diff --git a/gnss/2.1/default/Android.bp b/gnss/2.1/default/Android.bp
new file mode 100644
index 0000000..a7cf63d
--- /dev/null
+++ b/gnss/2.1/default/Android.bp
@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+cc_binary {
+    name: "android.hardware.gnss@2.1-service",
+    init_rc: ["android.hardware.gnss@2.1-service.rc"],
+    relative_install_path: "hw",
+    vendor: true,
+    vintf_fragments: ["android.hardware.gnss@2.1-service.xml"],
+    srcs: [
+        "Gnss.cpp",
+        "GnssMeasurement.cpp",
+        "service.cpp"
+    ],
+    shared_libs: [
+        "libhidlbase",
+        "libutils",
+        "liblog",
+        "android.hardware.gnss.measurement_corrections@1.0",
+        "android.hardware.gnss.visibility_control@1.0",
+        "android.hardware.gnss@2.1",
+        "android.hardware.gnss@1.0",
+        "android.hardware.gnss@1.1",
+        "android.hardware.gnss@2.0",
+    ],
+    static_libs: [
+        "android.hardware.gnss@common-default-lib",
+    ],
+}
diff --git a/gnss/2.1/default/Gnss.cpp b/gnss/2.1/default/Gnss.cpp
new file mode 100644
index 0000000..2771f27
--- /dev/null
+++ b/gnss/2.1/default/Gnss.cpp
@@ -0,0 +1,301 @@
+/*
+ * Copyright (C) 2019 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 "Gnss"
+
+#include "Gnss.h"
+#include "GnssMeasurement.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<V2_1::IGnssCallback> Gnss::sGnssCallback_2_1 = nullptr;
+
+Gnss::Gnss() : mMinIntervalMs(1000) {}
+
+Gnss::~Gnss() {
+    stop();
+}
+
+Return<bool> Gnss::start() {
+    ALOGD("start");
+    if (mIsActive) {
+        ALOGW("Gnss has started. Restarting...");
+        stop();
+    }
+
+    mIsActive = true;
+    mThread = std::thread([this]() {
+        while (mIsActive == true) {
+            auto svStatus = Utils::getMockSvInfoListV2_1();
+            this->reportSvStatus(svStatus);
+
+            const auto location = Utils::getMockLocationV2_0();
+            this->reportLocation(location);
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(mMinIntervalMs));
+        }
+    });
+    return true;
+}
+
+Return<bool> Gnss::stop() {
+    ALOGD("stop");
+    mIsActive = false;
+    if (mThread.joinable()) {
+        mThread.join();
+    }
+    return true;
+}
+
+// Methods from V1_0::IGnss follow.
+Return<bool> Gnss::setCallback(const sp<V1_0::IGnssCallback>&) {
+    // TODO implement
+    return bool{};
+}
+
+Return<void> Gnss::cleanup() {
+    // TODO implement
+    return Void();
+}
+
+Return<bool> Gnss::injectTime(int64_t, int64_t, int32_t) {
+    // TODO implement
+    return bool{};
+}
+
+Return<bool> Gnss::injectLocation(double, double, float) {
+    // TODO implement
+    return bool{};
+}
+
+Return<void> Gnss::deleteAidingData(V1_0::IGnss::GnssAidingData) {
+    // TODO implement
+    return Void();
+}
+
+Return<bool> Gnss::setPositionMode(V1_0::IGnss::GnssPositionMode,
+                                   V1_0::IGnss::GnssPositionRecurrence, uint32_t, uint32_t,
+                                   uint32_t) {
+    // TODO implement
+    return bool{};
+}
+
+Return<sp<V1_0::IAGnssRil>> Gnss::getExtensionAGnssRil() {
+    // TODO implement
+    return ::android::sp<V1_0::IAGnssRil>{};
+}
+
+Return<sp<V1_0::IGnssGeofencing>> Gnss::getExtensionGnssGeofencing() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssGeofencing>{};
+}
+
+Return<sp<V1_0::IAGnss>> Gnss::getExtensionAGnss() {
+    // TODO implement
+    return ::android::sp<V1_0::IAGnss>{};
+}
+
+Return<sp<V1_0::IGnssNi>> Gnss::getExtensionGnssNi() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssNi>{};
+}
+
+Return<sp<V1_0::IGnssMeasurement>> Gnss::getExtensionGnssMeasurement() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssMeasurement>{};
+}
+
+Return<sp<V1_0::IGnssNavigationMessage>> Gnss::getExtensionGnssNavigationMessage() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssNavigationMessage>{};
+}
+
+Return<sp<V1_0::IGnssXtra>> Gnss::getExtensionXtra() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssXtra>{};
+}
+
+Return<sp<V1_0::IGnssConfiguration>> Gnss::getExtensionGnssConfiguration() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssConfiguration>{};
+}
+
+Return<sp<V1_0::IGnssDebug>> Gnss::getExtensionGnssDebug() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssDebug>{};
+}
+
+Return<sp<V1_0::IGnssBatching>> Gnss::getExtensionGnssBatching() {
+    // TODO implement
+    return ::android::sp<V1_0::IGnssBatching>{};
+}
+
+// Methods from V1_1::IGnss follow.
