Method for monitoring distortion of radio signal, related receiver and related system

Abstract

An embodiment of the invention relates to a method comprising the steps of: receiving, by a radio receiver, a radio frequency signal from a radio transmitter; synchronizing, by the radio receiver, a replica radio frequency signal of the received radio signal with the received radio frequency signal to obtain a synchronized replica radio frequency signal; correlating, by the radio receiver, the received radio frequency signal with a synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function, the first correlation function comprising a plurality of correlation function points, each correlation function point representing a differently delayed replica radio frequency signal; the method further comprises the step of carrying out difference on the first correlation function to obtain a chip domain observation value.

Description

Technical Field

[0001] The present invention relates to a method for monitoring distortion of a (GNSS) radio signal, a related system and a related radio receiver. Background Art

[0002] Monitoring and timely detecting distortions in received GNSS radio signals (also referred to as radio signals), which can cause unacceptable deviations in delay-locked loop (DLL) tracking points, is particularly important in satellite-based augmentation systems (SBAS), such as the European EGNOS system and the U.S. WAAS system, which provide integrity services. Such distortions, perceived at the receiver, can be caused by faults in the signal transmission and / or environmental factors, such as multipath reflections and interfering signals.

[0003] In operational satellite-based augmentation systems (such as EGNOS and WAAS) and their evolutions, conventional methods for monitoring radio signal distortion include the use of so-called multi-correlator GNSS receivers. Multi-correlator GNSS receivers differ from conventional GNSS receivers in that, in addition to the early and late correlators (typically used for delay-locked loop discriminators) and the immediate correlator (typically used for phase-locked loops and data retrieval and navigation information demodulation), additional correlators are introduced. The number and location of these additional correlators are determined by the specific integrity service (depending on the integrity and continuity requirements assigned to the signal distortion monitoring function). So-called signal quality monitoring (SQM) metrics are generated by combining these correlator values.

[0004] Instead of monitoring distortion in the "correlation domain," an alternative technique is configured to monitor the distortion of the received RF signal in the "chip domain." This technique is also known as "chip domain observation" (CDO). Compared to "correlation" observations, CDO can potentially provide more accurate information about signal distortion and therefore serve as a better input to the detection process. However, this advantage comes at the cost of complexity, as additional specific signal processing must be implemented in the dedicated GNSS radio receiver. Summary of the Invention

[0005] An object of embodiments of the present invention is to provide a method and system for monitoring distortion of a received radio frequency signal in the chip domain, which is of the above-mentioned known type, but wherein the monitoring of distortion of the radio signal in the chip domain does not require the use of a dedicated and complex hardware receiver architecture, but can be performed with the help of a simple receiver architecture.

[0006] Therefore, an embodiment of the present invention relates to a method for monitoring distortion of a received radio frequency signal in the chip domain using a radio frequency system, wherein the radio frequency system includes a radio transmitter for transmitting the radio frequency signal and a radio receiver for receiving the radio frequency signal, the method comprising the following steps:

[0007] - receiving, by the radio receiver, the radio frequency signal from the radio transmitter; and

[0008] - synchronizing, by the radio receiver, a replica radio frequency signal of the received radio signal with the received radio frequency signal to obtain a synchronized replica radio frequency signal; and

[0009] - correlating, by the radio receiver, the received radio frequency signal with the synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function, wherein the first correlation function includes a plurality of correlation function points, each correlation function point representing a replica radio frequency signal with a different delay, wherein the method further comprises the following steps:

[0010] - performing differentiation on the obtained first correlation function to obtain a chip domain observation value.

[0011] A subsequent embodiment of the present invention relates to the method for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 1, characterized in that the step of differentiating the first correlation function to obtain the chip domain observation value is obtained by:

[0012] - calculating the difference between each correlation function point belonging to the first correlation function and the previous successive correlation function point of the correlation function point.

