CN100426004C - Full signal sea echo simulator - Google Patents
Full signal sea echo simulator Download PDFInfo
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- CN100426004C CN100426004C CNB031311008A CN03131100A CN100426004C CN 100426004 C CN100426004 C CN 100426004C CN B031311008 A CNB031311008 A CN B031311008A CN 03131100 A CN03131100 A CN 03131100A CN 100426004 C CN100426004 C CN 100426004C
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Abstract
The present invention provides a full signal sea echo simulator which is used for simulating a radio-frequency sea echo. The present invention comprises a frequency synthesizing unit, a receiving unit, an up-conversion unit and a numerical control unit, wherein the frequency synthesizing unit is used for supplying standard local oscillation signals to the up-conversion unit and the receiving unit; the receiving unit is used for processing transmitting signals which are transmitted form an altimeter; the up-conversion unit is used for causing sea echo simulating signals or point target response signals which are transmitted from the numerical control unit to be modulated to the Chirp; the numerical control unit is mainly used for numerically synthesizing the sea echo simulating signals and the point target response signals. The present invention can accurately simulate a sea echo spectrum by the multiple frequency point digital synthesis technology, and avoids the disadvantages of complicated system, difficult match, distortion, small dynamic range, etc. in analog devices; the two-pass time delay of the point target response of the transmitting signals of the altimeter and the orbit perturbation of a satellite platform are accurately simulated by a pulse reconstruction technology, and the accurate test for the system time delay and the linearity of the altimeter is realized.
Description
Technical field
The present invention relates to the ground testing system of spaceborne ocean radar altimeter, specifically, relate to ocean return signal simulator wherein.
Background technology
Ocean return signal simulator is a most important equipment in the spaceborne ocean radar altimeter ground testing system, development along with the satellite height-finding technique, current spaceborne radar altitude gauge mostly adopts the system of high impulse ratio of compression and long chirp (Chirp) emission, its pulse width is generally about tens to 100 microseconds, is difficult to fly to reach the purpose that instrument is detected by the aviation school; Simultaneously, the altitude gauge system as high precision satell height finder device also needs accurate ground test and calibration.The ocean return signal simulator utilization realizes altitude gauge is carried out the total system test to the simulation of radio frequency sea echo, can the accurate system's time delay that detects altitude gauge, the dynamic tracking ability of oblique precision and height is gone in checking, the dynamic estimation ability of checking ocean significant wave height and backscattering coefficient.
The major function of ocean return signal simulator is to simulate ocean surface to the back scattering that altitude gauge transmits, and specifically comprises: the radar cross section (RCS) of (1) ocean surface; (2) ocean significant wave height (SWH); (3) satellite altitude angle; (4) highly, altitude rate, height acceleration; (5) the backward scattered statistical property in ocean; (6) the backward scattered room and time in ocean is relevant etc.
According to the sea backscattering model, the analogue echo power that the full signal echo simulator offers altitude gauge should comprise three information the most basic: the point target response of path transmission delay, sea echo wave spectrum and radar system.Fig. 1 is the principle of work block diagram of total system ocean return signal simulator.As can be seen, ocean return signal simulator comprises sea echo wave spectrum generator, modulator, delay line, adjustable attenuator and timer, and wherein adjustable attenuator links to each other with the transmitter of altitude gauge, and the output of delay line then links to each other with the receiver of altitude gauge.Signal from altitude gauge is controlled its amplitude by adjustable attenuator, and is modulated by the sea echo wave spectrum under the control of split-second timer, and the echoed signal of generation returns to the receiver of altitude gauge through delay line, handles the simulator signal of receiving by altitude gauge again.Because the signal that provides of simulator generates in strict accordance with altitude gauge sea backscattering model, so its standard of can be used as weighs the measuring error of altitude gauge, by making the operation of altitude gauge reach optimum condition to adjusting repeatedly of altitude gauge.