+Return<bool> Gnss::setCallback_1_1(const sp<V1_1::IGnssCallback>&) {
+    // TODO implement
+    return bool{};
+}
+
+Return<bool> Gnss::setPositionMode_1_1(V1_0::IGnss::GnssPositionMode,
+                                       V1_0::IGnss::GnssPositionRecurrence, uint32_t, uint32_t,
+                                       uint32_t, bool) {
+    return true;
+}
+
+Return<sp<V1_1::IGnssConfiguration>> Gnss::getExtensionGnssConfiguration_1_1() {
+    // TODO implement
+    return ::android::sp<V1_1::IGnssConfiguration>{};
+}
+
+Return<sp<V1_1::IGnssMeasurement>> Gnss::getExtensionGnssMeasurement_1_1() {
+    // TODO implement
+    return ::android::sp<V1_1::IGnssMeasurement>{};
+}
+
+Return<bool> Gnss::injectBestLocation(const V1_0::GnssLocation&) {
+    // TODO implement
+    return bool{};
+}
+
+// Methods from V2_0::IGnss follow.
+Return<bool> Gnss::setCallback_2_0(const sp<V2_0::IGnssCallback>&) {
+    // TODO implement
+    return bool{};
+}
+
+Return<sp<V2_0::IGnssConfiguration>> Gnss::getExtensionGnssConfiguration_2_0() {
+    // TODO implement
+    return ::android::sp<V2_0::IGnssConfiguration>{};
+}
+
+Return<sp<V2_0::IGnssDebug>> Gnss::getExtensionGnssDebug_2_0() {
+    // TODO implement
+    return ::android::sp<V2_0::IGnssDebug>{};
+}
+
+Return<sp<V2_0::IAGnss>> Gnss::getExtensionAGnss_2_0() {
+    // TODO implement
+    return ::android::sp<V2_0::IAGnss>{};
+}
+
+Return<sp<V2_0::IAGnssRil>> Gnss::getExtensionAGnssRil_2_0() {
+    // TODO implement
+    return ::android::sp<V2_0::IAGnssRil>{};
+}
+
+Return<sp<V2_0::IGnssMeasurement>> Gnss::getExtensionGnssMeasurement_2_0() {
+    // TODO implement
+    return ::android::sp<V2_0::IGnssMeasurement>{};
+}
+
+Return<sp<measurement_corrections::V1_0::IMeasurementCorrections>>
+Gnss::getExtensionMeasurementCorrections() {
+    // TODO implement
+    return ::android::sp<measurement_corrections::V1_0::IMeasurementCorrections>{};
+}
+
+Return<sp<visibility_control::V1_0::IGnssVisibilityControl>> Gnss::getExtensionVisibilityControl() {
+    // TODO implement
+    return ::android::sp<visibility_control::V1_0::IGnssVisibilityControl>{};
+}
+
+Return<sp<V2_0::IGnssBatching>> Gnss::getExtensionGnssBatching_2_0() {
+    // TODO implement
+    return ::android::sp<V2_0::IGnssBatching>{};
+}
+
+Return<bool> Gnss::injectBestLocation_2_0(const V2_0::GnssLocation&) {
+    // TODO implement
+    return bool{};
+}
+
+// Methods from V2_1::IGnss follow.
