Method for performing radar operation, radar device and radar system

Abstract

A method is provided that includes transmitting a first radar frame on a first communication channel and transmitting a second radar frame on a second communication channel. A reflection of the first radar frame is received, and a first channel impulse response is estimated based on the reflection of the first radar frame. A reflection of the second radar frame is received, and a second channel impulse response is estimated based on the reflection of the second radar frame. The first channel impulse response estimate and the second channel impulse response estimate are combined to obtain a channel impulse response estimate having a higher resolution than each of the first channel impulse response estimate and the second channel impulse response estimate.

Description

Technical Field

[0001] This disclosure relates to a method for performing radar operation. Furthermore, this disclosure relates to a corresponding radar apparatus and a corresponding radar system. Background Technology

[0002] Ultra-wideband (UWB) communication technology is a technology that utilizes high signal bandwidth, specifically for transmitting digital data over a wide frequency spectrum with extremely low power. For example, UWB technology can use a spectrum from 3.1 to 10.6 GHz and can feature high-frequency bandwidths greater than 500 MHz and very short pulse signals, thus potentially supporting high data rates. UWB technology can provide communication devices with high data throughput and enable high-precision positioning. Specifically, UWB technology can be used for so-called ranging operations, i.e., determining the distance between communication devices. Therefore, UWB technology can be advantageously used in various applications, such as automotive applications. Additionally, UWB technology can be used for radar operations, for example, to detect objects or people within a predefined area. Summary of the Invention

[0003] According to a first aspect of this disclosure, a method for performing radar operation is contemplated, the method comprising: transmitting a first radar frame on a first communication channel, wherein the first radar frame comprises a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame on the first communication channel comprises transmitting the radar frame within a first frequency band; transmitting a second radar frame on a second communication channel, wherein the second radar frame comprises a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel comprises transmitting the radar frame within a second frequency band; receiving a reflection of the first radar frame and estimating a first channel impulse response based on the reflection of the first radar frame; receiving a reflection of the second radar frame and estimating a second channel impulse response based on the reflection of the second radar frame; and combining the first channel impulse response estimate with the second channel impulse response estimate to obtain a channel impulse response estimate having a higher resolution than each of the first channel impulse response estimate and the second channel impulse response estimate.

[0004] In one or more embodiments, the first frequency band and the second frequency band are non-overlapping frequency bands.

[0005] In one or more embodiments, the first frequency band and the second frequency band are adjacent frequency bands.

[0006] In one or more embodiments, combining the first channel impulse response estimate with the second channel impulse response estimate includes performing equalization and addition operations on the first channel impulse response estimate and the second channel impulse response estimate.

[0007] In one or more embodiments, the first stream of the ultra-wideband radio frequency pulse is based on the following function:

[0008]

[0009] Where t represents time, and:

[0010]

[0011] Where p(t) is a real-valued ultra-wideband radio frequency pulse waveform with bandwidth BW, and Let p(t) represent the Hilbert transform.

[0012] In one or more embodiments, the second stream of the ultra-wideband radio frequency pulse is based on the following function:

[0013]

[0014] Where t represents time, and:

[0015]

[0016] Where p(t) is a real-valued ultra-wideband radio frequency pulse waveform with bandwidth BW, and Let p(t) represent the Hilbert transform.

[0017] In one or more embodiments, the method further includes applying the same radio filter settings for transmitting a first radar frame and a second radar frame, and increasing the bandwidth of the filter for transmitting the first radar frame and the second radar frame.

[0018] In one or more embodiments, the method further includes applying the same radio filter settings for receiving reflections of a first radar frame and a second radar frame, and increasing the bandwidth of the filter for receiving reflections of the first and second radar frames.

[0019] In one or more embodiments, the first frequency band and the second frequency band have the same bandwidth or approximately the same bandwidth.

[0020] In one or more embodiments, each of the first and second frequency bands has an approximate bandwidth of 500 MHz.

[0021] In one or more embodiments, the steps of transmitting a first radar frame and transmitting a second radar frame, receiving reflections of the first radar frame and the second radar frame, and combining the first channel impulse response estimate and the second channel impulse response estimate are performed by a single radar device.

[0022] In one or more embodiments, the steps of transmitting the first radar frame and transmitting the second radar frame are performed by the first radar device, and the steps of receiving the reflections of the first radar frame and the second radar frame and combining the first channel impulse response estimate and the second channel impulse response estimate are performed by the second radar device.