[0013] Another embodiment of the present invention relates to the method for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 1, characterized in that the step of differentiating the first correlation function to obtain the chip domain observation value is obtained by:

[0014] - shifting, by the radio receiver, the replica radio frequency signal of the received radio signal relative to the received radio frequency signal by a sampling period to obtain a shifted synchronized replica radio frequency signal; and

[0015] generating, by the radio receiver, a second correlation function of the received RF signal and the shifted synchronized replica RF signal by correlating the received RF signal with the shifted synchronized replica RF signal, the second correlation function comprising a plurality of correlation function points, each correlation function point representing a differently delayed replica RF signal; and

[0016] - generating, by the receiver, the chip domain observations of the received signal by differentiating (subtracting) the second correlation function from the first correlation function.

[0017] Another embodiment of the present invention relates to the method for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 1, characterized in that the step of differentiating the first correlation function to obtain the chip domain observation value is obtained by:

[0018] - generating, by the radio receiver, a synchronized second correlation function by shifting the first correlation function by one sampling period during a correlation sampling phase; and

[0019] - generating, by the radio receiver, the chip domain observations of the received signal by differentiating the second correlation function from the first correlation function.

[0020] Yet another embodiment of the present invention relates to a radio receiver (Rx) for monitoring distortion of a radio frequency signal received at a radio receiver (Rx) of a radio frequency system in the chip domain, the radio frequency system further comprising a radio transmitter (Tx) for transmitting the radio frequency signal to the radio receiver, the radio receiver comprising:

[0021] - a signal receiving means (SRM) configured to receive said radio frequency signal from said radio transmitter; and

[0022] - a signal processing means (SPM), said signal processing means (SPM) being configured to:

[0023] - synchronizing the replica radio frequency signal of the received radio signal with the received radio frequency signal to obtain a synchronized replica radio frequency signal; and

[0024] - correlating the received radio frequency signal with the synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function, wherein the first correlation function comprises a plurality of correlation function points, each correlation function point representing a replica radio frequency signal with a different delay, wherein the signal processing means (SPM) is further configured to:

[0025] - differentiating said first correlation function to obtain chip-domain observations of said received radio frequency signal in said chip-domain.

[0026] Another embodiment of the present invention relates to a radio receiver (Rx) for monitoring distortion of a received radio frequency signal in the chip domain according to claim 5, characterized in that, in order to differentiate the first correlation function to obtain the chip domain observation value, the signal processing device (SPM) is further configured to:

[0027] The difference between each correlation function point belonging to the first correlation function and a previous correlation function point of the correlation function point is calculated.

[0028] Another embodiment of the present invention relates to a radio receiver (Rx) for monitoring distortion of a received radio frequency signal in the chip domain according to claim 5, characterized in that, in order to differentiate the first correlation function to obtain the chip domain observation value, the signal processing device (SPM) is further configured to:

[0029] - shifting the replica radio frequency signal of the received radio signal relative to the received radio frequency signal by a sampling period to obtain a shifted synchronized replica radio frequency signal; and

[0030] - correlating the received RF signal with the shifted synchronized replica RF signal to generate a second correlation function, the second correlation function comprising a plurality of correlation function points, each correlation function point representing a replica RF signal with a different delay; and

[0031] - Differentiating the second correlation function from the first correlation function to generate the chip-domain observation value.

[0032] Another embodiment of the present invention relates to a radio receiver (Rx) for monitoring distortion of a received radio frequency signal in the chip domain according to claim 5, characterized in that, in order to differentiate the first correlation function to obtain the chip domain observation value, the signal processing means (SPM) is further configured to:

[0033] - generating a synchronized second correlation function by shifting said first correlation function by one sampling period in a correlation sampling phase (domain); and

[0034] - Differentiating the second correlation function from the first correlation function to generate the chip-domain observation value.

