diff --git a/gnss/2.1/default/Android.bp b/gnss/2.1/default/Android.bp
index 1f1078e..c4dc8fd 100644
--- a/gnss/2.1/default/Android.bp
+++ b/gnss/2.1/default/Android.bp
@@ -22,6 +22,7 @@
     vintf_fragments: ["android.hardware.gnss@2.1-service.xml"],
     srcs: [
         "Gnss.cpp",
+        "GnssAntennaInfo.cpp",
         "GnssDebug.cpp",
         "GnssMeasurement.cpp",
         "GnssMeasurementCorrections.cpp",
diff --git a/gnss/2.1/default/Gnss.cpp b/gnss/2.1/default/Gnss.cpp
index 679eb35..c1af103 100644
--- a/gnss/2.1/default/Gnss.cpp
+++ b/gnss/2.1/default/Gnss.cpp
@@ -17,6 +17,7 @@
 #define LOG_TAG "Gnss"
 
 #include "Gnss.h"
+#include "GnssAntennaInfo.h"
 #include "GnssDebug.h"
 #include "GnssMeasurement.h"
 #include "GnssMeasurementCorrections.h"
@@ -334,9 +335,10 @@
 
     sGnssCallback_2_1 = callback;
 
-    using Capabilities = V2_0::IGnssCallback::Capabilities;
+    using Capabilities = V2_1::IGnssCallback::Capabilities;
     const auto capabilities = Capabilities::MEASUREMENTS | Capabilities::MEASUREMENT_CORRECTIONS |
-                              Capabilities::LOW_POWER_MODE | Capabilities::SATELLITE_BLACKLIST;
+                              Capabilities::LOW_POWER_MODE | Capabilities::SATELLITE_BLACKLIST |
+                              Capabilities::ANTENNA_INFO;
     auto ret = sGnssCallback_2_1->gnssSetCapabilitiesCb_2_0(capabilities);
     if (!ret.isOk()) {
         ALOGE("%s: Unable to invoke callback", __func__);
@@ -374,6 +376,11 @@
     return new GnssMeasurementCorrections();
 }
 
+Return<sp<V2_1::IGnssAntennaInfo>> Gnss::getExtensionGnssAntennaInfo() {
+    ALOGD("Gnss::getExtensionGnssAntennaInfo");
+    return new GnssAntennaInfo();
+}
+
 void Gnss::reportSvStatus(const hidl_vec<GnssSvInfo>& svInfoList) const {
     std::unique_lock<std::mutex> lock(mMutex);
     // TODO(skz): update this to call 2_0 callback if non-null
diff --git a/gnss/2.1/default/Gnss.h b/gnss/2.1/default/Gnss.h
index c47206a..bd5e6e8 100644
--- a/gnss/2.1/default/Gnss.h
+++ b/gnss/2.1/default/Gnss.h
@@ -22,6 +22,7 @@
 #include <atomic>
 #include <mutex>
 #include <thread>
+#include "GnssAntennaInfo.h"
 #include "GnssConfiguration.h"
 
 namespace android {
@@ -91,6 +92,7 @@
     Return<sp<V2_1::IGnssConfiguration>> getExtensionGnssConfiguration_2_1() override;
     Return<sp<measurement_corrections::V1_1::IMeasurementCorrections>>
     getExtensionMeasurementCorrections_1_1() override;
+    Return<sp<V2_1::IGnssAntennaInfo>> getExtensionGnssAntennaInfo() override;
 
