Radar system for determining the position of two or more objects

• US 5,001,486 A
• Filed: 08/04/1989
• Issued: 03/19/1991
• Est. Priority Date: 08/04/1989
• Status: Expired due to Fees

• Current Assignee: Siemens-Albis
• Original Assignee: Siemens-Albis
• Inventors: Bachtiger, Rolf
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Sotomayor, John B.
• Application Number:
  US07/389,450
• Time in Patent Office: 592 Days
• Field of Search: 342/42, 342/43, 342/50, 342/58, 342/59, 342/60, 342/73, 342/74, 342/146, 342/62, 244/3.11, 244/3.13, 244/3.15, 244/3.19
• US Class Current: 342/42
• CPC Class Codes: G01S 13/767 Responders; Transponders teaching or practice apparatus for gun-aiming or gun-laying using reflecting targets or active targets F41G3/26
• CPC Class Codes: G01S 13/784 Coders or decoders therefor; Degarbling systems; Defruiting systems

Abstract

A radar system operating by the line-of-sight method requires an accurate measurement of the relative position of at least two objects. By sending out coded radar transmission pulses, control data are transmitted to a guided flying body in a radar beam, which sends back an echo signal to the receiver via a transponder. In order to measure the passive signal and the transponder echo signal in the radar beam as accurately as possible, common reception channels are provided for both echo signals containing, inter alia, arrangements to equalize the dynamic levels of the echo signals. The returned transponder echo signal corresponds with respect to coding and bandwidth to the transmission pulses originally generated in the transmitter and that are phase-coded but not provided with the control code.

Claims

1. A radar system for determining the position of at least two objects, including a first, guided object and a second, target object, said radar system having a transmitter for transmitting pulse transmission signals and a receiver for receiving echo signals from said guided and target objects, wherein the transmitter sends control data to said guided object, by utilizing a control code impressed on a phase-coded pulse transmission, wherein said guided object sends a transponder echo signal back via a transponder to the receiver, said receiver including a microwave network on its input side, said microwave network being coupled by a plurality of reception signal processing channels to a mixing and preamplifying arrangement, characterized in that the same ones of said reception channels are provided in said receiver for both a passive echo signal that is a reflection of a pulse transmission signal from said target object and said transponder echo signal and in that said transponder provides said transponder echo signal similar with respect to coding and bandwidth to said pulse transmission originally sent by said transmitter and said transponder echo signal is phase-coded but not provided with said control code, and wherein the received echo signals are correlated in said receiver with a phase coded signal similar to said pulse transmission originally sent by said transmitter.

2. A radar system for determining the position of at least two objects, including a first, guided object and a second, target object, said radar system having a transmitter for transmitting pulse transmission signals and a receiver for receiving echo signals from said guided and target objects, wherein the transmitter sends control data to said guided object, by utilizing a control code impressed on a phase-coded pulse transmission, wherein said guided object sends a transponder echo signal back via a transponder to the receiver, said receiver including a microwave network on its input side, said microwave network being coupled by a plurality of reception signal processing channels to a mixing and preamplifying arrangement, characterized in that the same ones of said reception channels are provided in said receiver for both a passive echo signal that is a reflection of a pulse transmission signal from said target object and said transponder echo signal and in that said transponder provides said transponder echo signal similar with respect to coding and bandwidth to said pulse transmission originally sent by said transmitter and said transponder echo signal is phase-coded but not provided with said control code, and

wherein a common intermediate frequency amplifier is provided in the reception signal path of said receiver for the signals of all of said reception signal processing channels, to which the signals of said parallel reception signal processing channels are successively applied via an intermediate frequency multiplexer, and wherein a demultiplexer is coupled downstream of said intermediate frequency amplifier which separates the serially amplified signals for further processing by said reception signal processing channels.

4. A radar system according to claim 2 wherein said intermediate frequency amplifier includes a control unit for amplitude regulation and wherein, depending on the dynamic level of the received echo signals determined in a digital signal processor, said control unit controls the attenuation factor of said intermediate frequency amplifier by means of a keyed regulating arrangement such that both said transponder and said passive echo signals present an approximately matching signal level.

