Method for optimally detecting environment of radar system, authentication unit and radar system

Abstract

The invention relates to a method for detecting the environment of a radar system (1) in an optimized manner, to an authentication unit for a radar system, and to a radar system, comprising the following steps: transmitting a radar signal (RS1) by means of a transmitting unit (2) of the radar system (1), embedding an authentication sequence (AS1) matching the channel characteristics of the physical transmission channel into the transmitted radar signal (RS1); receiving a radar signal (RS2) via the physical transmission channel by means of a receiving unit (3) of the radar system (1); and receiving (S3) that the radar signal (RS2) received by a receiving unit (3) of the radar system (1) is valid if the authentication sequence (AS2) contained in the received radar signal (RS2) has sufficient similarity to the matched authentication sequence (AS1) embedded in the transmitted radar signal (RS1).

Description

Technical Field

[0001] The present invention relates to a method for detecting the environment of a radar system in a channel-optimized manner and an authentication unit for a radar system, the authentication unit being used to protect the radar system from third-party attacks by using an authentication sequence that matches the channel characteristics of the transmission channel. Background Technology

[0002] Radar technology is used in various fields to detect objects in the environment using radio waves. The key aspect here is the identification and localization of these objects. Depending on the radar technology and the signal processing used, the distance, angle, and velocity of objects in the environment can be determined by the radar system.

[0003] DE102014017671A1 relates to a conventional method for authenticating data packets in an open network, in which a transmitter and a receiver are interconnected. The transmitter has a plurality of predefined allowed authentication numbers, and marks data packets by adding an allowed authentication number to the packet. This authentication number then becomes disallowed by the transmitter. The transmitter transmits the marked data packets over the network. The receiver receives the marked data packets, and checks the received data packets for the presence of allowed authentication numbers. If no allowed authentication number is identified in the received data packet, the receiver discards the received data packet. Conversely, if an allowed authentication number is identified in the received data packet, the receiver accepts the received data packet for further processing. This authentication number then becomes disallowed by the receiver.

[0004] Radar systems are generally based on the principle that the reflected radar signal emitted by the system is received again by the same system. Based on the characteristics of the received radar signal, information about the radar system's environment can be extracted. Different radar technologies exist, such as Frequency Modulated Carrier Wave (FMCW) radar systems. Furthermore, there are radar variants, such as digital radar systems, which transmit specific types of message packets and subsequently identify the reception of the same message packets. Due to interference and noise, the received signal is usually correlated with the transmitted message packets to establish a defined tolerance for transmission errors.

[0005] Traditional radar systems do not authenticate the measured radar signals, making them vulnerable to spoofing by attackers. An attacker could thus transmit a signal with a different meaning, which the radar system incorrectly identifies as a reflection of its own signal, leading to erroneous conclusions about the environment. For example, an object might be incorrectly identified at a much shorter distance from the radar system or at a speed different from the actual speed relative to the radar system. Similarly, in cases where objects are classified based on radar data, the classification can be manipulated depending on the resolution of the radar image, potentially misidentifying a pedestrian as a car in the environment. Summary of the Invention

[0006] According to a first aspect, the present invention provides a method for detecting the environment of a radar system in an optimized manner, the method comprising the following steps: The radar system transmits radar signals through its transmitting unit, wherein an authentication sequence matching the channel characteristics of the physical transmission channel is embedded in the transmitted radar signals. The radar system receives radar signals via the physical transmission channel through its receiving unit; and If the authentication sequence contained in the received radar signal is sufficiently similar to the matched authentication sequence embedded in the transmitted radar signal, then accepting the radar signal received by the receiving unit of the radar system is valid.

[0007] The core idea of ​​this invention is to extend existing radar systems in such a way that an authentication sequence is constructed or embedded in the radar signal, particularly in the radar data packet or frame, and in the reception of the reflected radar signal (especially the radar data packet), the authentication sequence contained therein is compared with the cached expected authentication sequence to distinguish between valid and invalid radar data packets.

[0008] Thus, the method according to the invention prevents potential attacks on traffic participants using radar systems, particularly spoofing-Angriffe and jamming-Angriffe attacks.

[0009] The main advantage of the method according to the invention is that it takes into account the channel characteristics of the physical transmission channel used to transmit radar signals, and it can use authentication sequences that match these channel characteristics. The channel characteristics of the transmission channel can be predetermined or known, or can be obtained by means of measurement signals.

[0010] Furthermore, the method according to the invention results in a more reliable classification of objects in the environment of the radar system.

[0011] The method according to the invention preferably includes a computer-implemented method for detecting the environment of the radar system. The computational steps of different algorithms executed by the computing unit are preferably performed in real time with high data processing speed.

[0012] In traditional protocols, authentication sequences are used to authenticate messages transmitted from one party to another. However, the method according to the invention differs from this method in that it involves two different parties with two different identities communicating with each other. Furthermore, the primary function here is data exchange via authenticated message packets, not radar-based environmental detection. The method according to the invention is used to protect data used for environmental detection. This data is transmitted and received by the same identity, thus avoiding data exchange with other identities.

[0013] Unlike traditional schemes, the method according to the invention does not aim to protect communication between two parties, but rather only one party or identity "communicates" with itself to a certain extent, thus simplifying the requirements for message security. Complex key management can be eliminated in the method according to the invention, and pre-synchronization of multiple parties is also unnecessary. Instead, in the method according to the invention, the participating party, or the radar system, can, for example, simply instantiate the authentication sequence as a random sequence, or, if a scheme employing a cryptographic key is deemed advantageous, the radar system, as the sole participating party, can generate the cryptographic key locally without complexity and without synchronizing it with other parties or other devices.

[0014] In one possible implementation of the method for detecting the environment of a radar system according to the present invention, the authentication sequence is generated based on a provided random sequence.

[0015] In one possible implementation of the method for detecting the environment of a radar system according to the invention, the random sequence has a sequence of random numbers generated by a random number generator of the radar system. This allows for a simple and reliable implementation.

[0016] In one possible alternative embodiment of the method for detecting the environment of a radar system according to the invention, the random sequence is generated by the encryption unit of the radar system according to an encryption function. This allows the use of an existing encryption unit.

[0017] In one possible embodiment of the method for detecting the environment of a radar system according to the present invention, the random sequence is modified according to a first predetermined function using a first algorithm to generate a modified random sequence. This allows it to be matched to the characteristics of the transmission path of the radar signal.

[0018] In one possible embodiment of the method for detecting the environment of a radar system according to the invention, a modified random sequence is generated by interleaving the random sequence with additional provided bits to produce a modified random sequence that matches the signal characteristics of an authentication sequence embedded in a radar signal transmitted by the transmitting unit in such a way that the authentication sequence contained in the radar signal received by the receiving unit via the physical transmission channel can be identified more definitively.

[0019] In one possible implementation of the method for detecting the environment of a radar system according to the invention, the bits provided by the random sequence interleaving (interlacing) include a fixed, predetermined sequence of bits, or are selected according to a bit sequence within the random sequence.

[0020] In one possible embodiment of the method for detecting the environment of a radar system according to the invention, the random sequence has a random bit sequence divided into multiple random bit groups, wherein provided bits are inserted between two consecutive random bit groups, the provided bits matching the signal characteristics of an authentication sequence embedded in a radar signal transmitted by the transmitting unit in such a way that the authentication sequence contained in the radar signal received by the receiving unit of the radar system via the physical transmission channel can be identified in a more definitive manner.

