Methods Circuits Devices Assemblies Systems and Related Machine Executable Code for Providing and Operating an Active Sensor on a Host Vehicle

Abstract

The present application relates to active sensors for vehicles to detect possible obstacles. The application teaches an obstacle detection system for a host vehicle which includes: (a) a vehicle navigation system comprising: (a) a vehicle trajectory detector, (b) a geolocator circuit, and (c) a clock output; (b) an energy emitting type sensor (active sensor) to transmit energy (Tx Signal) towards a direction in a field of view of said active sensor and to receives a Tx Signal reflection (Rx Signal) reflected off of objects present within the field of view, wherein the field of view is directed towards a front of the host vehicle and said active sensor is digitally configurable to operate according to at least two different operating regimes; and (c) an active sensor controller configured to select an operating regime for said digitally configurable active sensor based on a ruleset which factors one or more navigation system outputs provided by said vehicle navigation system.

Claims

1. An obstacle detection system for a host vehicle, said system comprising: a vehicle navigation system comprising: (a) a vehicle trajectory detector, (b) a geolocator circuit, and (c) a clock output; an energy emitting type sensor (active sensor) to transmit energy (Tx Signal) towards a direction in a field of view of said active sensor and to receives a Tx Signal reflection (Rx Signal) reflected off of objects present within the field of view, wherein the field of view is directed towards a front of the host vehicle and said active sensor is digitally configurable to operate according to at least two different operating regimes; and an active sensor controller configured to select an operating regime for said digitally configurable active sensor based on a ruleset which factors one or more navigation system outputs provided by said vehicle navigation system.

2. The system according to claim 1, wherein said active sensor is of a sensor type selected from the group consisting of: (1) Radar, (2) Lidar and (3) Sonar.

3. The system according to claim 1, wherein the ruleset of said active sensor controller factors one or more navigation system outputs selected from the ground consisting of: (a) present time; (b) host vehicle location; and (c) host vehicle trajectory.

4. The system according to claim 3, wherein said active sensor controller is configured to adjusts a characteristic of the Tx Signal of said active sensor based on the one or more navigation system outputs.

5. The system according to claim 4, wherein the adjustable characteristic of the Tx Signal is selected from group consisting of: (1) transmission modulation or coding regime of the Tx Signal, (2) a transmission direction or scanning pattern of the Tx Signal, (3) transmission timing (TDM) of the Tx Signal, and (4) transmission polarization of the Tx Signal.

6. The system according to claim 5, wherein said active sensor controller is configured to adjusting Rx Signal receiver circuit operation of said active sensor corresponding to any Tx Signal adjustments.

7. The system according to claim 1, wherein said active sensor is a multi-modulation radar and said active sensor controller causes the radar to switch between two or more operating standards selected from the group consisting of: (1) Frequency Modulated Constant Wave (FMCW), (2) Orthogonal Frequency Division Multiplexing (OFDM), and (3) Pulse Doppler, and Step Frequency or Frequency Hopping (SF/FH).

8. The system according to claim 1, further comprising an active sensor output processor functionally associated with said active sensor and adapted to process active sensor output signals from said active sensor at least partially based on a ruleset which factors one or more system outputs provided by said vehicle navigation system.

9. The system according to claim 8, wherein the ruleset of said active sensor output processor factors one or more navigation system outputs selected from the ground consisting of: (a) present time; (b) host vehicle location; and (c) host vehicle trajectory.

10. The system according to claim 9, wherein processing of active sensor output signals includes detecting an alert condition, maneuvering the host vehicle and/or stopping the host vehicle.

11. The system according to claim 10, wherein said navigation system is functionally associated with a digital road map and wherein active sensor output processing includes detecting obstacles around a host vehicle and estimating a position of the obstacle within a reference frame defined by the road map.

12. The system according to claim 11, wherein active sensor output processing further includes estimating a velocity vector and trajectory of the obstacle within the reference frame defined by the road map.