[0023] According to a second aspect of this disclosure, a radar apparatus is provided, the radar apparatus comprising: a transmitter configured to transmit a first radar frame on a first communication channel, wherein the first radar frame includes a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame on the first communication channel includes transmitting the radar frame within a first frequency band; the transmitter is further configured to transmit a second radar frame on a second communication channel, wherein the second radar frame includes a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band; a receiver configured to receive a reflection of the first radar frame and estimate a first channel impulse response based on the reflection of the first radar frame; the receiver is further configured to receive a reflection of the second radar frame and estimate a second channel impulse response based on the reflection of the second radar frame; and a processing unit configured to combine the first channel impulse response estimate with the second channel impulse response estimate to obtain a channel impulse response estimate having a higher resolution than each of the first channel impulse response estimate and the second channel impulse response estimate.

[0024] According to a third aspect of this disclosure, a radar system is provided, the radar system comprising: a first radar device configured to transmit a first radar frame on a first communication channel, wherein the first radar frame includes a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame on the first communication channel includes transmitting the radar frame within a first frequency band; the first radar device is further configured to transmit a second radar frame on a second communication channel, wherein the second radar frame includes a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band; a second radar device configured to receive a reflection of the first radar frame and estimate a first channel impulse response based on the reflection of the first radar frame; the second radar device is further configured to receive a reflection of the second radar frame and estimate a second channel impulse response based on the reflection of the second radar frame; the second radar device is further configured to combine the first channel impulse response estimate with the second channel impulse response estimate to obtain a channel impulse response estimate having a higher resolution than each of the first channel impulse response estimate and the second channel impulse response estimate. Attached Figure Description

[0025] The embodiments will be described in more detail with reference to the accompanying drawings.

[0026] Figure 1 An example of a target detection system is shown.

[0027] Figure 2 An example of the ideal channel impulse response is shown in a radar system with two targets.

[0028] Figure 3 An illustrative embodiment of a method for performing radar operations is shown.

[0029] Figure 4A An illustrative embodiment of a radar device is shown.

[0030] Figure 4B An illustrative embodiment of a radar system is shown.

[0031] Figure 5 The pulse waveform in the time domain is shown.

[0032] Figure 6 The UWB pulse is shown.

[0033] Figure 7 The subchannel pulse shape is shown in the frequency domain.

[0034] Figure 8 This illustrates the combination of pulse transmission and CIR technology. Detailed Implementation

[0035] Ultra-wideband (UWB) technology—also known as ultra-wideband pulse radio (IR-UWB)—is an RF communication technology that uses short-duration pulses for data communication. A key feature of IR-UWB technology is its ability to securely and accurately measure distances between two or more devices. Typical distance measurement methods include the so-called single-sided two-way ranging (SS-TWR) and two-sided two-way ranging (DS-TWR) methods. In addition to these ranging operations, UWB devices can also perform radar operations. Therefore, UWB devices can operate in both ranging and radar modes.

[0036] In ranging operation mode, frames are typically exchanged between the two devices via at least one antenna on each device, and at least SS-TWR or DS-TWR operation is performed. Specifically, the channel impulse response (CIR) is estimated on both devices, timestamps are generated based on the CIR on both devices, and those timestamps are exchanged. These timestamps form the basis for calculating the distance between the two devices.

[0037] In radar operating modes, frames are transmitted by at least one device and received by the same device and / or by one or more other devices. The CIR is then estimated on one or more devices receiving the frames, and the range and / or velocity and / or AoA are calculated based on the estimated CIR. Radar operating modes can be used advantageously to detect (i.e., sense) the presence of objects or persons. Those skilled in the art should understand that the given examples are non-limiting examples of how different operating modes can be implemented. In other words, the modes can be implemented in different ways, depending on, for example, the requirements imposed by the application.

[0038] While UWB-based radar systems can effectively detect targets within a predefined area, the accuracy of that detection may not always be sufficient, especially when the system's bandwidth is limited. For example, a UWB-based radar system with a bandwidth limited to 500 MHz cannot properly distinguish between two targets spaced less than 30 cm apart. The resolution required to differentiate such closely spaced targets necessitates a wider bandwidth pulse transmission, which means increasing the bandwidth of both the transmitter and receiver, including the antenna, analog-to-digital converter (ADC) sampling rate, and associated digital signal processing. However, designing antennas and ADCs with sampling rates exceeding 1 GHz increases the cost, complexity, and power consumption of the device.