6. A radar system according to claim 2, wherein in order to equalize the dynamic levels of said passive and said transponder echo signals in the mixing and preamplifying arrangement, two switchable parallel signal paths of varying attenuation or amplification are provided for each reception processing channel, and wherein switch-over occurs via a central control arrangement such that said transponder echo signal is applied to a controlled attenuator and said passive echo signal is applied to a preamplifier.

8. A transponder for a radar system according to claim 2, wherein a decoder is coupled on the input side of said transponder with a series arrangement comprising an antenna, a limiter, a circulator and a microwave network, and wherein said decoder derives control signals for said guided object from received coded radar transmission pulses and establishes a trigger signal for a signal generator, and wherein a delay arrangement which can be switched on by way of said decoder is provided for said trigger signal, enabling a delayed transponder echo signal triggering in said signal generator, said signal generator being coupled to said circulator by way of a frequency converter coupled to an oscillator and followed by a power amplifier.

10. A transponder for a radar system according to claim 4, wherein a decoder is coupled on the input side of said transponder echo with a series arrangement comprising an antenna, a limiter, a circulator and a microwave network, and wherein said decoder derives control signals for said guided object from received coded radar transmission pulses and establishes a trigger signal for a signal generator, and wherein a delay arrangement which can be switched on by way of said decoder is provided for said trigger signal, enabling a delayed transponder echo signal triggering in said signal generator, said signal generator being coupled to said circulator by way of a frequency converter coupled to an oscillator and followed by a power amplifier.

12. A transponder for a radar system according to claim 6, wherein a decoder is coupled on the input side of said transponder with a series arrangement comprising an antenna, a limiter, a circulator and a microwave network, and wherein said decoder derives control signals for said guided object from received coded radar transmission pulses and establishes a trigger signal for a signal generator, and wherein a delay arrangement which can be switched on by way of said decoder is provided for said trigger signal, enabling a delayed transponder echo signal triggering in said signal generator, said signal generator being coupled to said circulator by way of a frequency converter coupled to an oscillator and followed by a power amplifier.

14. A transponder according to claim 8, wherein the pulse repetition frequency of said transponder echo signals is synchronous and identical with that of the transmitter'"'"'s pulse repetition frequency.

15. A transponder according to claim 12, wherein the pulse repetition frequency of said transponder echo signals is synchronous and identical with that of the transmitter'"'"'s pulse repetition frequency.

3. A radar system for determining the position of at least two objects, including a first, guided object and a second, target object, said radar system having a transmitter for transmitting pulse transmission signals and a receiver for receiving echo signals from said guided and target objects, wherein the transmitter sends control data to said guided object, by utilizing a control code impressed on a phase-coded pulse transmission, wherein said guided object sends a transponder echo signal back via a transponder to the receiver, said receiver including a microwave network on its input side, said microwave network being coupled by a plurality of reception signal processing channels to a mixing and preamplifying arrangement, characterized in that the same ones of said reception channels are provided in said receiver for both a passive echo signal that is a reflection of a pulse transmission signal from said target object and said transponder echo signal and in that said transponder provides said transponder echo signal similar with respect to coding and bandwidth to said pulse transmission originally sent by said transmitter and said transponder echo signal is phase-coded but not provided with said control code, and

wherein a common intermediate frequency amplifier is provided in the reception signal path of said receiver for the signals of all of said reception signal processing channels, and said intermediate frequency amplifier includes a control unit for amplitude regulation and wherein, depending on the dynamic level of the received echo signals determined in a digital signal processor, said control unit controls the attenuation factor of said intermediate frequency amplifier by means of a keyed regulating arrangement such that both said transponder and said passive echo signals present an approximately matching signal level.

9. A transponder for a radar system according to claim 3, wherein a decoder is coupled on the input side of said transponder with a series arrangement comprising an antenna, a limiter, a circulator and a microwave network, and wherein said decoder derives control signals for said guided object from received coded radar transmission pulses and establishes a trigger signal for a signal generator, and wherein a delay arrangement which can be switched on by way of said decoder is provided for said trigger signal, enabling a delayed transponder echo signal triggering in said signal generator, said signal generator being coupled to said circulator by way of a frequency converter coupled to an oscillator and followed by a power amplifier.

