ADR Sign Convention used in NovAtel GPS Receivers and RINEX Almanac Injection Procedure Amperage vs Voltage ASCII to binary log conversion example Can carbon fiber be used as an antenna cover? Can the GPGGA positions be output with more decimal places? Destination IP Should be Set in ICOMCONFIG if Setting up UDP Connection Difference Between Message Latency and Time Accuracy DL-4 DL-V script Example Do GPS-700 series antennas have a defined "North point"? GNSS-750 MTBF GNSS Ephemerides and Almanacs GNSS Frequencies and Signals GPS Receiver and SPAN SDLC card synchronization GPS Tracking Performance on Aircraft (Power Supply Issues) How does RTKANTENNA work? How Electrical Overstress damage is caused How often does Averaging Filter in POSAVE Command get Applied? How to Connect to PwrPak7 How to Determine the Channel in an ASSIGN Command How to extract 85-bit string from GLORAWFRAME log How to identify my PwrPak7 How to Recover Abbreviated ASCII Logs from Raw Data How to Use PASSCOM to Redirect Data HxGN SmartNet on NovAtel receivers In what frame is CORRIMUDATAS output in OEM6? ITK and Dual Antenna Receivers Maximum Cable Length vs. Data Rate MIC Mating Connectors MSM 6 and MSM 7 Issue MTBF Specifications for GPS-700 Series New ALIGN Message Lengths OEM4 and OEMV Reporting 1994 (Week Roll Over) OEM615 MTBF OEM628 MTBF OEM6 Dev Kit weight OEMStar API Specifcations OEMStar MTBF OEMV1-DF MTBF OEMV-2 & OEMV-2G MTBF OEMV Auth Codes for 3.907 ProPak6 FTP ProPak6 - USB Drive File Format Recommended Alignment Procedures Recommended Logs for Post Processing Regarding Absolute and Relative Antenna Calibrations Regarding standard deviations used in RBV Calibration Remaining memory on OEM638/ProPak6 Reporting a Stolen Receiver RTK Quality Mode, Extra Safe Mode SBAS Position Mode Sending Batch File and Logging Binary Data in Real Term SPAN-CPT Commonly Asked Questions SPAN-CPT Power specifications SPAN Troubleshooting logs Understanding IMU Data Gaps: Causes and Mitigation Strategies Updating SMART6 firmware from 6.230 or 6.231 to 6.510 (or later) USB Not Supported in WinLoad Software Using RTCM ephemeris data to speed up Time To First Fix (TTFF) WGS84 to ETRS89 datum transformations What Ionospheric Correction will SETIONOTYPE AUTO use? What is a EURO card? What is the Difference Between Active and Passive Serial Connection in CDU/Connect? What is the Effect of Bad Lever Arms in the GNSS/INS Filter? What is the Maximum Accepted Latency in ALIGN? What would cause speed (Field 8) in GPRMC to remain constant for some amount of time? Why am I seeing Two Kinds of HEADING2 Logs when Using two PP6Ds in Relative INS? Why Can't I disable RXSTATUSEVENTA permanently? Why is there no decoding information on the CAN PGNs? Why is the standard deviation of the BESTPOS log larger than the spec on the data sheet? Support Search

Why is the standard deviation of the BESTPOS log larger than the spec on the data sheet?

Why is the standard deviation of the BESTPOS log larger than the spec on the data sheet? The standard deviation field in the BESTPOS log contains the instantaneous (single epoch) estimated standard deviations of the position and NOT the standard deviation of the actual position error. The estimated standard deviations refer to a confidence range where the receiver estimates its antenna is in real time, relative to the truth position. The position error RMS in the data sheet refers to the receivers actual position accuracy given truth position.

The estimated standard deviation is a measure on how confident about our estimated position based on the consistency of the measurements, the geometry of the satellites (a.k.a. DOP) and estimates of the measurement errors. The estimated standard deviation is usually slightly pessimistic because outperforming a slightly higher estimated standard deviation is more acceptable than underperforming an optimistic estimated standard deviation. In some applications, including DGPS, information about the quality of the data is missing because of the data transmission format. In these applications a more pessimistic estimated standard deviation is reported as a usual worst case given the missing information.