Automatic guidance system for vehicles by means of dielectric changes in a prerecorded rail-guide

Abstract

System of automatic guidance of vehicles by means of the detection of changes of the dielectric properties in a pre-recorded rail-guide, wherein the dielectric changes are detected by a high resolution radar device and wherein the control system of the vehicle has the ancillary means required to convert it to an auto guidance system characterized in that the system is composed of the following elements: pre-recorded rail-guide (1) information reading device auxiliary means of the control of the vehicle.

Claims

1. System of automatic guidance of vehicles by means of the detection of changes of the dielectric properties in a pre-recorded rail-guide, wherein the dielectric changes are detected by a high resolution radar device and wherein the control system of the vehicle has the ancillary means required to convert it to an auto guidance system characterized in that the system is composed of the following elements: pre-recorded rail-guide (1) information reading device auxiliary means of the control of the vehicle.

2. The system according with claim 1 and characterized in that the rail-guide pre-recorded (1) is composed of a piece with a straight rectangular parallelepiped with various shoulders located un there side faces (7), manufactured in non-conductive material, preferably polymeric and with preferred dimensions of 1.5 cm width and 5 cm deep.

3. The system according with claim 2, and characterized in that in the rail-guide pre-recorded (1) there are different boreholes mechanized, being the preferred form of the boreholes, in the lower area, that of the dihedral that generate borders of dielectric change, while in the upper part, the border created by the dielectric differentiation between the lane material (1) and the surrounding air is treated.

4. The system according with claim 3 and characterized in that the central band dihedrals (4 and 5) are oriented in perpendicular form related to that of the side bands (2 and 3), while the side bands dihedrals (2 and 3) are located at the same distance from the external edges but a different height

5. The system according with claim 4 and characterized in that the dihedrals of the centre band (4 and 5) are located in the central area of the rail-guide, located perpendicular to the external dihedrals and at different heights, to determine at least two logical levels, a logical level 1 as the upper one and a logical level 0 as the lower one.

6. The system according with claim 5 and characterized in that there is a lower border end of trail (6) at the lower part of the rail (1), as well as a border in the upper part (8), being constituted said border by the dielectric differentiation between the material of the rail (1) and the surrounding media

7. The system according with claim 6 and characterized in that the recorded information reading device in the rail-guide uses a radar sensor installed on the underside of the vehicle with an antenna composed of a dual horn Potter type and a lens or reflector that enlighten a 1 square cm area of the road (area defined by 3 Db) and having a resolution at a distance of 1 centimetre, for what it is required the transmission of a frequency signal and a sufficient bandwidth and being the antenna protected by a radome composed of hydrophobic and water repellent material.

8. The system according with claim 7 and characterized in that the radar sensor is preferably a continuous wave radar and modulated frequency LFMCW (Linear Frequency Modulated Continuous Wave Radar) that transmits a chirp signal with a period of 37.5 s.

9. The system according with claim 8 and characterized in that the power level is obtained using a single horn as element of transmission and reception and a subharmonic mixer.

10. The system according with claim 9 and characterized in that applying a local oscillator power of 10 dBm and considering that the product 2 OL has a finite isolation towards the horn of 30 dB, it is achieved a transmission power of 10 W.

11. The system according with claim 10 and characterized in that the radar signal to transmit is obtained through the generation at a low frequency of a chirp signal through a DDS (Direct Digital Synthesizer) and the use of power multipliers, oscillators and subsequent power amplifiers.

12. The system according with claim 11 and characterized in that the signal at the mixer output (beat signal) is amplified by a LNA and subsequently digitized by an ADC (Analog to Digital Converter) that samples at a rate of 8 MS/s. A FPGA applies a FFT (Fast Fourier Transform) to each period of the received signal to obtain the distances profile in each interrogation.

13. The system according with claim 12 and characterized in that the radar sensor will be provided with a blowing element directed toward the enlightened area by the antenna in order to facilitate the evacuation of the stored water on the thread surface of the road where it is installed or on the same surface of the rail-guide y wherein the blowing jet can be heated to be able to melt snow or ice sheets that could de formed.

14. The system according with claim 1, wherein the means required to control the vehicle would be communication means by systems V2V.

15. The system according with claim 1, wherein the means required to control the vehicle would be means to detect the rail-guide.

16. The system according with claim 1, wherein the means required to control the vehicle would be global positioning an navigation means.

17. The system according with claim 1, wherein the means required to control the vehicle would be vehicle and obstacle detection means.