[0039] Figure 1 An example of a target detection system 100 is shown. The target detection system 100 includes a radar device 102 configured to detect targets 104, 106 in a predefined area. Specifically, the radar device 102 is configured to transmit short pulses and listen for reflections from targets to estimate their distances. In this monostatic radar system 100, pulse transmission and reception are performed by a single radar device 102. A radar receiver (not shown) included in the radar device 102 estimates the channel impulse response (CIR) from the reflected pulses; the number of different pulses in the CIR determines the number of targets in the line-of-sight (LOS) environment, where there are different paths from each target to the radar device, with no additional reflection paths.

[0040] Figure 2 An example of an ideal channel impulse response (CIR) 200 in a radar system with two targets is shown. The interval between the reflected pulses in the CIR (i.e., the first path 202 and the strongest path 204) (indicated by arrows in the figure) is proportional to the relative distance between the targets, and the pulse width itself is inversely proportional to the system bandwidth (BW), which includes the transmitter and receiver filters as well as the antenna bandwidth. Note that the range resolution of the radar system is defined as... Where C represents the speed of light propagation. As the target gets closer, it becomes more difficult to distinguish reflected pulses; bandwidth limitations affect the resolution of radar systems because reflected pulses from one target are hidden behind reflected pulses from another target.

[0041] This paper discusses a method for performing radar operation, a corresponding radar device, and a corresponding radar system, which help increase the range resolution of the radar device and radar system respectively, without significantly increasing cost in terms of complexity and power consumption. Specifically, the currently disclosed method helps increase the range resolution of the radar device or radar system without significantly increasing the bandwidth of the transmitter and receiver or the ADC sampling rate of the receiver. More specifically, the currently disclosed method helps improve the range resolution of a pulse radar system; it can be classified as a pulse compression technique used in radar systems to improve range resolution.

[0042] Figure 3 An illustrative embodiment of a method 300 for performing radar operation is shown. Method 300 includes the following steps: At 302, a first radar frame is transmitted on a first communication channel, wherein the first radar frame comprises a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame on the first communication channel includes transmitting the radar frame within a first frequency band. At 304, a second radar frame is transmitted on a second communication channel, wherein the second radar frame comprises a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band. Note that steps 302 and 304 may be performed simultaneously or sequentially. Furthermore, if performed sequentially, step 302 may be performed before step 304, and vice versa. Furthermore, at 306, a reflection of the first radar frame is received, and a first channel impulse response is estimated based on the reflection of the first radar frame. Furthermore, at 308, a reflection of the second radar frame is received, and a second channel impulse response is estimated based on the reflection of the second radar frame. Note that steps 306 and 308 may be performed simultaneously or sequentially. Furthermore, if executed sequentially, step 306 can be performed before step 308, and vice versa. Finally, at 310, the first channel impulse response estimate is combined with the second channel impulse response estimate to obtain a channel impulse response estimate with a higher resolution than each of the first and second channel impulse response estimates. This allows for an increase in the range resolution of the radar device or radar system without significantly increasing cost in terms of complexity and power consumption.

[0043] In one or more embodiments, the first and second frequency bands are non-overlapping frequency bands. This makes the method practically feasible to implement. Furthermore, in one or more embodiments, the first and second frequency bands are adjacent frequency bands. This also makes the method practically feasible to implement. Additionally, in one or more embodiments, combining the first channel impulse response estimate with the second channel impulse response estimate includes performing equalization and addition operations on the first and second channel impulse response estimates. In embodiments where the radio filter behavior of the first and second frequency bands may differ, equalization of individual CIRs may be necessary. Implementing the combination as an addition operation makes the increase in complexity and power consumption negligible.

[0044] In one or more embodiments, the first stream of the ultra-wideband radio frequency pulse is based on the following function:

[0045]

[0046] Where t represents time, and:

[0047]

[0048] Where p(t) is a real-valued ultra-wideband radio frequency pulse waveform with bandwidth BW, and Let p(t) be the Hilbert transform. This impulse construction technique facilitates the process of combining a first channel impulse response estimate with a second channel impulse response estimate to obtain a channel impulse response estimate with higher resolution than each of the first and second channel impulse response estimates. Specifically, the impulse p u (t) is the basic pulse shape used on the first communication channel. More specifically, the radar frame transmitted on the first communication channel uses p u (t) is a series of modulated pulses with a pulse shape. Furthermore, pulse p u (t) is achieved by rotating p using a time-varying phasor. + (t) is obtained by centering the pulse spectrum.

