diff --git a/lib/plugins/Label_SQ.ts b/lib/plugins/Label_SQ.ts
index 06990c7..0676d67 100644
--- a/lib/plugins/Label_SQ.ts
+++ b/lib/plugins/Label_SQ.ts
@@ -1,6 +1,43 @@
 import { DecoderPlugin } from '../DecoderPlugin';
 import { DecodeResult, Message, Options } from '../DecoderPluginInterface';
 
+/**
+ * Label SQ — Ground Station Squitter
+ *
+ * ACARS label SQ denotes a "squitter" — an ID and uplink test message
+ * transmitted at regular intervals from ACARS ground stations. It is a
+ * ground-to-air BROADCAST (not a downlink from an aircraft), announcing
+ * the ground station's presence, position, and VDL-2 capability to any
+ * aircraft in range.
+ *
+ * Extended squitter (version 02) format:
+ *
+ *   0 2 X A YVR CYVR 1 4911 N 12310 W V 136975 /ARINC
+ *   | | | | |   |    | |    | |     | | |      |
+ *   | | | | |   |    | |    | |     | | |      └ Provider suffix: /ARINC or empty (SITA)
+ *   | | | | |   |    | |    | |     | | └──────── VDL-2 frequency (kHz), 136975 → 136.975 MHz
+ *   | | | | |   |    | |    | |     | └────────── Separator flag (often 'V' for VDL, but 'B'
+ *   | | | | |   |    | |    | |     |             and other letters have been observed; the
+ *   | | | | |   |    | |    | |     |             specific meaning is not documented)
+ *   | | | | |   |    | |    | |     └──────────── Longitude hemisphere (E/W)
+ *   | | | | |   |    | |    | └──────────────── Longitude (DDDMM) — deg + 2 digits min
+ *   | | | | |   |    | |    └────────────────── Latitude hemisphere (N/S)
+ *   | | | | |   |    | └─────────────────────── Latitude (DDMM) — deg + 2 digits min
+ *   | | | | |   |    └───────────────────────── Ground station number (1-9)
+ *   | | | | |   └────────────────────────────── ICAO airport code of the station (4 chars)
+ *   | | | | └────────────────────────────────── IATA airport code of the station (3 chars)
+ *   | | | └──────────────────────────────────── Provider ID: A = ARINC (RC), S = SITA
+ *   | | └────────────────────────────────────── Category: X = ground-to-air uplink broadcast
+ *   | └──────────────────────────────────────── Version: 2 = extended squitter with position + VDL-2
+ *   └────────────────────────────────────────── Version digit 1 (always '0')
+ *
+ * Coordinate encoding: lat is 4 digits DDMM, lng is 5 digits DDDMM.
+ * Example: 5109 N 00012 W → 51°09'N, 000°12'W → London Gatwick (EGKK).
+ *
+ * Real-world examples observed:
+ *   0EYVRCYVR14911N12310WV136975/ARINC   ← Vancouver, V separator
+ *   02XALGWEGKK15109N00012WB136975/ARINC ← Gatwick,   B separator
+ */
 export class Label_SQ extends DecoderPlugin {
   name = 'label-sq';
 
@@ -11,42 +48,76 @@ export class Label_SQ extends DecoderPlugin {
   }
 
   decode(message: Message, options: Options = {}): DecodeResult {
-    const decodeResult = this.initResult(message, 'Ground Station Squitter');
+    const decodeResult = this.initResult(
+      message,
+      'Ground Station Squitter (ID / Uplink Test — ground-to-air broadcast)'
+    );
 
     decodeResult.raw.preamble = message.text.substring(0, 4);
     decodeResult.raw.version = Number(message.text.substring(1, 2));
     decodeResult.raw.network = message.text.substring(3, 4);
+    // Category char (typically 'X' for uplink broadcast)
+    decodeResult.raw.category = message.text.substring(2, 3);
 