[0021] In one possible implementation of the method for detecting the environment of a radar system according to the present invention, the random bit groups within the random bit sequence of the random sequence each include a specific number of random bits.

[0022] In one possible embodiment of the method for detecting the environment of a radar system according to the invention, the bits inserted between two consecutive random bit groups of the random bit sequence of the random sequence include at least one code bit sequence of a code set, the code set including different code bit sequences, the at least one code bit sequence being selected based on a previous random bit group and / or a subsequent random bit group of the random sequence.

[0023] In one possible implementation of the method for detecting the environment of a radar system according to the present invention, the random bits of the preceding random bit group and the random bits of the subsequent random bit group respectively constitute an index for selecting the inserted code bit sequence.

[0024] In one possible embodiment of the method for detecting the environment of a radar system according to the present invention, radar data packets are calculated based on the modified random sequence using a second algorithm according to a second predetermined function.

[0025] In one possible embodiment of the method for detecting the environment of a radar system according to the present invention, the calculated radar data packets are transmitted by the transmitting unit of the radar system and cached as internal radar data packets in the buffer unit of the radar system. This enables a reliable and robust comparison between the transmitted and received radar data packets.

[0026] In one possible embodiment of the method for detecting the environment of a radar system according to the present invention, a third algorithm is used to compare radar data packets received by the receiving unit of the radar system with internal radar data packets cached in the buffer unit to determine whether the authentication sequence contained in the received radar data packets has sufficient similarity to the authentication sequence contained in the cached internal radar data packets. The required sufficient similarity can be flexibly adjusted in the third algorithm according to the application of the radar system and the desired security level.

[0027] In one possible embodiment of the method for detecting the environment of a radar system according to the present invention, the acceptance of a radar data packet received by the receiving unit of the radar system is valid if the authentication sequence contained in the received radar data packet is sufficiently similar to the authentication sequence contained in the cached internal radar data packet.

[0028] According to another aspect, the present invention also provides an authentication unit for a radar system, the authentication unit being designed to accept radar signals received by a receiving unit of the radar system via a physical transmission channel if the authentication sequence contained in the received radar signal is sufficiently similar to an authentication sequence embedded in a radar signal transmitted by a transmitting unit of the radar system and matching the channel characteristics of the physical transmission channel.

[0029] In one possible embodiment of the authentication unit for a radar system according to the present invention, the authentication unit includes a random number generator designed to generate a sequence of random numbers as a random sequence.

[0030] In another possible embodiment of the authentication unit according to the invention, the authentication unit of the radar system has an encryption unit designed to generate a random sequence according to an encryption function, wherein the authentication sequence embedded in the transmitted radar signal is generated based on the generated random sequence.

[0031] In another possible embodiment of the authentication unit according to the invention, a modified random sequence is generated by interleaving (interlacing) the generated random sequence with additional provided bits to match the signal characteristics of the authentication sequence embedded in the radar signal transmitted by the transmitting unit in such a way that the authentication sequence contained in the radar signal received by the receiving unit via the physical transmission channel can be identified in a more explicit manner.

[0032] In one possible embodiment of the authentication unit for a radar system according to the present invention, the authentication unit includes a computing unit designed for, The generated random sequence is modified according to a first predetermined function using a first algorithm to produce the modified random sequence. The radar data packet is calculated based on the modified random sequence using a second algorithm according to a second predetermined function. The calculated radar data packets are transmitted by the transmitting unit of the radar system and cached as internal radar data packets in the cache unit of the authentication unit.

[0033] In one possible embodiment of the authentication unit for a radar system according to the invention, the computing unit is further designed to compare radar data packets received by the receiving unit of the radar system with cached internal radar data packets using a third algorithm to determine whether the authentication sequence contained in the received radar data packets is sufficiently similar to the authentication sequence contained in the cached internal radar data packets.

[0034] The use of different programmable algorithms provides a high degree of flexibility and facilitates the matching of the authentication unit according to the invention for different application scenarios.

[0035] According to another aspect, the present invention also provides a radar system comprising: A transmitting unit for transmitting radar signals, wherein an authentication sequence is embedded in the transmitted radar signals, and wherein the embedded authentication sequence matches the channel characteristics of the physical transmission channel; A receiving unit for receiving radar signals via a physical transmission channel; and An authentication unit is designed to accept radar signals received by the receiving unit of the radar system via the physical transmission channel if the authentication sequence contained in the received radar signal is sufficiently similar to an authentication sequence embedded in the radar signal transmitted by the transmitting unit of the radar system and matches the channel characteristics of the physical transmission channel.

[0036] In one possible embodiment of the radar system according to the invention, the received radar signal, which is accepted as valid, is further processed by the signal processing unit of the radar system to detect the environment of the radar system.

[0037] In one possible embodiment of the radar system according to the invention, the radar system is a monostatic or bistatic radar system.

[0038] A bistatic radar system is a radar system in which the transmitting and receiving units are located in separate positions. Conversely, a radar system in which the transmitting and receiving units are located in the same position or even use the same antenna is called a monostatic radar system. Radar devices that use separate transmitting and receiving antennas (but these separate transmitting and receiving antennas are installed closely side by side or stacked vertically) also constitute monostatic radar devices.

[0039] The above-described configurations and extensions can be combined arbitrarily, as long as they are meaningful. Other possible configurations, extensions, and implementations of the invention also include combinations of features of the invention not explicitly mentioned, whether described above or below with reference to the embodiments. In particular, those skilled in the art will also add individual aspects here as improvements or additions to the corresponding basic forms of the invention. Attached Figure Description

[0040] The method according to the invention and possible embodiments of the radar system according to the invention will be described in more detail below with reference to the accompanying drawings.

[0041] The attached diagram shows: Figure 1 : A flowchart illustrating one possible implementation of the method according to the present invention; Figure 2 : A block diagram illustrating a possible implementation of a radar system according to the present invention; Figure 3 : A schematic diagram illustrating the functional principle of the radar system according to the present invention; Figure 4 : A block diagram illustrating another possible implementation of the radar system according to the present invention; Figure 5 : A possible attack scenario for radar systems; Figure 6A , Figure 6B Other possible attack scenarios for radar systems.

[0042] The accompanying drawings are intended to aid in a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, are used to explain the principles and concepts of the invention. Other embodiments and many of the advantages mentioned are revealed when the drawings are taken into account. Elements in the drawings are not necessarily shown to scale relative to each other.

[0043] In the accompanying drawings, unless otherwise specified, the same elements, features and components that are identical in function and function are given the same reference numerals. Detailed Implementation

[0044] According to a first aspect, the present invention provides a method for detecting the environment of a radar system 1 in an optimized manner. One possible implementation of the radar system 1 is illustrated in... Figure 2 As shown in the diagram. In one possible implementation, the method mainly includes several key steps, such as those described in accordance with... Figure 1 As shown in the schematic flowchart.