[0035] Another embodiment of the present invention relates to a radio frequency system, which is used to monitor the distortion of a (digital) radio frequency signal received at a radio receiver Rx of the radio frequency system in the code chip domain, and the radio frequency system also includes a radio transmitter Tx for transmitting the radio frequency signal to the radio receiver, characterized in that the radio frequency system includes a radio receiver according to any one of claims 5 to 8.

[0036] In fact, this object is achieved by: first, synchronizing a replica RF signal of the received radio signal with the received RF signal to obtain a synchronized replica RF signal that is well synchronized with the received RF signal; and then, by means of the receiver, correlating the received RF signal with the synchronized replica RF signal of the received radio signal to obtain a first correlation function, wherein the first correlation function includes a plurality of correlation function points, each correlation function point representing a replica RF signal of a different delay, and then, by differentiating the obtained first correlation function, obtaining a chip domain observation value, wherein the chip domain observation value belongs to / corresponds to the received RF signal in the chip domain.

[0037] Synchronization of the replica RF signal of the received radio signal with the received RF signal can be achieved, for example, by means of a closed-loop time delay estimation technique, such as a delay-locked loop (DLL) or a combination of a delay-locked loop (DLL) and a phase-locked loop (PLL) and / or frequency-locked loop (FLL) estimation technique.

[0038] Correlating the received radio frequency signal with said synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function may be performed by means of a multi-correlator.

[0039] The "instant" correlator stays on the peak of the correlation function, thereby obtaining synchronization, and based on the synchronization value, multiple additional correlators are used (whether delayed or advanced relative to the instant correlator, and at intervals of any length, which does not have to be an integer number of samples) to obtain other values of the correlation function required to use this method.

[0040] The step of generating a first differenced correlation function can be achieved by selecting a point in the correlation function, the correlation function comprising a plurality of consecutive correlation function points, and subtracting the value of the selected point from the next adjacent point to the right of the selected point, thereby providing a first bin of chip-domain observations. The same operation is performed for the adjacent point and the next adjacent point to the right, thereby obtaining a second bin of chip-domain observations, and so on. This sequence is repeated until a final correlation function point of the correlation function is reached.

[0041] In an embodiment of the present invention, the step of generating a differentiated first correlation function can be achieved by calculating the difference between each correlation function point belonging to the first correlation function and the immediately preceding correlation function point. To this end, a point is selected in the first correlation function, which includes a plurality of immediately preceding correlation function points, and the value of the selected point is subtracted from the next adjacent correlation function point to the right of the selected point to provide a first interval of CDO. The same operation is performed for the aforementioned adjacent point and the immediately preceding adjacent point to the right to obtain a second CDO interval, and so on. This sequence is repeated until the final correlation function point of the correlation function is reached.

[0042] Another embodiment of the present invention relates to a method for monitoring the distortion of a received radio frequency signal in the code domain, wherein the step of generating a differentiated first correlation function to obtain the code domain observation value is obtained in the following manner: first, with the help of the receiver, the replica radio frequency signal of the received radio signal is offset by a sampling period relative to the received radio frequency signal to obtain an offset synchronized replica radio frequency signal; and then, with the help of the receiver, a second correlation function of the received radio frequency signal and the offset synchronized replica radio frequency signal is generated by correlating the received radio frequency signal with the offset synchronized replica radio frequency signal.

[0043] The intended correlation function includes a plurality of correlation function points, wherein each correlation function point represents a replica RF signal of a different delay, and then, the chip domain observation value CDO of the received signal is generated by differentiating the second correlation function from the first correlation function (i.e., subtracting the second correlation function from the first correlation function).

[0044] The "instant" correlator stays on the peak of the correlation function, thereby obtaining synchronization, and based on this synchronization value, multiple additional correlators can be used (regardless of the interval, whether delayed or advanced relative to the instant correlator), considering that in this alternative embodiment, the interval must be an integer number of samples to obtain other values of the correlation function required to use this method.

