Patent Application
20100238066
Not Applicable.
Not Applicable.
This invention relates generally to vehicle radar systems and more particularly to vehicle radar systems adapted to detect other vehicles and objects in proximity to the vehicle.
As is known by those in the art, radar systems have been developed for various applications associated with vehicles, such as automobiles and boats. A radar system mounted on a vehicle detects the presence of objects including other vehicles in proximity to the vehicle. In an automotive application, such a radar system can be used in conjunction with the braking system to aid in collision avoidance or in conjunction with the automobile cruise control system to provide intelligent speed and traffic spacing control. In a further application, the vehicle radar system provides a passive indication of obstacles to a driver of the vehicle on a display, and in particular, detects objects in a so-called blind spot of the vehicle.
In an effort to reduce the number and impact of blind spots, rear and side view mirrors of various sizes and types are typically mounted on the vehicle. While the use of mirrors helps reduce the number of blind spots on a vehicle, mirrors cannot eliminate all blind spots. Also, the view through mirrors degrades during conditions of rain, snow, or darkness.
Cameras mounted on the back and sides of a vehicle can also be effective in reducing blind spots. However, this approach is relatively expensive and at least a portion of the camera must be exposed to external elements. Also, the view through a camera degrades during severe weather (e.g. rain, show) and in darkness.
The present invention provides a system and method for generating a target alert. While examples of the method and system shown below include a radar system as used on an automobile, and, in particular, a side object detection (SOD) radar, the method and system apply to any radar system that provides an alert associated with an object.
In accordance with the present invention, a method of generating an alert associated with a radar system includes detecting an object when the object is within a predetermined detection zone to provide one or more detection range values indicative of ranges between the radar system and the object. The method further includes receiving a host vehicle velocity value indicative of a velocity of a host vehicle upon which the radar system is mounted and calculating a relative velocity value indicative of a relative velocity between the host vehicle and the detected object. The method further includes combining the one or more detection range values, the relative velocity value, and the host vehicle velocity value to identify the alert.
In accordance with another aspect of the present invention, apparatus for generating an alert associated with a radar system includes a detection processor adapted to detect an object when the object is within a predetermined detection zone and to provide one or more detection range values indicative of ranges between the radar system and the object. The apparatus further includes a transceiver adapted to receive a host vehicle velocity value indicative of a velocity of a host vehicle upon which the radar system is mounted and a relative velocity calculation processor adapted to calculate a relative velocity value indicative of a relative velocity between the object and the host vehicle. The apparatus further includes an alert identification processor adapted to combine the one or more detection range values, the host vehicle velocity value, and the relative velocity value, and to generate an alert identification signal indicative of the alert in response to the combination.
The foregoing features of the invention, as well as the invention itself may be more fully understood from the following detailed description of the drawings, in which:
Before describing the present invention, some introductory concepts and terminology are explained. As used herein, the term “received RF signal” is used to describe a radio frequency (RF) signal received by a receiving radar antenna. As used herein, the term “transmitted RF signal” is used to describe an RF signal transmitted through a transmitting radar antenna. The transmit and receive antennas may be the same physical antenna (i.e. one antenna is used for both transmit and receive paths of the radar system) or may be separate antennae. As used herein, the term “echo RF signal” is used to describe an RF signal resulting from a transmitted RF signal impinging upon an object and reflecting and/or scattering from the object. As used herein, the term “interfering RF signal” is used to describe an RF signal generated (or otherwise provided by or resultant from) another radar system.
In view of the above definitions, it should be appreciated that a received RF signal may or may not include an echo RF signal. The received RF signal may also include or not include an interfering RF signal.
As used herein, the term “composite signal” is used to describe a signal with contributions from at least one of a received RF signal and a noise signal.
As used herein, the term “chirp signal” (or more simply “chirp”) is used to describe a signal having a frequency that varies with time during a time window, and which has a start frequency and an end frequency associated with each chirp. A chirp can be a linear chirp, for which the frequency varies in a substantially linear fashion between the start and end frequencies. A chirp can also be a non-linear chirp, in which the frequency varies in a substantially non-linear fashion between the start and end frequencies. A chirp signal can be transmitted through a variety of media, for example, through the air as a transmitted RF chirp signal, or through some other type of transmission media (e.g. a coaxial cable).