Echo simulator can be divided into point target simulator and sea-surface target simulator on form and purposes that signal is provided; From technical standpoint, can be divided into signal repetition type and pulse reconstruction type.Only introduce two kinds of existing echo simulators below: pulse is rebuild and is removed digital point target simulator of oblique type and pulse reconstruction type sea-surface target simulator.
Pulse rebuild remove the digital point target simulator of oblique type block diagram as shown in Figure 2.The Chirp signal of input is gone tiltedly by a up-conversion Chirp with identical chromatic dispersion and pulsewidth after decaying, and the pulse capture ring is adjusted Chirp and regularly is detected in low-pass filter up to intermediate-freuqncy signal.By the I of digitized sampling, the foundation of Q passage, intermediate-freuqncy signal is carried out analysis of spectrum.Sampled point is stored the usefulness of preparing against afterwards; Adopt little delay technique can be when going oblique mixing smart time shifting between simulator and altitude gauge Chirp calculate, the timing that is improved is used to revise the triggering of delay counter impact pulse generator.Constantly corresponding with the echo arrival, counter is trigger pulse triggers Chirp generator once more.The intermediate frequency storage signal change back again analog form and with the Chirp mixing, the waveform of regeneration has identical frequency-time response with the Chirp that receives from altitude gauge.Through after the up-conversion, signal is launched back altitude gauge again.
This simulator has only been realized the simulation to the altitude gauge point target response, can only test the system's time delay and the linearity of altitude gauge, can not carry out total system test and calibration to altitude gauge, and the generation of its little time-delay realizes having very big ambiguity on the time by the dither method.
The sea-surface target simulator is on the basis of point target simulator, and the sea echo wave spectrum is modulated on the radiofrequency signal, makes the signal that offers altitude gauge simulate the back scattering on sea truly.Structure such as Fig. 3 of pulse reconstruction type sea-surface target simulator comprise multitone marine echo function generator (ORF), modulator, chronotron, adjustable attenuator, timer and switch, and it regularly triggers from altitude gauge.The emission trigger pulse of altitude gauge starts the timing of simulator, simulator is synchronous triggering switch and multitone ORF under the control of timer, the transponder pulse of altitude gauge arrives modulator through switch, adjustable attenuator, simultaneously, the sea echo waveform that multitone ORF generates simulation in modulator to altitude gauge pulse modulate, altitude gauge is beamed back in the simulation as sea echo after delaying time of the signal after the modulation.
Because the time-delay that this simulator produces is the emission trigger pulse with respect to altitude gauge, it is not transponder pulse with respect to altitude gauge, and that test height meter needs is the latter, therefore must take Other Instruments that the time-delay between altitude gauge emission trigger pulse and transponder pulse is accurately measured, this is to be difficult to realize in practice.In addition, the sea echo waveform that multitone ORF generates is that the method by hardware simulation realizes, can only simulate the sea echo in certain sea situation scope, can not simulate completely sea echo under the full sea conditions.
Summary of the invention
Technical matters to be solved by this invention is to provide the ocean return signal simulator of full signal, to solve can not accurately simulating round trip path transmission delay, can not simulate sea echo under the full sea conditions, can not can realizing that the point target response simulation can realize problems such as sea echo simulation again by an echo simulator of existing in the prior art.
Full signal ocean return signal simulator of the present invention comprises and combines unit, receiving element, up-conversion unit and numerical control unit frequently;
Described frequency is combined the unit, is used to up-conversion unit and receiving element that the local oscillation signal of standard is provided;
Described receiving element is used for handling from transmitting of altitude gauge, and the I, the Q signal that are obtained is delivered to described numerical control unit handle;
Described up-conversion unit is used for sea echo simulating signal or point target response signal from described numerical control unit are modulated to chirp, and the analog echo signal of gained is sent to altitude gauge;
Described numerical control unit is used for removing tiltedly back altitude gauge signal according to signal capture tracking altitude meter signal, collection and the storage of described receiving element, and it is synthetic to finish the numeral of sea echo simulating signal and point target response, and exports to described up-conversion unit.
