Frequency stitching for radar systems
By dividing the channel sequence of the radar system into multiple parts and using multiple transmitters to transmit RF signals in time overlap, the problems of long coherence time and complex antenna design in the prior art are solved, achieving faster target detection and reduced costs.
Patent Information
- Application Number
- CN202511068680.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-09-17
- Filing Date
- 2025-07-31
- Publication Date
- 2026-03-17
AI Technical Summary
Existing radar systems suffer from long coherence times and high antenna design complexity in frequency stitching, which limits system performance and antenna selection.
A frequency-stitched channel impulse response is generated by dividing the channel sequence into multiple parts and transmitting RF signals by multiple transmitters in a manner that at least partially overlaps in time.
It shortens the coherence time, reduces the complexity and cost of antenna design, while maintaining improved sensing performance metrics such as signal-to-noise ratio and detection accuracy.
Smart Images
Figure CN121679490A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to apparatus and methods for performing frequency stitching in radar systems. Background Technology
[0002] Frequency splicing is a known technique applicable to radar systems, in which a total effective bandwidth greater than the RF channel bandwidth is achieved by combining (or splicing together) the channel impulse responses from multiple adjacent channels.
[0003] This disclosure is intended to provide improved apparatus and methods for performing frequency stitching in radar systems. Summary of the Invention
[0004] Various aspects of this disclosure are set forth in the appended independent and dependent claims. Combinations of features from dependent claims may be combined with features of the independent claim where appropriate, and not merely as expressly stated in the claims.
[0005] According to a first aspect of this disclosure, a radar system is provided, comprising a first transmitter, a second transmitter, a first receiver, a second receiver, and a processor electrically connected to the first and second transmitters and the first and second receivers. The processor is configured to: determine a channel sequence for frequency stitching, wherein the channel sequence comprises a plurality of RF channels, each RF channel having a corresponding carrier frequency and bandwidth; divide the channel sequence into a first portion and a second portion; instruct the first transmitter to transmit RF signals on each RF channel of the first portion of the channel sequence within a first time period; instruct the second transmitter to transmit RF signals on each RF channel of the second portion of the channel sequence within a second time period, wherein the second time period at least partially overlaps with the first time period; and generate a frequency-stitched channel impulse response from reflected RF signals received from each receiver in response to the transmitted RF signals.
[0006] Therefore, the radar system is configured to control the frequency splicing process of multiple transmitters.
[0007] It should be understood that each RF signal transmitted by the first transmitter or the second transmitter is an RF signal modulated onto the corresponding carrier frequency of the corresponding RF channel in the channel sequence.
[0008] A radar system may include additional circuitry or components shared by the radar units. It should be understood that each transmitter may be equivalently referred to as a transmitter unit, where a unit may include multiple components and / or circuitry.
[0009] It should be understood that each receiver can be equivalently referred to as a receiver unit, where a unit may include multiple components and / or circuits.
[0010] For example, each transmitter may have an associated carrier generation unit.
[0011] Each transmitter may include one or more of an RF digital-to-analog converter, a mixer, or a power amplifier.
[0012] Each carrier generation unit may include an RF phase-locked loop and a local oscillator generation circuit (e.g., a frequency divider).
[0013] Each receiver may include one or more of a low-noise amplifier, a mixer, or an analog filter.
[0014] Optionally, the radar system can be monostatic. Therefore, the receiver and transmitter can be juxtaposed. Optionally, a first transmitter and a first receiver can form a first monostatic unit, and a second transmitter and a second receiver can form a second monostatic unit.
[0015] Alternatively, the radar system can be multistatic. Therefore, the receiver can be physically separated from the transmitter (e.g., located in a separate unit).
[0016] It should be understood that it is not necessary for the antenna to be part of the radar system. Typically, the one or more antennas will be located outside or separately from the radar system, which includes the transmitter and receiver.
[0017] A first transmitter is configured to be coupled to a first antenna, and a second transmitter is configured to be coupled to a second antenna. In this disclosure, the term "coupled" can refer to a wired or radio connection.
[0018] The first receiver can be configured to couple to the first antenna or another antenna (e.g., the fourth antenna).
[0019] The second receiver can be configured to couple to the second antenna or another antenna (e.g., the fifth antenna).