[0049] In one or more embodiments, the second stream of the ultra-wideband radio frequency pulse is based on the following function:

[0050]

[0051] Where t represents time, and:

[0052]

[0053] Where p(t) is a real-valued ultra-wideband radio frequency pulse waveform with bandwidth BW, and Let p(t) be the Hilbert transform. This impulse construction technique facilitates the process of combining a first channel impulse response estimate with a second channel impulse response estimate to obtain a channel impulse response estimate with higher resolution than each of the first and second channel impulse response estimates. Specifically, the impulse p l (r) is the basic pulse shape used on the second communication channel. More specifically, the radar frame transmitted on the second communication channel uses p l (t) is a series of modulated pulses with a pulse shape. Furthermore, pulse p l (t) is achieved by rotating p using a time-varying phasor. - (r) is obtained by centering the pulse spectrum.

[0054] In one or more embodiments, the method further includes applying the same radio filter setup for transmitting a first radar frame and a second radar frame, and increasing the bandwidth of the filter for transmitting the first radar frame and the second radar frame. This can further increase the range resolution of the radar device or radar system without significantly increasing cost in terms of complexity and power consumption. In one or more embodiments, the method further includes applying the same radio filter setup for receiving reflections of the first radar frame and the second radar frame, and increasing the bandwidth of the filter for receiving reflections of the first radar frame and the second radar frame. This can further increase the range resolution of the radar device or radar system without significantly increasing cost in terms of complexity and power consumption. In a practical implementation, the first frequency band and the second frequency band have the same bandwidth or approximately the same bandwidth. Furthermore, in a practical implementation, each of the first frequency band and the second frequency band has an approximate bandwidth of 500 MHz.

[0055] In one or more embodiments, the steps of transmitting a first radar frame and a second radar frame, receiving reflections of the first and second radar frames, and combining the first and second channel impulse response estimates are performed by a single radar device. In this way, the currently disclosed method can be implemented in a monostatic radar system. Furthermore, in the case of updating the first stream of ultra-wideband radio frequency pulses by centering the pulse spectrum using time-varying phase rotation, this step is also performed by a single radar device. Similarly, in the case of updating the second stream of ultra-wideband radio frequency pulses by centering the pulse spectrum using time-varying phase rotation, this step is also performed by a single radar device. Furthermore, in one or more embodiments, the steps of transmitting the first and second radar frames are performed by a first radar device, and the steps of receiving reflections of the first and second radar frames and combining the first and second channel impulse response estimates are performed by a second radar device. In this way, the currently disclosed method can be implemented in a multistatic radar system. Furthermore, in the case of updating the first stream of ultra-wideband radio frequency pulses by centering the pulse spectrum using time-varying phase rotation, this step is also performed by a second radar device. Furthermore, in the case where the second stream of the ultra-wideband radio frequency pulse is updated by centering the pulse spectrum using time-varying phase rotation, this step is also performed by the second radar device. Note that when the currently disclosed method is implemented in a multi-static radar system, it may be necessary to estimate and compensate for the carrier frequency offset between the radar devices.

[0056] Figure 4AAn illustrative embodiment of a radar device 400 is shown. The radar device 400 includes a transmitter 402, a receiver 404, and a processing unit 406. The radar device 400 is configured to detect an external target 408. The transmitter 402 is configured to transmit a first radar frame on a first communication channel, wherein the first radar frame includes a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame on the first communication channel includes transmitting the radar frame within a first frequency band. The transmitter 402 is further configured to transmit a second radar frame on a second communication channel, wherein the second radar frame includes a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band. Furthermore, the receiver 404 is configured to receive a reflection of the first radar frame and estimate a first channel impulse response based on the reflection of the first radar frame. The receiver 404 is further configured to receive a reflection of the second radar frame and estimate a second channel impulse response based on the reflection of the second radar frame. Furthermore, processing unit 406 is configured to combine the first channel impulse response estimate with the second channel impulse response estimate to obtain a channel impulse response estimate having a higher resolution than each of the first and second channel impulse response estimates. Radar device 400 represents a monostatic radar system implementing the currently disclosed method.