[0045] In the first step S1, a radar signal RS1 is transmitted through the transmitting unit 2 of the radar system 1, wherein an authentication sequence AS1 is embedded in the transmitted radar signal RS1. Here, the authentication sequence AS1, matching the channel characteristics of the physical transmission channel PHY, is embedded in the transmitted radar signal RS1. The channel characteristics of the transmission channel are known and sufficiently stable in many cases. In some applications, the channel characteristics of the physical transmission channel PHY may change due to environmental factors. Therefore, in one possible implementation of this method, the instantaneous channel characteristics of the transmission channel PHY are measured periodically or by event triggering, for example, using the transmitted measurement signal.

[0046] In another step S2, the radar signal RS2 reflected by the object OBJ is received by the receiving unit 3 of the radar system 1, such as... Figure 3 As shown schematically in the diagram.

[0047] In another step S3, if the authentication sequence AS2 contained in the received radar signal RS2 is sufficiently similar to the authentication sequence AS1 embedded in the transmitted radar signal RS1 that matches the channel characteristics of the transmission channel PHY, then the acceptance of the radar signal RS2 received by the receiving unit 3 is valid.

[0048] In the method according to the invention, an authentication sequence AS is constructed or embedded into the transmitted radar signal RS1, particularly a radar data packet or frame RDP. During the reception of the radar signal RS2, particularly the radar data packet RDP, the authentication sequence contained therein is compared with an expected authentication sequence to distinguish between valid and invalid radar signals or valid and invalid radar data packets.

[0049] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, the authentication sequence AS is generated based on the provided random sequence ZS. In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, the random sequence ZS has a sequence of random numbers generated by the random number generator RNG (RNG = RandomNumber Generator = Zufallszahlengenerator) of radar system 1. This random number generator can also be a pseudo-random number generator (PRNG). Alternatively, other methods for generating the authentication sequence AS can be used. The random number generator RNG or the pseudo-random number generator PRNG is one possible instantiation, but other possibilities exist for implementing the unit for generating the random sequence ZS. For example, the pseudo-random number generator PRNG can be implemented using an encryption function with a suitable bit sequence as input. Depending on the computational algorithm used, the resulting output sequence can be sufficiently close to a pseudo-random sequence. In one embodiment of the method for detecting the environment of radar system 1 according to the present invention, the random sequence ZS is generated by the encryption unit of radar system 1 according to an encryption function.

[0050] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, a generated random sequence ZS is modified according to a first predetermined function (f) by means of a first algorithm to generate a modified random sequence ZSM.

[0051] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, a modified random sequence ZSM is generated by interleaving or interleaving a random sequence ZS with other provided bits. The modified random sequence matches the signal characteristics of the authentication sequence AS1 embedded in the radar signal RS1 transmitted by the transmitting unit 2 in such a way that the authentication sequence AS2 contained in the radar signal RS2 received by the receiving unit 3 via the physical transmission channel PHY can be identified in a more explicit manner.

[0052] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, the bits provided by interleaving or interweaving with the random sequence ZS include a fixedly predetermined sequence of bits or selected according to the bit sequence within the random sequence ZS.

[0053] In one possible embodiment of the method according to the invention for detecting the environment of radar system 1 in a channel-optimized manner, the random sequence ZS has a random bit sequence divided into multiple random bit groups. Provided bits are inserted between two consecutive random bit groups, the provided bits matching the signal characteristics of the authentication sequence AS1 embedded in the radar signal RS1 transmitted by the transmitting unit 2 in such a way that the authentication sequence AS2 contained in the radar signal RS2 received by the receiving unit 3 of radar system 1 via the physical transmission channel can be identified more definitively. In one possible embodiment of the method according to the invention for detecting the environment of radar system 1, the random bit groups within the random bit sequence of the random sequence ZS each include a specific number of random bits.

[0054] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, the bits inserted between two consecutive random bit groups of a random bit sequence ZS include at least one code bit sequence or code C of a code set CS, which includes different code bit sequences or codes C, the at least one code bit sequence being selected based on a previous random bit group and / or a subsequent random bit group of the random sequence ZS.

[0055] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, the random bits of the previous random bit group and the random bits of the subsequent random bit group respectively constitute an index, which is used to select the inserted code bit sequence C.

[0056] There are several possibilities for embedding the authentication sequence AS into the radar data packet RDP.

[0057] One possibility for embedding the authentication sequence AS into the radar data packet RDP is to modulate the authentication bit of the authentication sequence AS and use that authentication bit directly as part of the radar data packet RDP, and to check that authentication bit when sensing the received radar data packet RDP.

[0058] A second possibility for embedding the authentication sequence AS into the radar data packet RDP is to use the authentication bits from the authentication sequence AS to pseudo-randomly select a specific code C or sequence that is favorable for identification.

[0059] First, let's describe the following scenario as the first possibility: embedding authentication bits into the radar data packet RDP.

[0060] In one possible implementation of the method according to the invention, the first algorithm or its function is instantiated using the following algorithm or the following function.

[0061] Here, the authentication sequence AS is interleaved or interleaved with other bits to ensure better signal characteristics when the entire sequence is modulated onto the physical channel PHY. In particular, the non-random bits can be selected in such a way that the autocorrelation properties or other properties of the signal are improved, making identification, for example, less ambiguous.

[0062] In the method according to the invention, instead of random attempts to improve signal quality, either a fixed sequence (which always or in most cases leads to improved recognition performance) is used, or bits are selected based on the authentication bits.

[0063] The following describes this interleaving of authentication bits and code bits based on a simple example.

[0064] In an exemplary partition of 50% authentication bits and 50% code bits for improved probing, the following logic produces the authentication sequence AS used in one possible implementation.

[0065] Here, length (ZS) = |ZS| = n = Bit.

[0066] 1. Generate a length (ZSM) = The bit sequence ZSM.

[0067] 2. For i in [0, 4, 8, ..., n-4] a. ZSM [ , +1, +2, +3] = ZS [i, i+1, i+2, i+3] b. Determine the code C for ZS [i, i+1, i+2, i+3] (see below) c. ZSM [ +4, +5, +6, +7] = C[i, i+1, i+2, i+3] The newly obtained ZSM is therefore: ZSM = [ZS [0, 3] ||code|| ZS [4, 7] ||code|| ZS [8, 11] || ...] ZSM = ZS [0] ZS [1]ZS [2] ZS [3]C[0] C[1]C[2] C[3]ZS[4] ZS[5]ZS[6] ZS[7]C[4] C[5]C[6] C[7] The notations ZSM [a, b] and ZS [a, b] indicate that this is the bit starting at index a and extending up to index b. ZSM [a] and ZS [a] indicate that this is the value at index a in the sequence.

[0068] The algorithm described above should be considered as an example. In other embodiments of the method according to the invention, additional interleaving of authentication bits and code bits is employed.

[0069] Alternatively, a smaller or larger number of random bits can be used compared to a fixed symbol. The algorithm described above is an example for a 50 / 50 partition and for 4 bits per type in each row. The placement of the bits can also vary. For example, it could be 8 random bits followed by 8 bits for improved recognition characteristics, and so on.

[0070] Regarding the determination of code C, there are multiple possibilities for determining the code to be embedded.

[0071] In one possible first embodiment of the method according to the invention, a fixed code may be used, which remains unchanged independently of the content of random bits, in order to improve the detection characteristics of the obtained signal.