[0020] It should be understood that a radar system can consist of multiple components that communicate with each other. In some embodiments, a radar system may include multiple microchips or integrated circuits. In some embodiments, a radar system may be implemented on a single chip (i.e., a system-on-a-chip).
[0021] A processor may include multiple processors, multiple processing resources, or multiple processing units or devices. In other embodiments, a single processor may be provided.
[0022] Optionally, each RF channel has a bandwidth of approximately 500 MHz or 1 GHz. In some embodiments, each RF channel has a bandwidth of 499.2 MHz.
[0023] A time gap can be set between each RF signal transmitted.
[0024] Optionally, the second time period and the first time period occur simultaneously, or the second time period and the first time period completely overlap.
[0025] Optionally, each part of the channel sequence includes at least two of the plurality of RF channels.
[0026] Optionally, the plurality of RF channels in the channel sequence do not overlap. Therefore, the corresponding carrier frequency and bandwidth of each RF channel can be selected such that a frequency gap is set between each adjacent RF channel.
[0027] Optionally, adjacent RF channels in the channel sequence may overlap at least partially.
[0028] Optionally, each RF signal is an ultra-wideband (UWB) RF signal. Therefore, the radar system can be a UWB radar system.
[0029] Optionally, the plurality of RF channels in the channel sequence include channels defined in the IEEE 802.15.4 standard. For example, the channel sequence may include channels CH5, CH6, CH8, and CH9.
[0030] In some embodiments of this disclosure, the processor may divide a channel sequence into three or more parts, wherein each part of the channel sequence is associated with a corresponding transmitter.
[0031] The processor can be configured to generate a frequency-stitched channel impulse response from the reflected RF signals received from each receiver in response to the transmitted RF signal.
[0032] Optionally, the radar system further includes a third transmitter and a third receiver, and the processor is further configured to divide the channel sequence into a first part, a second part, and a third part.
[0033] Optionally, the processor is further configured to instruct the third transmitter to transmit RF signals on each RF channel in the third part of the channel sequence during the third time period, wherein the third time period at least partially overlaps with at least one of the first or second time periods.
[0034] Optionally, the processor is further configured to generate a frequency-stitched channel impulse response from the reflected RF signal received from the first receiver, the second receiver, and the third receiver in response to the transmitted RF signal.
[0035] Optionally, the third time period may at least partially overlap with both the first and second time periods.
[0036] Optionally, the third time period may occur simultaneously with the first and second time periods.
[0037] Optionally, the radar system may further include multiple antennas, each coupled to a corresponding transmitter and / or receiver of the radar system. Therefore, in some embodiments, the radar system may include antennas.
[0038] Alternatively, the antenna can be mounted via an antenna-in-package (AiP) configuration.
[0039] Alternatively, the receiver can be coupled to the same antenna as the associated transmitter. Alternatively, the receiver can be coupled to a different antenna.
[0040] Therefore, a radar system may include at least a first antenna and a second antenna. The first antenna is coupled to a first transmitter, and the second antenna is coupled to a second transmitter.
[0041] Optionally, the first receiver is coupled to the first antenna, or the first receiver is coupled to another antenna (e.g., a third or fourth antenna).
[0042] Optionally, the second receiver is coupled to the second antenna, or the second receiver is coupled to another antenna (e.g., the fourth or fifth antenna).
[0043] The radar system can be installed in the vehicle, making it either an integral part of the vehicle's radar system.
[0044] Alternatively, the radar system may be a child presence detection system or an adaptive cruise control system (or form part of it).
[0045] According to a second aspect of this disclosure, a method for performing a multi-transmitter frequency splicing process is provided, the method comprising: determining a channel sequence for frequency splicing, wherein the channel sequence includes a plurality of RF channels, each RF channel having a corresponding carrier frequency and bandwidth; dividing the channel sequence into a first portion and a second portion; transmitting RF signals on each RF channel of the first portion of the channel sequence using a first transmitter and a first antenna during a first time period; transmitting RF signals on each RF channel of the second portion of the channel sequence using a second transmitter and a second antenna during a second time period, wherein the second time period at least partially overlaps with the first time period; receiving reflected RF signals for the transmitted RF signals at a first receiver and a second receiver; and generating a frequency-spliced channel impulse response from the received reflected RF signals.
[0046] It should be understood that any embodiments or features described above in conjunction with the first aspect of this disclosure are equally applicable to the second aspect of this disclosure.