13. The system according to claim 12, wherein active sensor output processor is further adapted to generate an alert notification if the estimated trajectory of the detected obstacle and the trajectory of the host vehicle intersect.

14. The system according to claim 1, wherein said active sensor is adapted to transmit and receive electromagnetic signals within each of two or more frequency bands and said controller is adapted to select in which band the active sensor is operating based on information provided by said navigation system.

15. The system according to claim 14, wherein said active sensor is adapted to operate within different frequency bands at different angles relative to a host vehicle.

16. The system according to claim 15, wherein said controller configures said active sensor to operate in a first frequency band at angles towards the left side of a host vehicle and to operate in a second frequency band at angles towards the right side of a host vehicle.

17. The system according to claim 16, wherein said controller configures said radar to swap or otherwise alternate directions of the first and second bands of operation, such that the first band is used to operate towards the right side of a host vehicle and the second band is used to operate towards the left side of a host vehicle.

18. The system according to claim 16, wherein said controller configures said radar to adjust the frequencies of each of the first and second bands of operation.

19. The system according to claim 8, wherein said active sensor output processor is further adapted to distinguish between a received (Rx) signal which originated as a Transmission (Tx) from by said active sensor and a received signal which originated from an interfering signal source.

20. The system according to claim 8, wherein said active sensor output processor or said active sensor controller are configured to mitigate interference to the operation of said active sensor from external signal sources.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0036] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[0037] FIG. 1A is a top view illustration of an exemplary vehicle including a proposed mesh of sensors of deferring sensor types and working together as an integrated sensor solution to provide advanced driver assistance (ADAS) functionality and optionally to provide input to an autonomous vehicular control/navigation control system;

[0038] FIG. 1B is a photograph of an actual autonomous vehicle being operated in Berlin and utilizing a variety of shortrange, midrange and long-range sensors as input to the autonomous vehicle drive control system;

[0039] FIG. 1C is a side illustration of vehicle with active forward scanning sensors, each with a different coverage area at least partially defined as a function of range from the vehicle;

[0040] FIG. 2A is a functional block diagram of an exemplary vehicular radar with obstacle detection system according to advanced driver assisted embodiments of the present invention;

[0041] FIG. 2B is a functional block diagram of an exemplary vehicular radar with obstacle detection system according to autonomous vehicle embodiments of the present invention;

[0042] FIGS. 3A & 3B are exemplary antenna element array configurations, for Tx and Rx chains respectively, in accordance with embodiments of the present invention;

[0043] FIG. 3C shows a generic radar signal parameter detection matrix used to estimate detected object characteristics, such as location, velocity and spatial direction;

[0044] FIGS. 4A to 4C relate to FMCW radars usable in conjunction with embodiments of the present invention, wherein: (a) FIG. 4B are frequency domain and amplitude domain signal graphs illustrating FMCW radar transmission (Tx) waveforms; (b) FIG. 4C is a frequency domain signal graph illustrating range and doppler shift indicators within a return (Rx) FMCW radar signal; and (c) FIG. 4C is a functional block diagram of an exemplary FMCW radar usable in accordance with embodiments of the present invention;

[0045] FIGS. 5A to 5C relate to OFDM radars usable in conjunction with embodiments of the present invention, wherein: (a) FIG. 5A is a functional block diagram of an exemplary OFDM radar usable in accordance with embodiments of the present invention; (b) FIG. 5B is a frequency domain signal graph illustrating the waveform of an exemplary Tx OFDM packet; and (c) FIG. 5C is a spectrogram illustrating an exemplary OFDM radar reflection from targets within an inspection zone of an OFDM radar in accordance with embodiments of the present invention;

[0046] FIGS. 6A and 6B relate to Pulse Doppler Radar usable in conjunction with embodiments of the present invention, wherein: (a) FIG. 6A is a signal graph illustrating the stepped frequency waveform of this radar type's Tx signal; and (b) FIG. 6B is a spectrogram illustrating an exemplary Rx radar reflection from two targets within an inspection zone of the radar which is illuminated by 144 transmitted Tx pulses in accordance with embodiments of the present invention;

