公开(公告)号：EP1879045A2

公开(公告)日：2008-01-16

申请号：EP07016165.8

申请日：2001-08-16

Applicant: Raytheon Company

Inventor： Woodington, Walter Gordon ,  Delcheccolo, Michael Joseph ,  Pleva, Joseph S. ,  Russell, Mark E. ,  Van Rees, Barteld H. ,  Hanson, James T.

IPC: G01S13/93 ,  G01S7/40 ,  G01S7/35 ,  G01S7/36 ,  G01S13/34

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.

Abstract translation: 雷达检测过程包括计算FFT输出信号的导数以检测指定检测区域内的对象。 在一个实施例中，FFT输出信号的二阶导数中的零交叉指示物体的存在。 物体的范围根据零交叉出现的频率来确定。 还描述了包含各个雷达波束和处理周期内存在或不存在对象的指示符的检测表。 至少两个这样的指示器被组合以检测检测区域内的物体的存在，并且在每个天线波束中改变的距离门可以改变检测区域的覆盖范围。

公开(公告)号：EP1873551A1

公开(公告)日：2008-01-02

申请号：EP07018064.1

申请日：2001-08-16

Applicant: Raytheon Company

Inventor： Woodington, Walter Gordon ,  Delcheccolo, Michael Joseph ,  Pleva, Joseph S. ,  Russell, Mark E. ,  Van Rees, H. Barteld ,  Hanson, James T.

IPC: G01S7/36

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A radar transmitter includes a digital ramp generator circuit for generating a VCO control signal. The ramp generator includes a digital signal processor and a digital-to-analog converter. In one embodiment, the VCO output signal is up-converted to provide the transmit signal and in another embodiment, the VCO operates over the transmit frequency. Also described is a VCO comprising a DR and a phase shifter. A temperature compensation feature includes detecting the transmit frequency and comparing the DSP output generating the detected frequency to a DSP output stored in association with the detected frequency. Also described is a technique for compensating for non-linear VCO operation in which the DSP output words are adjusted to provide a waveform complementary in shape to the non-linear VCO characteristic. Susceptibility of the radar to interference is reduced by randomly varying at least one parameter of the ramp signal, such as offset interval or voltage range, in at least one ramp signal cycle.

Abstract translation: 雷达发射器包括用于产生VCO控制信号的数字斜坡发生器电路。 斜坡发生器包括数字信号处理器和数模转换器。 在一个实施例中，VCO输出信号被上变频以提供发射信号，而在另一实施例中，VCO在发射频率上工作。 还描述了包括DR和移相器的VCO。 温度补偿功能包括检测发射频率并将产生检测到的频率的DSP输出与检测到的频率相关联地存储的DSP输出进行比较。 还描述了一种用于补偿非线性VCO操作的技术，其中DSP输出字被调整以提供与非线性VCO特性形状互补的波形。 在至少一个斜坡信号周期中，通过随机地改变斜坡信号的至少一个参数（例如偏移间隔或电压范围）来减少雷达对干扰的敏感性。

公开(公告)号：EP1309883B1

公开(公告)日：2007-01-31

申请号：EP01967994.3

申请日：2001-08-16

Applicant: RAYTHEON COMPANY

Inventor： HANSON, James, T. ,  WOODINGTON, Walter, Gordon ,  DELCHECCOLO, Michael, Joseph ,  PLEVA, Joseph, S. ,  RUSSELL, Mark, E. ,  VAN REES, H., Barteld

IPC: G01S7/40 ,  G01S7/35 ,  H03F1/30

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A video amplifier for a radar receiver includes a temperature compensating attenuator. The attenuator includes a temperature sensitive device, such as a thermistor, arranged in a voltage divider network and is coupled in cascade between two filter stages. Each of the filter stages has a bandpass characteristic in order to filter low-frequency leakage signals and provide sensitivity control based on frequency and thus range, while also filtering high frequency signals to reduce aliasing.