18. The system according with claim 1, wherein the means required to control the vehicle would be inertial systems.

19. The system according with claim 1, wherein the means required to control the vehicle would be incidences and traffic signals communication means.

20. The system according with claim 1 and characterized in that the rail-guide (1) will be installed at the thread layer level of the road where it is to be installed.

21. The system according with claim 1 and characterized in that the rail-guide (1) can be hidden under the thread of the road where it is to be installed and said thread is treated with a water repellent paint.

Description

DESCRIPTION OF THE DRAWINGS

[0049] For a better understanding of the invention attached can be found a sheet of drawings in which the following is appreciated

[0050] FIG. 1. Perspective view and with a side cut in the lane.

[0051] FIG. 2.Lateral cut view of the lane.

[0052] FIG. 3.Perpendicular section view of the lane.

[0053] And in said figures, identical elements have the same reference, among which it can be distinguished: [0054] (1).rail-guide, [0055] (2).dihedral from the right side band [0056] (3).dihedral from the left side band, [0057] (4).dihedral in the logic level 1, [0058] (5).dihedral in the logic level 0, [0059] (6).border at the end of the trail, [0060] (7).collocation shoulders, [0061] (8).upper border non visible, [0062] (9).logic level 1, [0063] (10).logic level 0.

[0064] FIG. 4.Diagram that represents the pre-recorded message that may exist on the road, namely, the radar sensor detects the borders in the distances profile, being configured as a positioning system, detecting the vehicle on the rail-guide, the lateral drift and the longitudinal advance.

[0065] FIG. 5.Diagram presenting the auxiliary means of the control of the vehicle.

[0066] The necessary means to control the vehicle would be at least: [0067] communication means by systems V2V, [0068] means to detect the rail-guide, [0069] global positioning an navigation means, [0070] vehicle and obstacle detection means. [0071] inertial systems, [0072] incidences and traffic signals communication means.

PREFERRED EMBODIMENT OF THE INVENTION

[0073] The proposed invention refers to a system of automatic guidance of vehicles by means of the detection of changes of the dielectric properties in a pre-recorded rail-guide, wherein the dielectric changes are detected by a high resolution radar device and wherein the control system of the vehicle has the ancillary means required to convert it to an auto guidance system.

[0074] More particularly, the system is composed of the following elements: [0075] pre-recorded rail-guide (1) [0076] information reading device [0077] auxiliary means of the control of the vehicle.

[0078] The pre-recorded rail-guide (1) is composed of a piece with a straight rectangular parallelepiped, with various shoulders on their sides (7) for correct attachment and its is manufactured in non conductive material, preferably polyethylene,

[0079] The rail-guide (1) will be installed level with the firm of the road, although it can optionally be hidden under a layer of asphalt treated with a layer of hydrophobic material.

[0080] The preferred dimensions of the rail-guide (1) are 1.5 cm wide by 5 cm deep.

[0081] Inside, the boreholes will be mechanized, being the boreholes preferred form that of dihedrals, since the planes of the dihedrals increase the reflected signal, facilitating therefore its detection.

[0082] The situation of the dihedrals that create the borders is the following:

[0083] The dihedrals of the centre band (4 and 5) are oriented perpendicular to the side strips (2 and 3), since in the first case it is pretended obtaining a variable signal level according to the longitudinal advance of the vehicle along the track and in the second case, it is obtained based on the lateral drift thereof by way of border.

[0084] The dihedrals of the side strips (2 and 3) are located at the same distance from the outer edges but at different heights, so the border established in each end is easily identified.

[0085] The dihedrals of the centre band (4 and 5) are located in the central area of the lane, located perpendicular to the external dihedrals and at different heights, to determine at least two logical levels, a logical level 1 the upper one and a logical level 0 the lower.

[0086] There is also a lower border at the end of track (6) in the bottom, as well as a border at the upper part (8), being the lower part formed by a borehole and the upper one (8) by the dielectric difference between the material of the rail (1) and the air or the asphalt (in the case of the rail-guide buried).

[0087] The preferred way to code the rail message is based on a binary codification. The logic 1 is associated with the detection of an higher dihedral and the 0 with that of a lower one.

[0088] In the code of 1 and 0s the information about the coordinates by which passes the road can be recorded. Using the 56 bit decoding it is possible to identify uniquely each square decimetre of the ground surface.

[0089] With the codes of randomization as a help, it is possible to avoid the sequences of 1 or 0 long that may cause ambiguity in the measure.