[0047] FIGS. 7A and 7B relate to an exemplary automotive navigation system in accordance with embodiments of the present invention, wherein: (a) FIG. 7A shows a functional block diagram of a vehicular navigation system including a geolocator; and (b) FIG. 7B is an illustration depicting how a navigation system according to embodiments of the present invention estimates a host car's future point location based on road information within a stored map rather than a straight trajectory from a current point based on a current velocity vector;

[0048] FIG. 7C is a functional block diagram of an autonomous driving system receiving multifactor input including active sensor outputs, digital maps and location/velocity information according to embodiments of the present invention;

[0049] FIGS. 8A & 8B illustrate an exemplary FMCW radar and the (cross) interference which the radar may experience from signals originating from of FMCW radars. FIG. 8A is a simplified block diagram while FIG. 8B includes signal graphs illustrating the aforementioned interference;

[0050] FIGS. 9A & 9B are signal graphs illustrating issues related with interference in pulsed radar systems;

[0051] FIG. 10 relates to a method of spatial direction processing associated with ranging and doppler-shift measurement associated with an object being detected in accordance with embodiments of the present invention;

[0052] FIG. 11A to 11C illustrate an exemplary radar chip (FIG. 11A), and exemplary spatially encoded BPM-MIMO output waveform of the chip (FIG. 11B), and antenna arrays (Tx and Rx) corresponding to the chip and its Tx & Rx signal paths.

[0053] FIG. 12. Illustrates how circular polarization can be used to obtain signal orthogonality/isolation between a transmission from a transmitted antenna in a direction of a receiver antenna facing the transmitting antenna; and

[0054] FIGS. 13A and 13B illustrate two separate computational methods of mitigating the impact of signal interference from nearby interference sources, including by using a Kalman filter to eliminate a radar ghost.

[0055] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE FIGURES

[0056] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.

[0057] Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as processing, computing, calculating, determining, or the like, may refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices.

[0058] In addition, throughout the specification discussions utilizing terms such as storing, hosting, caching, saving, or the like, may refer to the action and/or processes of writing and keeping digital information on a computer or computing system, or similar electronic computing device, and may be interchangeably used. The term plurality may be used throughout the specification to describe two or more components, devices, elements, parameters and the like.

[0059] Some embodiments of the invention, for example, may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment including both hardware and software elements. Some embodiments may be implemented in software, which includes but is not limited to firmware, resident software, microcode, or the like.

[0060] Furthermore, some embodiments of the invention may take the form of a computer program product accessible from a computer-usable or computer-readable medium providing program code for use by or in connection with a computer or any instruction execution system. For example, a computer-usable or computer-readable medium may be or may include any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.

[0061] In some embodiments, the medium may be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system (or apparatus or device) or a propagation medium. Some demonstrative examples of a computer-readable medium may include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), any composition and/or architecture of semiconductor based Non-Volatile Memory (NVM), any composition and/or architecture of biologically based Non-Volatile Memory (NVM), a rigid magnetic disk, and an optical disk. Some demonstrative examples of optical disks include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-RW), and DVD.

[0062] In some embodiments, a data processing system suitable for storing and/or executing program code may include at least one processor coupled directly or indirectly to memory elements, for example, through a system bus. The memory elements may include, for example, local memory employed during actual execution of the program code, bulk storage, and cache memories which may provide temporary storage of at least some program code in order to reduce the number of times code must be retrieved from bulk storage during execution.

[0063] In some embodiments, input/output or I/O devices (including but not limited to keyboards, displays, pointing devices, etc.) may be coupled to the system either directly or through intervening I/O controllers. In some embodiments, network adapters may be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices, for example, through intervening private or public networks. In some embodiments, modems, cable modems and Ethernet cards are demonstrative examples of types of network adapters. Other functionally suitable components may be used.

