Claims:1. A system for a frequency-modulated continuous-wave (FMCW) ranging system, the system comprising:
a transmitting circuitry comprising a transmitter for generating intermediate frequency (IF) signals and a variable gain frequency translator for converting the generated IF signal to radio frequency (RF) signals;
a receiving circuitry communicatively coupled with the transmitting circuitry to receive the RF signals from the transmitting circuitry and comprising a RF leakage canceller, an IF leakage canceller, a baseband (BB) leakage canceller, and a first frequency translator; and
an assisting circuitry connected with the transmitting circuitry and the receiving circuitry to provide one or more inputs pertaining to power control to the receiving circuitry;
wherein the RF leakage canceller, the IF leakage canceller, the BB leakage canceller and the frequency translator are configured to perform multi stage leakage cancellation operation on the RF signals received from the transmitting circuitry.
2. The system as claimed in claim 1, wherein the system comprises a first BB card configured with the transmitting circuitry and a second BB card configured with the receiving circuitry for achieving high degree of isolation between the transmitter of the transmitting circuitry and a receiver of the receiving circuitry to reduce transmitter to receiver leakage.
3. The system as claimed in claim 1, wherein the system comprises a reference clock operatively coupled between the transmitter circuitry and the receiving circuitry to enable the transmitter circuitry and the receiving circuitry to work in coordination in time for synchronization between the transmitter circuitry and receiving circuitry.

4. The system as claimed in claim 1, wherein the assisting circuitry comprises a second frequency translator, a first power splitter and a variable attenuator, and wherein the assisting circuitry provides reference inputs to the IF leakage canceller and the BB leakage canceller to cancel transmitter self-leakage signal.
5. The system as claimed in claim 1, wherein multi stage leakage cancellation using the RF leakage canceller, the IF leakage canceller, the BB leakage canceller are based on distributed architecture approach.
, Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of ranging systems. More particularly, the present disclosure relates to improved synchronized multi stage self-leakage cancellation frequency-modulated continuous-wave (FMCW) ranging system using assisting channel.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
[0003] As is well known that an airborne radar system is used for measurement of range and velocity of an object within its operational range and is required to work under high dynamics environment with high relative velocity. The airborne radar system is required to provide measurement values in real-time to on-board computer for decision making and guidance purposes. The radar system detects reflected/scattered radio frequency (RF) signal from the object within a specified range and provides continuous updates of range and range rate of the detected object. The reflected signal from object is received and converted to digital signal. The digital signal is provided to matched filter based spread spectrum correlate or for range estimation and Doppler estimation.
[0004] In a conventional FMCW ranging system always transmitter ON condition leads to unavoidable leakage coupling in receiver, ultimately suppress information processing at sensitivity power level in receiver. Thus, it would be advantageous to provide a simple and efficient solution to eliminate problem of the conventional FMCW ranging system.
[0005] Patent Document EP2999180A1 discloses a signal cancellation device for a wireless communication system and a signal cancellation method for a wireless communication system. The method includes splitting a transmitted signal to obtain a main channel signal transmitted on a main channel and an auxiliary channel signal transmitted on an auxiliary channel, performing digital domain channel characteristic matching processing on the main channel signal and the auxiliary channel signal respectively to obtain a main channel characteristic matched signal and an auxiliary channel characteristic matched signal, and combining the main channel characteristic matched signal and the auxiliary channel characteristic matched signal which are coupled to a receiving channel in order for signal cancellation is also provided. Through the technical solution of the disclosure, the signal cancellation problem of a bandwidth can be solved better.
[0006] Another patent document US8364092B2 discloses an active cancellation unit for improving noise cancellation between a transmitter and a receiver which are connected to an antenna using a duplexer. The active cancellation unit includes a coupler sampling a signal to transmit provided by the transmitter, a cancellation duplexer having characteristics similar to the duplexer and receiving the sampled signal to provide a simulated signal and an active component receiving the simulated signal and providing an amplified signal having a phase 180 degree shifted with respect to the simulated signal, and a coupler for injecting the simulated signal at the receiver.
[0007] Yet another patent document US8364092B2 discloses a system including a transmitter and a receiver that are loosely synchronized, the transmitter encodes signal waveforms having a start time, a width and a height that are determined based on a range of possible relative drifts of a receiver clock with respect to a transmitter clock and the receiver decodes the waveforms based on a sequence of tests, chosen to account for any uncertainty that may arise due to the lack of tight synchronization.