As used herein, the term “controller area network” or “CAN” is used to describe a control bus and associated control processor commonly disposed in automobiles. The CAN bus is typically coupled to a variety of vehicle systems (e.g. air bag, brakes, etc.) A CAN processor is coupled to vehicle systems through the CAN bus which allows the CAN processor to control a variety of automobile functions, for example, anti-lock brake functions. The CAN network may be implemented as a wired or a wireless network.
Reference is made herein below to certain processing operations, which are accomplished using fast Fourier transforms (FFTs). It should, of course, be appreciated that other techniques can also be used to convert time domain signals to the frequency domain. These techniques include, but are not limited to, discrete Fourier transforms (DFTs).
Referring to
The second vehicle 18 may be traveling slower than, faster than, or at the same speed as the first vehicle 12. With the relative position of the vehicles 12, 18 shown in
The SOD radar 14 generates multiple receive beams (e.g., a receive beam 22a, a receive beam 22b, a receive beam 22c, a receive beam 22d, a receive beam 22e, a receive beam 22f and a receive beam 22g) and an associated detection zone 24 having edges 24a-24d. The edges 24a-24c of the detection zone 24 are formed by the SOD radar 14 by way of maximum detection ranges associated with each one of the receive beams 22a-22g, for example, the maximum detection range 26 associated with the receive beam 22c. Each of the receive beams 22a-22g may also have a minimum detection range (not shown), forming the edge 24d of the detection zone 24 closest to the first vehicle. It should be appreciated that in this exemplary embodiment the detection zone 24 is selected having a size and shape such that at least a portion of the detection zone lies over (or “covers”) a blind spot of the vehicle.
In one particular embodiment, the SOD radar 14 is a frequency modulated continuous wave (FMCW) radar, which transmits continuous wave chirp RF signals, and which processes received RF signals accordingly. In some embodiments, the SOD radar 14 may be of a type described, for example, in U.S. Pat. No. 6,577,269, issued Jun. 10, 2003; U.S. Pat. No. 6,683,557, issued Jan. 27, 2004; U.S. Pat. No. 6,642,908, issued Nov. 4, 2003; U.S. Pat. No. 6,501,415, issued Dec. 31, 2002; and U.S. Pat. No. 6,492,949, issued Dec. 10, 2002, which are all incorporated herein by reference in their entirety.
In operation, the SOD radar 14 transmits an RF signal. At least portions of the transmitted RF signal impinge upon and are reflected from the second vehicle 18. The reflected signals (also referred to as “echo” RF signals) are received in one or more of the receive beams 22a-22g. Other ones of the radar beams 22a-22g, which do not receive the echo RF signal from the second vehicle 18, receive and/or generate other RF signals, for example, noise signals.
In some embodiments, the SOD radar 14 can transmit RF energy in a single broad transmit beam (not shown). In other embodiments, the SOD radar 14 may transmit RF energy in multiple transmit beams (not shown), for example, in seven transmit beams associated with the receive beams 22a-22g. It should be appreciated, of course, that the principles described herein apply regardless of the particular number of receive beams.
The SOD radar 14 processes the received RF signals associated with each one of the receive beams 22a-22g in sequence, in parallel, or in any other time sequence. The SOD radar 14 detects echo RF signals associated with the second vehicle 18 when any portion of the second vehicle 18 is within the detection zone 24. Therefore, the SOD radar 14 is adapted to detect the second vehicle 18 when at least a portion of the second vehicle is in or near the blind spot of the first vehicle 12.
To this end, signal processing provided by the SOD radar 14, in some embodiments, can be of a type described, for example, in U.S. Pat. No. 6,577,269, issued Jun. 10, 2003, U.S. Pat. No. 6,683,557, issued Jan. 27, 2004, U.S. patent application Ser. No. ______, filed ______, entitled “Generating Event Signals in a Radar System,” having inventors Dennis Hunt and Walter Gordon Woodington, and having attorney docket number VRS-019PUS, U.S. patent application Ser. No. ______, filed ______, entitled “System and Method for Generating a Radar Detection Threshold,” having inventors Steven P. Lohmeier and Wilson J. Wimmer, and having attorney docket number VRS-014PUS, and U.S. patent application Ser. No. ______, filed ______, entitled “System and Method for Verifying a Radar Detection,” having inventors Steven P. Lohmeier and Yong Liu, and having attorney docket number VRS-015PUS. Each of these patents and patent applications is incorporated herein by reference in its entirety. Further processing of the composite signal by the SOD radar 14 is described more fully below.