[0047] Transmitting an RF signal may include modulating the RF signal onto the corresponding carrier frequency of the corresponding RF channel in the channel sequence.
[0048] Optionally, generating a frequency-stitched channel impulse response includes applying a frequency-stitching algorithm to the received reflected RF signal.
[0049] Optionally, each RF channel has a bandwidth of approximately 500 MHz or 1 GHz. In some embodiments, each RF channel has a bandwidth of 499.2 MHz.
[0050] Optionally, a time gap can be set between each transmitted RF signal.
[0051] Optionally, the second time period and the first time period occur simultaneously, or the second time period and the first time period completely overlap.
[0052] Optionally, each part of the channel sequence includes at least two of the plurality of RF channels.
[0053] Optionally, the plurality of RF channels in the channel sequence do not overlap. Therefore, the corresponding carrier frequency and bandwidth of each RF channel can be selected such that a frequency gap is set between each RF channel.
[0054] Optionally, adjacent RF channels in the channel sequence may overlap at least partially.
[0055] Optionally, each RF signal is an ultra-wideband (UWB) RF signal.
[0056] Optionally, the plurality of RF channels in the channel sequence include channels defined in the IEEE 802.15.4 standard. For example, the channel sequence may include channels CH5, CH6, CH8, and CH9.
[0057] Optionally, the method includes dividing the channel sequence into three or more parts, wherein each part of the channel sequence is transmitted by a corresponding transmitter and antenna.
[0058] Optionally, the method includes dividing the channel sequence into a first part, a second part, and a third part, and transmitting RF signals on each RF channel of the third part of the channel sequence using a third transmitter and a third antenna during a third time period, wherein the third time period at least partially overlaps with at least one of the first time period or the second time period.
[0059] Optionally, the method includes receiving reflected RF signals for the transmitted RF signals at a first receiver, a second receiver, and a third receiver.
[0060] Optionally, the third time period may at least partially overlap with both the first and second time periods.
[0061] Optionally, the third time period occurs simultaneously with the first and second time periods (i.e., they completely overlap).
[0062] Optionally, the first receiver is coupled to the first antenna or another (e.g., the fourth) antenna.
[0063] Optionally, the second receiver is coupled to the second antenna or another (e.g., the fifth) antenna.
[0064] Optionally, the third receiver is coupled to a third antenna or another (e.g., a sixth) antenna.
[0065] Optionally, the method for performing the multi-transmitter frequency stitching process is incorporated into the automotive radar sensing method. Attached Figure Description
[0066] Embodiments of this disclosure will be described below by way of example only with reference to the accompanying drawings, in which the same reference numerals refer to the same elements, and wherein:
[0067] Figure 1 A diagram illustrating a channel sequence for frequency splicing according to the prior art is shown;
[0068] Figure 2 This is a block diagram illustrating an embodiment of a radar system according to the prior art;
[0069] Figure 3 A diagram illustrating a channel sequence for frequency splicing according to an embodiment of the present disclosure is shown;
[0070] Figure 4 A diagram illustrating a channel sequence for frequency splicing according to another embodiment of the present disclosure is shown;
[0071] Figure 5 This indicates that the method for transmitting according to embodiments of the present disclosure is as follows: Figure 3 A block diagram of an embodiment of a radar system with the shown channel sequence;
[0072] Figure 6 This is a block diagram illustrating another embodiment of a radar system according to the present disclosure;
[0073] Figure 7 This is a block diagram illustrating another embodiment of a radar system according to the present disclosure;
[0074] Figure 8 A chip implementation scheme of an embodiment of a radar system according to the present disclosure is shown;
[0075] Figure 9A chip implementation scheme according to another embodiment of the radar system of this disclosure is shown; and
[0076] Figure 10 This is a flowchart illustrating a method for performing a multi-transmitter frequency splicing process according to an embodiment of the present disclosure. Detailed Implementation
[0077] Embodiments of the present disclosure are described below with reference to the accompanying drawings. It should be understood that the drawings are provided for illustrative purposes only, and features are not shown to scale unless explicitly indicated.
[0078] Frequency stitching is a known technique in radar systems or radar sensing / ranging systems. A channel (or RF channel) is a radio frequency channel having a bandwidth (e.g., in Hz) as the channel's frequency width and a carrier frequency (e.g., in Hz) as the channel's center frequency. The purpose of frequency stitching is to improve sensing performance metrics such as signal-to-noise ratio or detection accuracy by combining (i.e., stitching together) RF signals from multiple adjacent channels to achieve a total effective bandwidth greater than the channel bandwidth. Figure 1 The image shows an example of a channel sequence (or channel order) used in frequency splicing according to existing technology.