[0008] The referred patent documents provide complex and sophisticated communications devices/systems based on cancellation methods, which make the systems not feasible for applications having size constraints, and fail to provide an efficient and cost-effective solution of the above stated problem.
[0009] Therefore, there is a need in the art for a simple, efficient and compact arrangement for transmitter leakage signal reduction in the FMCW ranging system.
OBJECTS OF THE PRESENT DISCLOSURE
[0010] Some of the objects of the present disclosure, which at least one embodiment herein satisfies are as listed herein below.
[0011] It is an object of the present disclosure to provide a simple, efficient and compact solution for transmitter leakage signal reduction in FMCW ranging systems required in space constraint applications.
[0012] It is an object of the present disclosure to provide an improved synchronized multi stage self-leakage cancellation FMCW ranging system.
[0013] It is an object of the present disclosure to provide a simple and compact arrangement for reducing transmitter leakage signal in ranging systems required in space constraint applications.
[0014] It is an object of the present disclosure to provide a FMCW ranging system capable of operating in transmitter self-leakage condition in wider dynamic range with precision and configurability.
[0015] It is an object of the present disclosure to provide an improved, simple and efficient synchronized multi stage self-leakage cancellation FMCW ranging system using assisting channel.
[0016] These and other objects of the present invention will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY
[0017] The present disclosure relates to ranging systems. More particularly, the present disclosure relates to improved synchronized multi stage self-leakage cancellation frequency-modulated continuous-wave (FMCW) ranging system using assisting channel.
[0018] An aspect of the present disclosure provides a system for a frequency-modulated continuous-wave (FMCW) ranging system. The proposed system is designed for highly demanding requirements of the FMCW ranging system for flawless operation. The proposed system can include a transmitting circuitry comprising a transmitter for generating intermediate frequency (IF) signals and a variable gain frequency translator for converting the generated IF signal to radio frequency (RF) signals; a receiving circuitry communicatively coupled with the transmitting circuitry to receive the RF signals from the transmitting circuitry and comprising a RF leakage canceller, an IF leakage canceller, a baseband (BB) leakage canceller, and a first frequency translator; and an assisting circuitry connected with the transmitting circuitry and the receiving circuitry to provide one or more inputs pertaining to the power control to the receiving circuitry.
[0019] In an aspect, the RF leakage canceller, the IF leakage canceller, the BB leakage canceller and the frequency translator can be configured to perform multi stage leakage cancellation operation on the RF signals received from the transmitter to receiver leakage.
[0020] In an embodiment, the system comprises a first BB card configured with the transmitting circuitry and a second BB card configured with the receiving circuitry for achieving high degree of isolation between the transmitter of the transmitting circuitry and a receiver of the receiving circuitry to reduce transmitter to receiver leakage.
[0021] In an embodiment, the system comprises a reference clock operatively coupled between the transmitter circuitry and receiving circuitry to enable the transmitter circuitry and receiving circuitry to work in coordination in time to maintain synchronization between the transmitter circuitry and receiving circuitry.
[0022] In an embodiment, the assisting circuitry can include a second frequency translator, a first power splitter and a variable attenuator. The assisting circuitry can provide reference inputs to the IF leakage canceller and BB leakage canceller to effectively cancel the transmitter self-leakage signal.
[0023] In an embodiment, the multi stage leakage cancellation using the RF leakage canceller, the IF leakage canceller, the BB leakage canceller can be based on distributed architecture approach.
[0024] In an embodiment, the transmitter can be a baseband transmitter. The transmitting circuitry can include an amplifier to change gain of any of the IF signals or RF signals.
[0025] In an embodiment, the receiving circuitry can include one or more processors.
[0026] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0028] The diagrams are for illustration only, which thus is not a limitation of the present disclosure, and wherein:
[0029] FIG. 1 illustrates a schematic diagram of proposed system for a FMCW ranging system, in accordance with embodiments of the present invention.
[0030] FIG. 2 schematically illustrates isolation between a transmitting circuitry and a receiving circuitry of the proposed system in case of two separate baseband cards for wide dynamic range, in accordance with embodiments of the present invention.
[0031] FIG. 3 schematically illustrates a reference clock for synchronization between a transmitting circuitry and a receiving circuitry of the proposed system, in accordance with embodiments of the present invention.