Referring now to
As described above, the SOD radars 56, 58 can be coupled to the vehicle 52 in a variety of ways. In some embodiments, the SOD radars can be coupled to the vehicle 52 as described in U.S. Pat. No. 6,489,927, issued Dec. 3, 2002, which is incorporated herein by reference it its entirety.
Each one of the SOD radars 56, 58 can be coupled to a central SOD processor 64 via a Controller Area Network (CAN) bus 66. Other automobile systems can also be coupled to the CAN bus 66, for example, an air bag system 72, a braking system 74, a speedometer 76, and a CAN processor 78.
The system 50 includes two side view mirrors 80, 84, each having an alert display 82, 86, respectively, viewable therein. Each one of the alert displays 82, 86 is adapted to provide a visual alert to an operator of the vehicle 52, indicative of the presence of another automobile or other object in a blind spot of the vehicle 52.
Upon detection of an object (e.g., another vehicle) in the detection zone 24, the SOD radar 56 sends an alert signal indicating the presence of an object to either or both of the alert displays 82, 84 through the CAN bus 66. In response to receiving the alert signal, the displays 82, 84 provide an indicator (e.g., a visual, audio, or mechanical indicator), which indicates the presence of an object. Similarly, upon detection of an object in the detection zone 62, the SOD radar 58 sends an alert signal indicating the presence of another vehicle to one or both of alert displays 82, 86 through the CAN bus 66. However, in an alternate embodiment, the SOD radar 56 can communicate the alert signal to the alert display 82 through a human/machine interface (HMI) bus 68. Similarly, the SOD radar 58 can communicate an alert signal to the other alert display 86 through another human/machine interface (HMI) bus 70.
In some embodiments, the central processor 64 can combine or “fuse” data associated with each one of the SOD radars 56, 58, in order to provide fused detections of other automobiles present within the detections zones 60, 62, resulting is further display information in the alert displays 82, 86. Alternatively, the data from each SOD radar 56, 58 can be shared among all SOD radars 56, 58 and each SOD radar 56, 58 can combine (or fuse) all data provided thereto.
While two SOD radars 56, 58 are shown, the system 50 can include any number of SOD radars, including only one SOD radar. While the alert displays 82, 86 are shown to be associated with side view mirrors, the alert displays can be provided in a variety of ways. For example, in other embodiments, the alert displays can be associated with a central rear view mirror. In other embodiments, the alert displays are audible alert displays (e.g. speakers) disposed inside (or at least audible inside) the portion of the vehicle in which passengers sit.
While the CAN bus 66 is shown and described, it will be appreciated that the SOD radars 56, 58 can couple through any of a variety of other busses within the vehicle 52, including, but not limited to, an Ethernet bus, and a custom bus.
Referring now to
The fiberglass circuit board 102 has disposed thereon a signal processor 104 coupled to a control processor 108. In general, the signal processor 104 is adapted to perform signal processing functions, for example, fast Fourier transforms. The signal processor can include a detection processor 104a adapted to detect targets in the detection zone (e.g., detection zone 24,
The control processor 108 is adapted to perform other digital functions, for example, to identify conditions under which an operator of a vehicle on which the SOD radar 100 is mounted should be alerted to the presence of another object such as a vehicle in a blind spot. To this end, the control processor 108 includes a detection verification processor 108a and an alert processor 108b, each of which are descried more fully below.
While the detection processor 104a, the detection verification processor 108a, and the alert processor 108b are shown to be partitioned among the signal processor 104 and control processor 108 in a particular way, any partitioning of the functions is possible.