[0079] exist Figure 1 In this sequence, the channel sequence includes a first channel CH(0), a second channel CH(1), a third channel CH(2), and a fourth channel CH(3). It should be understood that the notation CH(X) only represents the nominal channel frequency and has no specific meaning in this technique. Frequency splicing can be performed using overlapping or non-overlapping channels, where overlap refers to frequency overlap between channels. Figure 1 The example in the text shows no overlap between adjacent channels. The carrier frequency grid configuration can be used to determine the percentage of overlap. For example, if the channel bandwidth is 499.2 MHz, the gap between adjacent carrier frequencies can be selected as 124.8 MHz, 249.6 MHz, 374.4 MHz, and 499.2 MHz, indicating 75%, 50%, 25%, and 0% (no overlap) overlap, respectively.
[0080] like Figure 2 The radar system or equipment shown can be used based on Figure 1 The channel sequence shown performs a frequency splicing process. System 20 includes a processor 22 and a transmitter and receiver unit 24. The transmitter and receiver unit (TRX) 24 is coupled to an antenna 30 for transmitting RF signals.
[0081] During the transmission of radar signals, RF signals (or sensing frames) are transmitted via antenna 30 on each channel CH(0) to CH(3) of the sequence, wherein there is a time gap x between adjacent RF signals (or sensing frames). Typically, the time gap x is on the order of a few microseconds to one millisecond. Thus, a first RF signal or sensing frame 10 is transmitted on channel CH(0), a second RF signal or sensing frame 12 is transmitted on channel CH(1), a third RF signal or sensing frame 14 is transmitted on channel CH(2), and a fourth RF signal or sensing frame 16 is transmitted on channel CH(3). In this disclosure, it should be understood that in practice, transmitting an RF signal "on a channel" means modulating the RF signal onto the carrier frequency of said channel.
[0082] Therefore, in this example, the total effective bandwidth (Δfeff) of the transmitted RF signal is equal to the sum of the bandwidths of each channel in the sequence, since the channels do not overlap. The total time spent transmitting the signal across the entire channel sequence is Δt, which is called the coherence time. The reflected RF signal is then received at TRX 24 and combined by processor 22 to form a frequency-stitched channel impulse response.
[0083] Therefore, in the prior art, the RF signal is transmitted via a transmitter coupled to antenna 30, reflected from the environment, and a channel impulse response (CIR) is generated from the reflection in the receiver. The resulting CIR is combined by processor 22 to form a CIR corresponding to the frequency-stitched channel (i.e., the equivalent channel with a total effective bandwidth of Δfeff Hz). Since there is only one antenna, the required antenna bandwidth is equal to the total effective bandwidth.
[0084] The problem with this frequency stitching technique is that, in order to achieve the desired advantages provided by a large effective bandwidth, it can impose stringent requirements on the system implementation. First, regarding the coherence time (Δt), it is assumed that the target (i.e., the target or object of the radar system) is stationary during the measurement time to avoid any error. Therefore, the more channels stitched together, the longer the required coherence time, and this assumption limits the performance and potential use cases of frequency stitching. Second, the more channels stitched together, the larger the effective antenna bandwidth (Δfeff), which imposes design constraints on antenna 30, as it must support this entire bandwidth (i.e., be able to transmit and receive RF signals across the entire effective bandwidth). This can make antenna design more challenging, increase costs, and limit antenna selection. Therefore, in this example, the effective antenna bandwidth equals the total effective bandwidth (Δfeff).
[0085] This disclosure is intended to alleviate these problems while still providing the advantages resulting from the splicing of large effective bandwidth frequencies that improve sensing performance metrics such as signal-to-noise ratio or detection accuracy.
[0086] In this disclosure, the above-mentioned problem is solved by splitting or dividing the channel sequence into at least two parts (or channel subsequences) and transmitting those parts (or subsequences) that overlap at least partially in time via multiple transmitters. Figure 3 and 4 An embodiment of a channel sequence (or channel order) for use in frequency splicing, according to the present disclosure, is shown.