The present invention has realized accurate analog sea echo wave spectrum by multifrequency point numeral synthetic technology, the system complex of having avoided adopting analog device to bring, be not easy to mate, the restriction of shortcoming such as distortion and dynamic range are little; By adopting the pulse reconstruction technique that round trip time delay and satellite platform orbit perturbation that altitude gauge transmits are accurately simulated, realized the accurate test of the system's time delay and the linearity of altitude gauge; By the analog radio frequency sea echo, realize checking, and then realized the demarcation that altitude gauge is measured to mean sea level height, ocean significant wave height satellite platform altitude gauge acquisition and tracking pattern; By adopting adjustable attenuator analog sea backscattering coefficient, realized the accurate test of altitude gauge automatic gain control (AGC) ring, and then realized the demarcation that altitude gauge is measured the sea backscattering coefficient.
Description of drawings
Fig. 1 is the principle of work block diagram of total system ocean return signal simulator;
Fig. 2 is that the structured flowchart that removes the digital point target simulator of oblique type is rebuild in existing pulse;
Fig. 3 is the structural drawing of existing pulse reconstruction type sea-surface target simulator;
Fig. 4 is the system chart of full signal ocean return signal simulator of the present invention;
Fig. 5 is the structured flowchart of full signal ocean return signal simulator of the present invention;
Fig. 6 is a structured flowchart of combining unit medium frequency compositor frequently;
Fig. 7 is the structured flowchart of numerical control unit;
Fig. 8 is the functional block diagram of FPGA circuit;
Fig. 9 is the hardware time order figure of numerical control unit;
Figure 10 is based on the embedded software process flow diagram of C30.
Embodiment
Below in conjunction with accompanying drawing, the present invention is further detailed.Fig. 1 to Fig. 3 is the introduction to prior art, describes in detail in front, repeats no more herein.
The present invention combines point target simulator and ocean return signal simulator, both realize can the simulated altitude meter point target response, again can the analog sea echoed signal.
Fig. 4, Fig. 5 have provided the block diagram of full signal ocean return signal simulator of the present invention, and it comprises combines unit, receiving element, up-conversion unit and numerical control unit frequently.
Frequently combine the unit and be used to up-conversion unit and receiving element that the local oscillation signal of standard is provided, specifically comprise frequency synthesizer, chirp (Chirp) generator, frequency multiplier, isolator, first local oscillator, second local oscillator, up-conversion amplifier 1, up-conversion amplifier 2, wave filter and 2 frequency mixer.
Frequency synthesizer is used to produce combines all inner required frequencies of unit frequently, as shown in Figure 6, comprise that crystal oscillator, 1,2 low-pass filters of phase detector, voltage controlled oscillator 1, power splitter, shunt, overstable oscillation device USO, amplification shunt, burst pulse form device, sampling thief, voltage controlled oscillator 2, phase detector 2, balanced mixer, 5 frequency dividers, 22 frequency dividers, 78 frequency dividers, 11 frequency multipliers, 5 wave filters and 6 amplifiers.The signal that crystal oscillator produces carries out 78 frequency divisions through behind the phase detector 1, be divided into two-way through voltage controlled oscillator 1 back by power splitter, one the tunnel directly exports the 1.17GHz reference signal gives first local oscillator, another road with from the signal mixing of shunt and give the power splitter 2 of up-conversion unit by output 1.245GHz reference signal behind wave filter and the amplifier; The high stability that overstable oscillation device (USO) provides, high precision canonical reference signal are divided into 4 the tunnel by amplifying shunt: the first via through frequency division, filtering, with the second road 75MHz mixing after output 80MHz reference signal give numerical control unit as timing reference; The second the tunnel through frequency division, mixing, filtering, amplification, along separate routes back output 75MHz to the phase detector of the quadrature modulator of up-conversion unit, receiving element as local oscillation signal; Third Road is exported the 550MHz signal and is used to generate Chi rp signal for the Chirp generator of combining the unit frequently after amplification, frequency multiplication, filtering, amplification; The four the tunnel through amplification, burst pulse formation device, sampling, low-pass filtering, voltage controlled oscillator 2, phase detector 2, and the 13.35GHz signal that obtains and the 550MHz signal of Third Road carry out balanced mixing, and filtering, amplification back output 12.8GHz reference signal are to second local oscillator.