The control processor 108 is coupled to an electrically erasable read-only memory (EEPROM) 112 adapted to retain a variety of values, for example, threshold values described more fully below. Other read-only memories associated with processor program memory are not shown for clarity.
The control processor 108 can also be coupled to a CAN transceiver 120, which is adapted to communicate, via a connector 128, on a CAN bus 136. The CAN bus 136 can be the same as or similar to the CAN bus 66 of
The control processor 108 can also be coupled to an optional human/machine interface (HMI) driver 118, which can communicate via the connector 128 to an HMI bus 138. The HMI bus 138 can be the same as or similar to the HMI busses 68, 70 of
The fiberglass circuit board 102 receives a power signal 140 and a ground signal 142. In a U.S. automobile, the power signal 140 would typically be provided as a 12 Volt DC signal (relative to the ground signal 142). The system may of course be adapted to use other voltage levels (e.g. voltage levels used in European automobiles). Via the connector 128, the power and ground signals 140, 142, respectively, can be coupled to one or more voltage regulators 134 (only voltage regulator one being shown in
The SOD radar 100 also includes the PTFE circuit board 150, on which is disposed radar transmitter 152 and a transmit antenna 154, which is coupled to the transmitter 154. The transmitter 152 is coupled to the signal processor 104 and the antenna 154 is coupled to the transmitter 152.
The SOD radar 100 also includes the LTCC circuit board 156 on which is disposed a radar receiver 158 and a receive antenna 160. The receiver 158 is coupled to the signal processor 104 and to the receive antenna 160. The receiver 158 can also be coupled to the transmitter 152, providing one or more RF signals 162 described below. The radar transmitter 152 and the radar receiver 158 receive regulated voltages from the voltage regulator 134.
In some embodiments, the transmit antenna 154 and the receive antenna 160 can be of a type described, for example, in U.S. Pat. No. 6,642,908, issued Nov. 4, 2003, U.S. Pat. No. 6,492,949, issued Dec. 10, 2002, U.S. patent application Ser. No. 10/293,880, filed Nov. 13, 2002, and U.S. patent application Ser. No. 10/619,020, filed Jul. 14, 2003. Each of these patents is incorporated herein by reference in its entirety.
In operation, the signal processor 104 generates one or more ramp signals 144 (also referred to as chirp control signals), each having a respective start voltage and a respective end voltage. The ramp signals are fed to the transmitter 152. In response to the ramp signals 144, and in response to RF signals 162 provided by the receiver 158, the transmitter 152 generates RF chirp signals having waveform characteristics controlled by the ramp signals. The RF signals are provided from the transmitter to the transmit antenna 154, where the signal is emitted (or radiated) as RF chirp signals.
The transmit antenna 154 can be configured such that the RF chirp signals are transmitted in a single transmit beam. Alternatively, the transmit antenna can be configured such that the RF chirp signal is emitted in more than one transmit beam. In either arrangement, the transmit antenna 154 transmits the RF chirp signal in an area generally encompassing the extent of a desired detection zone, for example, the detection zone 60 of
The receive antenna 160 can form more than one receive beam, for example, seven receive beams 22a-22g as shown in
It should be appreciated that, for the SOD FMCW chirp radar system 100, the converted signal 148 has a frequency content, wherein different frequencies of peaks therein correspond to detected objects at different ranges. The above-described amplification of the receiver 158 can be a time-varying amplification, controlled, for example, by a control signal 146 provided by the signal processor 104.
The signal processor 104 analyzes the converted signals 148 to identify an object in the above-described detection zone. To this end, in one particular embodiment, the signal processor 104 performs a frequency domain conversion of the converted signals 148. In one exemplary embodiment, this is accomplished by performing an FFT (fast Fourier transform) in conjunction with each one of the receive beams.
Some objects detected in the converted signal 148 by the signal processor 104 may correspond to objects for which an operator of a vehicle has little concern and need not be alerted. For example, an operator of a vehicle may not need to be alerted as the existence of a stationary guardrail along a roadside. Thus, further criteria can be used to identify when an alert signal should be generated and sent to the operator.