[0087] exist Figure 3 In this embodiment, the channel sequence CH(0), CH(1), CH(2), CH(3) is divided into a first part (CH(0) + CH(1)) and a second part (CH(2) + CH(3)), represented by the dashed line A. Although the channel sequence includes four channels in this embodiment, it should be understood that any number of channels (e.g., two or more) can be provided in the sequence. Furthermore, although Figure 3 Each portion of the channel sequence comprises two channels; however, it should be understood that the number of channels may not be equally divided between the portions. In some embodiments, a portion of the channel sequence may include a single channel, and another portion may include two or more channels.
[0088] exist Figure 3 In the illustrated embodiment, during a first time period Δt1, a first transmitter (TX1, TRX1) coupled to a first antenna transmits a first RF signal or sensing frame 100 on channel CH(0) and a second RF signal or sensing frame 102 on channel CH(1). During a second time period Δt2, a second transmitter (TX2, TRX2) coupled to a second antenna transmits a third RF signal or sensing frame 104 on channel CH(2) and a fourth RF signal or sensing frame 106 on channel CH(3). In this embodiment, the first time period Δt1 and the second time period Δt2 occur simultaneously or completely overlap. Therefore, the RF signals 104, 106 of the second part of the channel sequence are transmitted simultaneously with the RF signals 100, 102 of the first part of the channel sequence. Time gaps are still provided between adjacent RF signals 100 and 102 and between adjacent RF signals 104 and 106.
[0089] Although the notation CH(0)-CH(3) is used Figure 3 The carrier frequency of the sequence, but in order to... Figure 1 Consistently, in some embodiments, the carrier frequencies of the channel sequence can be selected to correspond to channels defined in the IEEE 802.15.4 standard, such as channels CH5, CH6, CH8, and CH9. Therefore, in this disclosure, the RF signal can be a UWB radar signal. The radar system can be a UWB radar system (or part of it), or part of a UWB ranging / detection system.
[0090] In some embodiments of this disclosure, the channel sequence can be divided into two or more parts, such as Figure 4 As shown. In Figure 4 In the illustrated embodiment, the channel sequence is divided into three parts. The first part of the channel sequence corresponds to white rectangles 100 and 102, the second part of the channel sequence corresponds to diagonal striped rectangles 104 and 106, and the third part of the channel sequence corresponds to vertical striped rectangles 108 and 110.
[0091] In this embodiment, during a first time period Δt1, a first transmitter coupled to a first antenna transmits a first RF signal or sensing frame 100 on a first channel and a second RF signal or sensing frame 102 on a second channel. During a second time period Δt2, a second transmitter coupled to a second antenna transmits a third RF signal or sensing frame 104 on a third channel and a fourth RF signal or sensing frame 106 on a fourth channel. During a third time period Δt3, a third transmitter coupled to a third antenna transmits a fifth RF signal or sensing frame 108 on a fifth channel and a sixth RF signal or sensing frame 110 on a sixth channel. The first time period Δt1, the second time period Δt2, and the third time period Δt3 all partially overlap. In other embodiments, only two time periods may at least partially overlap.
[0092] exist Figure 4 In the sequence, adjacent channels have approximately 50% overlap in channel bandwidth (or frequency), while... Figure 3 There is no channel overlap in the illustrated embodiments. Typically, in this disclosure, each channel has a corresponding bandwidth of approximately 500 MHz or 1 GHz. Furthermore, the channel sequence (or channel order) used in frequency splicing can be sequential or unordered. Figure 3 and 4 In this embodiment, the channel sequence is sequential, meaning the carrier frequency of each adjacent channel increases sequentially. However, it should be understood that in other embodiments of this disclosure, an unordered channel sequence may be provided.
[0093] Accordingly, such as Figure 3 and 4 As shown, when each part of the channel sequence is transmitted by a corresponding transmitter coupled to a separate antenna (see...) Figure 5-9 This reduces the overall coherence time, allowing the entire radar / ranging system to detect faster-moving targets or incur fewer errors during detection. Furthermore, each antenna only needs to support the bandwidth Δf (i.e., the effective bandwidth of the corresponding portion of the channel sequence), rather than the total effective bandwidth Δfeff of the entire channel sequence. This makes antenna design less challenging, reduces costs, and improves the available antenna choices.