+Return<bool> Gnss::setCallback_2_1(const sp<V2_1::IGnssCallback>& callback) {
+    ALOGD("Gnss::setCallback_2_1");
+    if (callback == nullptr) {
+        ALOGE("%s: Null callback ignored", __func__);
+        return false;
+    }
+
+    sGnssCallback_2_1 = callback;
+
+    using Capabilities = V2_0::IGnssCallback::Capabilities;
+    const auto capabilities = Capabilities::MEASUREMENTS | Capabilities::MEASUREMENT_CORRECTIONS |
+                              Capabilities::LOW_POWER_MODE | Capabilities::SATELLITE_BLACKLIST;
+    auto ret = sGnssCallback_2_1->gnssSetCapabilitiesCb_2_0(capabilities);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
+
+    V1_1::IGnssCallback::GnssSystemInfo gnssInfo = {.yearOfHw = 2020};
+
+    ret = sGnssCallback_2_1->gnssSetSystemInfoCb(gnssInfo);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
+
+    auto gnssName = "Android Mock GNSS Implementation v2.1";
+    ret = sGnssCallback_2_1->gnssNameCb(gnssName);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
+
+    return true;
+}
+
+Return<sp<V2_1::IGnssMeasurement>> Gnss::getExtensionGnssMeasurement_2_1() {
+    ALOGD("Gnss::getExtensionGnssMeasurement_2_1");
+    return new GnssMeasurement();
+}
+
+void Gnss::reportSvStatus(const hidl_vec<GnssSvInfo>& svInfoList) const {
+    std::unique_lock<std::mutex> lock(mMutex);
+    if (sGnssCallback_2_1 == nullptr) {
+        ALOGE("%s: sGnssCallback v2.1 is null.", __func__);
+        return;
+    }
+    auto ret = sGnssCallback_2_1->gnssSvStatusCb_2_1(svInfoList);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
+}
+
+void Gnss::reportLocation(const V2_0::GnssLocation& location) const {
+    std::unique_lock<std::mutex> lock(mMutex);
+    if (sGnssCallback_2_1 == nullptr) {
+        ALOGE("%s: sGnssCallback v2.1 is null.", __func__);
+        return;
+    }
+    auto ret = sGnssCallback_2_1->gnssLocationCb_2_0(location);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
+}
+
+}  // namespace implementation
+}  // namespace V2_1
+}  // namespace gnss
+}  // namespace hardware
+}  // namespace android
diff --git a/gnss/2.1/default/Gnss.h b/gnss/2.1/default/Gnss.h
new file mode 100644
index 0000000..a61f71c
--- /dev/null
+++ b/gnss/2.1/default/Gnss.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#pragma once
+
+#include <android/hardware/gnss/2.1/IGnss.h>
+#include <hidl/MQDescriptor.h>
+#include <hidl/Status.h>
+#include <atomic>
+#include <mutex>
+#include <thread>
+
+namespace android {
+namespace hardware {
+namespace gnss {
+namespace V2_1 {
+
+using GnssSvInfo = IGnssCallback::GnssSvInfo;
+
+namespace implementation {
+
+struct Gnss : public IGnss {
+    Gnss();
+    ~Gnss();
+    // Methods from V1_0::IGnss follow.