   private:
     void reportLocation(const V2_0::GnssLocation&) const;
diff --git a/gnss/2.1/default/GnssAntennaInfo.cpp b/gnss/2.1/default/GnssAntennaInfo.cpp
new file mode 100644
index 0000000..d32a0af
--- /dev/null
+++ b/gnss/2.1/default/GnssAntennaInfo.cpp
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "GnssAntennaInfo"
+
+#include "GnssAntennaInfo.h"
+#include "Utils.h"
+
+#include <log/log.h>
+
+using ::android::hardware::gnss::common::Utils;
+
+namespace android {
+namespace hardware {
+namespace gnss {
+namespace V2_1 {
+namespace implementation {
+
+sp<IGnssAntennaInfoCallback> GnssAntennaInfo::sCallback = nullptr;
+
+GnssAntennaInfo::GnssAntennaInfo() : mMinIntervalMillis(1000) {}
+
+GnssAntennaInfo::~GnssAntennaInfo() {
+    stop();
+}
+
+// Methods from ::android::hardware::gnss::V2_1::IGnssAntennaInfo follow.
+Return<GnssAntennaInfo::GnssAntennaInfoStatus> GnssAntennaInfo::setCallback(
+        const sp<IGnssAntennaInfoCallback>& callback) {
+    ALOGD("setCallback");
+    std::unique_lock<std::mutex> lock(mMutex);
+    sCallback = callback;
+
+    if (mIsActive) {
+        ALOGW("GnssAntennaInfo callback already set. Resetting the callback...");
+        stop();
+    }
+    start();
+
+    return GnssAntennaInfoStatus::SUCCESS;
+}
+
+Return<void> GnssAntennaInfo::close() {
+    ALOGD("close");
+    std::unique_lock<std::mutex> lock(mMutex);
+    stop();
+    sCallback = nullptr;
+    return Void();
+}
+
+// Private methods
+void GnssAntennaInfo::start() {
+    ALOGD("start");
+    mIsActive = true;
+    mThread = std::thread([this]() {
+        while (mIsActive == true) {
+            if (sCallback != nullptr) {
+                auto antennaInfos = Utils::getMockAntennaInfos();
+                this->reportAntennaInfo(antennaInfos);
+            }
+
+            /** For mock implementation this is good. On real device, we should only report
+                antennaInfo at start and when there is a configuration change. **/
+            std::this_thread::sleep_for(std::chrono::milliseconds(mMinIntervalMillis));
+        }
+    });
+}
+
+void GnssAntennaInfo::stop() {
+    ALOGD("stop");
+    mIsActive = false;
+    if (mThread.joinable()) {
+        mThread.join();
+    }
+}
+
+void GnssAntennaInfo::reportAntennaInfo(
+        const hidl_vec<IGnssAntennaInfoCallback::GnssAntennaInfo>& antennaInfo) const {
+    std::unique_lock<std::mutex> lock(mMutex);
+
+    if (sCallback == nullptr) {
+        ALOGE("%s: No non-null callback", __func__);
+        return;
+    }
+
+    auto ret = sCallback->gnssAntennaInfoCb(antennaInfo);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
+}
+
+}  // namespace implementation
+}  // namespace V2_1
+}  // namespace gnss
+}  // namespace hardware
+}  // namespace android
\ No newline at end of file
diff --git a/gnss/2.1/default/GnssAntennaInfo.h b/gnss/2.1/default/GnssAntennaInfo.h
new file mode 100644
index 0000000..f4bfd24
--- /dev/null
+++ b/gnss/2.1/default/GnssAntennaInfo.h
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2020 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_HARDWARE_GNSS_V2_1_GNSSANTENNAINFO_H
+#define ANDROID_HARDWARE_GNSS_V2_1_GNSSANTENNAINFO_H
+
+#include <android/hardware/gnss/2.1/IGnssAntennaInfo.h>
+
+#include <mutex>
+#include <thread>
+
+namespace android {
+namespace hardware {
+namespace gnss {
+namespace V2_1 {
+namespace implementation {
+
+using ::android::sp;
+using ::android::hardware::Return;
+using ::android::hardware::Void;
+
+struct GnssAntennaInfo : public IGnssAntennaInfo {
+    GnssAntennaInfo();
+    ~GnssAntennaInfo();
+
+    // Methods from ::android::hardware::gnss::V2_1::IGnssAntennaInfo follow.
+    Return<GnssAntennaInfoStatus> setCallback(
+            const sp<IGnssAntennaInfoCallback>& callback) override;
+    Return<void> close() override;
+
+  private:
+    void start();
+    void stop();
+    void reportAntennaInfo(
+            const hidl_vec<IGnssAntennaInfoCallback::GnssAntennaInfo>& antennaInfo) const;
+
+    static sp<IGnssAntennaInfoCallback> sCallback;
+    std::atomic<long> mMinIntervalMillis;
+    std::atomic<bool> mIsActive;
+    std::thread mThread;
+    mutable std::mutex mMutex;
+};
+
+}  // namespace implementation
+}  // namespace V2_1
+}  // namespace gnss
+}  // namespace hardware
+}  // namespace android
+
+#endif  // ANDROID_HARDWARE_GNSS_V2_1_GNSSCONFIGURATION_H
\ No newline at end of file