[0094] Figure 5 An embodiment of a radar system according to this disclosure is illustrated. Radar system 120 includes a processor 122, a first transmitter and a first receiver (TRX1), a second transmitter and a second receiver (TRX2). TRX1 is coupled to a first antenna 130, and TRX2 is coupled to a second antenna 132. Figure 5 As shown, antennas 130 and 132 may not be part of system 120 because they can be located outside the radar system 120. However, in some embodiments, antennas 130 and 132 may be part of the radar system 120. The first antenna 130 and the second antenna 132 are each configured to radiate radio waves generated from RF signals received from their respective transmitters into the environment. Thus, as is the standard case in this art, the transmitter generates an electrical RF signal (or RF current), which is converted into radio waves and output by the antenna.
[0095] The first transmitter TRX1 is configured to transmit RF signals on each channel in the first part of the channel sequence, and the second transmitter TRX2 is configured to transmit RF signals on each channel in the second part of the channel sequence (e.g., Figure 3 As shown). If the channel sequence is divided into more than two parts (e.g., as shown). Figure 4 As shown), additional transmitters and receivers are required because the number of TRX units must correspond to the number of segments into which the channel sequence is divided.
[0096] The transmitted RF signal is reflected by the environment. The resulting channel impulse response is received at antennas 130 and 132 and converted back into an electrical signal by the corresponding receivers RX1 and RX2. The channel impulse response is processed and combined by processor 122 to form a channel impulse response corresponding to the frequency-stitched channel. Processor 122 may be a microcontroller or other type of processing device. Processor 122 may include multiple processors, microcontrollers, or processing devices communicating with each other.
[0097] The notations TRX1 and TRX2 are typically used to refer to monostatic radar systems (see [link]). Figure 6 However, separate transmitters and receivers can be provided. It should be understood that... Figure 5 This is a functional diagram, and the radar system (and the units represented therein) actually includes all the standard circuitry and components for such radar / RF systems. In this disclosure, each transmitter is configured to modulate an RF signal onto the carrier frequency of a selected RF channel, and each receiver is configured to demodulate an RF signal from the carrier frequency of the selected RF channel. Thus, each transmitter-receiver unit (or TRX unit) typically includes a transmitter unit, a receiver unit, and a carrier generation unit, which are used to form... Figure 5This is part of the TRX unit. The transmitter unit may include an RF digital-to-analog converter or mixer and a power amplifier. The receiver unit may include a low-noise amplifier, a mixer or an analog filter. The carrier generation unit may include an RF phase-locked loop and a local oscillator generation circuit (e.g., a frequency divider).
[0098] It should be understood that a potential drawback of the multi-transmitter solution provided in this disclosure is the need for at least a second transmitter and receiver, which increases the overall implementation complexity (chip area, power consumption). However, there are many use cases where, in practice, this potential drawback is not a problem, particularly considering the technical advantages offered by improved frequency stitching and relaxed antenna requirements. In some embodiments, the radar system may be a dual TRX radar chip (or part of it), or it may be used in a multi-device radar system, such as for a child presence detection system in an automotive environment (in-cabin sensing). It should be understood that these are merely two possible applications of the systems and methods of this disclosure.
[0099] Figure 6 An embodiment of a monostatic radar system according to the present disclosure is shown. In this embodiment, radar system 120 includes a first transmitter TX1 124 and a first receiver RX1 125 co-located; and a second transmitter TX2 126 and a second receiver RX2 127 co-located. A first antenna 130 is coupled to the first transmitter 124, and a second transmitter 132 is coupled to the second transmitter 126. Instead of... Figure 5 The receiver is coupled to the same antenna as the associated transmitter, providing an additional antenna. Thus, the first receiver 125 is coupled to the third antenna 134, and the second receiver 127 is coupled to the fourth antenna 136.
[0100] Figure 7 An embodiment of a multistatic radar system according to this disclosure is shown. In this embodiment, physical space is provided between the receiver and the corresponding transmitter. Therefore, the first receiver 125 and the second receiver 127 are physically separated from the first transmitter 124 and the second transmitter 126. Antenna arrangement and Figure 6 Same as above.
[0101] In some embodiments, Figure 6 The radar system shown in Figure 7 may include multiple additional transmitters and receivers, either juxtaposed or physically separated, each coupled to a corresponding antenna, wherein the number of transmitters, receivers, and antennas corresponds to the number of segments into which the channel sequence is divided. In other embodiments, one or more transmitter and receiver pairs may share a common antenna (e.g., Figure 5 (As shown).