[0064] Turning now to FIG. 1A, there is shown a top view illustration of an exemplary vehicle including a proposed mesh of sensors of deferring sensor types and working together as an integrated sensor solution to provide advanced driver assistance (ADAS) functionality and optionally to provide input to an autonomous vehicular control/navigation control system. While FIG. 1B is a photograph of an actual autonomous vehicle being operated in Berlin and utilizing a variety of shortrange, midrange and long-range sensors as input to the autonomous vehicle drive control system. FIG. 1C is a side illustration of a vehicle with active forward scanning sensors, each with a different coverage area at least partially defined as a function of range from the vehicle and possibly direction. Details relating to the various, short, mid and long-range sensors reference and illustrated in these figures can be found in the background section.

[0065] Turning now to FIG. 2A, there is a functional block diagram of an exemplary vehicular radar with obstacle detection system according to advanced driver assisted embodiments of the present invention. FIG. 2B is a functional block diagram of an exemplary vehicular radar with obstacle detection system according to autonomous vehicle embodiments of the present invention. Both embodiments include Tx Signal and Rx Signal chains, including optional MIMO and/or Beamforming networks with associated antenna arrays. Both Figs include a controller, a navigation system and a Rx output processor, all of which operate in accordance with the various embodiments described herein. The embodiments in FIGS. 2A and 2B differ only on the type of interface they show in connection with their respective host vehicles. The embodiment of FIG. 2A sends notifications to a driver while the embodiment of FIG. 2B interacts with a Host Vehicles autonomous controller/guidance.

[0066] FIGS. 3A & 3B are exemplary antenna element array configurations, for Tx and Rx chains respectively, in accordance with embodiments of the present invention with target direction estimation. With regard to the AESA antenna of FIG. 3A, it is usable for target direction estimation. Direction is estimated by combination of AESA.sup.1 antenna. The AESA antenna consists of plurality of elements, usually organized in rows and columns. The antenna operation equals the time delay of waves coming from specific direction, which results in summing up the input of output of those elements. AESA, consisting of N elements, has maximal gain of N times the gain of each element. AESA beam width or direction resolution.sup.2, is defined by

[00001]${}_{\mathrm{beamwidth}}=\frac{k.Math.}{D}.Math.\left(\mathrm{redians}\right)k.Math.\frac{57}{D.Math.\text{/}.Math.}.Math.\left(\mathrm{degrees}\right),$

where 0.5k1, D is the antenna length (in the same axis as ) and is the wavelength. The distance between elements is

[00002]$\frac{1}{1+\sin .Math..Math.}.Math.\left(k\right),$

where the boresight scanning width is. (In our case 30, which produces k=0.67). .sup.1 AESAactive electronically scanned array (AESA), is a type of phased array antenna,.sup.2 Resolution in here is defined by the required distance between two reflecting objects for distinction of both.

[0067] AESA is a MISO.sup.3 antenna. In MISO systems, the spatial location of the reception beams tilting is agnostic to the transmitter location. .sup.3 MISOmany in single out.

[0068] FIG. 3B shows a MIMO.sup.4 technology array where radar's based on MIMO systems use several transmitters and the target location is estimated for each transmitter separately. The result is significant reduction of the number of antenna elements. Full AESA with MN elements beam width is achievable with MIMO array of M+N elements, according to embodiments of the present invention.