公开(公告)号：EP1310012B1

公开(公告)日：2006-05-03

申请号：EP01964092.9

申请日：2001-08-16

Applicant: RAYTHEON COMPANY

Inventor： VIANA, Luis, M. ,  DELCHECCOLO, Michael, Joseph ,  PLEVA, Joseph, S. ,  RUSSELL, Mark, E. ,  WOODINGTON, Walter, Gordon ,  VAN REES, H., Barteld ,  LEBLANC, Stephen, P. ,  LIPPERT, Delbert ,  SCHNEIDER, Scott, H.

IPC: G01S7/03 ,  G01S7/35 ,  G01S7/40 ,  H01Q1/38 ,  H01Q3/24 ,  H01Q13/10 ,  H01Q21/00 ,  H01Q25/00 ,  B60K31/00 ,  B60Q1/26

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A multiple beam array antenna system comprises a plurality of radiating elements provided from stripline-fed open-ended waveguide coupled to a Butler matrix beam forming network. The Butler matrix beam forming network is coupled to a switched beam combining circuit. The antenna can be fabricated as a single Low Temperature Co-fired Ceramic (LTCC) circuit.

公开(公告)号：EP1309883A2

公开(公告)日：2003-05-14

申请号：EP01967994.3

申请日：2001-08-16

Applicant: Raytheon Company

Inventor： HANSON, James, T. ,  WOODINGTON, Walter, Gordon ,  DELCHECCOLO, Michael, Joseph ,  PLEVA, Joseph, S. ,  RUSSELL, Mark, E. ,  VAN REES, H., Barteld

IPC: G01S13/00

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A video amplifier for a radar receiver includes a temperature compensating attenuator. The attenuator includes a temperature sensitive device, such as a thermistor, arranged in a voltage divider network and is coupled in cascade between two filter stages. Each of the filter stages has a bandpass characteristic in order to filter low-frequency leakage signals and provide sensitivity control based on frequency and thus range, while also filtering high frequency signals to reduce aliasing.

公开(公告)号：EP1310018B1

公开(公告)日：2018-07-25

申请号：EP01965964.8

申请日：2001-08-16

Applicant: Valeo Radar Systems, Inc.

Inventor： BREGLIA, Caroline ,  FRENCH, Thomas, W. ,  PLEVA, Joseph, S.

IPC: G01S7/03 ,  G01S7/26 ,  G01S7/35 ,  G01S7/40 ,  G01S13/04 ,  G01S13/28 ,  G01S13/34 ,  G01S13/48 ,  G01S13/87 ,  H01Q1/32 ,  H01Q3/40 ,  H01Q1/38 ,  H01Q13/10

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A radar system includes a transmit antenna for transmitting a first RF signal, a receive antenna for receiving a second RF signal, and a receiver circuit coupled to the receive antenna for processing the second RF signal and comprising a video amplifier having a temperature compensating attenuator. A radar receiver includes an RF amplifier, a down-converter and a video amplifier comprising a temperature compensating attenuator. The RF amplifier has an input terminal adapted to receive an RF signal and an output terminal at which an amplified RF signal is provided. The down-converter has an input terminal coupled to the output terminal of the RF amplifier and an output terminal at which a lower frequency signal is provided. The video amplifier has an input terminal coupled to the output terminal of the down-converter and an output terminal at which a filtered signal is provided.

公开(公告)号：EP1912080A3

公开(公告)日：2011-03-30

申请号：EP08075061.5

申请日：2001-08-16

Applicant: Valeo Radar Systems, Inc.

Inventor： Woodington, Walter Gordon ,  Delcheccolo, Michael Joseph ,  Pleva, Joseph S. ,  Russell, Mark E. ,  Van Rees, H. Barteld ,  Hanson, James T.

IPC: G01S13/93 ,  G01S7/40 ,  G01S7/35 ,  G01S7/36 ,  G01S13/34

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.