+    Return<bool> setCallback(const sp<V1_0::IGnssCallback>& callback) override;
+    Return<bool> start() override;
+    Return<bool> stop() override;
+    Return<void> cleanup() override;
+    Return<bool> injectTime(int64_t timeMs, int64_t timeReferenceMs,
+                            int32_t uncertaintyMs) override;
+    Return<bool> injectLocation(double latitudeDegrees, double longitudeDegrees,
+                                float accuracyMeters) override;
+    Return<void> deleteAidingData(V1_0::IGnss::GnssAidingData aidingDataFlags) override;
+    Return<bool> setPositionMode(V1_0::IGnss::GnssPositionMode mode,
+                                 V1_0::IGnss::GnssPositionRecurrence recurrence,
+                                 uint32_t minIntervalMs, uint32_t preferredAccuracyMeters,
+                                 uint32_t preferredTimeMs) override;
+    Return<sp<V1_0::IAGnssRil>> getExtensionAGnssRil() override;
+    Return<sp<V1_0::IGnssGeofencing>> getExtensionGnssGeofencing() override;
+    Return<sp<V1_0::IAGnss>> getExtensionAGnss() override;
+    Return<sp<V1_0::IGnssNi>> getExtensionGnssNi() override;
+    Return<sp<V1_0::IGnssMeasurement>> getExtensionGnssMeasurement() override;
+    Return<sp<V1_0::IGnssNavigationMessage>> getExtensionGnssNavigationMessage() override;
+    Return<sp<V1_0::IGnssXtra>> getExtensionXtra() override;
+    Return<sp<V1_0::IGnssConfiguration>> getExtensionGnssConfiguration() override;
+    Return<sp<V1_0::IGnssDebug>> getExtensionGnssDebug() override;
+    Return<sp<V1_0::IGnssBatching>> getExtensionGnssBatching() override;
+
+    // Methods from V1_1::IGnss follow.
+    Return<bool> setCallback_1_1(const sp<V1_1::IGnssCallback>& callback) override;
+    Return<bool> setPositionMode_1_1(V1_0::IGnss::GnssPositionMode mode,
+                                     V1_0::IGnss::GnssPositionRecurrence recurrence,
+                                     uint32_t minIntervalMs, uint32_t preferredAccuracyMeters,
+                                     uint32_t preferredTimeMs, bool lowPowerMode) override;
+    Return<sp<V1_1::IGnssConfiguration>> getExtensionGnssConfiguration_1_1() override;
+    Return<sp<V1_1::IGnssMeasurement>> getExtensionGnssMeasurement_1_1() override;
+    Return<bool> injectBestLocation(const V1_0::GnssLocation& location) override;
+
+    // Methods from V2_0::IGnss follow.
+    Return<bool> setCallback_2_0(const sp<V2_0::IGnssCallback>& callback) override;
+    Return<sp<V2_0::IGnssConfiguration>> getExtensionGnssConfiguration_2_0() override;
+    Return<sp<V2_0::IGnssDebug>> getExtensionGnssDebug_2_0() override;
+    Return<sp<V2_0::IAGnss>> getExtensionAGnss_2_0() override;
+    Return<sp<V2_0::IAGnssRil>> getExtensionAGnssRil_2_0() override;
+    Return<sp<V2_0::IGnssMeasurement>> getExtensionGnssMeasurement_2_0() override;
+    Return<sp<measurement_corrections::V1_0::IMeasurementCorrections>>
+    getExtensionMeasurementCorrections() override;
+    Return<sp<visibility_control::V1_0::IGnssVisibilityControl>> getExtensionVisibilityControl()
+            override;
+    Return<sp<V2_0::IGnssBatching>> getExtensionGnssBatching_2_0() override;
+    Return<bool> injectBestLocation_2_0(const V2_0::GnssLocation& location) override;
+
+    // Methods from V2_1::IGnss follow.
+    Return<bool> setCallback_2_1(const sp<V2_1::IGnssCallback>& callback) override;
+    Return<sp<V2_1::IGnssMeasurement>> getExtensionGnssMeasurement_2_1() override;
+
+  private:
+    void reportLocation(const V2_0::GnssLocation&) const;
+    void reportSvStatus(const hidl_vec<GnssSvInfo>&) const;
+
+    static sp<V2_1::IGnssCallback> sGnssCallback_2_1;
+    std::atomic<long> mMinIntervalMs;
+    std::atomic<bool> mIsActive;
+    std::thread mThread;
+    mutable std::mutex mMutex;
+};
+
+}  // namespace implementation
+}  // namespace V2_1
+}  // namespace gnss
+}  // namespace hardware
+}  // namespace android
diff --git a/gnss/2.1/default/GnssMeasurement.cpp b/gnss/2.1/default/GnssMeasurement.cpp
new file mode 100644
index 0000000..ebfa7dd
--- /dev/null
+++ b/gnss/2.1/default/GnssMeasurement.cpp
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2019 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 "GnssMeasurement"
+
+#include "GnssMeasurement.h"
+#include <log/log.h>
+#include "Utils.h"
+
+namespace android {
+namespace hardware {
+namespace gnss {
+
+using common::Utils;
+
+namespace V2_1 {
+namespace implementation {
+
+sp<V2_1::IGnssMeasurementCallback> GnssMeasurement::sCallback = nullptr;
+
+GnssMeasurement::GnssMeasurement() : mMinIntervalMillis(1000) {}
+
+GnssMeasurement::~GnssMeasurement() {
+    stop();
+}
+
+// Methods from V1_0::IGnssMeasurement follow.
+Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> GnssMeasurement::setCallback(
+        const sp<V1_0::IGnssMeasurementCallback>&) {
+    // TODO implement
+    return V1_0::IGnssMeasurement::GnssMeasurementStatus{};
+}
+
+Return<void> GnssMeasurement::close() {
+    ALOGD("close");
+    std::unique_lock<std::mutex> lock(mMutex);
+    stop();
+    sCallback = nullptr;
+    return Void();
+}
+
+// Methods from V1_1::IGnssMeasurement follow.
+Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> GnssMeasurement::setCallback_1_1(
+        const sp<V1_1::IGnssMeasurementCallback>&, bool) {
+    // TODO implement
+    return V1_0::IGnssMeasurement::GnssMeasurementStatus{};
+}
+
+// Methods from V2_0::IGnssMeasurement follow.
+Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> GnssMeasurement::setCallback_2_0(
+        const sp<V2_0::IGnssMeasurementCallback>&, bool) {
+    // TODO implement
+    return V1_0::IGnssMeasurement::GnssMeasurementStatus{};
+}
+
+// Methods from V2_1::IGnssMeasurement follow.
+Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> GnssMeasurement::setCallback_2_1(
+        const sp<V2_1::IGnssMeasurementCallback>& callback, bool) {
+    ALOGD("setCallback_2_1");
+    std::unique_lock<std::mutex> lock(mMutex);
+    sCallback = callback;
+
+    if (mIsActive) {
+        ALOGW("GnssMeasurement callback already set. Resetting the callback...");
+        stop();
+    }
+    start();
+
+    return V1_0::IGnssMeasurement::GnssMeasurementStatus::SUCCESS;
+}
+
+void GnssMeasurement::start() {
+    ALOGD("start");
+    mIsActive = true;
+    mThread = std::thread([this]() {
+        while (mIsActive == true) {
+            auto measurement = Utils::getMockMeasurementV2_1();
+            this->reportMeasurement(measurement);
+
+            std::this_thread::sleep_for(std::chrono::milliseconds(mMinIntervalMillis));
+        }
+    });
+}
+
+void GnssMeasurement::stop() {
+    ALOGD("stop");
+    mIsActive = false;
+    if (mThread.joinable()) {
+        mThread.join();
+    }
+}
+
+void GnssMeasurement::reportMeasurement(const GnssDataV2_1& data) {
+    ALOGD("reportMeasurement()");
+    std::unique_lock<std::mutex> lock(mMutex);
+    if (sCallback == nullptr) {
+        ALOGE("%s: GnssMeasurement::sCallback is null.", __func__);
+        return;
+    }
+    auto ret = sCallback->gnssMeasurementCb_2_1(data);
+    if (!ret.isOk()) {
+        ALOGE("%s: Unable to invoke callback", __func__);
+    }
+}
+
+}  // namespace implementation
+}  // namespace V2_1
+}  // namespace gnss
+}  // namespace hardware
+}  // namespace android
diff --git a/gnss/2.1/default/GnssMeasurement.h b/gnss/2.1/default/GnssMeasurement.h
new file mode 100644
index 0000000..ee32903
--- /dev/null
+++ b/gnss/2.1/default/GnssMeasurement.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2019 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.
+ */
+
+#pragma once
+
+#include <android/hardware/gnss/2.1/IGnssMeasurement.h>
+#include <hidl/MQDescriptor.h>
+#include <hidl/Status.h>
+#include <atomic>
+#include <mutex>
+#include <thread>
+
+namespace android {
+namespace hardware {
+namespace gnss {
+namespace V2_1 {
+namespace implementation {
+
+using GnssDataV2_1 = V2_1::IGnssMeasurementCallback::GnssData;
+
+using ::android::sp;
+using ::android::hardware::hidl_array;
+using ::android::hardware::hidl_memory;
+using ::android::hardware::hidl_string;
+using ::android::hardware::hidl_vec;
+using ::android::hardware::Return;
+using ::android::hardware::Void;
+
+struct GnssMeasurement : public IGnssMeasurement {
+    GnssMeasurement();
+    ~GnssMeasurement();
+    // Methods from V1_0::IGnssMeasurement follow.