[0057] Figure 4B An illustrative embodiment of radar system 410 is shown. Radar system 410 includes a first radar device 412 and a second radar device 414. Radar system 410 is configured to detect an external target 416. The first radar device 412 is configured to transmit a first radar frame on a first communication channel, wherein the first radar frame includes a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame on the first communication channel includes transmitting the radar frame within a first frequency band. The first radar device 412 is further configured to transmit a second radar frame on a second communication channel, wherein the second radar frame includes a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band. Furthermore, the second radar device 414 is configured to receive reflections of the first radar frame and estimate a first channel impulse response based on the reflections of the first radar frame. The second radar device 414 is further configured to receive reflections of the second radar frame and estimate a second channel impulse response based on the reflections of the second radar frame. The second radar device 414 is further configured to combine the first channel impulse response estimate with the second channel impulse response estimate to obtain a channel impulse response estimate having a higher resolution than each of the first and second channel impulse response estimates. Radar system 410 represents a multistatic radar system 410 implementing the currently disclosed method.

[0058] As mentioned above, the currently disclosed method helps to increase range resolution without significantly increasing transmitter or receiver bandwidth. Specifically, the method involves, for example, transmitting radar frames and receiving their reflections on two sub-channels with half the bandwidth, and efficiently combining the reflected signals without significantly increasing the bandwidth or the ADC sampling rate at the receiver. More specifically, a wide-bandwidth transmission (e.g., 1 GHz) can be split into multiple transmissions on different sub-channels (e.g., each 500 MHz wide), and the received reflected radar frames across sub-channels can be combined to improve range resolution. Thus, each sub-channel can have a smaller bandwidth (e.g., 500 MHz), and therefore does not require a wide-bandwidth antenna or a higher sampling rate or increased digital signal processor (DSP) power consumption. Specific pulse-building techniques can be applied to each sub-channel, and associated simplified combination methods in the form of addition can be applied to facilitate the implementation of the currently disclosed method.

[0059] The currently disclosed method circumvents high bandwidth requirements by splitting a wideband transmission into multiple non-overlapping sub-channels. Multiple CIR measurements can be performed on each RF sub-channel, and the CIRs from each measurement can be combined to obtain an effective widebandwidth CIR. For example, a 1 GHz bandwidth channel can be split into two non-overlapping sub-channels, each with a bandwidth of 500 MHz. The CIR measurement on each sub-channel can involve the transmission of one or more pulses; this repetitive pulse stream is called a radar frame. On the receiver side, the reflected pulse streams on the same sub-channel can be coherently summed to improve the quality of the CIR estimates. This combination only improves the quality of the estimates, not the resolution, due to averaging over noise. The resolution of the CIR estimates from each sub-channel is limited by the 500 MHz bandwidth. The CIR estimates from each sub-channel can be combined in a manner comparable to the resolution of a 1 GHz wideband channel. Appropriate selection of the pulses transmitted on each sub-channel can facilitate the implementation of the step of combining the CIR estimates from each sub-channel to achieve the desired resolution.

[0060] Figure 5 , 6 Figures 5 and 7 show the pulse waveform in the time domain 500, the UWB pulse 600, and the sub-channel pulse shape in the frequency domain 700, respectively. Specifically, Figure 5 , 6 Figures 7 and 8 illustrate the pulse characteristics when the following pulse construction technique is applied. This technique is based on the assumption that p(t) is a real-valued UWB pulse waveform with a bandwidth BW optimized for radar applications (e.g., 1 GHz). In this case, two composite waveforms can be created as follows: and in Let p(r) be the Hilbert transform. It can be seen that p + (r) and p - (t) are all pulses with a bandwidth of BW / 2, where p + The bandwidth of (t) is limited to 0 ≤ f ≤ BW / 2, while p - The bandwidth of (t) is limited to -BW / 2 ≤ f ≤ 0. Pulses can be rotated such that the "center" frequency shifts, and their bandwidths are all limited to -BW / 4 ≤ f ≤ BW / 4. This produces the following function: and Note that the UWB pulse p(t) can be selected or optimized to make the pulse p u Both p(t) and p(t) satisfy the transmission requirements specified in various standards, such as the IEEE / FiRa / FCC requirements for BW / 2 bandwidth UWB systems. Furthermore, it should be noted that... Figure 5 and 6 A system with a 1 GHz bandwidth BW is shown, and Figure 7 The sub-channels are shown, each with a bandwidth of 500MHz.