[0072] An embodiment of this first implementation of the method according to the invention includes: 1. Example: Maximum length sequence (MLS) can be embedded as a fixed sequence into the above code sequence to improve the correlation properties.

[0073] 2. Example: Barker codes can be used as fixed sequence embeddings to improve the correlation properties with the code sequence portion mentioned above.

[0074] 3. Example: Gold codes can also be embedded in the code sequence portion.

[0075] 4. Example: The Zadoff-Chu sequence can also be embedded into the code sequence portion to take advantage of its beneficial properties.

[0076] 5. Example: Other CAZAC sequences can also be used.

[0077] Depending on the portion of the sequence to be inserted for relevant improvements, match the length of the gap if necessary.

[0078] In another possible second embodiment of the method according to the invention, code C may be dynamically calculated based on previous random bits and may additionally depend on subsequent random bits.

[0079] The advantage of this second implementation is that it can achieve matching of code sequences based on the selected random bits.

[0080] An embodiment of this second implementation of the method according to the invention includes: 1. Example: In the case of short intervals in the sequence, local decisions can be made based on an offline-prepared decision matrix that selects values ​​in a way that minimizes local cross-correlation. While this technique cannot globally minimize cross-correlation, it significantly improves performance on average compared to a completely random sequence due to local optimization. For example, considering the 4-bit interval example above, for code block C [a, b], the preceding and subsequent authentication bits ZS [b-1, b] and ZS [b+1, b+2] can be considered. In this case, since the system pre-stores the optimal code for each bit combination, it needs to buffer 2^4 = 16 codes from which locally optimal codes can be selected.

[0081] 2. Example: In the case of longer intervals, prospective choices of code C can be stored. If there are a few segments with random and correlated optimized bit sequences, the optimal choice can be attempted globally simultaneously for all correlated optimized bit sequences, or locally iteratively for each correlated optimized bit sequence. Then, the attempted code for the optimal choice of the current authentication bit can be used.

[0082] 3. Example: An algorithm can be used to optimize the autocorrelation with the next block to be selected, for example, based on all previous bits. Alternatively, algorithms can be used to find bit sequences with low cross-correlation. These algorithms can also be applied to portions of a sequence.

[0083] The proposed scheme is advantageous in terms of security compared to simply randomly selecting the code, using it as the authentication sequence AS, and abandoning the selection of the random portion, although the random portion reduces recognition performance compared to a fixed, optimized sequence. This is because there are typically not enough optimal sequences available to achieve our security objective for the analyzed code. The probability of an attacker successfully forging the signal must be very low to ensure the secure operation of radar system 1. However, in efficient radar or ICAS systems, the radar frames or radar data packets RDP used for identification cannot be arbitrarily large; instead, radar frames of fixed length must be used in many applications. Therefore, there is a finite number of such optimal or near-optimal sequences. However, from a security perspective, the number of such sequences often proves insufficient. If an attacker has a success probability of, for example, one in 100 attempts or better, then in a short sampling period, there is a good chance for that attacker to succeed a few times, which can already have serious consequences.

[0084] On the other hand, the method according to the invention can reduce the success rate of an attack by several orders of magnitude, and can be designed in a way that achieves a balance between security and performance. Depending on the design and the length of the authentication sequence AS, the method according to the invention can achieve a success rate of less than 1 in 1,000,000 attack attempts.

[0085] As mentioned above, a second possibility for embedding the authentication sequence AS into the radar data packet RDP is to use the authentication bits in the authentication sequence AS to pseudo-randomly select a specific code C or sequence that is favorable for identification.

[0086] The authentication sequence AS can be used to protect radar data packets (RDP) from attacks by selecting the code C in an unpredictable manner, rather than directly embedding these bits. As an example of the code used, the one mentioned above still works.

[0087] Therefore, in this case, the corresponding pseudo-random or randomly selected code is modulated on the transmission channel used, rather than directly modulating the bits from the authentication sequence.

[0088] If we consider the code set (Codemenge or CodeSet, CS) to be selected for a radar data packet RDP of size N, these codes C can be assigned numbers to identify the corresponding code C, thus numbering the codes C in the set from 0 to N-1. This means that by specifying a number between 0 and N-1, the corresponding code C can be selected. The current part of the authentication sequence AS can be used to generate one or more pseudo-random numbers in the configuration range of 0 to N-1. These numbers are then used to randomly select a code from the code set CS.

[0089] If there is no x such that 2^x = N, then the processing used for code selection must take this into account in order to still select codes C uniformly and randomly. For example, after extracting bits covering a range up to 2^y > N from the authentication sequence AS, the current part of the authentication sequence can be skipped and subsequent parts taken until the numbers are valid indices for the code set CS. Alternatively, the number of codes C in the code set CS can be reduced to a power of 2 or other preprocessing algorithms can be used to produce the correct index range.

[0090] Next, the index provided by the authentication sequence AS can be used. In the simplest case, there is a sufficiently large set of codes C in the code set CS. In this case, a pseudo-random number is taken from the next part of the random sequence ZS, and a code C is selected from the code set CS as the next input for the radar data packet RDP. Thus, for example, the random sequence ZS[a, b] is selected, and the index equal to ZS[a, b] is converted to an integer c. The code C with index c is selected from the code set CS. Then CS[c], i.e., the code C with index c, is embedded into the next radar data packet RDP. If ZS[a, b] is, for example, 0010, it can be read as the binary encoded number 2, and CS[2] can be selected, for example, this might be a code C with the bit sequence "11101".

[0091] As mentioned above, the number of codes C with good or near-ideal cross-correlation properties is finite. If the code set CS is not large enough, this can be compensated for by selecting multiple codes C from the code set CS and concatenating these selected codes C with each other.

[0092] Unlike single code selection, multiple intervals in the authentication sequence AS are now used, namely ZS[a, b], ..., ZS[c, d], and a corresponding code C1, ..., Cm is selected for each index derived from it. The concatenation of these codes C1 || ... || Cm is then embedded into the radar data packet RDP.

[0093] To achieve an appropriate level of security, in any of the applied code selection methods, it must be sufficiently difficult for an attacker to guess the correct code C or the correct code sequence, or, in relevant cases, it must be sufficiently difficult to obtain an output that is close enough to this. Therefore, the selection of a single code C for a radar data packet (RDP) of fixed length is only feasible if the code set CS of the code C to be selected is sufficiently large for its length.

[0094] Based on the output of function f, function g must then construct the radar data packet RDP itself.

[0095] If radar system 1 is a digital radar system using OFDM, the aforementioned authentication sequence AS can be embedded in one or more locations within the radar data packet RDP, just like other valid data. That is, the existing packet structure can be reused. Alternatively, separate fields or additional, reduced packets can be inserted.

[0096] If radar system 1 is pulse-based, the following packet structure can be used for radar data packets RDP: SYNC || SFD || AS.

[0097] In this example, a synchronization field and a separator SFD can be placed before the authentication sequence AS for synchronization purposes, and then the authentication sequence AS is embedded. The resulting bit string is then modulated onto the pulse shape of the underlying PHY layer.

[0098] For a radar system capable of practically embedding this sequence of pulses, the pulse rate must be high enough to achieve sufficiently reliable authentication from a security perspective without excessively delaying the radar output. This requirement is met, for example, for Ultra-Wide-Band High-Rate-Pulse Repetition Frequency (UWBHRP).