+    Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> setCallback(
+            const sp<V1_0::IGnssMeasurementCallback>& callback) override;
+    Return<void> close() override;
+
+    // Methods from V1_1::IGnssMeasurement follow.
+    Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> setCallback_1_1(
+            const sp<V1_1::IGnssMeasurementCallback>& callback, bool enableFullTracking) override;
+
+    // Methods from V2_0::IGnssMeasurement follow.
+    Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> setCallback_2_0(
+            const sp<V2_0::IGnssMeasurementCallback>& callback, bool enableFullTracking) override;
+
+    // Methods from V2_1::IGnssMeasurement follow.
+    Return<V1_0::IGnssMeasurement::GnssMeasurementStatus> setCallback_2_1(
+            const sp<V2_1::IGnssMeasurementCallback>& callback, bool enableFullTracking) override;
+
+  private:
+    void start();
+    void stop();
+    void reportMeasurement(const GnssDataV2_1&);
+
+    static sp<IGnssMeasurementCallback> 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
diff --git a/gnss/2.1/default/OWNERS b/gnss/2.1/default/OWNERS
new file mode 100644
index 0000000..b7b4a2e
--- /dev/null
+++ b/gnss/2.1/default/OWNERS
@@ -0,0 +1,4 @@
+gomo@google.com
+smalkos@google.com
+wyattriley@google.com
+yuhany@google.com
diff --git a/gnss/2.1/default/android.hardware.gnss@2.1-service.rc b/gnss/2.1/default/android.hardware.gnss@2.1-service.rc
new file mode 100644
index 0000000..5926c77
--- /dev/null
+++ b/gnss/2.1/default/android.hardware.gnss@2.1-service.rc
@@ -0,0 +1,4 @@
+service vendor.gnss-2-1 /vendor/bin/hw/android.hardware.gnss@2.1-service
+    class hal
+    user system
+    group system
diff --git a/gnss/2.1/default/android.hardware.gnss@2.1-service.xml b/gnss/2.1/default/android.hardware.gnss@2.1-service.xml
new file mode 100644
index 0000000..12a1fdf
--- /dev/null
+++ b/gnss/2.1/default/android.hardware.gnss@2.1-service.xml
@@ -0,0 +1,12 @@
+<manifest version="1.0" type="device">
+    <hal format="hidl">
+        <name>android.hardware.gnss</name>
+        <transport>hwbinder</transport>
+        <version>2.1</version>
+        <version>1.1</version>
+        <interface>
+            <name>IGnss</name>
+            <instance>default</instance>
+        </interface>
+    </hal>
+</manifest>
diff --git a/gnss/2.1/default/service.cpp b/gnss/2.1/default/service.cpp
new file mode 100644
index 0000000..5e004d5
--- /dev/null
+++ b/gnss/2.1/default/service.cpp
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2019 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 "android.hardware.gnss@2.1-service"
+
+#include <hidl/HidlSupport.h>
+#include <hidl/HidlTransportSupport.h>
+#include "Gnss.h"
+
+using ::android::OK;
+using ::android::sp;
+using ::android::hardware::configureRpcThreadpool;
+using ::android::hardware::joinRpcThreadpool;
+using ::android::hardware::gnss::V2_1::IGnss;
+using ::android::hardware::gnss::V2_1::implementation::Gnss;
+
+int main(int /* argc */, char* /* argv */[]) {
+    sp<IGnss> gnss = new Gnss();
+    configureRpcThreadpool(1, true /* will join */);
+    if (gnss->registerAsService() != OK) {
+        ALOGE("Could not register gnss 2.1 service.");
+        return 1;
+    }
+    joinRpcThreadpool();
+
+    ALOGE("Service exited!");
+    return 1;
+}
\ No newline at end of file