[0090] Once the vehicle has travelled 0.56 m and knows the exact point (with an accuracy of less than 1 cm in the three axes xyz), the number of bits to increase by cm the value of the position can be counted (which will be updated again every 0.56 meters).

[0091] That is to say, in less than 0.56 meters of trail decoded (or even at a lower distance), detailed information about the vehicle circulating can be obtained. It should be noted that the guidance system has stored the sequence of positions through which the road passes. This fact offers advantages to the receiver, allowing the reduction of the likelihood of a reading error.

[0092] The guidance system of the vehicle may have loaded in its memory the morphology of the road by which it passes. This way, the guidance system of the vehicle can anticipate changes in the direction; adapt the speed in certain areas o increase the engine power to face a high slope.

[0093] In addition to working with very low powers (even of tens of microwatios), the possibility of interference between systems, even of the same model, is not possible. This is due to the high bandwidth transmitted. The interference with systems that operate at different frequencies is discarded.

[0094] The radar system can contain 2 antennas (transmitter o receiver) or only one (through the use of circulators or even by taking advantage of the local oscillator signal of the mixer that is transmitted by the receiver horn due to the finite isolation between the door OL and the horn, [0095] information reading device.

[0096] To read the information of the rail-guide, a a radar sensor installed preferably to the underside of the vehicle is used.

[0097] The required antenna is an antenna electrically large to limit the size of the track

[0098] To obtain an enlightened area of about 1 square cm (defined area at 3 dB) and to have a resolution related to the distance of 1 cm, it is required to transmit a signal centred on 340 GHz (window of atmospheric attenuation) with a bandwidth of 34 GHz.

[0099] With this bandwidth, a resolution at a theory resolution is obtained (capacity to solve two near borders) defined by the equation

[00001]$.Math..Math.R=\frac{C}{2.Math..Math.B}=4.4.Math..Math.\mathrm{mm}$

wherein c is the speed of light in the media and B the bandwidth transmitted.

[0100] The antenna can be a horn of high gain or its combination a lens or a reflector o concentrate more effectively the energy radiated in the volume of interest.

[0101] The antenna is protected by a radome whose material is hydrophobic and water repellent.

[0102] The preferred radar sensor is a continuous wave radar and modulated frequency (Linear Frequency Modulated Continuous Wave Radar) that transmits a chirp signal with a period of 37.5 ps. With this ramp period, a vehicle circulating at 120 Km/h will interrogate 16 times between 2 consecutive boreholes separated 1 cm.

[0103] The power level transmitted is of the order of a few dozen W. This power level is easy to obtain using a single horn as element of transmission and reception and a subarmonic mixer,

[0104] Applying a local oscillator power of 10 dBm and considering that the product 2 OL has a finite isolation towards the horn of 30 dB, it is achieved a transmission power of 10 W.

[0105] The radar signal to transmit is obtained through the generation at a low frequency of a chirp signal through a DDS (Direct Digital Synthesizer) and the use of power multipliers, oscillators and subsequent power amplifiers.

[0106] The signal at the mixer output (beat signal) is amplified by an LNA (Low Noise Amplifier), filtered and subsequently digitized by an ADC (Analog to Digital Converter) that samples at a rate of 8 MS/s

[0107] A FPGA (Field Programmable Gate Array) applies a FFT (Fast Fourier Transform) to each period of the received signal to obtain the distances profile of each interrogation.

[0108] The rest of the logic of the systems that have to be implemented can be performed using ASICs, FPGAs, PCs etc.

[0109] At the work frequency proposed, the water presents a high electromagnetic absorption capacity.

[0110] So the radar signal can penetrate the firm of the track and reach the polymer rail-guide, it is necessary the absence of water between the radar and the propagation direction of the waves.

[0111] Therefore, the presence of water on the surface of the track where the rail-guide is located has to be avoided or in the same rail-guide when it is positioned at the circulation road level.

[0112] In this case, it is proposed that the profile of the rail-guide should have a slight slope towards the sides of the road to facilitate the evacuation of the water which could fall.

[0113] Both the rail-guide and the tread of the track that can cover it can be treated with repellent and hydrophobic paints.

[0114] The radar sensor may be fitted with a blowing element to point in the area illuminated by the antenna in order to facilitate the evacuation of the water on the surface.

[0115] In addition, the blowing jet may be heated to be able to melt snow or ice sheets that can be formed.

[0116] Having sufficiently described the nature of the invention, as well as how to be implemented, it must be stated that the provisions referred to above and shown in the accompanying drawings can be modified in detail provided they do not alter the fundamental principles set out in the above paragraphs and summarized in the following claims.