Note that the symmetry in wave equations in wave directions allows swapping of transmitters and receivers.
MIMO concept is shown in FIG. 1MIMO array example. The inner circles represent transmitting elements. There are 19 transmitting elements and 3 receiving elements [0069] OOrigin of transmission array. Contains Xmtr & Rcvr. [0070] O.sub.vposition of Receiver at the center of virtual array [X.sub.ov, Y.sub.ov] [0071] eposition of a Tx element, at [X.sub.e, Y.sub.e] [0072] e.sub.vvirtual position of a Rx element, at [X.sub.ev, Y.sub.ev] relative to O.sub.v
The position of e relative to origin equals to the position of e.sub.v relative to O.sub.v.
Distance is translated to phase by multiplying by k (=2/) [0073] r.sub.e: difference of target's distance of e and origin [0074] r.sub.ev: difference of target's distance of e.sub.v and origin [0075] r.sub.ov: difference of target's distance of O.sub.v and origin [0076] Symmetry: note that [X.sub.e, Y.sub.e]=[X.sub.ev, Y.sub.ev], assuming target at FIG. 1MIMO ARRAY EXAMPLE infinity [0077] Position of virtual element in the original axis: e.sub.v [X.sub.eX.sub.ov, X.sub.eY.sub.ov] [0078] Difference of distance of target at (,) of virtual element e.sub.v and orgin: (X.sub.eX.sub.ov)cos cos +(Y.sub.eY.sub.ov)sin cos =r.sub.ev=r.sub.er.sub.ov [0079] The difference of distance of target at (, ) of virtual origin o.sub.v and transmission element e. The virtual elements phase around o.sub.v can be obtained by measuring the phase of each of the transmitters [0080] Conclusion: the phase difference of e.sub.v and o.sub.v is the same to phase and phase (o). 3 receivers and 19 transmitters produce same resolution as AESA with 57 elements (193) .sup.4 MIMOmany in many out, used in radar and communication. In radar, it is used for reduction of AESA elements

[0081] There is an assumption that the receivers can identify and separate the multiple transmissions. There are 3 methods of separation: [0082] 1. Time domain: sequential transmission (losing energy). [0083] 2. Frequency domain (reduce available spectrum) [0084] 3. Phase domain, using Walsh-Hadamard sequences or other binary orthogonal sequences.

[0085] In long range radar, the possible series length is much larger than the number of required orthogonal transmitters. For instance: PRI 5 of 30 microseconds within CPI of 50 milliseconds generates over 1600 series for 12 transmitters, there over 130 orthogonal codes combination, that could serve other radars. .sup.5 PRIpulse repetition interval

[0086] The processing of the coded signals may be performed using butterfly machine of ones and zeros. Most used sequence is Walsh-Hadamard series (WHS) and transform. (See FIG. 3C). The method is used in Wi-Fi 6 MIMO systems.

[0087] The WHS have the following features: [0088] Its elements are merely 1. [0089] The transform matrix is based on butterflies, which allows decoding several inputs simultaneously. [0090] Coding and decoding matrices are equal.

[0091] FIGS. 4A to 4C relate to FMCW radars usable in conjunction with embodiments of the present invention, wherein: (a) FIG. 4B are frequency domain and amplitude domain signal graphs illustrating FMCW radar transmission (Tx) waveforms; (b) FIG. 4C is a frequency domain signal graph illustrating range and doppler shift indicators within a return (Rx) FMCW radar signal; and (c) FIG. 4A is a functional block diagram of an exemplary FMCW radar usable in accordance with embodiments of the present invention.

[0092] FMCW radars as shown in FIG. 4A are the most common as long-range sensors. The principal of the radars is transmitting a continuous carrier modulated by a periodic function such as a sinusoid or saw tooth wave to provide range data OFDM Radar (FIG. 4B). Range is estimated from the difference of the echo frequency and the local oscillator frequency. (Beat frequency). The range and the radial frequency are derived from the beat frequency, as shown in the following:

[00003]$r=\frac{{\mathrm{cT}}_s}{4.Math.B_{\mathrm{sweep}}}.Math.\left(f_{\mathrm{up}}+f_{\mathrm{dn}}\right)$$\stackrel{.}{r}=\frac{}{4}.Math.\left(f_{\mathrm{up}}-f_{\mathrm{dn}}\right)$

[0093] The structure of OFDM radar according to embodiments of the present invention may include multiple receiving antennas that are used for horizontal narrow beams generation, and AESA antenna for transmission elevated beams generation. The FMCW radars are coherent (phase continuous), hence additional FFT is performed on the detected ranges for obtaining range derivative, i.e. Doppler shift. Advantages of FMCW radars include simplicity and low cost.