The control processor 108 receives detections 106 from the signal processor 104. The control processor 108 can use the further criteria to control generation of an alert signal 114. Upon determination by the control processor 108, the alert signal 114 can be generated, which is indicative not only of an object in the detection zone, but also is indicative of an object having predetermined characteristics being in the detection zone, for example, a moving object. Alternatively, the control processor 104 can use criteria to determine that an alert signal should not be generated.
The alert signal 114 can be communicated on the CAN bus 136 by the CAN transceiver 120. In other embodiments, an alert signal 122 can be communicated on the HMI bus 138 by the optional HMI driver 118.
The fiberglass circuit board 102, the PTFE circuit board 150, and the LTCC circuit board 156 are comprised of materials having known characteristics (including but not limited to insertion loss characteristics) for signals within particular frequency ranges. It is known, for example, that fiberglass circuit boards have acceptable signal carrying performance at signal frequencies up to a few hundred MHz. LTCC circuit boards and PTFE circuit boards are know to have acceptable signal carrying performance at much higher frequencies, however, the cost of LTCC and PTFE boards is higher than the cost of fiberglass circuit boards. Thus, the lower frequency functions of the SOD radar 100 are disposed on the fiberglass circuit board 102, while the functions having frequencies in the range of frequencies are disposed on the LTCC and on the PTFE circuit boards 150, 156, respectively.
While three circuit boards 102, 150, 156 are shown, the SOD radar 100 can be provided on more than three or fewer than three circuit boards. Also, the three circuit boards 102, 150, 156 can be comprised of materials other than those described herein.
It should be appreciated that
Alternatively, the processing and decision blocks represent steps performed by functionally equivalent circuits such as a digital signal processor circuit or an application specific integrated circuit (ASIC). The flow diagrams do not depict the syntax of any particular programming language. Rather, the flow diagrams illustrate the functional information one of ordinary skill in the art requires to fabricate circuits or to generate computer software to perform the processing required of the particular apparatus. It should be noted that many routine program elements, such as initialization of loops and variables and the use of temporary variables are not shown. It will be appreciated by those of ordinary skill in the art that unless otherwise indicated herein, the particular sequence of blocks described is illustrative only and can be varied without departing from the spirit of the invention. Thus, unless otherwise stated the blocks described below are unordered meaning that, when possible, the steps can be performed in any convenient or desirable order.
Referring now to
In general, different radars operate in different ways. In the discussion herein, a SOD radar is described (e.g., 100,
At block 166, a host vehicle velocity, e.g., a host automobile velocity, is received by the SOD radar. For example, the SOD radar 56 of
At block 167, an object relative velocity value is calculated, which is indicative of a relative velocity between the host vehicle and the detected object. The relative velocity value can be calculated in a variety of ways, some of which are further described below.
At block 168, which includes blocks 170-177 described more fully below, the one or more detection range values, the relative velocity value, and the host vehicle velocity value are combined to generate an alert.
At block 170, a map of host vehicle velocities versus object relative velocities is generated, wherein the map has a map area. Referring briefly to
Referring again to
Having both the object relative velocity from block 167 and the host vehicle velocity from block 166, at block 172, a point is identified on the map generated at block 170.
At block 173, a detection range value associated with the object detection, and therefore, with the point generated at block 172, is examined to determine if the detection range value, i.e., the object, is within a predetermined detection zone. The predetermined detection zone can be the same as or similar to the detection zone 24 of
The point generated at block 172 is examined at block 174. If the point is within the map region selected at block 171, then the process continues to block 175, where an alert is identified and generated. The alert can be in the form of a display, for example the alert display 82 of
Having generated the alert, the process continues to block 177, where if the detection being examined (which ca, for example, be associated with a particular radar receive beam) is the last available detection, the process ends. If, however, the detection is not the last detection, the process continues to block 177, where the next detection (for example, the next receive beam having a detection) is selected. The next detection has an associated range to a target. The process then returns to block 166.
At block 173, if the detection range value (i.e., detected object) is not within the predetermined detection zone (e.g., 24,
At block 174, if the identified point is not within the region selected at block 162 of the map generated at block 179, then an alert is not generated and the process continues at block 176.