[0102] Figure 8 and9 Two possible chip implementations of the radar system according to the present invention are shown. Figure 8 The device includes two separate integrated circuits (or chips, or devices) 140 and 142. The first integrated circuit 140 includes a first transmitter 124, a first receiver 125, and a local oscillator 128. The second integrated circuit 142 includes a second transmitter 126, a second receiver 127, and a local oscillator 128. Electrical connections are provided on each integrated circuit 140 and 142 for coupling to one or more antennas. A separate processor (e.g., a microcontroller) 122 is provided to perform frequency splicing.
[0103] exist Figure 9 The device includes a single integrated circuit (or chip, or device) 150. The single integrated circuit 150 includes first transmitters and receivers 124 and 125, second transmitters and receivers 126 and 127, two local oscillators 128, and an on-chip processor (or controller) 122. Electrical connections are provided for coupling to at least two antennas.
[0104] Figure 10 The present disclosure illustrates a method for performing a multi-transmitter frequency splicing process 200 according to an embodiment of the present disclosure. Initially, at step 202, a channel sequence for frequency splicing is provided.
[0105] The channel sequence can be defined in IEEE 802.15.4ab revision and is given by the channel mapping function:
[0106] CH(f(p(OF+1))+q), p=0, 1,..., N-1, q>=0,
[0107] Where p is an integer from 0 to N-1, N is the total number of channels to be spliced, OF is the overlap factor, q is the channel offset, and the function f is:
[0108]
[0109] in Let f(x) represent the lower bound function. Therefore, the channel sequence is generated by sampling the function f(x) at point p(OF+1) (p = 0, ..., N-1) and adding the channel offset q.
[0110] If N=4, OF=0 and q=0, then the channel sequence is CH(0), CH(1), CH(2), CH(3), and according to the previous example, the first and second parts (or channel subsequences) used for transmission can be CH(0), CH(1) and CH(2), CH(3), respectively. Similarly, in some embodiments, the channel can be a UWB channel as defined in the IEEE 802.15.4 standard, corresponding to channels CH5, CH6, CH8, and CH9, respectively.
[0111] At step 204, the channel sequence is divided into at least a first part and a second part (therefore, multiple (N) parts or subsequences are provided, where N is any integer greater than or equal to 2).
[0112] At step 206, during the first time period, the first portion of the channel sequence is transmitted via a first transmitter coupled to the first antenna. In practice, transmitting the first portion of the channel sequence means transmitting an RF signal on each channel of the first portion of the channel sequence (i.e., the RF signal is modulated onto the corresponding carrier frequency of each channel in the first portion of the sequence), such as... Figure 3 and 4 As shown.
[0113] At step 208, during the second time period, the second portion of the channel sequence is transmitted via a second transmitter coupled to the second antenna. In practice, transmitting the second portion of the channel sequence means transmitting an RF signal on each channel of the second portion of the channel sequence (i.e., the RF signal is modulated onto the corresponding carrier frequency of each channel in the second portion of the sequence), such as... Figure 3 and 4 As shown. Since the first and second time periods overlap at least partially, steps 206 and 208 are performed at least partially simultaneously.
[0114] If the channel sequence is divided into three or more parts, repeat steps 206 / 208 for each additional part of the channel sequence until the entire channel sequence has been transmitted.
[0115] At step 210, the reflected RF signal from the transmitted signal is received at the radar system, and the channel impulse response is processed to generate a frequency-stitched channel impulse response. Step 210 may include applying a known frequency stitching algorithm to the received channel impulse response, wherein a variety of suitable algorithms are known in this art.
[0116] Accordingly, a radar system has been described comprising a first transmitter and a first receiver, a second transmitter and a second receiver, and a processor, wherein the processor is configured to: determine a channel sequence for frequency stitching; divide the channel sequence into a first portion and a second portion; instruct the first transmitter to transmit RF signals on each RF channel of the first portion of the channel sequence within a first time period; instruct the second transmitter to transmit RF signals on each RF channel of the second portion of the channel sequence within a second time period, wherein the second time period at least partially overlaps with the first time period; and generate a frequency-stitched channel impulse response from reflected RF signals received from each receiver in response to the transmitted RF signals. Corresponding systems and methods have also been disclosed above.