[0099] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, radar data packets RDP are calculated based on a modified random sequence ZSM using a second algorithm according to a second predetermined function (g). In another possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, the calculated radar data packets RDP are transmitted by the transmitting unit 2 of radar system 1 and cached in the buffer unit of radar system 1 as internal radar data packets RDPintern.

[0100] In one possible embodiment of the method for detecting the environment of radar system 1 according to the present invention, the radar data packet RDP received by the receiving unit 3 of radar system 1 is compared with the internal radar data packet RDPintern cached in the buffer unit using a third algorithm (h) to determine whether the authentication sequence AS2 contained in the received radar data packet RDP is sufficiently similar to the authentication sequence AS1 contained in the cached internal radar data packet RDPintern. If the received radar data packet RDP... Empf If the authentication sequence AS2 contained in the cached internal radar data packet RDPintern is sufficiently similar to the authentication sequence AS1 contained in the cached internal radar data packet RDPintern, then the radar data packet RDP received by the receiving unit 3 of radar system 1 will be accepted. Empf It is valid.

[0101] The first algorithm f is an algorithm that takes a random sequence ZS as at least one input and provides a corresponding value ZSM as the output. The instantiation of algorithm f depends on the radar technology used.

[0102] The second algorithm, g, is an algorithm that takes the ZSM as at least one input and outputs the corresponding radar data packet RDP. Alternatively, g can also be referred to as a function. The radar data packet RDP is transmitted for environmental detection.

[0103] The third algorithm, h, is an algorithm that obtains the received radar data packets (RDP). Empf The third algorithm (h) takes at least two inputs: the radar data packets (RDP_intern) and the internally cached radar data packets (RDP_intern). The third algorithm compares these two radar data packets, particularly comparing the authentication sequences they contain, and provides an output from the authentication unit 4 indicating or characterizing the similarity between the two authentication sequences. This similarity allows the application or authentication unit 4 to determine whether the consistency is good enough to securely accept the received radar signal or the received radar data packet RDP (frame). The algorithm used here is application-specific and depends on the corresponding radar system 1. For example, this can be achieved by calculating the correlation in the form of Channel Impulse Responses (CIRs) on the corresponding parts of the message. In the case of the ICAS radar system, this check can be combined with the authentication of the potentially contained data.

[0104] According to another aspect, the present invention also provides an authentication unit 4 for a radar system 1, which is designed to make it valid to accept the radar signal RS2 received by the receiving unit 3 of the radar system 1 if the authentication sequence AS2 contained in the received radar signal RS2 is sufficiently similar to the authentication sequence AS1 embedded in the radar signal RS1 transmitted by the transmitting unit 2 of the radar system 1.

[0105] In one possible embodiment of the authentication unit 4 for radar system 1 according to the present invention, the authentication unit 4 has a random number generator RNG designed to generate a random number sequence as a random sequence ZS. The authentication sequence AS1 embedded in the transmitted radar signal RS1 is generated based on the generated random sequence ZS.

[0106] In another possible embodiment of the authentication unit 4 according to the invention, the authentication unit 4 has an encryption unit designed to generate a random sequence ZS according to an encryption function, wherein the authentication sequence AS1 embedded in the transmitted radar signal RS1 is generated based on the generated random sequence ZS.

[0107] In one possible embodiment of the authentication unit 4 for radar system 1 according to the present invention, the authentication unit 4 includes a calculation unit BE, such as... Figure 4 As illustrated in the diagram, the computing unit BE is designed to modify the generated random sequence ZS according to a first predetermined function (f) using a first algorithm to produce a modified random sequence ZSM. The computing unit BE, integrated in the authentication unit 4, is also designed to calculate the radar data packet RDP based on the modified random sequence ZSM using a second predetermined function (g) using a second algorithm. The calculated data with the authentication sequence AS1 can be used as the radar data packet RDP. Sende It is then transmitted by transmitting unit 2 of radar system 1, and simultaneously serves as an internal radar data packet RDP. intern The data is cached in the cache unit ZSPE of the authentication unit 4. In one possible embodiment of the authentication unit 4 for radar system 1 according to the present invention, wherein the integrated computing unit BE is further designed to process the radar data packets RDP received by the receiving unit 3 of radar system 1 using a third algorithm (h). empf With cached internal radar data packets RDP intern A comparison is made to determine the received radar data packet RDP. empf Does the authentication sequence AS2 contained therein match the cached internal radar data packet RDP? intern The authentication sequence AS1 contained therein has sufficient similarity.

[0108] According to another aspect, the present invention also creates a radar system 1, as schematically shown in a block diagram. Figure 2 As shown in the diagram, radar system 1 includes a transmitting unit 2 for transmitting radar signal RS1, wherein an authentication sequence AS1 is embedded in the transmitted radar signal RS1. Here, an authentication sequence AS1 that matches the channel characteristics of the physical transmission channel PHY is embedded in the transmitted radar signal (RS1).

[0109] In one possible embodiment of the method according to the invention, the channel characteristics of the physical transmission channel (PHY) are measured periodically or as a consequence of a detected event. The authentication sequence AS1 is then matched with the currently measured channel characteristics of the PHY. This can further improve the identifiability of the authentication sequence AS embedded in the received radar signal RS2.

[0110] Radar system 1 also has a receiving unit 3 for receiving radar signal RS2, such as Figure 2 As shown in the diagram. The radar system 1 also includes an authentication unit 4, designed to accept the radar signal RS2 received by the receiving unit 3 of the radar system 1 as valid if the authentication sequence AS2 contained in the received radar signal RS2 has sufficient similarity to the authentication sequence AS1 embedded in the radar signal RS1 transmitted by the transmitting unit 2 of the radar system 1. In one possible embodiment of the radar system 1 according to the invention, the received radar signal RS2, accepted as valid, is further processed by the signal processing unit 5 of the radar system 1 to detect the environment of the radar system 1. The transmitting unit 2 and the receiving unit 3 can be integrated into a transceiver 6, such as... Figure 4 As shown schematically, transceiver 6 is connected to at least one antenna 7 of radar system 1 for transmitting and receiving radar signals.

[0111] In one possible embodiment of the radar system 1 according to the present invention, the radar system 1 has a monostatic radar system, such as Figures 1 to 4 As illustrated schematically. In another possible alternative embodiment of the radar system 1 according to the invention, the radar system 1 has a bistatic radar system in which the transmitting unit 2 is located remotely from the receiving unit 3.

[0112] The authentication component or authentication unit 4 can be integrated into the existing radar system 1. The built-in authentication unit 4 is configured for each new radar data packet (RDP) to be transmitted. Sende Add at least one authentication sequence AS1 to the corresponding radar data packet RDP.

[0113] This is via RDP used to transmit the next radar data packet. Sende The following steps are required to achieve this: Authentication unit 4 obtains the next correct length random number sequence ZS by calling the RNG algorithm.

[0114] The calculation unit BE of authentication unit 4 calculates ZSM = f(ZS).

[0115] The calculation unit BE of authentication unit 4 then calculates the RDP. Sende =g(ZSM).

[0116] Authentication Unit 4 will use RDP Sende The radar data packet to be transmitted is output to transmitting unit 2.

