fr) * 1942-03-23
US3243804A (en) * 1963-07-26 1966-03-29 Jr Ira D Smith Four horn sequential lobing radar
US3355733A (en) * 1964-10-19 1967-11-28 Bell Aerospace Corp Designated area instrument landing system
GB1092821A (en) * 1965-02-02 1967-11-29 Richard Thomas Cella Instrument landing system
GB1375221A (fr) * 1970-04-13 1974-11-27
US3739385A (en) * 1970-07-15 1973-06-12 Texas Instruments Inc Mechanically swept radar antenna for use with an aircraft landing monitor system
US3716855A (en) * 1970-07-15 1973-02-13 Texas Instruments Inc Glideslope position detection system for use with an independent aircraft landing monitor
US3754252A (en) * 1971-10-06 1973-08-21 Itt Adaptive array retrodirective landing control responser
US3765019A (en) * 1972-03-20 1973-10-09 United Aircraft Corp Passive radar glide slope orientation indication
SU695586A3 (ru) * 1973-12-14 1979-10-30 Томсон-Цсф (Фирма) Система приборной аэронавигации
US3922674A (en) * 1974-01-24 1975-11-25 Raytheon Co Transponder for use in a radio frequency communication system
US3934250A (en) * 1974-06-07 1976-01-20 The United States Of America As Represented By The Secretary Of The Navy Helicopter blind landing and hover system
FR2445534A1 (fr) * 1978-12-29 1980-07-25 Thomson Csf Dispositif de telemetrie radar air-sol pour systeme de conduite de tir aeroporte et systeme de conduite de tir comportant un tel dispositif
DE3644478A1 (de) * 1986-12-24 1988-07-07 Licentia Gmbh System fuer landehilfe fuer flugzeuge mit eigenem bordradar

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9004795A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5364716A (en) * 1991-09-27 1994-11-15 Fujitsu Limited Pattern exposing method using phase shift and mask used therefor

Also Published As

Publication number Publication date
CA2001488A1 (fr) 1990-04-26
GB2224903A (en) 1990-05-16
GB8924076D0 (en) 1989-12-13
WO1990004795A1 (fr) 1990-05-03
DK276090D0 (da) 1990-11-20
GB8825106D0 (en) 1988-11-30
DK276090A (da) 1990-11-20

Similar Documents

Publication Publication Date Title
US5945926A (en) Radar based terrain and obstacle alerting function
US8576112B2 (en) Broadband multifunction airborne radar device with a wide angular coverage for detection and tracking, notably for a sense-and-avoid function
US4429312A (en) Independent landing monitoring system
US4048637A (en) Radar system for detecting slowly moving targets
CA1139410A (fr) Systeme de controle aeroportuaire
US8265808B2 (en) Autonomous and automatic landing system for drones
US20100256841A1 (en) System and Method for Assisting in the Decking of an Aircraft
WO1997043666A9 (fr) Fonction d'alerte assistee par radar signalant la presence d'obtacles ou indiquant la nature du terrain
EP0394425A1 (fr) Systeme d'approche et d'atterrissage pour aeronefs
US4806932A (en) Radar-optical transponding system
WO2005101052A1 (fr) Procede et systeme d'evitement de relief au moyen d'altimetre radar, de cartes d'altitude numeriques et de radar d'evitement de relief frontal
KR20070092959A (ko) 충돌 경보 및 방지 시스템
US20090243911A1 (en) Method and device for positioning aircraft, such as for automatic guiding during the landing phase
US4939522A (en) Method and system for monitoring vehicle location
EP1749218B1 (fr) Altimetre radar d'helicoptere pour des operations au cours desquelles une charge est portee sous l'helicoptere
US4157544A (en) Hybrid terminal assist landing
US4990921A (en) Multi-mode microwave landing system
US6897803B2 (en) Radar altimeter with forward ranging capabilities
CN86105111A (zh) 改进的仪表着陆系统
Enge et al. Terrestrial radio navigation technologies
RU2192653C1 (ru) Радиолокационная система ближнего действия для предупреждения столкновения с препятствиями маневрирующих на аэродроме летательных аппаратов
US4250505A (en) Independent landing monitor
US6252537B1 (en) Air-to-air guidance system and method of operating same
JP2518530B2 (ja) 折線進入用着陸誘導装置
Davis et al. Development of a portable precision landing system

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19900706

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): BE DE FR GB IT NL SE

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19930501