公开(公告)号：EP1879047A3

公开(公告)日：2011-03-30

申请号：EP07020593.5

申请日：2001-08-16

Applicant: Valeo Radar Systems, Inc.

Inventor： Woodington, Walter Gordon ,  Russell, Mark E. ,  Delcheccolo, Michael Joseph ,  Van Rees, H. Barteld ,  Pleva, Joseph S. ,  Hanson, James T.

IPC: G01S13/93 ,  G01S7/40 ,  G01S7/35 ,  G01S7/36 ,  G01S13/34

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.

公开(公告)号：EP1879047A2

公开(公告)日：2008-01-16

申请号：EP07020593.5

申请日：2001-08-16

Applicant: Raytheon Company

Inventor： Woodington, Walter Gordon ,  Russell, Mark E. ,  Delcheccolo, Michael Joseph ,  Van Rees, H. Barteld ,  Pleva, Joseph S. ,  Hanson, James T.

IPC: G01S13/93 ,  G01S7/40 ,  G01S7/35 ,  G01S7/36 ,  G01S13/34

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs. Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.

公开(公告)号：EP1870729A2

公开(公告)日：2007-12-26

申请号：EP07018062.5

申请日：2001-08-16

Applicant: Raytheon Company

Inventor： Woodington, Walter Gordon ,  Delcheccolo, Michael Joseph ,  Pleva, Joseph S. ,  Russell, Mark E. ,  Van Rees, H. Barteld ,  Hanson, James T.

IPC: G01S13/93 ,  G01S7/40 ,  G01S7/35 ,  G01S7/36 ,  G01S13/34

CPC classification number: B60Q9/008 ,  B60K31/0008 ,  B60T2201/08 ,  B60T2201/081 ,  B60T2201/088 ,  B60W2530/10 ,  B60W2550/304 ,  G01S7/023 ,  G01S7/032 ,  G01S7/038 ,  G01S7/06 ,  G01S7/288 ,  G01S7/352 ,  G01S7/354 ,  G01S7/4004 ,  G01S7/4008 ,  G01S7/4021 ,  G01S13/04 ,  G01S13/282 ,  G01S13/343 ,  G01S13/346 ,  G01S13/48 ,  G01S13/584 ,  G01S13/726 ,  G01S13/87 ,  G01S13/931 ,  G01S2007/356 ,  G01S2013/0245 ,  G01S2013/9321 ,  G01S2013/9332 ,  G01S2013/9375 ,  G01S2013/9378 ,  G01S2013/9385 ,  G01S2013/9389 ,  H01Q1/3233 ,  H01Q1/3258 ,  H01Q1/3283 ,  H01Q1/38 ,  H01Q1/42 ,  H01Q3/24 ,  H01Q3/40 ,  H01Q13/10 ,  H01Q13/18 ,  H01Q21/0043 ,  H01Q21/0075 ,  H01Q21/0087 ,  H01Q21/065 ,  H01Q25/00

Abstract: A radar detection process includes computing a derivative of an FFT output signal to detect an object within a specified detection zone. In one embodiment, a zero crossing in the second derivative of the FFT output signal indicates the presence of an object. The range of the object is determined as a function of the frequency at which the zero crossing occurs.
Also described is a detection table containing indicators of the presence or absence of an object within a respective radar beam and processing cycle. At least two such indicators are combined in order to detect the presence of an object within the detection zone and with changing range gates in each of the antenna beams the coverage of the detection zone can be varied.

Abstract translation: 雷达检测处理包括计算FFT输出信号的导数以检测指定检测区域内的对象。 在一个实施例中，FFT输出信号的二阶导数中的零交叉表示存在对象。 物体的范围被确定为发生零交叉的频率的函数。 还描述了一种检测表，其包含相应雷达波束内的物体的存在或不存在的指示符以及处理周期。 至少两个这样的指示器被组合以便检测在检测区域内的物体的存在，并且在每个天线波束中改变范围门，可以改变检测区域的覆盖范围。