Chirp (Chirp) generator need adopt with altitude gauge in the same Chirp generator, can guarantee that like this point target response simulating signal that simulator provides has sufficiently high fidelity.Carry out the up-conversion mixing with second local oscillator of 12.8GHz behind the Chirp signal process frequency multiplier that the Chirp generator produces, the isolator, obtain the Chirp signal of 13.9GHz ± 166MHz, behind up-conversion amplifier 1 and wave filter with the first local oscillator mixing of 1.17GHz, produce the Chirp local oscillation signal of 15.07GHz ± 166MHz by up-conversion amplifier 2 backs, offer the reference signal of receiving element, offer the up-conversion mixing that the up-conversion unit is used for the sea echo analog intermediate frequency signal simultaneously as " going to the slope entirely ".
Frequently the standard local oscillator signal packet that combining the unit provides is drawn together Chirp local oscillation signal, intermediate frequency local oscillator signal, the sensitive detection local oscillator of phase place and orthogonal modulation local oscillator.
Receiving element is used for handling from transmitting of altitude gauge, comprises adjustable attenuator, intermediate frequency amplifilter 1, manual attenuator, intermediate frequency amplifilter 2, automatic gain control attenuator, intermediate frequency amplifilter 3, phase detector and 2 frequency mixer.Transmitting of altitude gauge carried out " going to the slope entirely " mixing through the Chirp local oscillation signal that provides with frequently comprehensive unit behind the adjustable attenuator, signal transformation is to first intermediate frequency, gain adjustment through amplification filtering and attenuator, carry out the down coversion mixing with the intermediate frequency local oscillator signal, output signal is second intermediate frequency.Utilize automatic gain control and intermediate frequency amplification filtering signal to be adjusted in the dynamic range of design again, carry out the sensitive detection of phase place in phase detector, I, the Q signal of acquisition are given numerical control unit and are handled.Because signal is directly from altitude gauge, the signal to noise ratio (S/N ratio) of signal is very high, so the receiving element front end does not adopt low noise amplifier, but directly carries out " going to the slope entirely " mixing.Consider that signal is very strong, utilize adjustable attenuator to reduce signal amplitude before the mixing, can provide overload protection for frequency mixer, and simulate the size of the backscattering coefficient under the different sea situations by the conversion damping capacity.
The up-conversion unit comprises circulator, bandpass filter, power splitter 1,2,3, up-conversion amplifilter 1, up-conversion amplifilter 2, quadrature modulator and 2 frequency mixer, its effect is that sea echo simulating signal or point target response signal from numerical control unit are modulated on the Chi rp, realizes the radio frequency analog echo.Quadrature modulator is realized the orthogonal modulation of the simulating signal of numerical control unit to the orthogonal modulation local oscillator, modulation back signal is through the output signal mixing of up-conversion amplifilter 1 with power splitter 2, after passing through up-conversion amplifilter 2 again, in frequency mixer with the mixing of Chirp local oscillation signal, generate Chirp radio frequency analog echo, in the input tape bandpass filter.In the up-conversion unit, be provided with three grades of bandpass filter, can effectively suppress to carry outer interference; Output terminal adds isolator, can realize the matched well of signal, and can realize that the local oscillator of 30dBc suppresses.Output signal is sent back to altitude gauge through behind the circulator.