[0045] An alternative embodiment of the present invention relates to a method for monitoring the distortion of a received radio frequency signal in the code domain, wherein the step of generating a differentiated first correlation function to obtain the code domain observation value is obtained in the following manner: first, the receiver generates a synchronized second correlation function by delaying or shifting the first correlation function by one sampling period in the correlation sampling phase (domain), and then, the receiver generates the code domain observation value of the received signal by differentiating the second correlation function with the first correlation function (i.e., subtracting the second correlation function from the first correlation function). BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and other objects and features of the present invention will become more apparent, and the invention itself will be best understood by reference to the following description of embodiments taken in conjunction with the accompanying drawings, in which:

[0047] Figure 1 represents a system for monitoring, in the chip domain, the distortion of a radio frequency signal received at a radio receiver Rx of said radio frequency system;

[0048] Figure 2 1 and 2 represent functional elements of a radio transmitter TX and a radio receiver RX according to an embodiment of the invention.

[0049] Figure 3 represents the construction of chip-domain observations by correlating the input signal with the derivative of the local replica;

[0050] Figure 4 shows that the chip-domain observations are constructed by differencing the replicas before multiplying with the input signal; and

[0051] Figure 5 The construction of chip-domain observations by differencing the correlation function according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0052] The description and drawings illustrate only the principles of the present invention. It will be understood that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the present invention and are encompassed within its spirit and scope. In addition, all examples listed herein are primarily intended to be used for teaching purposes only to help the reader understand the principles of the present invention and the concepts contributed by one or more inventors to advance the art, and should not be construed as being limited to these specifically listed examples and conditions. In addition, all statements herein listing the principles, aspects and embodiments of the present invention and specific examples thereof are intended to encompass their equivalents.

[0053] It should be understood by those skilled in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the present invention. Similarly, it should be understood that any flow charts, flow diagrams, state transition diagrams, pseudocode, etc. represent various processes that can be substantially represented in a computer-readable medium and thus executed by a computer or processor, whether or not such a computer or processor is explicitly shown.

[0054] The present invention will be described with respect to specific embodiments and with reference to certain drawings, but the invention is not limited thereto but only by the claims. The drawings described are for illustrative purposes only and are non-limiting. In the drawings, the dimensions of some elements may be exaggerated and not drawn to scale for illustrative purposes. Dimensions and relative dimensions do not necessarily correspond to actual reductions in practice of the invention.

[0055] Furthermore, the terms "first," "second," "third," etc., in the description and claims are used to distinguish similar elements and are not necessarily used to describe a sequential or chronological order. Therefore, these terms are interchangeable under appropriate circumstances, and the embodiments of the invention may operate in other ways than described or illustrated herein.

[0056] Furthermore, the terms "top," "bottom," "above," "below," etc., in the description and claims are used for descriptive purposes and are not necessarily used to describe relative positions. Therefore, these terms are interchangeable under appropriate circumstances, and the embodiments of the invention described herein may operate in other ways than described or shown herein.

[0057] The term "comprising" used in the claims should not be construed as being limited to the means listed thereafter; it does not exclude other elements or steps. It should be interpreted as specifying the presence of the features, integers, steps, or components as recited, but does not preclude the presence or addition of one or more other features, integers, steps, or components, or combinations thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting solely of components A and B. This means that, for the purposes of the present invention, the only relevant components of the device are A and B.

[0058] Similarly, it should be noted that the term "coupled" used in the claims should not be construed as limited to direct connections. Therefore, the scope of the expression "device A coupled to device B" should not be limited to devices or systems in which the output of device A is directly connected to the input of device B. This means that a path exists between the output of A and the input of B, which may include other devices or apparatuses.

[0059] It should be noted that the described functional means of the system may be distributed across the first communication device and / or one or more other network elements (such as a server device as described in the appended claims).

[0060] In the following paragraphs, reference is made to Figure 1 The accompanying drawings in FIG. 1 describe an implementation of a radio frequency system for monitoring distortion of a radio frequency signal received at a radio receiver Rx of the radio frequency system in the chip domain.