[0117] Although specific embodiments of this disclosure have been described, it should be understood that many modifications / additions and / or substitutions may be made within the scope of the claims.
Claims
1. A radar system, characterized by comprising: a first transmitter; a second transmitter; a first receiver; a second receiver; and a processor electrically coupled to the first and second transmitters and the first and second receivers, wherein the processor is configured to: determine a sequence of channels for frequency stitching, wherein the sequence of channels comprises a plurality of RF channels each having a respective carrier frequency and bandwidth; divide the sequence of channels into a first portion and a second portion; instruct the first transmitter to transmit RF signals on each RF channel of the first portion of the sequence of channels for a first time period; instruct the second transmitter to transmit RF signals on each RF channel of the second portion of the sequence of channels for a second time period, wherein the second time period at least partially overlaps the first time period; and generate frequency-stitched channel impulse responses from reflected RF signals received at each receiver for the transmitted RF signals. The second time period and the first time period are contemporaneous or fully overlapping.
2. The radar system of claim 1, wherein, Each portion of the sequence of channels comprises at least two of the plurality of RF channels.
3. The radar system of claim 1 or claim 2, wherein, The plurality of RF channels in the sequence of channels do not overlap.
4. The radar system of any of the preceding claims, characterized in that Each RF signal is a UWB RF signal.
5. The radar system of any of the preceding claims, characterized in that The plurality of RF channels in the sequence of channels comprise channels as defined in the IEEE 802.15.4 standard.
6. The radar system of any of the preceding claims, characterized in that Further comprising a third transmitter and a third receiver, wherein the processor is further configured to:
7. The radar system of any of the preceding claims, characterized in that divide the sequence of channels into the first portion, the second portion, and a third portion; and instruct the third transmitter to transmit RF signals on each RF channel of the third portion of the sequence of channels for a third time period, wherein the third time period at least partially overlaps at least one of the first time period or the second time period. The third time period at least partially overlaps both the first time period and the second time period.
8. The radar system of claim 7, wherein, Further comprising:
9. The radar system of any of the preceding claims, characterized in that a plurality of antennas, wherein each antenna is coupled to a respective transmitter and / or receiver of the radar system. The method comprises:
10. A method of performing a multi-transmitter frequency stitching process, characterized by, determining a sequence of channels for frequency stitching, wherein the sequence of channels comprises a plurality of RF channels each having a respective carrier frequency and bandwidth; dividing the sequence of channels into a first portion and a second portion; transmitting RF signals on each RF channel of the first portion of the sequence of channels using a first transmitter and a first antenna for a first time period; transmitting RF signals on each RF channel of the second portion of the sequence of channels using a second transmitter and a second antenna for a second time period, wherein the second time period at least partially overlaps the first time period; receiving reflected RF signals for the transmitted RF signals at a first receiver and a second receiver; and generating frequency-stitched channel impulse responses from the received reflected RF signals. The second time period and the first time period are contemporaneous or fully overlapping. Each portion of the sequence of channels comprises at least two of the plurality of RF channels. The plurality of RF channels in the sequence of channels do not overlap. Each RF signal is a UWB RF signal. The plurality of RF channels in the sequence of channels comprise channels as defined in the IEEE 802.15.4 standard. Further comprising a third transmitter and a third receiver, wherein the processor is further configured to: divide the sequence of channels into the first portion, the second portion, and a third portion; and instruct the third transmitter to transmit RF signals on each RF channel of the third portion of the sequence of channels for a third time period, wherein the third time period at least partially overlaps at least one of the first time period or the second time period. The third time period at least partially overlaps both the first time period and the second time period. Further comprising: a plurality of antennas, wherein each antenna is coupled to a respective transmitter and / or receiver of the radar system. The method comprises: determining a sequence of channels for frequency stitching, wherein the sequence of channels comprises a plurality of RF channels each having a respective carrier frequency and bandwidth; dividing the sequence of channels into a first portion and a second portion; transmitting RF signals on each RF channel of the first portion of the sequence of channels using a first transmitter and a first antenna for a first time period; transmitting RF signals on each RF channel of the second portion of the sequence of channels using a second transmitter and a second antenna for a second time period, wherein the second time period at least partially overlaps the first time period; receiving reflected RF signals for the transmitted RF signals at a first receiver and a second receiver; and generating frequency-stitched channel impulse responses from the received reflected RF signals.