[0061] Figure 8 This illustrates a pulse transmission and CIR combination technique 800. Based on the example of the pulse construction technique described above, pulse transmission and CIR combination can be implemented as follows. Let f c,u and f c,l This represents the center frequency of two UWB RF channels separated by BW / 2Hz. For example, as defined in the IEEE 802.15.4 UWB specification, f... c,l It can be channel #8 and f c,u It could be channel #9, provided BW = 1GHz. c,u Radar transmission on the surface can be implemented as follows: using pulse p u (t) in f c,u Radar frames (pulse streams) are transmitted on the centered sub-channel at a bandwidth of BW / 2 in f c,u The pulse stream is received on the central sub-channel, and the pulses are coherently combined to obtain the CIR estimate CIR(u). Furthermore, f c,l Radar transmission on the surface can be implemented as follows: using pulse p l (t) in f c,l Radar frames (pulse streams) are transmitted on a 500MHz sub-channel centered on the radar, with a bandwidth of BW / 2 at f c,lThe pulse stream is received on the central sub-channel, and the pulses are coherently combined to obtain a CIR estimate CIR(l). Then, using the two CIR estimates (which have limited resolution due to bandwidth BW / 2), a new CIR estimate is created by addition: CIR estimate = CIR(u) + CIR(l). Note that the CIR estimates can be upsampled 818, 819, for example, by interpolation using a factor of 2. Furthermore, mixers 820, 822 perform a mixing operation before performing addition 816. Specifically, the first CIR estimate is re-aligned to the lower channel by a frequency shift of the baseband CIR, and the second CIR estimate is re-aligned to the upper channel by a frequency shift of the baseband CIR. Furthermore, equalization is performed by filtering the first and second CIR estimates. The new CIR estimate created by addition 816 has improved range resolution.

[0062] By constructing and transmitting on two adjacent channels with a bandwidth of BW / 2, the combined CIR estimate is expected to have a higher resolution equivalent to a full BW Hz radar system. The receiver and transmitter operate on sub-channels with a bandwidth of BW / 2, and therefore, there is less complexity and power consumption compared to transmitting and receiving pulses on the BW bandwidth. The constructed sub-channel pulses inherit certain characteristics from pulse shapes with wider bandwidths, thus the pulse construction technique described above is well-suited for designing pulse shapes that meet various regulatory constraints regarding occupied bandwidth.

[0063] Note that the resolution of the combined CIR depends on the transmitter and receiver filter bandwidths. If the filter responses between the two sub-channels change significantly due to different RF tuning, the achievable distance resolution may be less than that of an ideal BWHz UWB system. In this case, an alternative approach is to widen the analog transmit and receive filter bandwidths (i.e., BW Hz) and use the same filter settings for both sub-channels. However, in this case, there is no need to increase the sampling rate; the ADC can continue to operate in a lower bandwidth mode (BW / 2Hz).

[0064] Note that the above embodiments have been described with reference to different subjects. Specifically, some embodiments may have been described with reference to method claims, while others may have been described with reference to device claims. However, those skilled in the art will understand from the foregoing that, unless otherwise specified, any combination of features relating to different subjects, in particular a combination of features of method claims and features of device claims, is also considered to be disclosed herein, except for any combination of features belonging to one type of subject matter.

[0065] Additionally, it should be noted that the drawings are schematic. Similar or identical elements are represented by the same reference numerals in different drawings. Furthermore, it should be noted that, in order to provide a concise description of the illustrative embodiments, implementation details that are customary to those skilled in the art may not be described. It should be understood that, as in any engineering or design project, numerous implementation-specific decisions must be made during the development of any such implementation to achieve the developer's specific objectives, such as complying with system-related and business-related constraints, which can vary from one implementation to another. Furthermore, it should be understood that this development work may be complex and time-consuming, but will still be the common practice for those skilled in the art to engage in design, fabrication, and manufacturing.

[0066] Finally, it should be noted that those skilled in the art will be able to devise numerous alternative embodiments without departing from the scope of the appended claims. Any reference numerals placed between parentheses in the claims should not be construed as limiting the claims. The words “comprise(s)” or “comprising” do not exclude the presence of elements or steps other than those listed in the claims. The words “a / an / a” preceding an element do not exclude the presence of a plurality of such elements. The measures recited in the claims can be implemented by means of hardware comprising several distinct elements and / or by means of a suitably programmed processor. In a device claim listing several components, several of these components may be embodied by the same piece of hardware. The fact that certain measures are recited in mutually different dependent claims does not in itself indicate that a combination of these measures cannot be advantageously utilized.