[0032] FIG. 4 schematically illustrates isolation between an assisting circuitry and a receiving circuitry where assisting channel to main receiver channel leakage in receiver limits operational dynamic range of the receiving circuitry, in accordance with embodiments of the present invention.
[0033] FIG. 5 schematically illustrates a receiving circuitry of the proposed system for multi stage transmitter leakage cancellation to improve receiving circuitry sensitivity of a FMCW ranging system, in accordance with an embodiment of the present invention.
[0034] FIG. 6 schematically illustrates a transmitting circuitry 102 of the proposed system for RF signal output to achieve controllable range coverage using a variable gain frequency translator in path, in accordance with an embodiment of the present invention.
[0035] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION
[0036] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.
[0037] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.
[0038] Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure).
[0039] The present disclosure relates to a FMCW ranging system. More particularly, the present disclosure relates to a system to mitigate problem of transmitter leakage signal in the FMCW ranging system.
[0040] A FMCW based ranging system is required for measurement of range and velocity of the object within its operational range and is required to work under high dynamics environment with high relative velocity. The ranging system is required to provide measurement values in real-time to an on-board computer for decision making and guidance purposes. The ranging system detects reflected/scattered RF signal from an object within specified range and provides continuous updates of range and range rate of the detected object. The reflected signal from the object is received and converted to digital signal. The digital signal is provided to match filter based spread spectrum co-relator for range estimation and Doppler estimation.
[0041] In an aspect, the proposed system helps the FMCW ranging system capable of operating in transmitter self-leakage condition in wider dynamic range with precision and configurability. This proposed system improves sensitivity of a receiver significantly by reducing transmitter leakage signal.
[0042] In another aspect, to mitigate the above stated problem, the proposed system is built on two independent baseband cards dedicated to a transmitting circuitry and a receiving circuitry along with RF modules for the FMCW based ranging system.
[0043] Referring to FIG. 1, where a schematic diagram of proposed system for a FMCW ranging system is shown, the proposed system 100 includes a transmitting circuitry 102, a receiving circuitry 104, a reference clock 106 operatively coupled between the transmitter circuitry 102 and the receiving circuitry 104, and an assisting circuitry 108. The transmitting circuitry 102 can include a transmitter 110 for generating IF signals and a variable gain frequency translator 112 for converting the generated IF signal to RF signals for achieving higher resolution and accuracy having variable gain control for limiting range of operation dynamically for strategic applications. The transmitter 110 can be a baseband transmitter. The transmitting circuitry 102 can include an amplifier to change gain of any of the IF signals or RF signals.
[0044] In an embodiment, the reference clock 106 is configured to facilitate synchronization between the transmitter circuitry 102 and receiving circuitry 104. The reference clock 106 can be configured to enable the transmitter circuitry 102 and the receiving circuitry 104 to work in coordination in time to maintain synchronization between the transmitter circuitry and receiving circuitry.
[0045] The receiving circuitry 104 can be communicatively coupled with the transmitting circuitry 102 to receive the RF signals from the transmitting circuitry 102. The receiving circuitry 104 can include a RF leakage canceller 114 that is coupled with the transmitting circuitry 102 to receive the RF signals, an IF leakage canceller 116, a BB leakage canceller 118, and a first frequency translator 120. The assisting circuitry 108 can provide reference inputs to the IF leakage canceller 116 and BB leakage canceller 118 to effectively cancel the transmitter self-leakage signal. The assisting circuitry 108 can include a second frequency translator 122, a first power splitter 124 and a variable attenuator 126. The assisting circuitry 108 can provide the inputs pertaining to power control to the IF leakage canceller 116 and transmitting circuitry characterization to the BB leakage canceller 118. The first power splitter 124 can be operatively coupled to the IF leakage canceller 116.
[0046] In an embodiment, the RF leakage canceller 114, the IF leakage canceller 116, the BB leakage canceller 118 and the frequency translator 120 of the receiving circuitry 104 can be configured to perform multi stage leakage cancellation operation on the RF signals received from the transmitting circuitry 102. Multi stage leakage cancellation using the RF leakage canceller 114, the IF leakage canceller 116, the BB leakage canceller118 can be based on distributed architecture approach. As shown, the IF signals is communicated to the BB leakage canceller 118 from the IF leakage canceller 116 through a main receiver channel 140. The receiving circuitry 104 can include a digital processor 128 for processing the signals.
