MEX MARSIS Reduced Data Record – Active Ionosphere Sounding (RDRAIS)
RDRAIS – Reduced Data Record – Active Ionosphere Sounding
Instrument: Mars Advanced Radar for Subsurface and Ionosphere Sounding
PDS Data Set ID (Nominal Mission): MEX-M-MARSIS-3-RDR-AIS-V1.0
PDS Data Set ID (Extended Mission 1): MEX-M-MARSIS-3-RDR-AIS-EXT1-V1.0
PDS Data Set ID (Extended Mission 2): MEX-M-MARSIS-3-RDR-AIS-EXT2-V1.0
PDS Data Set ID (Extended Mission 3): MEX-M-MARSIS-3-RDR-AIS-EXT3-V1.0
PDS Data Set ID (Extended Mission 4): MEX-M-MARSIS-3-RDR-AIS-EXT4-V1.0
PDS Data Set ID (Extended Mission 5): MEX-M-MARSIS-3-RDR-AIS-EXT5-V1.0
DOI: Mars Express DOI Overview Page
The Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) Reduced Data Record – Active Ionosphere Sounding (RDRAIS) data products contain all spectral information calibrated in units of spectral density for the Active Ionospheric Sounder over the Mars Express mission. This dataset includes calibrated values for each transmit event and the corresponding temporal data for each frequency channel. This dataset comprises the electric field spectral densities obtained via the electric dipole antenna sensor.
The AIS calibrated full resolution dataset includes several binary tables of wave spectra as a function of time from each of the various transmit events. Interpreting the provided intensities as remote emissions requires knowledge of the time delay between the emitted pulse and the measured electric spectral density. The time offsets from the onset of the transmit pulse until the measurement of each spectral density value may be found from the relation:
Delay time (microseconds) = 162.5 + 91.4286 * [item], where [item] is the ITEM number from the SPECTRAL density column of the AIS_TABLE data products.
To make this more explicit, these time values are pre-calculated in the table below.
|
ITEM |
Delay (microsec) |
ITEM |
Delay (microsec) |
|
1 |
253.93 |
41 |
3911.07 |
|
2 |
345.36 |
42 |
4002.50 |
|
3 |
436.79 |
43 |
4093.93 |
|
4 |
528.21 |
44 |
4185.36 |
|
5 |
619.64 |
45 |
4276.79 |
|
6 |
711.07 |
46 |
4368.21 |
|
7 |
802.50 |
47 |
4459.64 |
|
8 |
893.93 |
48 |
4551.07 |
|
9 |
985.36 |
49 |
4642.50 |
|
10 |
1076.79 |
50 |
4733.93 |
|
11 |
1168.21 |
51 |
4825.36 |
|
12 |
1259.64 |
52 |
4916.79 |
|
13 |
1351.07 |
53 |
5008.21 |
|
14 |
1442.50 |
54 |
5099.64 |
|
15 |
1533.93 |
55 |
5191.07 |
|
16 |
1625.36 |
56 |
5282.50 |
|
17 |
1716.79 |
57 |
5373.93 |
|
18 |
1808.21 |
58 |
5465.36 |
|
19 |
1899.64 |
59 |
5556.79 |
|
20 |
1991.07 |
60 |
5648.21 |
|
21 |
2082.50 |
61 |
5739.64 |
|
22 |
2173.93 |
62 |
5831.07 |
|
23 |
2265.36 |
63 |
5922.50 |
|
24 |
2356.79 |
64 |
6013.93 |
|
25 |
2448.21 |
65 |
6105.36 |
|
26 |
2539.64 |
66 |
6196.79 |
|
27 |
2631.07 |
67 |
6288.21 |
|
28 |
2722.50 |
68 |
6379.64 |
|
29 |
2813.93 |
69 |
6471.07 |
|
30 |
2905.36 |
70 |
6562.50 |
|
31 |
2996.79 |
71 |
6653.93 |
|
32 |
3088.21 |
72 |
6745.36 |
|
33 |
3179.64 |
73 |
6836.79 |
|
34 |
3271.07 |
74 |
6928.21 |
|
35 |
3362.50 |
75 |
7019.64 |
|
36 |
3453.93 |
76 |
7111.07 |
|
37 |
3545.36 |
77 |
7202.50 |
|
38 |
3636.79 |
78 |
7293.93 |
|
39 |
3728.21 |
79 |
7385.36 |
|
40 |
3819.64 |
80 |
7476.79 |
A basic method for determining the range at which an emission was generated is to multiply the delays above with ½ the speed of light in a vacuum:
Apparent range (kilometers) = 0.1499 * (162.5 + 91.4286 * item) = 0.1499 * delay.
The assumption that the signal propagates at the speed of light in a vacuum does not hold when the pulse traverses regions where the local plasma frequency is near the pulse frequency.
MARSIS RDRAIS products have the following file names:
FRM_AIS_RDR_nnnn.DAT (with detached PDS label)
where:
FRM = frame file
AIS = active ionosphere sounder
nnnn = 4- or 5-digit orbit number
In ODE, RDRAIS products have the following Product IDs:
FRM_AIS_RDR_NNNN.DAT