Numerical control unit is the core of whole echo simulator, the numeral that is used for finishing sea echo simulating signal and point target response synthesizes, finishes acquisition and tracking to the altitude gauge signal, finish to the collection of removing oblique back altitude gauge signal and storage take advantage of with the copy of preserving altitude gauge Chirp signal, the signal complex phase of finishing copy and simulation and signal that will be synthetic give after through the DA conversion up-conversion unit quadrature modulator, realize whole simulator sequential control, produce timing pip, realize the full time-delay of signal and the AGC attenuator of controlling receiving element.Fig. 7 has provided the block diagram of numerical control unit, comprises computing machine, AD converter, dual port RAM, microprocessor, phase rotation device, DA converter and FPGA circuit, and wherein microprocessor has adopted TMS320C30 (hereinafter to be referred as C30).Computing machine adopts the RS232 serial communication port of standard to realize communicating by letter with C30; C30 links to each other with the FPGA circuit by self data, address and control bus, realizes the initialization to the FPGA circuit; The data line of AD converter, DA converter, dual port RAM, phase rotation device all is attempted by on the data bus of C30, and control line links to each other with FPGA; The simulating signal input port of AD converter links to each other with the output of the phase detector of receiving element; The simulating signal delivery outlet of DA converter links to each other with the input of the quadrature modulator of up-conversion unit; The data bus of C30 also connects the digital input port of the automatic gain control attenuator of receiving element; Come self-frequency to combine the 80MHz clock of unit and trigger the signal input part that is connected to FPGA circuit and numerical control chronotron (AD9501) from the emission of altitude gauge; The Chirp generator of combining the unit is frequently given in the output of AD9501.
Numerical control unit is core with C30, by the control of C30, realizes all sequential control by the FPGA circuit.The 80MHz that self-frequency is combined the unit since FPGA circuit and the C30 triggers as timing base with the emission from altitude gauge as clock reference.Fig. 8 has provided the block diagram of FPGA circuit, comprise delay counter, full delay counter, 2 pulse generators, 2 numerical control chronotrons (AD9501) and 2 or.C30 is by initialization and the control of bus realization to the FPGA circuit, and delay counter is used to oblique timing, and produces the AD conversion, writes the pulse train that dual port RAM needs by a pulse generator; Full delay counter is used for the timing of analogue echo, and produces the DA conversion, reads the pulse train that dual port RAM needs by another pulse generator; AD9501 is used to provide regularly required little time-delay.The timing control signal that the FPGA circuit produces is realized little time-delay by AD9501, accurately controls triggering, the I of Chirp generator, collection, RAM access and the synthetic digital signal DA conversion of Q signal.
Consider that C30 has high speed one-cycle instruction execution time and the 24 bit addressing spaces of 60ns, numerical control unit has adopted design more efficiently: the processing power of 1) utilizing computing machine, carry out the synthetic simulation of numeral of sea echo model and point target response with software, improved the accuracy of simulation and intelligent greatly, the simulation process of full signal farthest simplified; 2) RAM of employing large storage capacity.The analog signal data that computing machine provides and the initialization data of numerical control unit send C30 to by the RS232 serial communication interface and are stored among the RAM, make the function of numerical control unit more flexible; 3) adopt dual port RAM at a high speed can more effectively utilize high speed processing and the arithmetic capability of C30.Under the control of C30 high-speed procedure instruction, the copy signal data after receiving element goes are tiltedly at first carried out the processing of acquisition and tracking algorithm in the high speed dual port RAM, reach in the precision of design up to the timing of FPGA circuit with the altitude gauge signal.Then, the simulated data that copy data and computing machine transmit is carried out complex phase multiplication and phase place rotation fast, the result still is stored in the dual port RAM, when the counting of the delay counter in the FPGA circuit finishes, be synchronized with the trigger pulse of FPGA circuit to Ch i rp generator, result's process DA conversion of complex phase multiplication is given the up-conversion unit and is carried out orthogonal modulation.In addition, numerical control unit makes receiving element remain stable gain by the amplitude of the AGC attenuator adjustment copy of control receiving element.
