dcsloc [ parameter=value ... ] [ inputfile ... ]
Parameters are: ref_platform, cross_check, list_locations.
dcsloc computes the position of DCS platforms. It should be applied to DCS datasets immediately following the creation of the dataset by dcsin. dcsloc operates in place by adding latitude, longitude, and elevation variables to the dataset, if they do not already exist. Elevation is not computed. For reference platforms, the elevation is obtained from the reference data file dcs_data located in the REFDATA/dcs directory. For all other platforms the elevation is set to 0 meters.
If a reference platform is specified, a correction (time adjustment) to the satellite clock is calculated prior to computing the positions of the platforms. A reference platform can be any fixed platform with a good steady transmitter. Reference platforms are stored in the directory associated with the UNIX environment variable named REFDATA/dcs.
The accuracy of the algorithm depends on the number of good messages received from a given platform, the accuracy of the message times, plus the orientation of the satellite orbit relative to the platform. If there are not enough messages from a platform to start the algorithm, or if the algorithm fails to converge, the location of the platform is marked as bad.
dcsloc produces the most accurate locations for platforms well away from the satellite subtrack. If a reference platform is used that is close to subtrack, the time adjustment may be computed incorrectly. In these instances improved earth locations can be obtained by restoring the original earth transform with resetorb and then rerunning dcsloc with a different reference platform.
The algorithm for locating platforms is based on the paper: Satellite Doppler-Data Processing Using a Microcomputer, IEEE Transactions on Geoscience Electronics, Vol. GE-16, No. 4, October 1978, by Paul E. Schmid and J. J. Lynn
One or more TeraScan datasets are required as inputs. There are no output TeraScan datasets.
This is the platform identification number of a platform with a known position. The platform must exist in the file $REFDATA/dcs/dcs_data where REFDATA is a UNIX environment variable. If 0 is entered, a time adjustment will not be performed.
Valid responses are [0 or any existing platform identification number].
For multiple input files only. This parameter indicates whether the computed locations should be compared across the input files in order to detect and fix the cases when the algorithm converged at the wrong side from a satellite subtrack. All fixes will be reported on the terminal screen.
Valid responses are [yes or no] . The default is [no].
This parameter indicates whether the positions of the platforms should be listed on the terminal screen. This should be set to yes to see a list of platform locations sorted by platform identification number. no suppresses the platform position report.
Valid responses are [yes or no] . The default is [no].
Compute the DCS positions for the dataset named hugo.dcs. The dataset hugo.dcs was created in the dcsin example. Platforms that cannot be accurately located are reported during this function.
[1] % dcsloc hugo.dcs ref_platform : int ? [0] cross_check : char( 3) ? [no] list_locations : char( 3) ? [no] Platform 113: 1 hits not enough to locate Platform 429: 2 hits not enough to locate Platform 510: 1 hits not enough to locate Platform 1676: 2 hits not enough to locate Platform 2907: 2 hits not enough to locate Platform 2908: 3 hits not enough to locate Platform 2999: 1 hits not enough to locate Platform 3581: 3 hits not enough to locate Platform 3669: 2 hits not enough to locate Platform 3838: 1 hits not enough to locate Platform 3932: 1 hits not enough to locate Platform 4004: 1 hits not enough to locate Platform 5342: 7 hits 40 45.73 S 77 51.51 E 0 m Platform 5344: 8 hits 45 29.29 S 69 41.38 E 0 m Platform 6943: 2 hits not enough to locate Platform 7187: 2 hits not enough to locate Platform 7194: 2 hits not enough to locate Platform 7408: 1 hits not enough to locate Platform 7410: 1 hits not enough to locate Platform 7728: 2 hits not enough to locate Platform 7786: 3 hits not enough to locate Platform 7816: 2 hits not enough to locate Platform 7918: 1 hits not enough to locate Platform 8900: (fixed) 78 22.80 S 173 25.20 W 18 m Platform 8904: (fixed) 74 30.00 S 123 0.00 E 3280 m Platform 8905: (fixed) 74 55.20 S 163 36.00 E 80 m Platform 8286: 1 hits not enough to locate Platform 8291: 3 hits not enough to locate Platform 8292: 1 hits not enough to locate Platform 8293: 1 hits not enough to locate Platform 8294: 1 hits not enough to locate Platform 8961: 6 hits 67 0.32 S 104 26.56 E 0 m
dcsin, dcsmix, dcslist, weather, mcmegu, dcs
Fixed platforms will be given the latitude,longitude, and elevation specified in the file $REFDATA/dcs/dcs_data; the position will not be calculated.
Last Update: $Date: 1998/05/28 18:14:58 $