[0061] In further paragraphs, all connections between mentioned elements are defined.

[0062] Subsequently, the following will be described Figure 2 All relevant functional devices of a radio transmitter Tx and a radio receiver RX are presented and all interconnections are described.

[0063] In the following paragraphs, the actual implementation of the system will be described.

[0064] The radio frequency system includes a radio transmitter Tx for transmitting a radio frequency signal to the radio receiver, and the radio receiver is configured to receive the radio frequency signal.

[0065] It should be noted that, although only one radio transceiver Tx and only one radio receiver Rx are disclosed for the sake of clarity, the system according to the present invention may comprise a plurality of radio transmitters and corresponding radio receivers.

[0066] The radio navigation system according to an embodiment of the present invention may be a satellite radio navigation system, such as a global navigation satellite system GNSS, or may be a single positioning beacon, such as a pseudo-satellite (Pseudo-Lite) or a positioning beacon network, or may be a terrestrial system, such as a wireless communication network that requests synchronization from a user terminal.

[0067] Such a radio transmitter Tx can be a GNSS transmitter as a satellite that transmits radio navigation signals, a satellite part of a satellite communication network, a pseudo-satellite, or a transmitting device deployed in a terrestrial communication network (such as a base transceiver station (BTS), a fixed or mobile radio transmitter in the case of a wireless communication network), or a device deployed in a V2V or V2X communication network.

[0068] The second essential element of the system for monitoring distortion of received radio frequency signals is a user's radio receiver RX, wherein the radio receiver Rx is configured to receive radio frequency signals transmitted by a radio transmitter Tx of a radio navigation system according to an embodiment of the present invention. Such a radio receiver can be a GNSS receiver implemented by any type of radio receiver.

[0069] Such a radio receiver may be a GNSS receiver integrated in a user equipment (such as a navigation device) or a personal mobile device (like a smartphone), which is a device comprising a processor with coupled memory and interface means like a display and keyboard.

[0070] Such mobile computing devices are configured to have a variety of different types of applications installed, where each such application is executed to perform a different type of task, such as navigation.

[0071] Alternatively, the radio receiver of such an embodiment may comprise a (hardware) receiver dedicated to monitoring for harmful waveforms or a receiver such as a software defined radio (SDR) receiver, and these (hardware) receivers are deployed in the ground segment of an SBAS (e.g., EGNOS, WAAS), in which case the application of embodiments of the present invention is suitable for local assessment of signal quality (user-based integrity monitoring) by the end user.

[0072] The first basic element of the radio transmitter TX is a transmitting device TM, 12, which is configured to transmit a radio signal to the radio receiver via the radio network RN. The transmitted radio signal can be any GNSS radio signal that can be processed using only one spectral lobe, such as GPS C / AL1 or GLONASS C / A codes transmitted in the L1 band. This also applies to other GNSS signals that may have more than one spectral lobe (typically two spectral lobes) but can be processed taking only one spectral lobe into account, such as Galileo E1 or BeiDou B1 signals, which have two spectral lobes but are usually tracked in a so-called single sideband tracking manner, focusing on only one of the spectral lobes.

[0073] Such radio frequency signals may, for example, apply waveform modulation such as binary phase shift keying (BPSK) for GPS C / A signals or binary offset carrier (BOC) for Galileo E1-B / -C or GPS L1C.

[0074] The basic elements of a radio receiver Rx for monitoring the distortion of a received radio frequency signal in the chip domain are: a signal receiving means SRM configured to receive a radio frequency signal from said radio transmitter Tx; and a signal processing means SPM configured to:

[0075] - synchronizing the replica radio frequency signal of the received radio signal with the received radio frequency signal to obtain a synchronized replica radio frequency signal; and

[0076] - correlating the received radio frequency signal with a synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function, wherein the first correlation function comprises a plurality of correlation function points, each correlation function point representing a replica radio frequency signal with a different delay.