Fig. 9 is the hardware time order figure of numerical control unit.The timing of all sequential is a clock reference with the 80MHz clock that frequently comprehensive unit provides all, and triggering with the emission from altitude gauge is timing base.Altitude gauge emission trigger pulse triggers FPGA circuit, the FPGA circuit at first produces Chi rp trigger pulse sequence and starts delay counter.In one-period, preceding 5 trigger action are combined the Chi rp generator of unit frequently, be used for the Chirp signal from altitude gauge is carried out " going to the slope entirely " mixing, simultaneously, the FPGA circuit will produce synchronous AD trigger pulse sequence, go oblique signal to carry out 128 data acquisition to each, and data in real time is write in the dual port RAM.
In order to realize the synchronous processing of C30 processor to data, the C30 processor adopting interrupt mode, the FPGA circuit produce one the tunnel with the down trigger of the synchronous pulse signal of AD trigger pulse sequence as processor.After data successfully write dual port RAM, processor entered interrupt service routine.Interrupt service routine is finished the data of acquisition and tracking algorithm, collection and data complex phase multiplication, the phase place rotation of simulation by data processing before the time-delay counting finishes.
When the time-delay counting finishes, the FPGA circuit produces the Chirp generator of combining the unit with back 5 trigger action in one-period frequently, read the data result in the dual port RAM simultaneously, provide DA trigger pulse sequence, after producing I, the quadrature modulator of Q simulating signal through the up-conversion unit, carry out the up-conversion mixing with the Chirp local oscillator from the Chirp generator, the radio-frequency echo wave simulating signal of output is given altitude gauge.
Also comprise two softwares of C30 embedded software and analogue echoes software in the numerical control unit.Based on the embedded software flow process of C30 as shown in figure 10.Software initialization comprises: initialization FPGA circuit, initialization RAM, initialization dual port RAM, initialization are interrupted.After initialization finished, the C30 processor entered the interrupt latency state.Look-at-me is synchronized with the AD trigger pulse from the FPGA circuit.Look-at-me shows when arriving that receiving element finished " the going to the slope entirely " to the altitude gauge signal, and under the control of FPGA circuit, the data that AD gathers have write dual port RAM.At this moment, software enters interrupt service routine.Interrupt service routine at first reads in the data in the dual port RAM among the RAM, carries out then that acquisition and tracking algorithm, complex phase are taken advantage of, phase place is rotated, and the result is write in the dual port RAM again, withdraws from interrupt service routine at last, and C30 reenters the interrupt latency state.Before finishing, finish the full time-delay counting of the execution of above process in the FPGA circuit.Analogue echoes software is to realize the real simulation of sea echo according to the sea echo model.
It should be noted last that, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, although the present invention is had been described in detail with reference to preferred embodiment, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.
Claims (10)
1, the full signal ocean return signal simulator is characterized in that, comprises combining unit, receiving element, up-conversion unit and numerical control unit frequently;
Described frequency is combined the unit, is used to up-conversion unit and receiving element that the local oscillation signal of standard is provided;
Described receiving element is used for handling from transmitting of altitude gauge, and the I, the Q signal that are obtained is delivered to described numerical control unit handle;
Described up-conversion unit is used for sea echo simulating signal or point target response signal from described numerical control unit are modulated to chirp, and the analog echo signal of gained is sent to altitude gauge;
Described numerical control unit is used for removing tiltedly back altitude gauge signal according to signal capture tracking altitude meter signal, collection and the storage of described receiving element, and it is synthetic to finish the numeral of sea echo simulating signal and point target response, and exports to described up-conversion unit.
2, full signal ocean return signal simulator according to claim 1, it is characterized in that described frequency is combined the unit and comprised frequency synthesizer, chirp generator, frequency multiplier, isolator, first local oscillator, second local oscillator, the first up-conversion amplifier, wave filter, the second up-conversion amplifier and 2 frequency mixer;
Described frequency synthesizer is used to produce described frequency and combines all inner required frequencies of unit, and exports to described chirp generator;
Described chirp generator, be used to produce the chirp pulse signal of negative wire chirp rate, carry out the up-conversion mixing with second local oscillator behind this signal process frequency multiplier, the isolator, obtain chirp pulse signal, behind the first up-conversion amplifier and wave filter with the first local oscillator mixing, by producing the chirp local oscillation signal behind the second up-conversion amplifier, output in described receiving element and the described up-conversion unit.