[0094] Regardless of the radars type, the processing of the target's direction starts from the range/Doppler unambiguous plan. Each of the reception antennas, builds several plans, according to the number of transmitters. Separation of the transmissions is done by multiplying with inverse Hadamard matrix. Let us assume that the transmission AESA scans the space. Obviously, its beam is much wider. We sum up the vectors at specific direction which generates a narrow beam, thus improving the SNR and hence the radar detection range. The fine beams, within the gross transmission beam are generated simultaneously using FFT. The process is depicted in FIG. 4C. The layers represent the range Doppler unambiguous plan of each combination of transmitter/receiver. There are N.sub.receiversM.sub.transmitters, Therefore NM unambiguous planes. The direction is calculated by summing up the values with proper phase shifting according to the required spatial direction. If the antennas elements are ordered properly, the range distance (phase) between adjacent elements will be fixed, which allows summation of several beams using FFT.

[0095] Turning now to FIGS. 5A to 5C, they relate to OFDM radars usable in conjunction with embodiments of the present invention, wherein: (a) FIG. 5A is a functional block diagram of an exemplary OFDM radar usable in accordance with embodiments of the present invention; (b) FIG. 5B is a frequency domain signal graph illustrating the waveform of an exemplary Tx OFDM packet; and (c) FIG. 5C is a spectrogram illustrating an exemplary OFDM radar reflection from targets within an inspection zone of an OFDM radar in accordance with embodiments of the present invention.

[0096] OFDM is another option for wireless communication and long-range radar for autonomous car operation in accordance with embodiments of the present invention. It has inherent advantage of assimilation of two technologies that assist each other. The waveform contains plurality of orthogonal frequencies called subcarriers. In regular Wi-Fi protocol, the distance between the subcarriers is exactly an even fraction of the packet length. The energy is sent in pulses, called packets that are few microseconds long. The block diagram of the radar follows regular OFDM communication system, with multiple antennas. The digital symbols are divided between the subcarriers. The subcarriers vector is converted into a serial vector using IFFT. In reception, the inverse process is applied. The subcarriers are converted into a vector using FFT.

[0097] FIGS. 6A and 6B relate to Pulse Doppler Radar usable in conjunction with embodiments of the present invention, wherein: (a) FIG. 6A is a signal graph illustrating the stepped frequency waveform of this radar type's Tx signal; and (b) FIG. 6B is a spectrogram illustrating an exemplary Rx radar reflection from two targets within an inspection zone of the radar which is illuminated by 144 transmitted Tx pulses in accordance with embodiments of the present invention.

[0098] Pulse Doppler radars are most commonly used for alerts of aerial, naval and ground based targets. Different from FMCW and OFDM radars, the transmission and reception do not overlap. The advantage is common reception and transmission antennas. The disadvantage is the inability to receive during transmission timeshort blind range. A required minimal range of 15 m (50 nanoseconds) imposes range resolution, which is insufficient. The proposed solution according to embodiments of the present invention is a method of frequency hopping. Step-frequency with stretch processing is especially attractive in radar sensors for short ranges like automotive radar, for two reasons: [0099] i. The simplicity of the processor, hence its low cost [0100] ii. Since the typical delay could be shorter than pulse duration, and since the receiver is turned off during transmission, not all the reflected signal is available to the receiver.

[0101] Additionally, turning off the receiver during transmissions allows using some antennas for MIMO. The waveform is described in FIG. 6A. The range resolution is achieved by the spread of the waveform, from the lowest to the highest frequency.