Referring now to
At block 186, the plurality of composite signals is converted to a respective plurality baseband signals, i.e., signals at a lower frequency. At block 188, the baseband signals are converted to the frequency domain, and at block 190, thresholds are applied to the frequency domain signals to generate one or more detections of the object and a respective one or more detection state values, for example, true or false detection state values.
At block 192, for each detection of the object, i.e., for each true detection state value, a detection range value is generated. At least two detections and at least two respective detection range values are generated. At block 194, the at least two detection range values are combined to generate a relative velocity between the detected object and the SOD radar system.
The relative velocity can be computed at block 194 by dividing a change in distance directly identified by the detection range values, by an associated change in time. However, the relative velocity thus calculated will be direct path relative velocity along a line (a direct path) between the object and the radar system (host vehicle). In some embodiments, the direct path relative velocity is converted at block 194 to a coordinate parallel to a direction of travel of the host vehicle, thereby providing a parallel path relative velocity. This conversion can be performed with knowledge of the angle between the detected object and the direction of travel of the host vehicle, which can be provided by knowledge of which one of the receive beams (e.g., 22a-22g,
In other embodiments, relative velocity can be directly calculated using a Doppler frequency shift, without using the measured change in distance described above. Calculating a relative velocity in a radar system by way of Doppler shift is known. In these embodiments, only one detection of the object is required in order to generate the object relative velocity.
Further details of the above-described generation of detection state values and detection range values are described in the above-mentioned U.S. Pat. No. 6,577,269, issued Jun. 10, 2003, and U.S. Pat. No. 6,683,557, issued Jan. 27, 2004, which patents are incorporated herein by reference in their entirety.
While processing associated with an FMCW radar such as the SOD radar 100 of
Referring now to
In discussion of
Referring now to
A line 204 is indicative of the velocity of the host vehicle being opposite from the object relative velocity. It will be recognized that when the host vehicle velocity and the object relative velocity are opposite, the object must be stationary.
The horizontal axis is indicative of the object relative velocity being equal to zero. It will be recognized that when the object relative velocity is zero, the object is traveling at the same velocity and in the same direction as the host vehicle.
The vertical axis is indicative of the host vehicle being stationary and the object moving.
Regions 206 and 208 are both representative of the object moving faster and in the same direction as the host vehicle. The region 206 is representative of the object moving more than twice the velocity of the host vehicle, and the region 208 is representative of the object moving less than twice but greater than the velocity of the host vehicle. A region 210 is representative of the object moving slower and in the same direction as the host vehicle. A region 212 is representative of the object moving in the opposite direction from the host vehicle, for example, in a an opposite direction travel lane.
Referring now to
For a side-object detection system such as the SOD radar 100 of
Referring now to
The region 246 is a rectangular region bounded by a predetermined range of object relative velocity values (line segment 246a to line segment 246c) and a predetermined range of host vehicle velocity values (line segment 246d to line segment 246b).
If a vehicle operator is alerted only if a host vehicle velocity and an object relative velocity result in an associated point falling within the region 246, certain advantages result. For example, some objects traveling in the opposite direction to the host vehicle (typified by a point A) and some objects traveling at a slower velocity and in the same direction as the host vehicle (typified by a point B) do not result in an alert. However, some stationary objects (typified by a point C) result in an alert, when such an alert may not be desirable.
Referring now to
The region 266 is a polygonal region bounded by a line segment 266d having a first predetermined host vehicle velocity value along the line segment 266d, a line segment 266a having a first predetermined relative velocity value along the line segment 266a, a line segment 266b having a second predetermined host vehicle velocity value along the line segment 266b, and a line segment 266c having a second predetermined relative velocity value along the line segment 266c.
If a vehicle operator is alerted only if a host vehicle velocity and an object relative velocity result in an associated point being within the region 266, certain alert characteristics result. For example, some objects traveling in the opposite direction to the host vehicle (typified by a point A) and some objects traveling at a much faster velocity and in the same direction as the host vehicle (typified by a point B) do not result in an alert. However, some stationary objects (typified by a point C) result in an alert, when such an alert may not be desirable.