[0047] The system 100 can include a first BB card configured with the transmitting circuitry 102 and a second BB card configured with the receiving circuitry 104 for achieving high degree of isolation between the transmitter of the transmitting circuitry and a receiver 142 of the receiving circuitry to reduce transmitter to receiver leakage. The each of the first and second BB cards can be a transceiver.
[0048] In an embodiment, the variation in power output of assisting circuitry fed to the baseband card of the receiving circuitry can be achieved through the attenuator 126 to set noise floor of the receiver baseband card/receiver 142 during information processing at sensitivity level.
[0049] In an embodiment, the proposed system 100 can include a power distribution circuitry that can includes a power coupler 130 operatively coupled to the variable gain frequency translator 112 of the transmitting circuitry 102, and a second power splitter 132 operatively coupled to the second frequency translator 122 of the assisting circuitry 108. The second power splitter 132 can be operatively coupled to the RF leakage canceller of 114 the receiving circuitry 104.
[0050] In an embodiment, the proposed system 100 for the FMCW ranging system facilitates synchronized multi stage self-leakage cancellation. The system 100 for multistage leak cancellation and with improved isolation is important for strategic applications with high demand of processing capabilities.
[0051] FIG. 2 schematically illustrates isolation between a transmitter 110 a transmitting circuitry 102 and a receiver 142 of a receiving circuitry 104 of the proposed system 100 in case of two separate baseband cards for achieving wide dynamic range at sensitivity level. On board leakage can be drastically reduced by using dual BB card approach which reduces transmitter to receiver leakage. This improves system performance at minimum detectable signal linked with longer range.
[0052] FIG. 3 schematically illustrates a reference clock 106 for synchronization between a transmitter 110 of a transmitting circuitry and a receiver 142 of a receiving circuitry 104 of the proposed system 104. Information processing in the receiver 142 using a digital processor 128 can be efficiently synced with transmitter signals in case of common synchronization.
[0053] FIG. 4 schematically illustrates isolation between an assisting circuitry 108 and a receiving circuitry 104 where leakage limits operational dynamic range of the receiving circuitry. Assisting channel estimation and its usage is requirement for reference base of leakage cancellation. The power output to be optimized in such a way that it’s coupling to the receiving circuitry 104 should not limit sensitivity of a ranging system.
[0054] FIG. 5 schematically illustrates a receiving circuitry of the proposed system for multi stage transmitter leakage cancellation to improve receiving circuitry sensitivity of a FMCW ranging system, in accordance with an embodiment of the present invention. Leakage cancellation in multi stage i.e. by using a RF leakage canceller 114, an IF stage leakage canceller 116 and BB leakage canceller/Zero IF stage leakage canceller 118 is effective and simpler approach in spite of single stage approach due to better phase cancellation control and better isolation. As in single stage approach input to output RF coupling set limit on practically on achieved figure of RF leakage cancellation and presence of high phase tuning errors using phase shifters.
[0055] FIG. 6 schematically illustrates a transmitting circuitry 102 of the proposed system for RF signal output to achieve controllable range coverage using a variable gain frequency translator in path, in accordance with an embodiment of the present invention. It is prime requirement of a ranging system in use for strategic applications.
[0056] Thus, it will be appreciated by those of ordinary skill in the art that the diagrams, schematics, illustrations, and the like represent conceptual views or processes illustrating systems and methods embodying this invention. The functions of the various elements shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing associated software. Similarly, any switches shown in the figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the entity implementing this invention. Those of ordinary skill in the art further understand that the exemplary hardware, software, processes, methods, and/or operating systems described herein are for illustrative purposes and, thus, are not intended to be limited to any particular named.

ADVANTAGES OF THE INVENTION
[0057] The present disclosure provides a simple, efficient and compact solution for transmitter leakage signal reduction in FMCW ranging systems required in space constraint applications.
[0058] The present disclosure provides an improved synchronized multi stage self-leakage cancellation FMCW ranging system.
[0059] The present disclosure provides a simple and compact arrangement for reducing transmitter leakage signal in ranging systems required in space constraint applications.
[0060] The present disclosure provides a FMCW ranging system capable of operating in transmitter self-leakage condition in wider dynamic range with precision and configurability.
[0061] The present disclosure provides an improved, simple and efficient synchronized multi stage self-leakage cancellation FMCW ranging system using assisting channel.