[00004]$.Math..Math.r\frac{c}{2.Math.\mathrm{BW}}=\frac{c}{2.Math.\left(F_{\mathrm{high}}-F_{\mathrm{low}}\right)}$

[0102] The echoes in each frequency are reordered after the reception, from the lowest to the highest frequency. The result is similar to sampled FMCW, with much better side lobes performance. The result is low side lobe in the ambiguity plane (range-Doppler), as shown in FIG. 6B. The frequency stepping is usually done with DDS.sup.6. Another feature is the separation between transmitters: shuffling the starting point of the Costas sequence between the transmitters, separate the echoes among them. .sup.6 DDSDirect Digital Synthesizer

[0103] FIGS. 7A and 7B relate to an exemplary automotive navigation system in accordance with embodiments of the present invention, wherein: (a) FIG. 7A shows a functional block diagram of a vehicular navigation system including a geolocator; and (b) FIG. 7B is an illustration depicting how a navigation system according to embodiments of the present invention estimates a host car's future point location based on road information within a stored map rather than a straight trajectory from a current point based on a current velocity vector.

[0104] FIG. 7C is a functional block diagram of an autonomous driving system receiving multifactor input including active sensor outputs, digital maps and location/velocity information according to embodiments of the present invention.

[0105] FIGS. 8A & 8B illustrate an exemplary FMCW radar and the (cross) interference which the radar may experience from signals originating from of FMCW radars. FIG. 8A is a simplified block diagram while FIG. 8B includes signal graphs illustrating the aforementioned interference.

[0106] In the block diagram of FMCW FIG. 8A, a chirp signal is modulated by the VCO. The transmitted signal frequency is modulated up and down. The received signal lags in time, according to the distance from the radar to the target. Multiplying the transmitted signal by the received signal generated DC signal, which is relative to the distance. The up-down modulation enables differentiating the range and the Doppler shift. FMCW radar, operating in the frequency band, generates a ghost echo, which must be identified and omitted. The interference mechanism is different in case the interference is different, in case of FMCW signal that is modulated with different slope than the interfered signal. Same phenomenon happens with OFDM radar interference.

[0107] FIGS. 9A & 9B are signal graphs illustrating issues related with interference in pulsed radar systems. The specifics of that interference mechanism may be found the provisional application incorporated herein by reference in its entirety.

[0108] FIG. 10 relates to a method of spatial direction processing associated with cleaning ghosts from ranging and doppler-shift measurement associated with an object being detected in accordance with embodiments of the present invention. Independent of the radar type, processing the echoes results in unambiguous plane, for each receiving antenna. The spatial direction is calculated thereafter. Since each radar type, uses some method of orthogonality, the interference of different type of radar results in spread of interfering radar energy all over the unambiguous plane. As we see in FIG. 10 range/Doppler is generated independently of the radar type. If the same type of radar is interfering, the result will be appearances of ghostsunreal targets that are generated by reflections of the interfering radar and directly by the interfering radar waveform. Ghosts are generated by a neighboring same type of radar direct radiation. The energy could be picked up through back lobe and side lobes. Embodiments of the present invention cleans up the unambiguous plan from those interferences.

[0109] FIG. 11A to 11C illustrate an exemplary radar chip (FIG. 11A), and exemplary spatially encoded BPM-MIMO output waveform of the chip (FIG. 11B), and antenna arrays (Tx and Rx) corresponding to the chip and its Tx & Rx signal paths. More detail may be found in the provisional application incorporated by reference.

[0110] FIG. 12. Illustrates how circular polarization can be used to obtain signal orthogonality/isolation between a transmission from a transmitted antenna in a direction of a receiver antenna facing the transmitting antenna. This is applicable to mitigate interference signals coming from the opposite side of the road. The power generated by radars coming from the opposite side of the road will cause saturation the all radars in this side of the road. The reception power drops according to r.sup.2, compared to regular reflections that drop according to r.sup.4.

