![Radio Modem Telemetry [Image]](images/telem.gif)
The quality of the telecommunication link between the rover and the lander is the best measure of how effective the link is. Of course the link quality is sensitive to modem temperature, BER, data volume and rover location. The Rover link quality is a measure of how well it is getting acknowledgment of good frames by the lander (LMRE) side of the link. Rover link quality is the ratio of the change in the number of the RX frame counts to the change in the number of the TX frame counts from one measurement to the next. Mathematically Rover link quality= 100*(delta RX / delta TX). If the link is degraded, the rover will get a number of NAK's (No Acknowledges) or other comm errors from the lander and the TX count will increase. Also, if the LMRE radio was off or not responding, the rover would increase the TX frame counter because it would be constantly receiving timeout errors. When a data frame does get ACK'ed (Acknowledged) by the lander as being received, the RX frame count will increase by 2.
LMRE link quality is a measure of how well the lander is receiving data from the Rover. A frame with garbled data, like a bad CRC count, will be recorded by the lander. Also, a good (or complete) frame that was received by the lander will also be recorded. The LMRE link performance is a slightly better estimate of the overall UHF link quality than the Rover link quality performance because, in theory, it keeps a better count of good versus bad data frames (it doesn't count the 6 Byte ACK frames). The way the rover-lander protocols work (see Rover Telecom FAQ#5) the RX frame counter gets incremented when a 6 byte ACK frame and 256 Byte (or less) data frame get sent, while the TX frame count gets incremented whenever the Rover sends any type of frame to the Lander *AND* if any comm errors occur. The RX frame counter can never increase at a rate higher than the TX frame counter, so a 100% Rover link performance is achieved if the TX and RX frame counters increase at the same rate. One thing is certain however, when the link is degraded for any reason both the Rover and Lander link quality numbers do show it.
Sorry, no LMRE Radio plots because of insufficient data :(
Once you have downloaded the CSV data reduction Excel macro and have used it to clean up the unformated CSV data file you will see a list of data columns. Below we give an internal description of the data in those columns. The first value, e.g. R-xxxx, is the telemetry channel ID number, that is followed by the telemetry channel name and then a description of what it measures. To use the macro, first open the macro file and then open the *.csv file you want to look at. Go to the Tools menu and click on the Macro... field. Run the formatcsv1.xls!CSV_FORMAT macro and answer Yes or No to the dialog questions. Note that if you try to clean up the *.csv file more than once, it will corrupt the file and the statistics. If you have trouble downloading or using the tool, please let us know.
SCET - Space Craft Event Time; a time tag on each event that takes place on the spacecraft.
R-0006 Command Sequence Number - Number given to current command in the rover sequence.
R-3999 Command Name - Name of the command being executed in the sequence.
R-0123 Modem Temp - Rover modem temperature. Engineering Units (EU) of Centigrade.
R-2705 Cur,+9V Conv - Rover Modem +9V converter current, receive and standby; EU = mA.
R-0220 Cur,Modem TX - Rover Modem +9V converter Transmit current; EU = mA.
R-0236 Cur,Modem Heater - Rover Modem Heater current; EU = mA.
R-2904 Volts,+9 Conv - Rover Modem +9V Converter Voltage; EU = Volts.
R-2220 TX CH Frame Cnt - Rover Transmit Channel Frame Count; Data Number (DN) units, e.g. just an integer number that represents the accumulated count.
R-2221 RX CH Frame Cnt - Rover Transmit Channel Receive Acknowledge Count; DN
R-0022 RX Com Error - Rover Transmit Channel Receive Acknowledge Error Count; DN
R-0025 COM: Timeout - Rover Timeout Error Count; DN
R-0027 COM: Bad CRC - Rover Bad CRC Error Count; DN
R-0035 COM: RX Abort - Rover Receive Abort Error Count; DN
R-0024 COM: Unknown Error - Rover Unknown Communications Error Count (don't ask) ; DN
R-0028 COM: No Sync - Rover No Syncronization Error Count; DN
R-0033 COM: SW Error - Rover Communications Software Error Count; DN
R-0036 COM: Latchup - Rover Modem Latchup Error Count; DN
R-0034 COM: Overflow - Rover Modem Data Overflow Error Count; DN
R-0026 COM: Short Frame - Rover Modem Short Data Frame Error Count; DN
R-0029 COM: Bad FID - Rover Modem Bad Frame ID Error Count; DN
R-0030 COM: Bad FNUM - Rover Modem Bad Frame Number Error Count; DN
R-0031 COM: NOCMDDAT - Rover Modem No Command Data Error Count; DN
R-0550 X-Position - Rover X-Position relative to Lander Center; Meters
R-0551 Y-Position - Rover Y-Position relative to Lander Center; Meters
R-0552 Heading - Rover Forward Heading Angle; Degrees
V-0050 LMRE Modem B Status - LMRE Modem B-side Status; DN
V-0051 LMRE Modem A Status - LMRE Modem A-side Status; DN
P-0190 Battery Temp 1 Avg - Lander Battery Average Internal Temp1 sensor; EU = Centigrade.
P-0191 Battery Temp 2 Avg - Lander Battery Average Internal Temp2 sensor; EU = Centigrade.
V-0029 NUM Good Frames - LMRE Modem number of good Frames received; DN
V-0069 NUM Garbled Frames - LMRE Modem number of garbled Frames received, a garbled frame is a count of 7 different receive errors ; DN
V-0010 NUM Telem Ses - LMRE Modem Number of Telemetry Sessions; DN
V-0040 NUM NACKS - LMRE Modem Number NACKS (No Acknowledge); DN
V-0002 NUM Good Sess - LMRE Modem Number of Good Communication Sessions; DN
V-0003 LDR Abort Sess - Number of Lander Aborted Sessions; DN
V-0008 RVR Abort Sess - Number of Rover Aborted Sessions; DN
D-0069 NUM Buff Packet - Number of Rover packets buffered on the lander; DN
D-0070 NUM Sent Packet - Number of Rover packets downlinked from the lander ; DN
D-0070 NUM Sent Packet - Number of Rover packets downlinked from the lander ; DN
ERT - Earth Receive Time; a time tag on the time the event was received on earth.
SCLK - Spacecraft CLock; the onboard spacecraft clock used to control various activities.
SOL - Mars Sol Day; the mission day number.
TLST - True Local Solar Time; referred to as MLST (Mars Local Solar Time).
Pop Says: "Have fun and don't wear out your CPU playing with this stuff!"
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