5. A radar system for determining the position of at least two objects, including a first, guided object and a second, target object, said radar system having a transmitter for transmitting pulse transmission signals and a receiver for receiving echo signals from said guided and target objects, wherein the transmitter sends control data to said guided object, by utilizing a control code impressed on a phase-coded pulse transmission, wherein said guided object sends a transponder echo signal back via a transponder to the receiver, said receiver including a microwave network on its input side, said microwave network being coupled by a plurality of reception signal processing channels to a mixing and preamplifying arrangement, characterized in that the same ones of said reception channels are provided in said receiver for both a passive echo signal that is a reflection of a pulse transmission signal from said target object and said transponder echo signal and in that said transponder provides said transponder echo signal similar with respect to coding and bandwidth to said pulse transmission originally sent by said transmitter and said transponder echo signal is phase-coded but not provided with said control code, and

wherein in order to equalize the dynamic levels of said passive and said transponder echo signals in the mixing and preamplifying arrangement, two switchable parallel signal paths of varying attenuation or amplification are provided for each reception processing channel, and wherein switch-over occurs via a central control arrangement such that said transponder echo signal is applied to a controlled attenuator and said passive echo signal is applied to a preamplifier.

11. A transponder for a radar system according to claim 5 wherein a decoder is coupled on the input side of a transponder with a series arrangement comprising an antenna, a limiter, a circulator and a microwave network, and wherein said decoder derives control signals for said guided object from received coded radar transmission pulses and establishes a trigger signal for a signal generator, and wherein a delay arrangement which can be switched on by way of said decoder is provided for said trigger signal, enabling a delayed transponder echo signal triggering in said signal generator, said signal generator being coupled to said circulator by way of a frequency converter coupled to an oscillator and followed by a power amplifier.

7. A transponder for use with a radar system for determining the position of at least a guided object carrying said transponder and a target object, said radar system having a transmitter for transmitting pulse transmission signals and a receiver for receiving echo signals from said guided and target objects, wherein the transmitter sends control data to said guided object, by utilizing a control code impressed on a phase-coded pulse transmission, wherein said guided object sends a transponder echo signal back via said transponder to the receiver, said receiver including a microwave network on its input side, said microwave network being coupled by a plurality of reception signal processing channels to a mixing and preamplifying arrangement, characterized in that the same ones of said reception channels are provided in said receiver for both a passive echo signal that is a reflection of a pulse transmission signal from said target object and said transponder echo signal and in that said transponder provides said transponder echo signal similar with respect to coding and bandwidth to said pulse transmission originally sent by said transmitter and said transponder echo signal is phase-coded but not provided with said control code, and

wherein a decoder is coupled on the input side of said tranponder with a series arrangement comprising an antenna, a limiter, a circulator and a microwave network, and wherein said decoder derives control signals for said guided object from received coded radar transmission pulses and establishes a trigger signal for a signal generator, and wherein a delay arrangement which can be switched on by way of said decoder is provided for said trigger signal, enabling a delayed transponder echo signal triggered in said signal generator, said signal generator being coupled to said circulator by way of a frequency converter coupled to an oscillator and followed by a power amplifier.

13. A transponder according to claim 7, wherein the pulse repetition frequency of said transponder echo signals is synchronous and identical with that of the transmitter'"'"'s pulse repetition frequency.

16. A transponder according to claim 7, wherein said change-over from undelayed to delayed signal triggering in said signal generator takes place before the distance between two objects to be measured falls below the system'"'"'s distance resolving capacity, and in that the time delay of said transponder echo signal sent with delay in order of several μ

s.

17. A transponder according to claim 13, wherein said change-over from undelayed to delayed signal triggering in said signal generator takes place before the distance between two objects to be measured falls below the system'"'"'s distance resolving capacity, and in that the time delay of said transponder echo signal sent with delay in order of several μ

s.

18. A transponder according to claim 7, wherein the transponder oscillator is designed for several transmitting frequencies, which are selected via said decoder, depending on the received, coded transmission pulses.

19. A transponder according to claim 13, wherein the transponder oscillator is designed for several transmitting frequencies, which are selected via said decoder, depending on the received, coded transmission pulses.

20. A transponder according to claim 17, wherein the transponder oscillator is designed for several transmitting frequencies, which are selected via said decoder, depending on the received, coded transmission pulses.