3, full signal ocean return signal simulator according to claim 2, it is characterized in that described frequency synthesizer comprises that further crystal oscillator, first phase detector, 2 low-pass filters, first voltage controlled oscillator, power splitter, shunt, overstable oscillation device, amplification shunt, burst pulses form device, sampling thief, second voltage controlled oscillator, second phase detector, balanced mixer, 78 frequency dividers, 5 frequency dividers, 22 frequency dividers, frequency mixer, 11 frequency multipliers, 5 wave filters and 6 amplifiers;
The signal of described crystal oscillator is through behind described first phase detector, described 78 frequency dividers and described first voltage controlled oscillator, be divided into two-way by described power splitter, one the tunnel outputs to described first local oscillator, the signal mixing of another road and the output of described shunt also by behind first wave filter and first amplifier in described 6 amplifiers in described 5 wave filters, is exported to second power splitter of described up-conversion unit;
First low-pass filter in described 2 low-pass filters receives the signal of first phase detector input, and the resulting frequency accuracy of described first voltage controlled oscillator is controlled;
The reference signal of described overstable oscillation device is divided into 4 the tunnel by described amplification shunt: the first via is through second wave filter and 2 frequency dividers in described 5 frequency dividers, 5 wave filters, and exports to described numerical control unit after the second tunnel mixing: export to the intermediate frequency quadrature modulator of described up-conversion unit, the phase detector of described receiving element behind the second tunnel the 3rd wave filter, second amplifier in 6 amplifiers and the shunt in described 2 frequency dividers, frequency mixer, 5 wave filters; Export to the chirp generator that described frequency is combined the unit behind the 4th amplifier in the 4th wave filter in the 3rd amplifier of Third Road in described 6 amplifiers, 11 frequency multipliers, 5 wave filters, 6 amplifiers; The four tunnel the 5th amplifier, burst pulse in described 6 amplifiers carries out balanced mixing with the Third Road signal after forming second low-pass filter, second voltage controlled oscillator and second phase detector in device, sampling thief, 2 low-pass filters, exports to described second local oscillator behind the 6th amplifier in the 5th wave filter in described 5 wave filters, 6 amplifiers.
4, according to the arbitrary described full signal ocean return signal simulator of claim 1 to 3, it is characterized in that described receiving element comprises adjustable attenuator, the first intermediate frequency amplifilter, manual attenuator, the second intermediate frequency amplifilter, automatic gain control attenuator, the 3rd intermediate frequency amplifilter, phase detector and 2 frequency mixer;
Go the slope mixing from transmitting of altitude gauge entirely through the chirp local oscillation signal that provides with the comprehensive unit of described frequency behind the adjustable attenuator, signal transformation is to first intermediate frequency, gain adjustment through described first intermediate frequency amplifilter and described manual attenuator, carry out the down coversion mixing with the intermediate frequency local oscillator signal, output signal is second intermediate frequency, signal is adjusted in the dynamic range of design through described automatic gain control attenuator and described the 3rd intermediate frequency amplifilter again, in described phase detector, carry out the sensitive detection of phase place, and with the I that obtains, Q signal is given described numerical control unit and is handled.
5, according to the arbitrary described full signal ocean return signal simulator of claim 1 to 3, it is characterized in that described up-conversion unit comprises circulator, bandpass filter, first power splitter, second power splitter, the 3rd power splitter, the first up-conversion amplifilter, the second up-conversion amplifilter, quadrature modulator and 2 frequency mixer;
Described quadrature modulator will carry out orthogonal modulation through the simulating signal and the orthogonal modulation local oscillator from described numerical control unit of described first power splitter, modulation back signal is through the output signal mixing of the first up-conversion amplifilter and second power splitter, again through behind the second up-conversion amplifilter, in frequency mixer with chirp local oscillation signal mixing through the output of the second up-conversion amplifier of the 3rd power splitter, generate chirp radio frequency analog echo, through after the described band-pass filter, return to altitude gauge through described circulator.