     if (decodeResult.raw.version === 2) {
+      // Lat is 4 digits (DDMM), lng is 5 digits (DDDMM). Separator before
+      // frequency is typically 'V' but 'B' (and possibly others) have been
+      // observed; capture as a raw flag rather than constraining to 'V'.
       const regex =
-        /0(\d)X(?<org>\w)(?<iata>\w\w\w)(?<icao>\w\w\w\w)(?<station>\d)(?<lat>\d+)(?<latd>[NS])(?<lng>\d+)(?<lngd>[EW])V(?<vfreq>\d+)\/.*/;
+        /0(\d)(?<cat>[A-Z])(?<org>[A-Z])(?<iata>\w{3})(?<icao>\w{4})(?<station>\d)(?<lat>\d{4})(?<latd>[NS])(?<lng>\d{5})(?<lngd>[EW])(?<sep>[A-Z])(?<vfreq>\d+)(?:\/(?<suffix>\w*))?/;
       const result = message.text.match(regex);
 
       if (result?.groups && result.length >= 8) {
+        decodeResult.raw.category = result.groups.cat;
+        decodeResult.raw.network = result.groups.org;
+
+        // DDMM → decimal degrees (deg + min/60), signed by hemisphere
+        const latRaw = result.groups.lat;
+        const lngRaw = result.groups.lng;
+        const latDeg = Math.floor(Number(latRaw) / 100);
+        const latMin = Number(latRaw) % 100;
+        const lngDeg = Math.floor(Number(lngRaw) / 100);
+        const lngMin = Number(lngRaw) % 100;
+        const latitude =
+          (latDeg + latMin / 60) * (result.groups.latd === 'S' ? -1 : 1);
+        const longitude =
+          (lngDeg + lngMin / 60) * (result.groups.lngd === 'W' ? -1 : 1);
+
         decodeResult.raw.groundStation = {
           number: result.groups.station,
           iataCode: result.groups.iata,
           icaoCode: result.groups.icao,
           coordinates: {
-            latitude:
-              (Number(result.groups.lat) / 100) *
-              (result.groups.latd === 'S' ? -1 : 1),
-            longitude:
-              (Number(result.groups.lng) / 100) *
-              (result.groups.lngd === 'W' ? -1 : 1),
+            latitude: Math.round(latitude * 1e6) / 1e6,
+            longitude: Math.round(longitude * 1e6) / 1e6,
           },
         };
         decodeResult.raw.vdlFrequency = Number(result.groups.vfreq) / 1000.0;
+        decodeResult.raw.separator = result.groups.sep;
+        if (result.groups.suffix) {
+          decodeResult.raw.providerSuffix = result.groups.suffix;
+        }
       }
     }
 
     var formattedNetwork = 'Unknown';
-    if (decodeResult.raw.network == 'A') {
+    if (decodeResult.raw.network === 'A') {
       formattedNetwork = 'ARINC';
-    } else if (decodeResult.raw.network == 'S') {
+    } else if (decodeResult.raw.network === 'S') {
       formattedNetwork = 'SITA';
     }
+    var formattedCategory = String(decodeResult.raw.category || '');
+    if (formattedCategory === 'X') {
+      formattedCategory = 'X (ground-to-air uplink broadcast)';
+    }
+
     decodeResult.formatted.items = [
+      {
+        type: 'message_type',
+        code: 'MSGTYP',
+        label: 'Message Type',
+        value: 'Squitter (ID / Uplink Test — ground-to-air broadcast)',
+      },
       {
         type: 'network',
         code: 'NETT',
@@ -59,6 +130,12 @@ export class Label_SQ extends DecoderPlugin {
         label: 'Version',
         value: String(decodeResult.raw.version),
       },
+      {
+        type: 'category',
+        code: 'CAT',
+        label: 'Category',
+        value: formattedCategory,
+      },
     ];
 
     if (decodeResult.raw.groundStation) {
@@ -115,6 +192,25 @@ export class Label_SQ extends DecoderPlugin {
         value: `${decodeResult.raw.vdlFrequency} MHz`,
       });
     }
+
+    if (decodeResult.raw.separator) {
+      decodeResult.formatted.items.push({
+        type: 'separator',
+        code: 'SEP',
+        label: 'Separator Flag',
+        value: String(decodeResult.raw.separator),
+      });
+    }
+
+    if (decodeResult.raw.providerSuffix) {
+      decodeResult.formatted.items.push({
+        type: 'provider_suffix',
+        code: 'PROVSFX',
+        label: 'Provider Suffix',
+        value: `/${decodeResult.raw.providerSuffix}`,
+      });
+    }
+
     this.setDecodeLevel(decodeResult, true, 'full');
 
     return decodeResult;