[0117] During sensing, the following steps are performed when receiving radar frames (RDP): For the received radar signal RS2 or the received radar data packet RDPEmpf For the radar data packets RDP currently cached in the cache unit ZSPE intern Execute the third algorithm h(RDP) Empf RDP intern ).

[0118] Based on the similarity indicated by the output of the third algorithm h, authentication component 4 makes a decision on whether to accept or reject the current probe. The probe can be performed based on the configured security level. Multiple security levels can be supported to meet different applications with varying security requirements.

[0119] The components are described in more detail below.

[0120] Add an additional function / component, "authenticator," to radar system 1. This function / component matches and / or creates radar data packets (RDPs) as described below, passes them to subsequent components for reflection, and obtains, authenticates, and passes the authenticated data to another component.

[0121] This function / component, the "authenticator," can be implemented in hardware, software, or a hybrid of both. As a logical component, it can also be integrated into other existing radar components, such as those used for signal processing.

[0122] If the aforementioned individual function / component already exists based on the radar technology used, such as a suitable cache unit as described below, then the described function / component "authenticator" also includes a possible implementation in which the individual function / component is used collectively.

[0123] Preferably, an additional function RNG is added to the radar system 1, which is capable of generating a cryptographically secure pseudo-random sequence or a cryptographically secure random sequence ZS as output. The output of the random number generator RNG is referred to below as the random sequence ZS. This function (which may also be referred to as the random number generator RNG) can be added in hardware or software. The input to the random number generator RNG is an entropy source or seed, i.e., a random number sequence, such as a counter incremented by the caller on each call, and, depending on the implementation scheme, additional parameters for the output length. Optionally, additional data can also be used as input, which may be particularly meaningful for ICAS systems.

[0124] Furthermore, it is preferable to add a function logic f or algorithm f to the radar system 1, which takes a cryptographically secure pseudo-random sequence or random sequence ZS as input and converts it into a new output ZSM (modified random sequence), for example, the new output being more favorable for the autocorrelation of the received signal with the expected signal on the transmission medium.

[0125] This functionality can also be implemented in hardware or software. The input to function f can include additional parameters besides the random sequence ZS. Thus, for example, additional components or configuration parameters of the set radar data packet RDP can be used as input to match the output based on the current radar data packet or other environmental variables. This component can be omitted if algorithm f is not used (because it is not considered necessary due to radar technology). This is functionally equivalent to defining function f as an identity function x = f(x), which outputs its input as is. For further description, it is therefore assumed that function f exists, and this automatically includes the case where the function is not used or does not exist. In one possible implementation, function f can also call the random generator function RNG as a subfunction. In one possible implementation, function f can also have the radar data packet RDP already combined and output as output. In this case, function g will no longer need to be a separate function.

[0126] For each transmitted radar data packet RDP Sende (Also referred to as a frame in the terminology), a newly generated portion of a cryptographically secure pseudo-random sequence or random sequence ZS is produced as the output of RNG, and then transformed into a new sequence ZSM using a function or algorithm f. Therefore, ZS = RNG(_) and ZSM = f(ZS) are computed.

[0127] In one possible implementation, then to each of the transmitted RDPs Sende Add this value ZSM. That is, add the value ZSM to the RDP that combines this radar data packet. Sende The function g provides the calculated value ZSM as at least one of the inputs, and then outputs the radar data packet RDP. Sende Radar data packet RDP Sende The format is selected appropriately to include the sequence ZSM. However, this is only necessary as long as the sequence ZSM is included, either completely or divided into multiple subsequences, in the transmitted and buffered radar data packets RDP. intern In this invention, the method does not require the radar data packet RDP used for transmission. Sende A fixed data format.

[0128] During the duration of the reflection of the current radar data packet RDP, which is anticipated and identified by the receiving unit 3 of radar system 1 as containing the modified random sequence ZSM as the authentication sequence AS2 (for the purpose of environmental detection using the radar data packet RDP), the value ZSM is cached by radar system 1 in the cache unit ZSPE as the anticipated authentication sequence AS1. This time period can be adjusted in one possible implementation.

[0129] When receiving radar signal RS2 in the current measurement iteration, the received radar signal RS2 or the radar data packet RDP obtained from it will be... Empf With the expected and cached radar data packets RDP intern The comparison is performed by the computing unit BE using a third algorithm h, which obtains the currently received radar data packet RDP. Empf and the currently cached radar data packets RDP intern It takes at least two inputs as inputs and outputs the determined similarity between the two to determine whether to accept or reject the received radar data packet RDP. Empf .

[0130] Specifically, the received radar data packets RDP will also be included here. Empf The received sequence AS2 contained in the packet is compared with the locally cached sequence AS1. This can be achieved, for example, using a correlation algorithm that associates the expected sequence with the received sequence to determine similarity. Depending on the radar technology, desired security level, and application, the radar data packet RDP can be configured to... Empf The similarity or relevance threshold required to determine if something is real.

[0131] Now, unlike previous uncertified variants, only when the received radar data packet RDP... Empf When the received sequence AS2 contained therein—as described above—is sufficiently similar to the expected sequence AS1, the received radar data packet RDP... Empf Only then will it be considered valid and processed further. If the two values ​​of the parameters determined in the configuration deviate too much from each other, the received radar data packet RDP will be... Empf It is not considered valid and is not used or analyzed for further detection steps.

[0132] In one possible implementation of the method according to the invention, the received radar data packet RDP that was not deemed valid Empf They will be discarded. In another possible implementation of the method according to the invention, received radar data packets (RDPs) that are not deemed valid are discarded. Empf Instead of being discarded, the data packets are analyzed and processed for the detection and analysis of potential attacks. Furthermore, the number of radar data packets dropped sequentially can be counted to trigger a warning or other response from radar system 1, for example, when a threshold is exceeded.

[0133] As an alternative to the above implementation, the function RNG used to generate the sequence for authentication can also be implemented using other logic. For example, an algorithm using a Message Authentication Code (MAC) can be used. From a security perspective, this function is also suitable, but there is no tolerance for transmission errors, and error correction codes must be added separately. Therefore, implementations using random or pseudo-random sequences are generally more efficient, especially when no valid data is transmitted and transmission errors are expected. However, if a transmission method that compensates for bit errors or where transmission errors are sufficiently rare is used, the reuse of MAC-based pseudo-random sequences or encrypted data may be a meaningful implementation of the method according to the invention.

[0134] The pseudo-random generator (PRNG) can be initialized with the output of a slower RNG when radar system 1 starts up. Depending on the instantiation of the PRNG used to generate the authentication sequence AS, a secret cryptographic key can also be used as part of the input. However, unlike known applications, the latter is not absolutely necessary in the scenario considered here, thus simplifying the radar system.

[0135] The process for creating and subsequently receiving radar data packets (RDPs) is preferably performed for each newly transmitted radar data packet (RDP). Sende Or it can be repeated in each measurement cycle. For each transmitted radar data packet RDP Sende Preferably, a new value ZSM is generated and used. Otherwise, the attacker can also send the previously used and eavesdropped radar data packets RDP back to radar system 1 as a response for subsequent measurement cycles (Replay Angriff).