6, full signal ocean return signal simulator according to claim 5 is characterized in that, described up-conversion unit also comprises isolator, between described bandpass filter and described circulator, is used to realize that the local oscillator of 30dBc suppresses.
7, according to the arbitrary described full signal ocean return signal simulator of claim 1 to 3, it is characterized in that described numerical control unit comprises computing machine, AD converting unit, dual port RAM, microprocessor, phase rotation device, DA converting unit and FPGA circuit;
Described computing machine, the numeral that is used to finish sea echo simulating signal and point target response is synthetic, and the signal data of simulation is exported to described microprocessor by serial communication interface;
Described AD converting unit is used for I, Q signal from described receiving element are carried out analog to digital conversion, and is stored in the described dual port RAM;
Described dual port RAM is used to store the data from described microprocessor and described AD converting unit;
Described microprocessor, be used to carry out acquisition and tracking altitude gauge signal algorithm, the simulating signal that the copy data and the described computing machine of altitude gauge chirp pulse signal transmits is carried out the complex phase multiplication, and the result outputed in the described dual port RAM store, export to the automatic gain control attenuator in the described receiving element simultaneously;
Described phase rotation device is used for the data of described microprocessor output are carried out the phase place rotation, and the conversion of the described DA converting unit of process, exports to described up-conversion unit;
Described FPGA circuit is used to produce timing control signal, controls all sequential of described numerical control unit.
8, full signal ocean return signal simulator according to claim 7 is characterized in that, that described microprocessor adopts is TMS320C30.
9, according to claim 7 or 8 described full signal ocean return signal simulators, it is characterized in that, described FPGA circuit further comprise delay counter, full delay counter, first pulse generator, second pulse generator, 2 numerical control chronotrons and 2 or;
Described microprocessor through bus realizes initialization and the control to described FPGA circuit;
Described delay counter is used to oblique timing, and produces the AD conversion, writes the pulse train that dual port RAM needs by described first pulse generator;
Described full delay counter is used for the timing of analogue echo, and produces the DA conversion, reads the pulse train that dual port RAM needs by described second pulse generator;
The first numerical control chronotron in described 2 numerical control chronotrons and the second numerical control chronotron receive the pulse signal of described delay counter and full delay counter transmission respectively, be used to provide regularly required little time-delay, control the triggering of described chirp generator, I, the collection of Q signal, dual port RAM access and synthetic digital signal DA conversion, described 2 or in the described first numerical control chronotron of first or goalkeeper and the pulse signal after little time-delay of second numerical control chronotron output merge output, described 2 or in described first pulse generator of second or goalkeeper and the pulse signal after little time-delay of second pulse generator output merge output.
10, full signal ocean return signal simulator according to claim 9 is characterized in that, described numerical control chronotron adopts AD9501.
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| CN102778241B (en) * | 2012-07-31 | 2014-09-10 | 清华大学 | Echo simulator and simulated echo generating method of universal airborne radio altimeter |
| CN103675772B (en) * | 2013-11-26 | 2015-11-04 | 北京宇航系统工程研究所 | A kind of Multifunctional SAR complex electromagnetic environment simulator |
| CN103872990A (en) * | 2014-03-03 | 2014-06-18 | 中国电子科技集团公司第五十五研究所 | Microwave emission frequency variation method and emission device for marine environment satellite altimeter |
| CN108169741A (en) * | 2017-12-16 | 2018-06-15 | 贵州航天电子科技有限公司 | A kind of general typical target system for simulating feature |
| CN108089168A (en) * | 2017-12-16 | 2018-05-29 | 贵州航天电子科技有限公司 | A kind of Echo Doppler Frequency simulator based on orthogonal modulation |
| CN112947521B (en) * | 2021-02-10 | 2022-10-28 | 西南电子技术研究所（中国电子科技集团公司第十研究所） | Multifunctional simulation platform of spacecraft measurement and control system |
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