[0077] - generating said first correlation function to obtain chip-domain observations of the received radio frequency signal in the chip-domain.

[0078] Such a signal processing device SPM may include a microprocessor for processing signals for transmission, etc., and the processing device may also include a storage device connected to the microprocessor for storing electronic information, such as computer instructions, signal processing results (including final results and intermediate results) and other information.

[0079] The radio receiver Rx further comprises storage means SM, which is an internal memory SM for storing the program for actually carrying out the method for monitoring distortions of received radio signals, intermediate results and final results.

[0080] A second related function of the storage means SM may be to store a software application for monitoring distortion of received radio signals. The storage means SM is configured to store at least one other application executed by the computer processing means CPM. Such a memory SM may be a local computing storage device or alternatively an external computing memory, and optionally a distributed external computing memory.

[0081] In a first embodiment, to differentiate the first correlation function to obtain the chip-domain observation, the signal processing device SPM is configured to: first select a point in the correlation function (the correlation function comprises a plurality of correlation function points) and subtract the value of the selected point from the next adjacent correlation function point to the right of the selected point, thereby providing a first interval of the CDO. The same operation is performed for the aforementioned adjacent point and the next adjacent point to the right, thereby providing a second CDO interval, and so on. This sequence is repeated until the final correlation function point of the correlation function is reached, thereby providing the corresponding CDO.

[0082] In an alternative embodiment, in order to differentiate the first correlation function to obtain the chip domain observation value, the signal processing means SPM is further configured to:

[0083] - shifting the replica radio frequency signal of the received radio signal relative to the received radio frequency signal by a sampling period to obtain a shifted synchronized replica radio frequency signal;

[0084] as well as

[0085] - correlating the received RF signal with the shifted synchronized replica RF signal to generate a second correlation function, the second correlation function comprising a plurality of correlation function points, each correlation function point representing a replica RF signal with a different delay; and

[0086] - Differentiating the second correlation function from the first correlation function to generate the chip-domain observation value.

[0087] In yet another alternative embodiment, in order to differentiate said first correlation function to obtain said chip-domain observations, the signal processing means SPM is further configured to:

[0088] - generating a synchronized second correlation function by shifting said first correlation function by one sampling period in a correlation sampling phase; and

[0089] - Differentiating the second correlation function from the first correlation function to generate the chip-domain observation value.

[0090] The transmitting device TM is coupled to the receiving device RM of the radio receiver Rx via a wireless transmission path.

[0091] The receiving means RM of the radio receiver are further coupled to the signal processing means SPM which in turn are coupled to the CDO output means CDO_OM.

[0092] Furthermore, the signal processing means SPM are coupled to the storage means SM.

[0093] In the following paragraphs, a practical implementation of a system for monitoring the distortion of a received radio frequency signal in the chip domain according to an embodiment of the present invention will be described.

[0094] For the purpose of explaining the embodiments of the present invention, it is assumed that the radio transmitter Tx transmits a radio frequency signal, such as a GNSS signal modulated with a BPSK waveform, because the GPS C / A signal in the L1 band is currently transmitted toward the radio receiver Rx.

[0095] Alternatively, a signal that uses only one spectral lobe for processing may be used, such as the Galileo E1 signal or the BeiDou B1 signal. These signals have two spectral lobes, but typically use a single spectral lobe for tracking, for example. In other words, any signal that can be processed using a single sidelobe (which encompasses nearly all GNSS signals) may be applied to and associated with embodiments of the present invention.

[0096] The signal receiving means SRM of the radio receiver Rx then receives the transmitted GNSS signal modulated by the BPSK waveform as the transmitted current GPS C / A signal 41 in the L1 band from the radio transmitter Tx, as shown Figure 4 As shown in .

