Basic requirements of satellite signal receptor of national satellite navigation stations in Vietnam

1. What are basic requirements of antennas of national satellite navigation stations in Vietnam?

Pursuant to Clause 1, Article 9 of Circular 03/2020/TT-BTNMT, antenna receiving satellite signals shall be installed on top of the base section via the antenna mount, returned to flat surface; the antenna must face true north with deviation no more than ±5^o, if exceeding 5o, record the specific value in diary. antennas must meet following basic requirements:

a) Use antennas with choke rings, capable of receiving all signals (frequencies) available from satellite navigation systems at the time of installation such as: GPS, GLONASS, GALILEO, BDS, QZSS; encourage using antennas capable of receiving signals that are not transmitted by only planed to be transmitted from aforementioned satellite navigation systems or new satellite navigation systems such as the IRNSS;

b) Antenna’s name must be included in list of antenna whose phase center receives absolute calibration by the IGS;

c) Antennas must endure humidity up to 100 %; dust and water resistance standards must be at least IP67 according to stanrd3s of the International Electrotechnichal Committee (IEC);

d) Antennas must be able to operate in temperature ranging from -10^oC +70^oC;

dd) Base continuous operating reference stations must use antennas with choke rings made from Dorne-Margolin materials which are recommended for other stations;

e) Only use hemispherical protective covering for antennas, do not use conical protective covering;

g) Do not disassemble the antennas when the stations have initiated operation unless repair is required due to hardware damage.

2. What are basic requirements of satellite signal receivers of national satellite navigation stations in Vietnam?

Pursuant to Clause 2 of Article 9 of Circular 03/2020/TT-BTNMT, satellite signal receivers must be placed in dry and spacious areas and ensured regarding continuous operation. Receivers must meet following basic requirements:

a) Capable of receiving all available signals from satellite navigation systems at the time of installation such as: GPS, GLONASS, GALILEO, BDS, QZSS;

b) Have no less than 555 channels, at least 12 of which must be assigned to each frequency from ach aforementioned satellite navigation systems;

c) Capable of searching and receiving signals from satellites in mask angle of <10^o and eliminating multipath interference;

d) Capable of receiving signals with data sampling of 1 second or less, extracting data via current versions of RTCM such as 2.x/3.x, extracting data via CRM, CMR+, NMEA-0183, etc. and supporting Ntrip, TCP/IP and FTP;

dd) Have at least 2 power supply, support connecting directly with meteorology sensors and inclinometer;

e) Have all basic ports such as RJ-45, USB, 3G/4G/5G, RS-232;

g) Dust and water resistance standards must be at least IP67 according to stanrd3s of the International Electrotechnichal Committee (IEC);

h) Capable of operating in temperature ranging from -10^oC +65^oC;

i) Internal memory can store data for at least 60 days; support attachment of extended memory;

k) Signal cable from receivers to antennas must not exceed 70 meters. If necessary, measure and assess signal quality prior to official installation. With respect to areas with high lightning density, set the distance from the receivers to antennas as short as possible;

l) Connection between antennas and receivers must be placed in industrial PVC or HDPE pipes and buried underground level, if necessary, may design exposed transmission with firm shelves and do not leave the lines too tensed. Whichever end connects to the antenn3 must be watertight, especially when installed in coastal areas to prevent corrosion and rust;

m) Receivers are installed to receive signal 24 hours continuously from all visible satellite with data sampling of 1 second; mask angle in receivers is 0^o;

Best Regards!