[0111] The ratio between the strongest possible signal (car in the opposite side of the road) to the weakest signal (250 m ahead) is:

[00005]$\frac{P_{\mathrm{strong}}}{P_{\mathrm{weak}}}=\frac{P_T.Math.G_t.Math.G_r.Math.{}^2}{{\left(4.Math.\right)}^2.Math.r_{\min }^2}.Math.\text{/}.Math.\frac{P_T.Math.G_t.Math.G_r.Math.{}^2.Math.}{{\left(4.Math.\right)}^3.Math.r_{\max }^4}=\frac{4.Math..Math.r_{\max }^4}{.Math.r_{\min }^2}$

In dB

[0112] [00006]$\mathrm{AGC}=\frac{P_{\mathrm{strong}}}{P_{\mathrm{weak}}}=11+96+5-0-20=92.Math..Math.\mathrm{dB}$

[0113] Assuming RCS of 1 sqrm, and calculation is done per single reception. The result is a need for applying AGC (reference design has 24 dB AGC), but it reduces sensitivity. There are 2 methods for mitigating this interference: [0114] 1. Use slant 45 or circular polarity. The polarity becomes orthogonal in opposite directions. The practical isolation is less than 30 dB, due to inaccuracy in generating cross polarization, cars exact direction etc. Generation of both circular and slant 45 polarization, with simple antenna elements such as patch or slot, is implemented by spatial summation of 2 optional elements, either with same phase (slant 45) or with /4 difference. [0115] 2. Simple spectral separation. In mobile phones, reception and transmission use separate spectrum. In radars, we offer to separate the transmissions per driving direction. For example: North-West direction uses lower band and East-South uses higher band or 1 GHz of the available 4 will be allocated to driving direction (N, W, S or E). The GPS computes the diving direction.

[0116] FIGS. 13A and 13B illustrate two separate computational methods of mitigating Ghost interference, possibly from nearby interference sources. The term Ghosts Images in radars refers to the appearance of targets on radar screen that have not been generated from radar beams reflections, or irrelevant targets.

In the RadarINS system, there are several potential situations that could generate ghosts: [0117] 1. Targets reflections that produce no threat. Using the INS and road map eliminate the detect ghost [0118] 2. Ghosts are easily detected by shutting down the radar for a short period.

[0119] The DFS/DOA method is explained below with reference to FIG. 13A: [0120] 1. The radar on car is moving forward at speed of V, obtained from the INS. [0121] 2. The radar measures both the Doppler shift and the DOA (direction) to the possible target. [0122] 3. The accurate measurement of both the direction () and the Doppler shift f.sub.Doppler must comply with the equation:

[00007]$f_{\mathrm{Doppler}}=\frac{2.Math.v.Math.\sin .Math..Math.}{}.$

If it does not comply, its a ghost,

[0123] Time Binary Sequence Algorithm for mitigating ghosts is applicable to the active sensor controller or sensor output according to embodiments of the present invention. Binary Phase modulation is a necessity for generation the transmission orthogonality in the MIMO process. The main features relevant to interference mitigation: [0124] 1. Orthogonality. Their cross correlation is 1, where their summation reaches 1000, over 60 dB in power. It allows differentiating between the transmitters in the AESA array. [0125] 2. Interferences that are other types of radars are expanded all over the spectrum, which increases noise but does not generate false alarms. [0126] 3. The number of the series is half of their length

[0127] The number of available series in limited and obviously, cannot support all radars.

[0128] Orthogonality process: if ghosts flood the radar, select new set of orthogonal sequences. The selection will be done from a hash table. The index will generate by a function consisting of unique radar code and TOD from the INS (GPS).

[0129] Kalman Filter Approach: Target reflections generated by cars in opposite lane or by cars moving in the same lane. According to embodiments of the present invention, the radar absolute velocity, obtained by the INS, combined with measured range and measured Doppler shift, will detect that the reflections are generated not by the radar transmission. The radar controller builds a Kalman filter for each reflection and ignores reflections that the Kalman filter prediction does not agree with the measured position.

[0130] Functions, operations, components and/or features described herein with reference to one or more embodiments, may be combined or otherwise utilized with one or more other functions, operations, components and/or features described herein with reference to one or more other embodiments, or vice versa. While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.