[0136] Depending on the instantiation used, it may be necessary to update the state of the functional RNG for each call, store it between calls, and prepare it for use. For example, in the case of a pseudo-random number generator (PRNG), it is necessary to determine the seed for the start of the random sequence because, for the same seed, the PRNG will always output the same pseudo-random numbers. Accordingly, depending on the instantiation of the component, additional data processing steps or cached or permanently stored data may be set up.

[0137] Figure 3 The functional principle of radar system 1 is schematically illustrated, which transmits correspondingly authenticated radar data packets RDP. SendeAs radar signal RS1, the transmitted radar data packet is reflected by an object OBJ in the environment of radar system 1, and then received again as radar signal RS2 after reflection. The transmitted radar signal RS1 can propagate in a medium (e.g., air or water) and be reflected by an object OBJ (e.g., the body of a vehicle) located in the medium.

[0138] Figure 4 An exemplary illustration is shown in which the authentication component 4 implements the process described above according to the invention, in that the "authenticator" 4 uses a sub-component to authenticate radar data. Inputs to the "authenticator" 4 may include the control signal CTRL, because depending on the instantiation of the authenticator 4 or subsequent components, the radar data packet RDP to be transmitted can be generated entirely, thus requiring only control of component 4 as if it were started or configured. Alternatively, the radar data packet RDP modified by the "authenticator" 4 can be passed by adding the value ZSM. The latter may be the case when using an ICAS system that already provides a pseudo-random sequence, for example, through an encrypted bit sequence from the data to be transmitted simultaneously. In this case, it may not be necessary to set the sub-component RNG, and this input can be further processed here if necessary.

[0139] The method according to the invention can be used for both "stand-alone" radar systems and ICAS radar systems. In cases where the ICAS system performs dedicated sensing steps, the system described above can be used. Where data needs to be transmitted simultaneously for communication purposes, this data—if necessary—can be adapted and then transmitted in a suitable manner, rather than solely by the dedicated authentication sequence generated by authentication component 4.

[0140] One possible extension or alternative is to use authentication component 4 in a bistatic radar. It is important to note that for practical use, transmitter 2 and receiver 3 require a secure channel for data exchange, meaning either the current authentication sequence AS is always readily available to transmitter 2 and receiver 3, or pre-synchronization ensures that transmitter 2 and receiver 3 use consistent authentication sequences AS respectively. The latter synchronization may need to be repeated periodically (e.g., each time radar system 1 is restarted).

[0141] The method according to the invention can be used in all radar types that allow the embedding of authentication sequences (AS). These include, for example, digital radar (such as OFDM radar) or pulse-based radar. The method according to the invention can also be integrated into 6G standards.

[0142] The method according to the present invention can prevent various attacks targeting traffic participants. Figure 5An exemplary attack scenario (spoofing) is illustrated. While the forged signals emitted by the attacker (so-called spoofing in security terms) are the primary motivation for matching radar systems according to the present invention, such matching may potentially be useful in other attack scenarios. Similarly, the described method can reduce interference as a side effect.

[0143] For example, if an attacker attempts to specifically jam a conventional radar system (such as...) by emitting noise signals (so-called jamming in technical terms). Figure 6A , Figure 6B As shown in the diagram, if a traditional radar system is no longer able to perform meaningful detection, then the affected radar system is useless for environmental perception. This is especially dangerous when the radar system is used as a warning system (e.g., for collision recognition in a vehicle) and, for example, automatically triggers emergency braking, or when the radar system is used for other automated driving assistance functions that cannot correctly or timely identify radar system malfunctions or blockages.

[0144] Figure 6A , Figure 6B The consequences of two different types of attacks as interference are shown. Figure 6A The diagram illustrates a so-called forward interference, in which the adaptive cruise control of vehicle F is interfered with by means of a noise signal N. Figure 6B The so-called blind spot interference is shown, in which the detection of another vehicle in the blind spot or blind angle of vehicle F is prevented.

[0145] The method according to the invention adds authentication information to the radar signal RS used, with the intent that an attacker can no longer respond using a suitable radar signal. An attacker can only transmit a suitable sequence if he has received the radar signal RS1 transmitted by the radar system 1 according to the invention and if that radar signal has potentially already been reflected back through its physical surface.

[0146] Deceptive attacks (such as those in) Figure 5 As shown in the diagram, the transmission of a forged radar signal is blocked by the method according to the invention because the attacker cannot predict the authentication information and therefore cannot respond faster than the reflected signal.

[0147] Therefore, the method according to the invention prevents: Figure 5 The deception attacks illustrated are either successful or have adverse consequences. The importance of preventing such attacks depends on the intended use of the affected radar system and whether attack identification and follow-up responses have been adequately implemented for that application.

[0148] Interference attacks (such as those in) Figure 6A , Figure 6B As shown in the diagram, blocking the radar signal RS can be prevented depending on the underlying radar technology used. If the radar system can filter out other signals (such as noise) and / or simultaneously identify signals containing authentication information, then jamming attacks can be prevented, depending on the effectiveness of this distinction. Authentication information can be advantageous in this distinction because attackers cannot pre-embed this authentication information. Jamming is still possible if the radar system is completely blocked by signals emitted at high energy and can no longer distinguish signals based on authentication information.

[0149] Depending on the application, the method described can also facilitate the detection of such supplies in the event of a jamming attack by noticing, for example, the prolonged absence of properly authenticated radar data packets and triggering an appropriate response.

[0150] Figure 5 , Figure 6A , Figure 6B An exemplary attack scenario is illustrated. The method according to the invention can also be used in other scenarios involving radar systems. These include, for example, radar systems used for detecting the interior space of vehicles or radar systems used in other application areas.

[0151] Although the present invention has been fully described above based on preferred embodiments, the present invention is not limited thereto and can be modified in various ways.

Claims

1. A method for detecting the environment of a radar system (1) in an optimized manner, the method comprising the steps of: The radar system (1) transmits (S1) radar signal (RS1) through the transmitting unit (2), wherein an authentication sequence (AS1) matching the channel characteristics of the physical transmission channel (PHY) is embedded in the transmitted radar signal (RS1). The radar system (1) receives (S2) radar signals (RS2) via the physical transmission channel (PHY) through its receiving unit (3); and If the authentication sequence (AS2) contained in the received radar signal (RS2) is sufficiently similar to the authentication sequence (AS1) embedded in the transmitted radar signal (RS1) and matched with the channel characteristics of the physical transmission channel (PHY), then the acceptance (S3) of the radar signal (RS2) received by the receiving unit (3) of the radar system (1) is valid.

2. The method for detecting the environment of a radar system according to claim 1, wherein, The authentication sequence (AS1) is generated based on the provided random sequence (ZS).

3. The method for detecting the environment of a radar system according to claim 2, wherein, The random sequence (ZS) has a random bit sequence generated by the random number generator (RNG) of the radar system.

4. The method for detecting the environment of a radar system according to claim 2, wherein, The random sequence (ZS) is generated by the encryption unit of the radar system (1) according to the encryption function.

5. The method for detecting the environment of a radar system according to any one of claims 1 to 4, wherein, The generated random sequence (ZS) is modified according to a first predetermined function (f) using a first algorithm to produce a modified random sequence (ZSM).