Referring now to
The region 286 is a polygonal region bounded by a line segment 286d having a host vehicle velocity value equal to zero along the line segment 286d, a line segment 286a having a predetermined relative velocity value along the line segment 286a, a line segment 286b having a predetermined host vehicle velocity value along the line segment 286b, and a line segment 286c for which the relative velocity values along the line segment 286c are equal to the opposite of the host vehicle velocity values (i.e., the object is stationary).
If a vehicle operator is alerted only if a host vehicle velocity and an object relative velocity result in an associated point being within the region 286, certain alert characteristics result. For example, all objects traveling in the opposite direction to the host vehicle (typified by a point A) do not result in an alert. However, some stationary objects (typified by a point B) result in an alert, when such an alert may not be desirable.
Referring now to
The region 306 is a polygonal region bounded by a line segment 306d having a host vehicle velocity value equal to zero along the line segment 306d, a line segment 306a having a predetermined relative velocity value along the line segment 306a, a line segment 306b having a predetermined host vehicle velocity value along the line segment 306b, and a line segment 306c for which the relative velocity values along the line segment 306c are equal to the opposite of the host vehicle velocity values plus a predetermined offset relative velocity value 310 (i.e., the object is not stationary).
If a vehicle operator is alerted only if a host vehicle velocity and an object relative velocity result in an associated point being within the region 306, certain alert characteristics result. For example, all objects traveling in the opposite direction to the host vehicle (typified by a point A) do not result in an alert. Also, in comparison with the region 286 of
Referring now to
The region 326 is a polygonal region bounded by a line segment 326d having a first predetermined host vehicle velocity value along the line segment 326d, a line segment 326a having a first predetermined relative velocity value along the line segment 326a, a line segment 326b having a second predetermined host vehicle velocity value along the line segment 326b, and a line segment 326c having a second predetermined relative velocity value along the line segment 326c.
If a vehicle operator is alerted only if a host vehicle velocity and an object relative velocity result in an associated point being within the region 326, certain alert characteristics result. For example, all objects traveling in the opposite direction to the host vehicle (typified by a point A) do not result in an alert. Also, no stationary objects (typified by a point B) result in an alert. Also, no alerts are generated for very low host vehicle velocities (typified by a point C). Furthermore, many objects traveling in the same direction as the host vehicle but slower (typified by a point D), do not result in an alert.
Referring now to
The region 346 is a polygonal region bounded by a line segment 346d having a host vehicle velocity value equal to zero along the line segment 346d, a line segment 346a having a first predetermined relative velocity value along the line segment 346a, a line segment 346b having a first predetermined host vehicle velocity value along the line segment 346b, a line segment 346c having a second predetermined relative velocity value along the line segment 346c, a line segment 346d having a second predetermined host vehicle velocity value along the line segment 346d, and a line segment 346e having a third predetermined relative velocity value along the line segment 346e, here zero.
If a vehicle operator is alerted only if a host vehicle velocity and an object relative velocity result in an associated point being within the region 346, certain alert characteristics result. For example, all objects traveling in the opposite direction to the host vehicle (typified by a point A) do not result in an alert. Also, no stationary objects (typified by a point B) result in an alert. Furthermore, many objects traveling in the same direction as the host vehicle, but slower (typified by a point C) do not result in an alert.
Referring now to
The region 366 is a polygonal region bounded by a line segment 366d having a host vehicle velocity value equal to zero along the line segment 366d, a line segment 366a having a first predetermined relative velocity value along the line segment 366a, a line segment 366b having a first predetermined host vehicle velocity value along the line segment 366b, a line segment 366c having a second predetermined relative velocity value along the line segment 366c, a line segment 366d having a second predetermined host vehicle velocity value along the line segment 366d, and a line segment 346e having a third predetermined relative velocity value along the line segment 346e.
If a vehicle operator is alerted only if a host vehicle velocity and an object relative velocity result in an associated point being within the region 366, certain alert characteristics result. For example, all objects traveling in the opposite direction to the host vehicle (typified by a point A) do not result in an alert. Also, no stationary objects (typified by a point B) result in an alert. Also, no alerts are generated at some low host vehicle velocities (typified by a point C). Furthermore, many objects traveling in the same direction as the host vehicle, but slower (typified by a point D) do not result in an alert.