[0097] When the signal processing device SPM receives the GNSS signal, Figure 4 As shown in FIG, the replica radio frequency signal of the received radio signal is synchronized with the received radio frequency signal 41 to obtain a synchronized replica radio frequency signal 42, and then, as shown in FIG. Figure 4 As shown in , the received radio frequency signal is correlated 45 with a synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function 47, wherein the first correlation function includes a plurality of correlation function points, each correlation function point represents a replica radio frequency signal with a different delay, such as Figure 4 As shown in .

[0098] Finally, the first correlation function 47 is further differentiated by means of the signal processing means SPM to obtain chip-domain observation values of the received radio frequency signal in the chip domain.

[0099] In an embodiment of the present invention, the step of generating a differentiated first correlation function to obtain the chip-domain observations can be performed by calculating the difference between each correlation function point belonging to the first correlation function and the immediately preceding correlation function point. To this end, a point is selected in the first correlation function (the correlation function includes multiple immediately preceding correlation function points) and the value of the selected point is subtracted from the next adjacent correlation function point to the right of the selected point, thereby providing a first interval of the CDO. The same operation is performed for the aforementioned adjacent point and the immediately preceding adjacent point to the right, thereby providing a second CDO interval, and so on. This sequence is repeated until the final correlation function point of the correlation function is reached.

[0100] In a preferred embodiment of the present invention, Figure 4 As shown in FIG, in order to differentiate the first correlation function to obtain the chip domain observation value, the signal processing device SPM also shifts the replica radio frequency signal of the received radio signal relative to the received radio frequency signal by a single sampling period to obtain a shifted synchronized replica radio frequency signal (see FIG. Figure 4 44 in ), and then correlating the received RF signal with the shifted synchronized replica RF signal 46 to generate a second correlation function signal (see Figure 4 48 in), wherein the second correlation function comprises a plurality of correlation function points. Each such correlation function point represents a replica RF signal of a different delay. Finally, the signal processing means SPM differentiates the second correlation function from the first correlation function by subtracting 49 the second correlation function from the first correlation function (see Figure 4 49) to generate the chip domain observation value 50.

[0101] In such Figure 5 In an alternative advantageous embodiment of the invention shown, in order to differentiate a first correlation function to obtain the code chip domain observation value, the signal processing device SPM generates a synchronized second correlation function by offsetting the first correlation function by a single sampling period 55 in the correlation sampling phase (domain), and finally differentiates the second correlation function from the first correlation function by subtracting 56 the second correlation function from the first correlation function to generate the code chip domain observation value 57.

[0102] Finally, it should be noted that the embodiments of the present invention have been described above in terms of functional blocks. Based on the functional descriptions of these blocks, those skilled in the art of electronic device design will readily understand how to implement these blocks using well-known electronic components. Therefore, a detailed architecture of the functional block contents is not necessary.

[0103] Although the principles of the present invention have been described above in conjunction with specific devices, it should be clearly understood that this description is made by way of example only and is not intended to limit the scope of the invention, which is defined by the appended claims.

Claims

1. A method for monitoring distortion of a received radio frequency signal in the chip domain using a radio frequency system, the radio frequency system comprising a radio transmitter for transmitting the radio frequency signal and a radio receiver for receiving the radio frequency signal, the method comprising the following steps: - receiving, by the radio receiver, the radio frequency signal from the radio transmitter; as well as - synchronizing, by the radio receiver, a replica radio frequency signal of the received radio signal with the received radio frequency signal to obtain a synchronized replica radio frequency signal; as well as - correlating, by the radio receiver, the received radio frequency signal with the synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function, wherein the first correlation function includes a plurality of correlation function points, each correlation function point representing a replica radio frequency signal with a different delay, wherein the method further comprises the following steps: - performing differentiation on the obtained first correlation function to obtain a chip domain observation value.