6. The method for detecting the environment of a radar system according to claim 5, wherein, The generated random sequence (ZS) is modified by interleaving it with other provided bits to produce the modified random sequence (ZSM), which matches the signal characteristics of the authentication sequence (AS1) embedded in the radar signal (RS1) transmitted by the transmitting unit (2) in such a way that the authentication sequence (AS2) contained in the radar signal (RS2) received by the receiving unit (3) via the physical transmission channel (PHY) can be identified in a more explicit manner.

7. The method for detecting the environment of a radar system according to claim 6, wherein, The bits provided by the interleaving of the random sequence (ZS) include a fixed, predetermined sequence of bits, or are selected based on a bit sequence within the random sequence (ZS).

8. The method for detecting the environment of a radar system according to claim 7, wherein, The random sequence (ZS) has a random bit sequence, which is divided into multiple random bit groups, wherein provided bits are inserted between two consecutive random bit groups, and the provided bits are matched to the signal characteristics of the authentication sequence (AS1) embedded in the radar signal (RS1) transmitted by the transmitting unit (2) in such a way that the authentication sequence contained in the radar signal (RS2) received by the receiving unit (3) of the radar system (1) via the physical transmission channel can be identified in a more explicit manner.

9. The method for detecting the environment of a radar system according to claim 8, wherein, The random bit sequence (ZS) contains a specific number of random bits in each random bit group.

10. The method for detecting the environment of a radar system according to claim 9, wherein, Bits inserted between two consecutive random bit groups in the random bit sequence (ZS) include at least one code bit sequence (C) of a code set (CS) that includes different code bit sequences, the at least one code bit sequence being selected based on a previous random bit group of the random sequence (ZS) and / or a subsequent random bit group of the random sequence (ZS).

11. The method for detecting the environment of a radar system according to claim 10, wherein, The bits between two consecutive random bit groups of the at least one code bit sequence (C) inserted into the random bit sequence (ZS) are selected from a code set (CS) comprising different code bit sequences according to the channel characteristics of the physical transmission channel (PHY) and / or according to the previous random bit group of the random sequence (ZS) and / or according to the subsequent random bit group of the random sequence (ZS).

12. The method for detecting the environment of a radar system according to claim 10 or 11, wherein, The random bits of the previous random bit group and the random bits of the subsequent random bit group each constitute an index, which is used to select the inserted code bit sequence (C).

13. The method for detecting the environment of a radar system according to any one of claims 5 to 12, wherein, The radar data packet (RDP) is calculated based on the modified random sequence (ZSM) using a second algorithm according to a second predetermined function (g).

14. The method for detecting the environment of a radar system according to claim 13, wherein, The calculated radar data packet (RDP) is transmitted by the transmitting unit (2) of the radar system (1) and serves as an internal radar data packet (RDP). intern The cache is stored in the cache unit (ZSPE) of the radar system (1).

15. The method for detecting the environment of a radar system according to claim 14, wherein, The radar data packets (RDPs) received by the receiving unit (3) of the radar system (1) are processed using the third algorithm (h). Empf ) and the internal radar data packets (RDP) cached in the cache unit (ZSPE) intern The received radar data packets (RDPs) are compared to determine the nature of the radar data packets. Empf Does the authentication sequence (AS2) contained in the cached internal radar data packet (RDP) match the cached internal radar data packet (RDP)? intern The authentication sequence (AS1) contained in the ) has sufficient similarity.

16. The method for detecting the environment of a radar system according to claim 15, wherein, If the received radar data packet (RDP) Empf The authentication sequence (AS2) contained in the cached internal radar data packets (RDP) intern If the authentication sequence (AS1) contained in the radar system (1) has sufficient similarity, then the radar data packet (RDP) received by the receiving unit (2) of the radar system (1) is accepted. Empf () is valid.

17. An authentication unit (4) for a radar system (1), the authentication unit being designed to accept a radar signal (RS2) received by a receiving unit (3) of the radar system (1) via a physical transmission channel (PHY) if the authentication sequence (AS2) contained in the received radar signal (RS2) is sufficiently similar to an authentication sequence (AS1) embedded in a radar signal (RS1) transmitted by a transmitting unit (2) of the radar system (1) and matching the channel characteristics of the physical transmission channel (PHY).

18. The authentication unit for a radar system according to claim 17, wherein, The authentication unit (4) includes a random number generator (RNG) designed to generate a random bit sequence as a random sequence (ZS), and / or wherein the authentication unit (4) has an encryption unit designed to generate a random sequence (ZS) according to an encryption function, wherein the authentication sequence (AS1) embedded in the transmitted radar signal (RS1) is generated based on the generated random sequence (ZS).

19. The authentication unit for a radar system according to claim 18, wherein, The generated random sequence (ZS) is modified by interleaving it with other provided bits to produce a modified random sequence (ZSM). The modified random sequence matches the signal characteristics of the authentication sequence (AS1) embedded in the radar signal (RS1) transmitted by the transmitting unit (2) in such a way that the authentication sequence (AS2) contained in the radar signal (RS2) received by the receiving unit (3) via the physical transmission channel (PHY) can be identified in a more explicit manner.

20. The authentication unit for a radar system according to claim 18 or 19, wherein, The authentication unit (4) includes a computing unit (BE), which is designed for, The generated random sequence (ZS) is modified according to a first predetermined function (f) using a first algorithm to produce the modified random sequence (ZSM). The radar data packet (RDP) is calculated based on the modified random sequence (ZSM) using a second algorithm according to a second predetermined function (g). Among them, the calculated radar data packets (RDP) Sende The data packet is transmitted by the transmitting unit (2) of the radar system (1) and serves as an internal radar data packet (RDP). intern The cache is stored in the cache unit (ZSPE) of the authentication unit (4), and The computing unit (BE) is designed to, with the aid of a third algorithm (h), process the radar data packets (RDPs) received by the receiving unit (3) of the radar system (1). Empf ) and cached internal radar data packets (RDP) intern The received radar data packets (RDPs) are compared to determine the nature of the radar data packets. Empf Does the authentication sequence (AS2) contained in the cached internal radar data packet (RDP) match the cached internal radar data packet (RDP)? intern The authentication sequence (AS1) contained in the ) has sufficient similarity.

21. A radar system (1), the radar system comprising: Transmitting unit (2) is used to transmit radar signal (RS1), wherein an authentication sequence (AS1) is embedded in the transmitted radar signal (RS1), wherein the authentication sequence (AS1) is matched with the channel characteristics of the physical transmission channel (PHY); The receiving unit (3) is used to receive radar signals (RS2) via the physical transmission channel (PHY); and An authentication unit (4) is designed to accept the radar signal (RS2) received by the receiving unit (3) of the radar system (1) via the physical transmission channel (PHY) if the authentication sequence (AS2) contained in the received radar signal (RS2) is sufficiently similar to the authentication sequence (AS1) embedded in the radar signal (RS1) transmitted by the transmitting unit (2) of the radar system (1) and matches the channel characteristics of the physical transmission channel (PHY).

22. The radar system according to claim 21, wherein, The received radar signal (RS2) accepted as valid by the authentication unit is further processed by the signal processing unit (5) of the radar system (1) to detect the environment of the radar system (1).

23. The radar system according to claim 21 or 22, wherein, The radar system (1) is a monostatic or bistatic radar system.

Images