Referring now to
The radar receiver 408 can provide radio frequency (RF) signals 410 to a baseband converter 412. The baseband converter 412 is adapted to convert the RF signals 410 to baseband signals 414, which are provided to an A/D converter 416. The baseband signals 414 are generated by converting the RF signals 412 to a lower frequency. The radar receiver 406 in combination with the baseband converter 412 and the A/D converter 416 can be the same as or similar to the receiver 158 and receive antenna 160 of
The A/D converter 416 provides digital signals 418 to a detection processor 419. The detection processor 419 can be the same as or similar to the detection processor 104a of
The detection processor 419 includes a frequency domain processor 420 adapted to receive the digital signals 418 and to convert the digital signals 418 to frequency domain signals 422, 424. The frequency domain signals 424 are received by a threshold processor 426, which generates one or more detection thresholds 428. The frequency domain signals 422 and the detection thresholds 428 are received by a threshold application processor 430. The threshold application processor 430 is adapted to compare the frequency domain signals 422 with the detection thresholds 428 and to provide a detection signal 432 (i.e., a detection table) indicative of the presence or absence of an object in a detection zone (e.g. 24,
An optional detection verification processor 434 is adapted to receive the detection signals 432 and to further process the detection signals 432 in order to apply further criteria to validate or to invalidate a detection of an object. The detection verification processor 434 can generate verified detection signals 436, accordingly, which can include verified detection state values, e.g., verified true and false values, and can also include detection range values. The detection verification processor 434 can be the same as or similar to the detection verification processor 108a of
An alert processor 438 is adapted to receive the verified detection signals 436 and to generate an alert signal 468, if a detected object falls within a predetermined detection zone (e.g., 24,
The alert processor 438 can include a relative velocity calculation processor 440, adapted to receive the verified detection signals (which can include detection state values and detection range values), and to generate object relative velocity values 442.
A transceiver 454 is adapted to receive host vehicle velocity values 452, for example, from the host vehicle speedometer, and to provide the host vehicle velocity 456 to the alert processor 438. For example, the SOD radar 56 of
A map generation processor 444 is adapted to generate a map of host vehicle velocity and object relative velocity, and a region selection processor 448 is adapted to select a predetermined region 450 of the map. For example, as described above, the map can be one of the maps 220, 240, 260, 280, 300, 320, 340, 360 shown in
An alert identification processor 460 is adapted to receive the verified detection signals 436 (in particular, the detection range values), the object relative velocity values 442, the host vehicle velocity values 456, and the predetermined region 450, and to generate an alert identification signal 462 if the detected object is within the predetermined detection zone (e.g., 24,
It should be understood that, in other embodiments, the verified detection signals 436 need not be coupled to the alert identification processor 460. The verified detection signals 436 (in particular the verified detection range values) can be redundant with the relative velocity signals 442, for example, in the case where the relative velocity signals 442 are generated only for objects, which are known to be within the predetermined detection zone (e.g., 24,
An alert generator 454 is adapted to receive the alert identification signal 462 and to generate an alert signal 468. The alert signal 468 can be in a variety of forms, including, but not limited to, a visual alert signal and an audible alert signal to an operator of a vehicle. The alert signal 468 makes an operator of a vehicle, for example, the vehicle 12 of
Functions of the detection processor 419, the detection verification processor 434, and the alert processor 438 can be performed by the signal processor 104 and/or the control processor 108 of
Referring now to
A direct path relative velocity calculation processor 512 is adapted to generate direct path relative velocity signals 514 in response to the range change values 508 and the time change values 511. In one particular embodiment, the direct path relative velocity processor 512 divides the range change values 508 by the time change values 511 to generate the direct path relative velocity signals 514.
A coordinate transformation processor 516 is adapted to receive the direct path relative velocity signals 514 and to perform a coordinate transformation, resulting in above-described parallel path relative velocity values 518.
All references cited herein are hereby incorporated herein by reference in their entirety.
Having described preferred embodiments of the invention, it will now become apparent to one of ordinary skill in the art that other embodiments incorporating their concepts may be used. It is felt therefore that these embodiments should not be limited to disclosed embodiments, but rather should be limited only by the spirit and scope of the appended claims.