2. The method for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 1, wherein: The step of differentiating the first correlation function to obtain the chip domain observation value is achieved by: - calculating the difference between each correlation function point belonging to said first correlation function and the immediately preceding correlation function point of said correlation function point.

3. The method for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 1, wherein: The step of differentiating the first correlation function to obtain the chip domain observation value is achieved by: - shifting, by the radio receiver, the replica radio frequency signal of the received radio signal relative to the received radio frequency signal by a sampling period to obtain a shifted synchronized replica radio frequency signal; as well as generating, by the radio receiver, a second correlation function of the received RF signal and the shifted synchronized replica RF signal by correlating the received RF signal with the shifted synchronized replica RF signal, the second correlation function comprising a plurality of correlation function points, each correlation function point representing a differently delayed replica RF signal; as well as - generating, by the receiver, the chip domain observations of the received signal by differentiating (subtracting) the second correlation function from the first correlation function.

4. The method for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 1, wherein: The step of differentiating the first correlation function to obtain the chip domain observation value is achieved by: - generating, by the radio receiver, a synchronized second correlation function by shifting the first correlation function by one sampling period during a correlation sampling phase; as well as - generating, by the radio receiver, the chip domain observations of the received signal by differentiating the second correlation function from the first correlation function.

5. A radio receiver (Rx) for monitoring distortion of a radio frequency signal received at a radio receiver (Rx) of a radio frequency system in the chip domain, the radio frequency system further comprising a radio transmitter (Tx) for transmitting the radio frequency signal to the radio receiver, the radio receiver comprising: - a signal receiving means (SRM) configured to receive said radio frequency signal from said radio transmitter; and - a signal processing means (SPM), said signal processing means (SPM) being configured to: - synchronizing the replica radio frequency signal of the received radio signal with the received radio frequency signal to obtain a synchronized replica radio frequency signal; as well as - correlating the received radio frequency signal with the synchronized replica radio frequency signal of the received radio signal to obtain a first correlation function, wherein the first correlation function comprises a plurality of correlation function points, each correlation function point representing a replica radio frequency signal with a different delay, wherein the signal processing means (SPM) is further configured to: - differentiating the first correlation function to obtain chip-domain observations of the received radio frequency signal in the chip-domain.

6. The radio receiver (Rx) for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 5, characterized in that In order to differentiate the first correlation function to obtain the chip-domain observation value, the signal processing means (SPM) is further configured to: A difference between each correlation function point belonging to the first correlation function and a previous correlation function point of the correlation function point is calculated.

7. The radio receiver (Rx) for monitoring the distortion of a received radio frequency signal in the chip domain according to claim 5, characterized in that In order to differentiate the first correlation function to obtain the chip-domain observation value, the signal processing means (SPM) is further configured to: - shifting the replica radio frequency signal of the received radio signal relative to the received radio frequency signal by a sampling period to obtain a shifted synchronized replica radio frequency signal; as well as - correlating the received radio frequency signal with the shifted synchronized replica radio frequency signal to generate a second correlation function, wherein the second correlation function includes a plurality of correlation function points, each correlation function point representing a replica radio frequency signal with a different delay; as well as - Differentiating the second correlation function from the first correlation function to generate the chip-domain observation value.

8. The radio receiver (Rx) for monitoring distortion of a received radio frequency signal in the chip domain according to claim 5, characterized in that In order to differentiate the first correlation function to obtain the chip-domain observation value, the signal processing means (SPM) is further configured to: - generating a synchronized second correlation function by shifting said first correlation function by one sampling period in a correlation sampling phase (domain); and - Differentiating the second correlation function from the first correlation function to generate the chip-domain observation value.

9. A radio frequency system for monitoring distortion of a (digital) radio frequency signal received at a radio receiver Rx of the radio frequency system in the chip domain, the radio frequency system further comprising a radio transmitter Tx for transmitting the radio frequency signal to the radio receiver, characterized in that: The radio frequency system comprises a radio receiver according to any one of claims 5 to 8.

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