Claims

1. A method for performing radar operation, characterized in that, include: Transmitting a first radar frame on a first communication channel, wherein the first radar frame comprises a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame on the first communication channel comprises transmitting the radar frame within a first frequency band; A second radar frame is transmitted on a second communication channel, wherein the second radar frame comprises a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band; Receive the reflection of the first radar frame and estimate the first channel impulse response based on the reflection of the first radar frame; Receive the reflection of the second radar frame and estimate the second channel impulse response based on the reflection of the second radar frame; The first channel impulse response estimate is combined with the second channel impulse response estimate to obtain a channel impulse response estimate with a higher resolution than each of the first and second channel impulse response estimates.

2. The method according to claim 1, characterized in that, Combining the first channel impulse response estimate with the second channel impulse response estimate includes performing equalization and addition operations on the first channel impulse response estimate and the second channel impulse response estimate.

3. The method according to claim 1, characterized in that, The first stream of the ultra-wideband radio frequency pulse is based on the following function: p u (t)=p + (t)e -j2π(BW / 4)t , Where t represents time, and: Where p(t) is a real-valued ultra-wideband radio frequency pulse waveform with bandwidth BW, and Let p(t) represent the Hilbert transform.

4. The method according to claim 1, characterized in that, The second stream of the ultra-wideband radio frequency pulse is based on the following function: p l (t)=p - (t)e +j2π(BW / 4)t , Where t represents time, and: Where p(t) is a real-valued ultra-wideband radio frequency pulse waveform with bandwidth BW, and Let p(t) represent the Hilbert transform.

5. The method according to claim 1, characterized in that, Additionally, it includes applying the same radio filter settings for transmitting the first radar frame and the second radar frame, and increasing the bandwidth of the filter for transmitting the first radar frame and the second radar frame.

6. The method according to claim 1, characterized in that, Additionally, it includes applying the same radio filter settings to receive the reflections of the first radar frame and the second radar frame, and increasing the bandwidth of the filter to receive the reflections of the first radar frame and the second radar frame.

7. The method according to claim 1, characterized in that, The steps of transmitting the first radar frame and transmitting the second radar frame, receiving the reflections of the first radar frame and the second radar frame, and combining the first channel impulse response estimate and the second channel impulse response estimate are performed by a single radar device.

8. The method according to claim 1, characterized in that, The steps of transmitting the first radar frame and transmitting the second radar frame are performed by the first radar device, and the steps of receiving the reflections of the first radar frame and the second radar frame and combining the first channel impulse response estimate and the second channel impulse response estimate are performed by the second radar device.

9. A radar device, characterized in that, include: A transmitter configured to transmit a first radar frame over a first communication channel, wherein the first radar frame comprises a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame over the first communication channel comprises transmitting the radar frame within a first frequency band. The transmitter is further configured to transmit a second radar frame on a second communication channel, wherein the second radar frame comprises a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band. A receiver configured to receive the reflection of the first radar frame and estimate the first channel impulse response based on the reflection of the first radar frame; The receiver is further configured to receive the reflection of the second radar frame and estimate the second channel impulse response based on the reflection of the second radar frame; The processing unit is configured to combine a first channel impulse response estimate with a second channel impulse response estimate to obtain a channel impulse response estimate having a higher resolution than each of the first and second channel impulse response estimates.

10. A radar system, characterized in that, include: A first radar device is configured to transmit a first radar frame over a first communication channel, wherein the first radar frame includes a first stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the first radar frame over the first communication channel includes transmitting the radar frame within a first frequency band. The first radar device is further configured to transmit a second radar frame on a second communication channel, wherein the second radar frame includes a second stream of one or more ultra-wideband radio frequency pulses, and wherein transmitting the second radar frame on the second communication channel includes transmitting the radar frame within a second frequency band; A second radar device is configured to receive the reflection of the first radar frame and estimate a first channel impulse response based on the reflection of the first radar frame. The second radar device is further configured to receive the reflection of the second radar frame and estimate the second channel impulse response based on the reflection of the second radar frame; The second radar device is further configured to combine the first channel impulse response estimate with the second channel impulse response estimate to obtain a channel impulse response estimate with a higher resolution than each of the first and second channel impulse response estimates.

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