USN800USA Site Information Form (site log) International GNSS Service See Instructions at: https://files.igs.org/pub/station/general/sitelog_instr.txt 0. Form Prepared by (full name) : Arnold Colina Date Prepared : 2024-08-22 Report Type : UPDATE If Update: Previous Site Log : usn8_20240821.log Modified/Added Sections : 3.5, 3.6, 11, 12 1. Site Identification of the GNSS Monument Site Name : U.S. Naval Observatory Time Service Four Character ID : USN8 Monument Inscription : IERS DOMES Number : 40451S009 CDP Number : Monument Description : TRIANGULATED AL STRUTS Height of the Monument : 7.0 m Monument Foundation : ROOF Foundation Depth : Marker Description : MOUNTING BRACKET HOLE, ARP Date Installed : 2014-11-12T16:00Z Geologic Characteristic : on aluminum structure on roof of of 2-story Bedrock Type : Bedrock Condition : Fracture Spacing : Fault zones nearby : Distance/activity : Additional Information : Same DOMES number as USN7 since same antenna : The antenna is mounted on a baseball diamond : shaped aluminum structure mounted on the roof : (2 stories) of the Time Service department : building at the U.S. Naval Observatory, : Washington. D.C.. There are nearby geodetic : markers, but this antenna has not been surveyed : to those markers. (see accompanying pictures). : USN7 functionally replaces USN3. : The antenna mount was extended by 1.5m on : 2014-11-12. 2. Site Location Information City or Town : Washington State or Province : D.C. Country : United States of America (the) Tectonic Plate : NORTH AMERICAN Approximate Position (ITRF) X coordinate (m) : 1112162.1380 Y coordinate (m) : -4842854.6670 Z coordinate (m) : 3985497.0660 Latitude (N is +) : +385514.04 Longitude (E is +) : +2825601.40 Elevation (m,ellips.) : 58.9 Additional Information : 3. GNSS Receiver Information 3.1 Receiver Type : SEPT POLARX4TR Satellite System : GPS+GLO+GAL+SBAS Serial Number : SN11203000923 Firmware Version : 2.3.4 Elevation Cutoff Setting : 0 deg Date Installed : 2014-11-12T11:00Z Date Removed : 2015-01-22T20:08Z Temperature Stabiliz. : none Additional Information : Receiver installed prior to the start of this : monument. Actual receiver install date is : 2013-05-01T14:00Z. 3.2 Receiver Type : SEPT POLARX4TR Satellite System : GPS+GLO+GAL+SBAS Serial Number : SN11203000923 Firmware Version : 2.5.2 Elevation Cutoff Setting : 0 deg Date Installed : 2015-01-22T20:34Z Date Removed : 2018-07-09T14:40Z Temperature Stabiliz. : none Additional Information : Also tracking WAAS. 3.3 Receiver Type : SEPT POLARX4TR Satellite System : GPS+GLO+GAL+SBAS Serial Number : SN11203000923 Firmware Version : 2.9.6 Elevation Cutoff Setting : 0 deg Date Installed : 2018-07-09T14:40Z Date Removed : 2019-03-19T18:25Z Temperature Stabiliz. : none Additional Information : Also tracking WAAS. 3.4 Receiver Type : SEPT POLARX5TR Satellite System : GPS+GLO+GAL+BDS+SBAS Serial Number : 4701171 Firmware Version : 5.0.3 Elevation Cutoff Setting : 0 deg Date Installed : 2019-03-25T15:06Z Date Removed : 2019-04-03T07:50Z Temperature Stabiliz. : Additional Information : 3.5 Receiver Type : SEPT POLARX5TR Satellite System : GPS+GLO+GAL+BDS+SBAS Serial Number : 4701171 Firmware Version : 5.2.0 Elevation Cutoff Setting : 0 deg Date Installed : 2019-04-03T07:50Z Date Removed : 2024-07-30T00:00Z Temperature Stabiliz. : Additional Information : Receiver board serial number: 3013987 3.6 Receiver Type : SEPT POLARX5TR Satellite System : GPS+GLO+GAL+BDS+SBAS Serial Number : 4701171 Firmware Version : 5.5.0 Elevation Cutoff Setting : 0 deg Date Installed : 2024-07-30T00:00Z Date Removed : (CCYY-MM-DDThh:mmZ) Temperature Stabiliz. : Additional Information : Receiver board serial number: 3013987 3.x Receiver Type : (A20, from rcvr_ant.tab; see instructions) Satellite System : (GPS+GLO+GAL+BDS+QZSS+SBAS) Serial Number : (A20, but note the first A5 is used in SINEX) Firmware Version : (A11) Elevation Cutoff Setting : (deg) Date Installed : (CCYY-MM-DDThh:mmZ) Date Removed : (CCYY-MM-DDThh:mmZ) Temperature Stabiliz. : (none or tolerance in degrees C) Additional Information : (multiple lines) 4. GNSS Antenna Information 4.1 Antenna Type : TPSCR.G5 TPSH Serial Number : 762-11615 Antenna Reference Point : BPA Marker->ARP Up Ecc. (m) : 0.0000 Marker->ARP North Ecc(m) : 0.0000 Marker->ARP East Ecc(m) : 0.0000 Alignment from True N : 0 deg Antenna Radome Type : TPSH Radome Serial Number : Antenna Cable Type : Andrew FSJ1-50A (35422-33 phase stabilized) Antenna Cable Length : 39 m Date Installed : 2014-11-12T11:00Z Date Removed : (CCYY-MM-DDThh:mmZ) Additional Information : Antenna is a Multi-band GNSS unit with TOPCON : radome. Antenna cable : 14-April-2009 to present - Andrew FSJ1-50A : (35422-33 phase stabilized) 1/4 inch : Superflexible Foam Dielectric Heliax -- : physical length 130 feet (39 m), mostly : run in ceiling and floor of USNO Bldg 78; : specifications - Velocity factor 0.84 : DC resistance 2 to 3 ohms per 1000 foot : Capacitance, 24.2 pF/foot Inductance, : .061 uH/foot Loss at 1250 MHz, 6.77 dB/100 foot : Loss at 1500 MHz, : 7.47 dB/100 foot Electrical Length Change : versus Temperature - 400 PPM over : (-40 to 30 C) or 5.7 PPM/C => 0.02 ps/m/C : Antenna splitter - USNO specially designed : antenna splitter that has > 100 db : port to port isolation and flat group delay : response at L1 and L2. New 8-port : splitter installed 2014-11-12. Antenna : splitter cable - from splitter to : receiver. The Antenna splitter cable is : attached to a DC block and 20db PAD at : the receiver input to improve impedance : matching. A lightning arrestor was : introduced in-line 2014-11-12. The measured : delays through each component of : the system are summarized in the table below - : L1(ns) L2(ns) : --------- --------- : antenna total 18.64 15.60 * : change to TOPCON : antenna cable 150.10 150.10 * no : change but added short cable to : support lightning arrester : lightning arrester 0.47 0.50 * new : item : short cable 7.39 7.39 * new : item is short cable between : antenna and lightning arrester : antenna splitter 7.85 8.02 * : change to new 8 port splitter : cable to receiver 6.36 6.36 * no : change : DC block and 20db : PAD 0.50 0.50 * no : change 4.x Antenna Type : (A20, from rcvr_ant.tab; see instructions) Serial Number : (A*, but note the first A5 is used in SINEX) Antenna Reference Point : (BPA/BCR/XXX from "antenna.gra"; see instr.) Marker->ARP Up Ecc. (m) : (F8.4) Marker->ARP North Ecc(m) : (F8.4) Marker->ARP East Ecc(m) : (F8.4) Alignment from True N : (deg; + is clockwise/east) Antenna Radome Type : (A4 from rcvr_ant.tab; see instructions) Radome Serial Number : Antenna Cable Type : (vendor & type number) Antenna Cable Length : (m) Date Installed : (CCYY-MM-DDThh:mmZ) Date Removed : (CCYY-MM-DDThh:mmZ) Additional Information : (multiple lines) 5. Surveyed Local Ties 5.x Tied Marker Name : Tied Marker Usage : (SLR/VLBI/LOCAL CONTROL/FOOTPRINT/etc) Tied Marker CDP Number : (A4) Tied Marker DOMES Number : (A9) Differential Components from GNSS Marker to the tied monument (ITRS) dx (m) : (m) dy (m) : (m) dz (m) : (m) Accuracy (mm) : (mm) Survey method : (GPS CAMPAIGN/TRILATERATION/TRIANGULATION/etc) Date Measured : (CCYY-MM-DDThh:mmZ) Additional Information : (multiple lines) 6. Frequency Standard 6.1 Standard Type : EXTERNAL H-MASER Input Frequency : 10.0 MHz Effective Dates : 1998-03-24/CCYY-MM-DD Notes : Reference signal from USNO Master clock (MC2), : the primary realization of UTC(USNO), located : in Bldg. 78 in a thermal chamber. MC2 is : steered to UTC using information obtained : from the Bureau International des Poids : et Mesures (BIPM) roughly each month. See : the BIPM Circular T for more detail, : http://www.bipm.fr/enus/5_Scientific/c_time/ : time_ftp.shtml 6.x Standard Type : (INTERNAL or EXTERNAL H-MASER/CESIUM/etc) Input Frequency : (if external) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 7. Collocation Information 7.1 Instrumentation Type : GPS Status : PERMANENT Effective Dates : 2015-01-22/CCYY-MM-DD Notes : 7.x Instrumentation Type : (GPS/GLONASS/DORIS/PRARE/SLR/VLBI/TIME/etc) Status : (PERMANENT/MOBILE) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8. Meteorological Instrumentation 8.1.1 Humidity Sensor Model : HUMICA H-sensor (pn 16663) Manufacturer : Vaisala Serial Number : Data Sampling Interval : 15 sec Accuracy (% rel h) : 1 Aspiration : NATURAL Height Diff to Ant : -0.724 m Calibration date : Effective Dates : 2001-08-21/CCYY-MM-DD Notes : NOAA GSOS # 062 8.1.x Humidity Sensor Model : Manufacturer : Serial Number : Data Sampling Interval : (sec) Accuracy (% rel h) : (% rel h) Aspiration : (UNASPIRATED/NATURAL/FAN/etc) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.2.1 Pressure Sensor Model : PTB220 Manufacturer : Vaisala Serial Number : Data Sampling Interval : 15 sec Accuracy : 0.1 hPa Height Diff to Ant : -0.724 m Calibration date : Effective Dates : 2001-08-21/CCYY-MM-DD Notes : met sensors are located at USNO on rooftop : of Building 52A (~ few hundred m from GPS ant.) : NOAA GSOS # 062 8.2.x Pressure Sensor Model : Manufacturer : Serial Number : Data Sampling Interval : (sec) Accuracy : (hPa) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.3.1 Temp. Sensor Model : PT100 RTD 1/s DIN 43760B Manufacturer : Vaisala Serial Number : Data Sampling Interval : 15 sec Accuracy : 0.1 deg C Aspiration : NATURAL Height Diff to Ant : -0.724 m Calibration date : Effective Dates : 2001-08-21/CCYY-MM-DD Notes : NOAA GSOS # 062 8.3.x Temp. Sensor Model : Manufacturer : Serial Number : Data Sampling Interval : (sec) Accuracy : (deg C) Aspiration : (UNASPIRATED/NATURAL/FAN/etc) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.4.x Water Vapor Radiometer : Manufacturer : Serial Number : Distance to Antenna : (m) Height Diff to Ant : (m) Calibration date : (CCYY-MM-DD) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Notes : (multiple lines) 8.5.x Other Instrumentation : (multiple lines) 9. Local Ongoing Conditions Possibly Affecting Computed Position 9.1.x Radio Interferences : (TV/CELL PHONE ANTENNA/RADAR/etc) Observed Degradations : (SN RATIO/DATA GAPS/etc) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Additional Information : (multiple lines) 9.2.x Multipath Sources : (METAL ROOF/DOME/VLBI ANTENNA/etc) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Additional Information : (multiple lines) 9.3.x Signal Obstructions : (TREES/BUILDINGS/etc) Effective Dates : (CCYY-MM-DD/CCYY-MM-DD) Additional Information : (multiple lines) 10. Local Episodic Effects Possibly Affecting Data Quality 10.x Date : (CCYY-MM-DD/CCYY-MM-DD) Event : (TREE CLEARING/CONSTRUCTION/etc) 11. On-Site, Point of Contact Agency Information Agency : U.S. Naval Observatory Preferred Abbreviation : USNO Mailing Address : Precise Time Department : 3450 Massachusetts Ave., NW : Washington, D.C. 20392-5420 Primary Contact Contact Name : John Adams Telephone (primary) : 202-762-0740 Telephone (secondary) : Fax : 202-762-1511 E-mail : gnss@us.navy.mil Secondary Contact Contact Name : Arnold Colina Telephone (primary) : 202-762-1455 Telephone (secondary) : Fax : 202-762-1511 E-mail : gnss@us.navy.mil Additional Information : 12. Responsible Agency (if different from 11.) Agency : US Naval Observatory Preferred Abbreviation : USNO Mailing Address : 3450 Massachusetts Ave. NW : Washington, DC 20392 Primary Contact Contact Name : John Adams Telephone (primary) : +1 (202) 762-0740 Telephone (secondary) : Fax : E-mail : gnss@us.navy.mil Secondary Contact Contact Name : Arnold Colina Telephone (primary) : +1 (202) 762-1455 Telephone (secondary) : Fax : E-mail : gnss@us.navy.mil Additional Information : 13. More Information Primary Data Center : CDDIS Secondary Data Center : IGN URL for More Information : Hardcopy on File Site Map : N Site Diagram : N Horizon Mask : N Monument Description : no monument Site Pictures : N Additional Information : Antenna Graphics with Dimensions