PDS_VERSION_ID = PDS3 DATA_SET_ID = "MEX-M-MARSIS-5-DDR-SS-TEC-EXT1-V1.0" PRODUCT_ID = "IONOPROCESS_REPORT2" PRODUCT_CREATION_TIME = 2009-04-22T14:00 RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 80 RELEASE_ID = 0001 REVISION_ID = 0000 ^PDF_DOCUMENT = "IONOPROCESS_REPORT2.PDF" ^ASCII_DOCUMENT = "IONOPROCESS_REPORT2.ASC" ^PNG1_DOCUMENT = "IONOPROCESS_REPORT2_EQU1.PNG" ^PNG2_DOCUMENT = "IONOPROCESS_REPORT2_EQU2.PNG" ^PNG3_DOCUMENT = "IONOPROCESS_REPORT2_EQU3.PNG" ^PNG4_DOCUMENT = "IONOPROCESS_REPORT2_EQU4.PNG" ^PNG5_DOCUMENT = "IONOPROCESS_REPORT2_EQU5.PNG" ^PNG6_DOCUMENT = "IONOPROCESS_REPORT2_EQU6.PNG" ^PNG7_DOCUMENT = "IONOPROCESS_REPORT2_EQU7.PNG" ^PNG8_DOCUMENT = "IONOPROCESS_REPORT2_EQU8.PNG" ^PNG9_DOCUMENT = "IONOPROCESS_REPORT2_EQU9.PNG" ^PNG10_DOCUMENT = "IONOPROCESS_REPORT2_EQU10.PNG" ^PNG11_DOCUMENT = "IONOPROCESS_REPORT2_EQU11.PNG" ^PNG12_DOCUMENT = "IONOPROCESS_REPORT2_EQU12.PNG" ^PNG13_DOCUMENT = "IONOPROCESS_REPORT2_EQU13.PNG" ^PNG14_DOCUMENT = "IONOPROCESS_REPORT2_FIG1.PNG" ^PNG15_DOCUMENT = "IONOPROCESS_REPORT2_FIG2.PNG" ^PNG16_DOCUMENT = "IONOPROCESS_REPORT2_FIG3.PNG" OBJECT = PDF_DOCUMENT DOCUMENT_NAME = "CORRECTING THE IONOSPHERIC IMPACT ON MARSIS RADAR SIGNAL" DOCUMENT_FORMAT = "ADOBE PDF" DESCRIPTION = "A planetary ionosphere is a perturbing environment for radar waves. Unfortunately, it is an unavoidable obstacle along the propagation path of signals emitting by orbiting radar sounders. The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) is an instrument onboard the European Space Agency's Mars Express spacecraft. In order to deeply penetrate the surface, MARSIS operates at MHz frequencies for which the perturbations due the Martian ionosphere can be significant. Therefore, prior to any analyze, MARSIS data need to be corrected from the ionospheric effects. The aim of this document is to describe an approach to correct the impact of the ionosphere on MARSIS radar data. Among the three effects caused by the ionosphere, two (global absorption and Faraday rotation) can be easily avoided by choosing wisely the MARSIS band and the observation place. The impact of the third (phase distortion) is too important whatever the conditions of observation. A method is proposed to do a systematic correction of the phase distortion. The method is enhanced by using the digital elevation model MOLA as a reference for the position of the surface echo." DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" INTERCHANGE_FORMAT = "BINARY" PUBLICATION_DATE = 2009-04-22 END_OBJECT = PDF_DOCUMENT OBJECT = ASCII_DOCUMENT DOCUMENT_NAME = "CORRECTING THE IONOSPHERIC IMPACT ON MARSIS RADAR SIGNAL" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" INTERCHANGE_FORMAT = ASCII DOCUMENT_FORMAT = TEXT DESCRIPTION = "A planetary ionosphere is a perturbing environment for radar waves. Unfortunately, it is an unavoidable obstacle along the propagation path of signals emitting by orbiting radar sounders. The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) is an instrument onboard the European Space Agency's Mars Express spacecraft. In order to deeply penetrate the surface, MARSIS operates at MHz frequencies for which the perturbations due the Martian ionosphere can be significant. Therefore, prior to any analyze, MARSIS data need to be corrected from the ionospheric effects. The aim of this document is to describe an approach to correct the impact of the ionosphere on MARSIS radar data. Among the three effects caused by the ionosphere, two (global absorption and Faraday rotation) can be easily avoided by choosing wisely the MARSIS band and the observation place. The impact of the third (phase distortion) is too important whatever the conditions of observation. A method is proposed to do a systematic correction of the phase distortion. The method is enhanced by using the digital elevation model MOLA as a reference for the position of the surface echo." END_OBJECT = ASCII_DOCUMENT OBJECT = PNG1_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU1.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (1) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG1_DOCUMENT OBJECT = PNG2_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU2.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (2) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG2_DOCUMENT OBJECT = PNG3_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU3.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (3) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG3_DOCUMENT OBJECT = PNG4_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU4.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (4) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG4_DOCUMENT OBJECT = PNG5_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU5.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (5) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG5_DOCUMENT OBJECT = PNG6_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU6.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (6) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG6_DOCUMENT OBJECT = PNG7_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU7.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (7) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG7_DOCUMENT OBJECT = PNG8_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU8.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (8) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG8_DOCUMENT OBJECT = PNG9_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU9.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (9) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG9_DOCUMENT OBJECT = PNG10_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU10.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (10) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG10_DOCUMENT OBJECT = PNG11_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU11.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (11) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG11_DOCUMENT OBJECT = PNG12_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU12.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (12) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG12_DOCUMENT OBJECT = PNG13_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_EQU13.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Equation (13) from the document IONOPROCESS_REPORT2" END_OBJECT = PNG13_DOCUMENT OBJECT = PNG14_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_FIG1.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Fig. 1. (a) MARSIS pulse after ionospheric two-way propagation represented in time domain. One can see the spreading and the delay of the echo compared to (b) same pulse without ionospheric distortion [adapted from Mouginot et al., 2008]." END_OBJECT = PNG14_DOCUMENT OBJECT = PNG15_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_FIG2.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Fig. 2. Two MARSIS radargrams (orbit 2400 and 2682) corrected by our compensation method, and with the ionospheric impact. A radargram is the concatenation of several radar pulses as the one presented in figure 1 (see text for detailed) [from Mouginot et al., 2008]." END_OBJECT = PNG15_DOCUMENT OBJECT = PNG16_DOCUMENT DOCUMENT_NAME = "IONOPROCESS_REPORT2_FIG3.PNG" PUBLICATION_DATE = 2009-04-22 DOCUMENT_TOPIC_TYPE = "DERIVATION AND ANALYSIS TECHNIQUES" FILES = 1 ENCODING_TYPE = PNG INTERCHANGE_FORMAT = BINARY DOCUMENT_FORMAT = PNG DESCRIPTION = "Fig. 3. Total electon content as a function of the solar zenith angle. Each dots corresponds of TEC measurements by other instruments, and solid lines to derived TEC of some MARSIS orbits. The altitude ranges of the measurements changes with the altitude of MarsExpress. However, since the spacecraft is no less at 270 km above the suface and the the main electron density is between 100 and 150 km, the error is small [from Mouginot et al., 2008]." END_OBJECT = PNG16_DOCUMENT END