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LoRaWAN® Specification v1.0.3

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LoRaWAN 1.0.3 Specification ©2018 LoRa™ Alliance Page 55 of 72 The authors reserve the right to change specifications without notice. 15.3.1 Gateway GPS coordinate:InfoDesc = 0, 1 or 2 1454 For InfoDesc = 0 ,1 or 2, the content of the Info field encodes the GPS coordinates of the 1455 antenna broadcasting the beacon 1456 Size (bytes) 3 3 Info Lat Lng Figure 25 : beacon Info field format , infoDesc = 0,1,2 1457 The latitude and longitude fields (Lat and Lng, respectively) encode the geographical location 1458 of the gateway as follows: 1459 • The north-south latitude is encoded using a two's complement 24 bit word where -2 23 1460 corresponds to 90° south (the South Pole) and 2 23 -1 corresponds to ~90° north (the 1461 North Pole). The Equator corresponds to 0. 1462 • The east-west longitude is encoded using a two's complement 24 bit word where - 2 23 1463 corresponds to 180° West and 2 23 -1 corresponds to ~180° East. The Greenwich 1464 meridian corresponds to 0. 1465 15.3.2 NetID+GatewayID 1466 For InfoDesc = 3, the content of the Info field encodes the network's NetID plus a freely 1467 allocated gateway or cell identifier. The format of the Info field is: 1468 Size (bytes) 3 3 Info NetID GatewayID Figure 26 : beacon Info field format, infoDesc=3 1469 15.4 Beaconing precise timing 1470 The beacon is sent every 128 seconds starting at January 6, 1980 00:00:00 UTC (start of the 1471 GPS epoch) plus TBeaconDelay. Therefore the beacon is sent at 1472 B T = k * 128 + TBeaconDelay 1473 seconds after the GPS epoch. 1474 wherebyk is the smallest integer for which 1475 k * 128 >T 1476 whereby 1477 T = seconds since January 6, 1980 00:00:00 UTC (start of the GPS time). 1478 Note: T is GPS time and unlike Unix time, T is strictly monotonically 1479 increasing and is not influenced by leap seconds. 1480 1481 Whereby TBeaconDelay is 1.5 mSec +/- 1uSec delay. 1482 TBeaconDelay is meant to allow a slight transmission delay of the gateways required by the 1483 radio system to switch from receive to transmit mode. 1484 All end-devices ping slots use the beacon transmission start time as a timing reference, 1485 therefore the Network Server as to take TBeaconDelay into account when scheduling the 1486 class B downlinks. 1487 1488

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